CN110602420A - Camera, black level adjusting method and device - Google Patents

Abstract

Embodiments of the present application provide a camera, a black level adjustment method, and a device. The camera includes a single image sensor and a processing chip, and the image sensor is used to generate and output the first exposure parameter to the processing chip in the first working mode. An image signal; the processing chip is used to adjust the black level of the first image signal according to the first adjustment method to obtain the first adjustment signal; the image sensor is also used to alternately generate and process the signal through multiple exposures in the second working mode The chip outputs the second image signal and the third image signal; the processing chip is also used to adjust the black level of the second image signal according to the second adjustment method to obtain the second adjustment signal; according to the third adjustment method, the third image signal is adjusted The black level is adjusted to obtain a third adjustment signal. The embodiment of the present application can solve the problem that the image frame jumps seriously when adjusting the black level of multiple frames of image data.

Description

Camera, method and device for adjusting black level

technical field

The present application relates to the technical field of image processing, and in particular to a camera, a method and a device for adjusting a black level.

Background technique

An image sensor is a device that converts light signals into electronic signals. Before the image data obtained by the image sensor is generated into a digital image, black level calibration is usually required to determine the black level of the image sensor, so that the shadow area has full Digital images of contrast and fine detail.

In the existing black level adjustment method, for each frame of image data collected by the image sensor, the black level adjustment is usually performed inside the image sensor, for example, the black level of the black pixel area in the image data is averaged , to obtain the black level offset value of the image data, and then adjust the black level of the effective pixel area of the image data according to the black level offset value. However, when the existing black level adjustment method is aimed at multiple image signals collected by the same image sensor, when the exposure conditions of the multiple image signals are different, it is easy to cause the problem of unstable black level adjustment of the image.

Contents of the invention

Embodiments of the present application provide a camera, a method and a device for adjusting a black level, so as to solve the problem in the prior art that the black level adjustment is prone to be unstable when adjusting the black level of multi-frame image data.

In the first aspect, an embodiment of the present application provides a camera, including a single image sensor and a processing chip, the output end of the image sensor is connected to the processing chip, wherein:

The image sensor is used to generate and output a first image signal to the processing chip according to a first exposure parameter in a first working mode;

The processing chip is configured to, when receiving the first image signal, adjust the black level of the first image signal according to a first adjustment method to obtain a first adjustment signal;

The image sensor is also used to alternately generate and output a second image signal and a third image signal to the processing chip through multiple exposures in the second working mode, wherein the second image signal is based on the second exposure parameter generating, the third image signal is generated according to a third exposure parameter;

The processing chip is further configured to, when receiving the second image signal, adjust the black level of the second image signal according to a second adjustment method to obtain a second adjustment signal; For an image signal, adjust the black level of the third image signal according to a third adjustment method to obtain a third adjustment signal; alternately output the second adjustment signal and the third adjustment signal.

In a possible implementation manner, an exposure parameter control unit is also included, wherein:

The exposure parameter control unit is configured to alternately output the second exposure parameter and the third exposure parameter to the image sensor in the second working mode.

In a possible implementation manner, the second exposure parameter is different from at least one of the third exposure parameters, and the at least one exposure parameter is one or more of exposure time, exposure gain, and aperture size. One, the exposure gain includes analog gain, and/or, digital gain.

In a possible implementation manner, the first adjustment manner is specifically:

Determine the black level value of the first image signal of the current frame according to the received black level statistical value of the first image signal of the current frame and the received black level information of the first image signal of the historical frame, wherein, The first image signal of the historical frame is the first image signal of the previous frame of the first image signal of the current frame;

determining the black level offset of the first image signal of the current frame according to the black level value of the first image signal of the current frame and the first target black level value;

Adjusting the black level of the first image signal of the current frame according to the black level offset of the first image signal of the current frame to obtain a first adjustment signal corresponding to the first image signal of the current frame.

In a possible implementation manner, the second adjustment manner is specifically:

Determine the black level value of the second image signal of the current frame according to the received black level statistical value of the second image signal of the current frame and the received black level information of the second image signal of the historical frame, wherein, The second image signal of the historical frame is the second image signal of the previous frame of the second image signal of the current frame;

determining the black level offset of the second image signal of the current frame according to the black level value of the second image signal of the current frame and the second target black level value;

Adjusting the black level of the second image signal of the current frame according to the black level offset of the second image signal of the current frame to obtain a second adjustment signal corresponding to the second image signal of the current frame.

In a possible implementation manner, the third adjustment manner is specifically:

Determine the black level value of the third image signal of the current frame according to the received black level statistical value of the third image signal of the current frame and the received black level information of the third image signal of the historical frame, wherein, The third image signal of the historical frame is the third image signal of the previous frame of the third image signal of the current frame;

determining the black level offset of the third image signal of the current frame according to the black level value of the third image signal of the current frame and the third target black level value;

Performing black level adjustment on the third image signal of the current frame according to the black level offset of the third image signal of the current frame to obtain a third adjustment signal corresponding to the third image signal of the current frame.

In a possible implementation manner, the processing chip is also used for:

Processing the first adjustment signal in the first working mode to obtain and output a first processed image;

In the second working mode, the second adjustment signal is processed to obtain and output a second processed image, and the third adjustment signal is processed to obtain and output a third processed image; or, in the In the second working mode, fusion processing is performed on the second adjustment signal and the third adjustment signal to obtain and output a processed image.

In the second aspect, the embodiment of the present application provides a black level adjustment method, which is applied to a camera, the camera includes a single image sensor and a processing chip, and the output terminal of the image sensor is connected to the processing chip, the method include:

The first image signal is generated by the image sensor according to the first exposure parameter in the first working mode, and the black level of the first image signal is adjusted by the processing chip according to the first adjustment method to obtain the first adjustment Signal;

The second image signal and the third image signal are alternately generated by the image sensor through multiple exposures in the second working mode, wherein the second image signal is generated according to the second exposure parameter, and the third image signal is generated according to the third exposure parameter ; adjust the black level of the second image signal by the processing chip according to the second adjustment method to obtain a second adjustment signal; perform black level adjustment on the third image signal by the processing chip according to the third adjustment method level adjustment to obtain a third adjustment signal; and alternately output the second adjustment signal and the third adjustment signal through the processing chip.

In a possible implementation manner, the camera further includes an exposure parameter control unit, and the method further includes:

Alternately outputting the second exposure parameter and the third exposure parameter to the image sensor by the exposure parameter control unit in the second working mode;

In a possible implementation manner, the black level adjustment of the first image signal by the processing chip according to the first adjustment method to obtain the first adjustment signal includes:

Determine the black level value of the first image signal of the current frame according to the received black level statistical value of the first image signal of the current frame and the received black level information of the first image signal of the historical frame, wherein, The first image signal of the historical frame is the first image signal of the previous frame of the first image signal of the current frame;

determining the black level offset of the first image signal of the current frame according to the black level value of the first image signal of the current frame and the first target black level value;

Adjusting the black level of the first image signal of the current frame according to the black level offset of the first image signal of the current frame to obtain a first adjustment signal corresponding to the first image signal of the current frame

In a possible implementation manner, the black level adjustment of the second image signal by the processing chip according to the second adjustment method to obtain the second adjustment signal includes:

Determine the black level value of the second image signal of the current frame according to the received black level statistical value of the second image signal of the current frame and the received black level value information of the second image signal of the historical frame, wherein , the second image signal of the historical frame is the second image signal of the previous frame of the second image signal of the current frame;

determining the black level offset of the second image signal of the current frame according to the black level value of the second image signal of the current frame and the second target black level value;

Adjusting the black level of the second image signal of the current frame according to the black level offset of the second image signal of the current frame to obtain a second adjustment signal corresponding to the second image signal of the current frame.

In a possible implementation manner, the black level adjustment of the third image signal by the processing chip according to a third adjustment method to obtain a third adjustment signal includes:

Determine the black level value of the third image signal of the current frame according to the received black level statistical value of the third image signal of the current frame and the received black level information of the third image signal of the historical frame, wherein, The third image signal of the historical frame is the third image signal of the previous frame of the third image signal of the current frame;

determining the black level offset of the third image signal of the current frame according to the black level value of the third image signal of the current frame and the third target black level value;

Performing black level adjustment on the third image signal of the current frame according to the black level offset of the third image signal of the current frame to obtain a third adjustment signal corresponding to the third image signal of the current frame.

In a possible implementation, the method further includes:

Process the first adjustment signal by the processing chip in the first working mode to obtain and output a first processed image;

Processing the second adjustment signal by the processing chip in the second working mode to obtain and output a second processed image, and processing the third adjustment signal to obtain and output a third processed image; Alternatively, in the second working mode, fusion processing is performed on the second adjustment signal and the third adjustment signal to obtain and output a processed image.

In a third aspect, an embodiment of the present application provides a black level adjustment device, including:

The first processing module is configured to receive a first image signal when the image sensor is in the first working mode, and adjust the black level of the first image signal according to a first adjustment method to obtain a first adjustment signal;

The second processing module is configured to alternately receive the second image signal and the third image signal when the image sensor is in the second working mode, and adjust the performing black level adjustment on the second image signal to obtain a second adjustment signal, and performing black level adjustment on the third adjustment signal according to a third adjustment method when receiving the third image signal to obtain a third adjustment signal, And alternately output the second adjustment signal and the third adjustment signal.

In a possible implementation manner, the first processing module is specifically configured to:

Determine the black level value of the first image signal of the current frame according to the received black level statistical value of the first image signal of the current frame and the received black level information of the first image signal of the historical frame, wherein, The first image signal of the historical frame is the first image signal of the previous frame of the first image signal of the current frame;

determining the black level offset of the first image signal of the current frame according to the black level value of the first image signal of the current frame and the first target black level value;

Adjusting the black level of the first image signal of the current frame according to the black level offset of the first image signal of the current frame to obtain a first adjustment signal corresponding to the first image signal of the current frame.

In a possible implementation manner, the second processing module is specifically configured to:

Determine the black level value of the second image signal of the current frame according to the received black level statistical value of the second image signal of the current frame and the received black level value information of the second image signal of the historical frame, wherein , the second image signal of the historical frame is the second image signal of the previous frame of the second image signal of the current frame;

determining the black level offset of the second image signal of the current frame according to the black level value of the second image signal of the current frame and the second target black level value;

Adjusting the black level of the second image signal of the current frame according to the black level offset of the second image signal of the current frame to obtain a second adjustment signal corresponding to the second image signal of the current frame.

In a possible implementation manner, the second processing module is specifically configured to:

Determine the black level value of the third image signal of the current frame according to the received black level statistical value of the third image signal of the current frame and the received black level information of the third image signal of the historical frame, wherein, The third image signal of the historical frame is the third image signal of the previous frame of the third image signal of the current frame;

determining the black level offset of the third image signal of the current frame according to the black level value of the third image signal of the current frame and the third target black level value;

Performing black level adjustment on the third image signal of the current frame according to the black level offset of the third image signal of the current frame to obtain a third adjustment signal corresponding to the third image signal of the current frame.

In a possible implementation manner, a third processing module is also included, and the third processing module is configured to:

Processing the first adjustment signal in the first working mode to obtain and output a first processed image;

In the second working mode, the second adjustment signal is processed to obtain and output a second processed image, and the third adjustment signal is processed to obtain and output a third processed image; or, in the In the second working mode, fusion processing is performed on the second adjustment signal and the third adjustment signal to obtain and output a processed image.

The camera, black level adjustment method and device provided by the embodiments of the present application, wherein the camera includes a single image sensor and a processing chip, the output end of the image sensor is connected to the processing chip, the camera includes two working modes, in the first working mode , the image sensor generates and outputs the first image signal to the processing chip according to the first exposure parameter, and when the processing chip receives the first image signal, it adjusts the black level of the first image signal according to the first adjustment method to obtain the first image signal An adjustment signal; in the second working mode, the image sensor generates and outputs a second image signal to the processing chip according to the second exposure parameter, and generates and outputs a third image signal to the processing chip according to the third exposure parameter; the processing chip receives the For the second image signal, adjust the black level of the second image signal according to the second adjustment method to obtain the second adjustment signal; when receiving the third image signal, perform black level adjustment on the third image signal according to the third adjustment method Leveling adjustment, get the third adjustment signal. The camera provided in the embodiment of the present application can adjust the working mode of the camera correspondingly under different conditions. When the camera is in the second working mode, for the multi-frame second image signal and the third image signal generated by the image sensor, When performing black level adjustment, the second image signal and the third image signal are firstly distinguished, and then the black level adjustment processing is performed on the second image signal and the third image signal according to different adjustment methods, avoiding the existing The scheme sets the black level adjustment process in the image sensor. When adjusting the black level of the image signal, the black level adjustment process is carried out according to the corresponding adjustment method for the image signal under different exposure parameters, so that the multi-channel The image signal is adjusted separately, which makes the black level adjustment of the image more stable.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings that need to be used in the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description These are some embodiments of the present application. Those skilled in the art can also obtain other drawings based on these drawings without any creative effort.

FIG. 1 is a schematic structural diagram of a camera provided in an embodiment of the present application;

FIG. 2 is a schematic diagram of a target surface of an image sensor provided in an embodiment of the present application;

FIG. 3 is a schematic diagram of the working principle of the camera provided in the embodiment of the present application;

Fig. 4 is a schematic diagram of the photosensitive channel distribution mode of the RGBW sensor provided by the embodiment of the present application;

Fig. 5 is a schematic diagram of the photosensitive channel distribution mode of the Bayer sensor provided by the embodiment of the present application;

Fig. 6 is a schematic diagram of the photosensitive channel distribution mode of the RGB-IR sensor provided by the embodiment of the present application;

Fig. 7 is a schematic diagram of the induction curve of the RGBW sensor provided by the embodiment of the present application;

FIG. 8 is a schematic structural diagram of a camera provided in another embodiment of the present application;

FIG. 9 is a schematic diagram of the exposure sequence of the image sensor in the first working mode provided by the embodiment of the present application;

FIG. 10 is a first schematic diagram of the exposure sequence of the image sensor in the second working mode provided by the embodiment of the present application;

FIG. 11 is a second schematic diagram of the exposure sequence of the image sensor in the second working mode provided by the embodiment of the present application;

FIG. 12 is a schematic diagram of black level adjustment processing in the first working mode provided by the embodiment of the present application;

FIG. 13 is a schematic diagram of distinguishing multiple first image signals provided by the embodiment of the present application;

FIG. 14 is a first schematic diagram of black level adjustment processing in the second working mode provided by the embodiment of the present application;

FIG. 15 is a second schematic diagram of black level adjustment processing in the second working mode provided by the embodiment of the present application;

FIG. 16 is a first schematic diagram of camera processing provided by the embodiment of the present application;

Fig. 17 is the second schematic diagram of camera processing provided by the embodiment of the present application;

Fig. 18 is the third schematic diagram of camera processing provided by the embodiment of the present application;

FIG. 19 is a fourth schematic diagram of camera processing provided by the embodiment of the present application;

FIG. 20 is a schematic flowchart of a method for adjusting a black level provided by an embodiment of the present application;

FIG. 21 is a schematic structural diagram of a black level adjustment device provided by an embodiment of the present application.

Detailed ways

In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments It is a part of embodiments of the present invention, but not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the protection scope of the present invention.

First, some noun concepts involved in this application are explained.

Black pixel area: In the image sensor, there are usually some blacked-out pixels, which cannot receive the energy of external light, and are usually used for black level statistics. The black pixel area is also commonly referred to as an optical black (OB) area, an optical blackbody area, a black line, a light-shielding area, a black level area, a black level reference pixel, and the like.

Effective pixel area: In the image sensor, the area used to normally respond to external light energy.

FIG. 1 is a schematic structural diagram of a camera provided in an embodiment of the present application. As shown in FIG. 1 , the camera 10 includes an image sensor 11 and a processing chip 12, wherein,

The image sensor 11 is configured to generate and output a first image signal to the processing chip according to a first exposure parameter in a first working mode;

The processing chip 12 is configured to, when receiving the first image signal, adjust the black level of the first image signal according to a first adjustment method to obtain a first adjustment signal;

The image sensor 11 is also used to alternately generate and output a second image signal and a third image signal to the processing chip through multiple exposures in the second working mode, wherein the second image signal is based on the second exposure parameter generation, the third image signal is generated according to a third exposure parameter;

The processing chip 12 is further configured to, when receiving the second image signal, adjust the black level of the second image signal according to a second adjustment method to obtain a second adjustment signal; When there are three image signals, adjust the black level of the third image signal according to a third adjustment method to obtain a third adjustment signal; alternately output the second adjustment signal and the third adjustment signal.

The image sensor 11 is a photosensitive device that uses a target surface for photosensitive. The target surface of the image sensor 11 generally includes a black pixel area and an effective pixel area, and the data of the black pixel area and the effective pixel area can be output.

The image sensor supports two working modes and can switch between the two working modes. In the first working mode, according to the first exposure parameter, the first image signal is collected and output. In the second working mode, the second image signal and the third image signal can be simultaneously collected and output within a period of time through multiple exposures, wherein the second image signal is generated according to the second exposure parameters, and the third image signal is generated according to the third exposure parameter generated.

The first image signal, the second image signal and the third image signal include both black pixel area data and valid pixel area data.

The second exposure parameter and the third exposure parameter may use the same exposure parameter, or may use different exposure parameters. Exposure parameters include, but are not limited to, exposure time, analog gain, digital gain, and the like. When the second exposure parameter and the third exposure parameter adopt different exposure parameters, it usually means that the gain and the exposure time are different.

FIG. 2 is a schematic diagram of a target surface of an image sensor provided in an embodiment of the present application. FIG. 2 shows distributions of black pixel areas and effective pixel areas on target surfaces of two common image sensors 11 .

The target surface 21 includes a black pixel area 211 and an effective pixel area 212 , and the black pixel area 211 on the target surface 21 is distributed around the effective pixel area 212 . The target surface 22 includes a black pixel area 221 and an effective pixel area 222 , and the black pixel area 221 on the target surface 22 is distributed above the effective pixel area 222 .

In the embodiment of the present application, different methods can be used to prevent light from reaching the target surface of the image sensor 11 so that the corresponding area of the image sensor 11 cannot sense light, and this area is the black pixel area of the image sensor 11 . Specifically, opaque materials can be used, such as metals, baffles, etc., to block one or more rows and one or more columns of pixels in the target surface of the image sensor 11, so that one or more rows and one column of pixels in the target surface If no light passes through the pixel area of one or more rows, this area is the black pixel area, and the area except the black pixel area is the effective pixel area, and the effective pixel area can normally receive light.

It can be understood that the above-mentioned method of setting black pixel areas is just an example, and other methods of setting part of the target surface of the image sensor 11 to be insensitive to light so that the image sensor 11 forms black pixel areas can also achieve similar effects. Meanwhile, the distribution of the black pixel areas shown in FIG. 2 is only a schematic, and the specific distribution can be set according to actual needs, and black pixel areas of any shape and size and any area can be set.

When no light passes through the black pixel area on the target surface of the image sensor 11, the pixel value of the black pixel area should be 0 in theory, but due to some factors, the black level value of the black pixel area will not be 0. black level correction is required.

The camera in the embodiment of the present application includes two working modes, namely a first working mode and a second working mode. Figure 3 is a schematic diagram of the working principle of the camera provided by the embodiment of the present application. As shown in Figure 3, it mainly includes an image acquisition unit and a black level adjustment unit, wherein the image acquisition unit is used to perform image acquisition and generate image signals. In addition to the image sensor, it can also include the lens. The black level adjustment unit is a part of the processing chip, and is used for adjusting the black level of the image signal. The black level adjustment unit is a logic platform containing signal processing algorithms or programs, which can be a computer based on X86 or ARM architecture, or a field-programmable gate array (Field-Programmable Gate Array, FPGA for short) logic circuit.

The solution provided by the embodiment of the present application includes two working modes, and supports the mutual and linkage switching of the two modes, wherein the linkage switching means that when the image acquisition unit is in the first working mode, the black level adjustment unit switches to the corresponding The first working mode; when the image acquisition unit is in the second working mode, the black level adjustment unit switches to the corresponding second working mode, that is, when the working mode is switched, the image acquisition unit and the black level adjustment unit can be switched simultaneously to the corresponding working mode to work together.

When the image acquisition unit is in the first working mode, it can take multiple exposures under a certain exposure condition and output the first image signal; in the second working mode, it can collect and output two kinds of image signals by time-sharing multiple exposures.

The black level adjustment unit can adjust the black level of the first image signal in the first working mode and output the first adjustment signal; in the second working mode, the black level adjusting unit can adjust the black level of the second image signal and the third image signal to adjust the black level respectively, and output the second adjustment signal and the third adjustment signal. The black level adjustment unit obtains the black level offset value of the image by counting the black pixel area and calculating the black level offset value, thereby adjusting the black level of the effective pixel area to ensure that the brightness and color of the image can truly reflect the environmental conditions.

In the first working mode, the image acquisition unit collects the first image signal and transmits it to the black level adjustment unit for processing, and the black level adjustment unit processes the first image signal and outputs the first adjustment signal; in the second working mode , the image acquisition unit collects the second image signal and the third image signal, and transmits them to the black level adjustment unit for processing, and the black level adjustment unit processes the second image signal and the third image signal, and outputs the second adjustment signal and A third adjustment signal.

The image acquisition unit mainly refers to the image sensor, which acquires the second image signal and the third image signal through multiple exposures in the second working mode. Wherein, the second image signal is generated according to the second exposure condition, and the third image signal is generated according to the third exposure condition. When the black level adjustment unit is in the first working mode, it can perform black level adjustment processing on the first image signal; Black level adjustment processing.

In the first working mode, the image acquisition unit generates the first image signal according to the first exposure parameter, and sends it to the black level adjustment unit in the processing chip 12, and the black level adjustment unit adjusts the first image signal according to the first adjustment method. Black level adjustment is performed to obtain a first adjustment signal. Since the target surface of the image sensor 11 includes a black pixel area and an effective pixel area, the first image signal includes a black pixel area corresponding to the first image signal and an effective pixel area corresponding to the first image signal. The first image signal may be one of a plurality of image signals in a video sequence, and the plurality of image signals in the video sequence are generated by the image sensor 11 under the same exposure condition, that is, the corresponding exposure parameter is the first exposure parameter.

In the second working mode, the image acquisition unit generates a second image signal according to the second exposure parameter and sends it to the black level adjustment unit in the processing chip 12, and generates a third image signal according to the third exposure parameter and sends it to the processing chip The black level adjustment unit in 12, the black level adjustment unit adjusts the black level of the second image signal according to the second adjustment method to obtain the second adjustment signal, and performs black level adjustment on the third image signal according to the third adjustment method Leveling adjustment, get the third adjustment signal. The second image signal may belong to one of the plurality of image signals in the second video sequence, and the third image signal may belong to one of the plurality of image signals in the third video sequence.

Black level adjustment is usually to set an offset value, and then adjust the image signal according to the offset value. After the processing chip 12 receives the first image signal, for each first image signal of the current frame, obtain the black level of the black pixel area corresponding to the first image signal of the current frame and the black level of the black pixel area corresponding to the first image signal of the historical frame. Black level information. Wherein, the black level of the black pixel area corresponding to the first image signal of the current frame is the black level of each pixel in the black pixel area corresponding to the first image signal of the current frame. channel, you need to obtain the black level on each photosensitive channel. The first image signal of the historical frame is the first image signal of the previous frame of the first image signal of the current frame, and has a certain correlation with the first image signal of the current frame. For example, the first image signal of the current frame and the first image signal of the historical frame can be are two frames of image signals in the same video sequence. The black level information of the black pixel area corresponding to the first image signal of the historical frame may be the black level of the black pixel area corresponding to the first image signal of the historical frame, or the black level offset of the first image signal of the historical frame quantity.

Then, in the first working mode, the first adjustment method may be that the processing chip 12 is based on the black level of the black pixel area corresponding to the first image signal of the current frame and the black level of the black pixel area corresponding to the first image signal of the historical frame. Information, obtain the black level offset of the first image signal of the current frame, and perform black level adjustment processing on the effective pixel area of the first image signal of the current frame according to the black level offset of the first image signal of the current frame, A first adjustment signal is obtained.

In the second working mode, the processing chip 12 processes the second image signal and the third image signal separately. When processing the second image signal, the second adjustment method may be to use the black level information of the black pixel area corresponding to the second image signal of the current frame and the black level information of the black pixel area corresponding to the second image signal of the historical frame to adjust the current The black level adjustment process is performed on the second image signal of the frame. Similarly, when processing the third image signal, the third adjustment method may be to use the black level of the black pixel area corresponding to the third image signal of the current frame and the first black level of the historical frame. The black level information of the black pixel area corresponding to the three image signals performs black level adjustment processing on the third image signal of the current frame.

The camera provided by the embodiment of the present application includes a single image sensor and a processing chip, the output terminal of the image sensor is connected to the processing chip, and the camera includes two working modes. output the first image signal to the processing chip, and when the processing chip receives the first image signal, adjust the black level of the first image signal according to the first adjustment method to obtain the first adjustment signal; in the second working mode , the image sensor generates and outputs the second image signal to the processing chip according to the second exposure parameter, generates and outputs the third image signal to the processing chip according to the third exposure parameter; when the processing chip receives the second image signal, adjusts the signal according to the second adjust the black level of the second image signal to obtain the second adjustment signal; when receiving the third image signal, adjust the black level of the third image signal according to the third adjustment method to obtain the third adjustment signal. The camera provided in the embodiment of the present application can adjust the working mode of the camera correspondingly under different conditions. When the camera is in the second working mode, for the multi-frame second image signal and the third image signal generated by the image sensor, When performing black level adjustment, the second image signal and the third image signal are firstly distinguished, and then the black level adjustment processing is performed on the second image signal and the third image signal according to different adjustment methods, avoiding the existing The scheme sets the black level adjustment process in the image sensor. When adjusting the black level of the image signal, the black level adjustment process is carried out according to the corresponding adjustment method for the image signal under different exposure parameters, so that the multi-channel The image signal is adjusted separately, which makes the black level adjustment of the image more stable.

The principle and usage scheme of the camera will be described in detail below with reference to FIG. 4 and specific embodiments.

First, the image sensor is explained. The image sensor in the present application includes a plurality of photosensitive channels, and each photosensitive channel is used for sensing light in the visible light band, and/or, sensing light in the near infrared band. That is, each photosensitive channel can sense light in the visible light band and light in the near-infrared band, so that the first image signal can be guaranteed to have a complete resolution without missing pixel values.

Exemplarily, the image sensor may be an RGBW sensor, a Bayer sensor or an RGB-IR sensor, and sensors in other arrangements may also be used. Figure 4 is a schematic diagram of the photosensitive channel distribution of the RGBW sensor provided by the embodiment of the present application, Figure 5 is a schematic diagram of the photosensitive channel distribution of the Bayer sensor provided by the embodiment of the present application, and Figure 6 is a schematic diagram of the RGB-IR sensor provided by the embodiment of the present application Schematic diagram of the distribution of photosensitive channels, as shown in Figure 4 and Figure 5, the distribution of the R photosensitive channel, G photosensitive channel, B photosensitive channel and W photosensitive channel in the RGBW sensor can be seen in Figure 4, the R photosensitive channel in the Bayer sensor, The distribution of G photosensitive channel and B photosensitive channel can be seen in Figure 5. For example, the image sensor may be an RGB-IR sensor, wherein each IR photosensitive channel in the RGB-IR sensor can sense light in a near-infrared band, but not light in a visible light band. The distribution of the R photosensitive channel, G photosensitive channel, B photosensitive channel and W photosensitive channel in the RGB-IR sensor can be seen in Figure 6.

In some other embodiments, some photosensitive channels can only sense light in the near-infrared band, but not light in the visible light band. In this way, it can ensure that the first image signal has a complete resolution without missing pixel values. As an example, the plurality of light-sensing channels may include at least two of R light-sensing channels, G light-sensing channels, B light-sensing channels, and IR light-sensing channels. Among them, the R photosensitive channel is used to sense the light in the red and near-infrared bands, the G photosensitive channel is used to sense the light in the green and near-infrared bands, the B photosensitive channel is used to sense the light in the blue and near-infrared bands, and the IR photosensitive channel is used to sense the light in the blue and near-infrared bands. The photosensitive channel is used to sense light in the near-infrared band.

Further, the image sensor can also be an RGB sensor, wherein, when the image sensor is an RGB sensor, compared with other image sensors, such as RGB-IR sensors, the RGB information collected by the RGB sensor is more complete, and the RGB-IR sensor has a part The photosensitive channel of the RGB sensor cannot collect visible light, so the color details of the image collected by the RGB sensor are more accurate.

It is worth noting that the multiple photosensitive channels included in the image sensor can correspond to multiple sensing curves. Figure 7 is a schematic diagram of the sensing curve of the RGBW sensor provided by the embodiment of the present application. For example, refer to Figure 7, taking the image sensor as an RGBW sensor as an example, the R curve in Figure 7 represents the image sensor's sensitivity to light in the red band The G curve represents the image sensor's response curve to the light in the green band, the B curve represents the image sensor's response curve to the blue light band, and the W curve represents the image sensor's response curve to the full-band light.

Image sensors generate different image signals under different exposure parameters. Exemplarily, the camera may have two working modes, namely the first working mode and the second working mode. In the first working mode, the image sensor generates multiple frames of first image signals according to the first exposure parameters, and sends them to the processing chip in sequence. In the second working mode, the image sensor generates multiple frames of second image signals according to the second exposure parameters, and generates a third image signal according to the third exposure parameters, wherein, in the second working mode, the image sensor alternately generates the second image signal and the third image signal, and alternately output the second image signal and the third image signal to the processing chip. The processing chip adjusts the black level of the second image signal and the third image signal respectively, and alternately outputs the second adjustment signal and the third adjustment signal.

Fig. 8 is a schematic structural diagram of a camera provided in another embodiment of the present application. As shown in Fig. 8, a camera 80 includes an image sensor 81, a processing chip 82, an exposure parameter control unit 83 and a light fill device 84, wherein the exposure parameter control unit 83 is used for alternately outputting the second exposure parameter and the third exposure parameter to the image sensor 81 in the second working mode, and the supplementary light device 84 is used for supplementing light when the image sensor 81 is in the second working mode.

Further, the camera provided in the embodiment of the present application may also include a filter assembly 86, the filter assembly 86 includes a first filter, a second filter and a switching component, the first filter makes visible light and part of near-infrared light Through, both the first optical filter and the second optical filter are connected to the switching component, and the switching component is used to switch the second optical filter to the light-incident side of the image sensor 81 .

After the second optical filter is switched to the light-incident side of the image sensor 81, the second optical filter allows light in the visible light band to pass through and blocks light in the near-infrared light band, and the image sensor 81 is used to generate and output a third image through exposure Signal.

Before the image sensor 81, a lens 85 is also included. When the supplementary light device 84 performs supplementary light, the light passing through the lens 85 includes ambient light and supplementary light, and the supplementary light includes visible light supplementary light and near-infrared supplementary light.

In some embodiments, the light fill device 84 is specifically used to perform near-infrared supplementary light, specifically, to perform near-infrared supplementary light at least during a part of the time period when the image sensor 81 performs exposure according to the third exposure parameter.

In some other embodiments, the supplementary light device 84 is specifically used for supplementary light with visible light, specifically, supplementary light with visible light at least during a part of the time period when the image sensor 81 performs exposure according to the second exposure parameter.

The image sensor 81 is located on the light emitting side of the filter assembly 86 . In the second working mode, the image sensor 81 is used to generate and output the second image signal and the third image signal through multiple exposures. Wherein, the second image signal is an image signal generated according to the second exposure parameter, and the third image signal is an image signal generated according to the third exposure parameter. The light supplement 84 includes a first supplementary light device 841, and the first supplementary light device 841 is used for performing near-infrared supplementary light, wherein at least part of the time period during which the image sensor 81 performs exposure according to the third exposure parameter is to perform near-infrared supplementary light . The filter assembly 86 includes a first filter, and the first filter allows the light in the visible light band and the light in the near-infrared band to pass through, wherein the first light supplement device 841 passes through the first filter light when supplementing the near-infrared light. The intensity of the near-infrared light of the filter is higher than the intensity of the near-infrared light passing through the first filter when the first light supplement device 841 is not performing near-infrared supplementary light.

In the embodiment of the present application, a lens 85 may also be included. In this case, the filter assembly 86 may be located between the lens 85 and the image sensor 81 , and the image sensor 81 is located at the light output side of the filter assembly 86 . Alternatively, the lens 85 is located between the filter assembly 86 and the image sensor 81 , and the image sensor 81 is located at the light emitting side of the lens 85 . As an example, the first optical filter can be a filter film, and like this, when the optical filter assembly 86 is located between the lens 85 and the image sensor 81, the first optical filter can be attached to the surface of the light exit side of the lens 85, Alternatively, when the lens 85 is located between the filter assembly 86 and the image sensor 81 , the first filter can be attached to the surface of the lens 85 on the light incident side.

It should be noted that the light fill device 84 can be located inside the image acquisition unit or outside the image acquisition unit. The light fill device 84 can be a part of the image acquisition unit, or a device independent of the image acquisition unit. When the light fill device 84 is located outside the image acquisition unit, the light fill device 84 can communicate with the image acquisition unit, thereby ensuring that the exposure timing of the image sensor 81 in the image acquisition unit is consistent with the first supplementary light included in the light fill device 84. There is a certain relationship between the near-infrared fill-in light timing of the light device 841 , for example, near-infrared fill-in light is performed at least in a part of the exposure time period of the third exposure parameter, and no near-infrared fill-in light is performed in the exposure time period of the second exposure parameter.

In addition, the first supplementary light device 841 is a device that can emit near-infrared light, such as a near-infrared supplementary light lamp. The near-infrared supplementary light is performed in a manner, which is not limited in this embodiment of the present application. In some examples, when the first supplementary light device 841 performs near-infrared supplementary light in a stroboscopic manner, the first supplementary light device 841 can be manually controlled to perform near-infrared supplementary light in a stroboscopic manner, or can be controlled by a software program. Or specific equipment is used to control the first supplementary light device 841 to perform near-infrared supplementary light in a stroboscopic manner, which is not limited in this embodiment of the present application. Wherein, the time period of the near-infrared supplementary light by the first supplementary light device 841 may coincide with the exposure time period of the third exposure parameter, or may be greater than the exposure time period of the third exposure parameter or less than the exposure time period of the third exposure parameter, It only needs to perform near-infrared supplementary light in the whole exposure time period or part of the exposure time period of the third exposure parameter, and not perform near-infrared supplementary light in the exposure time period of the second exposure parameter.

It should be noted that no near-infrared supplementary light is used within the exposure time period of the second exposure parameter. For the global exposure method, the exposure time period of the second exposure parameter can be the time period between the start exposure time and the end exposure time. , for the rolling shutter exposure method, the exposure time period of the second exposure parameter may be the time period between the start exposure moment of the first line of effective image of the second image signal and the end exposure moment of the last line of effective image, but it does not limited to this. For example, the exposure time period of the second exposure parameter may also be the exposure time period corresponding to the target image in the second image signal. The time period between the start exposure moment and the end exposure moment of the effective line image can be regarded as the exposure time period of the second exposure parameter.

Another point that needs to be explained is that when the first supplementary light device 841 performs near-infrared supplementary light on the external scene, the near-infrared light incident on the surface of the object may be reflected by the object and enter the first filter 031 . And because generally, the ambient light may include visible light and near-infrared light, and the near-infrared light in the ambient light will be reflected by the object when incident on the surface of the object, and thus enter the first filter 031 . Therefore, the near-infrared light passing through the first optical filter 031 when performing near-infrared supplementary light may include the near-infrared light reflected by objects into the first optical filter 031 when the first supplementary light device 841 performs near-infrared supplementary light. The near-infrared light passing through the first optical filter 031 when the near-infrared supplementary light is not performed may include the near-infrared light reflected by objects and entering the first optical filter 031 when the first supplementary light device 841 is not performing near-infrared supplementary light. That is to say, the near-infrared light passing through the first optical filter 031 during the near-infrared supplementary light includes the near-infrared light emitted by the first supplementary light device 841 and reflected by the object, and the near-infrared light reflected by the object in the ambient light. The near-infrared light, the near-infrared light passing through the first filter 031 when the near-infrared supplementary light is not performed includes the near-infrared light reflected by objects in the ambient light.

In a possible implementation manner, referring to FIG. 6 , the supplementary light device 84 may further include a second supplementary light device 842 , and the second supplementary light device 842 is used for supplementary light with visible light. In some embodiments, the second supplementary light device 842 can be used to perform visible light supplementary light in a constant light mode; or, the second supplementary light device 842 can be used to perform visible light supplementary light in a strobe mode, wherein, at least in the second There is visible light supplementary light in part of the exposure time period of the exposure parameters, or the second supplementary light device 842 can be used to perform visible light supplementary light in a stroboscopic manner, wherein there is visible light supplementary light in part of the exposure time period of the second exposure parameter .

In some embodiments, the aforementioned multiple exposures refer to multiple exposures within one frame period, that is, the image sensor 81 performs multiple exposures within one frame period, thereby generating and outputting at least one frame of second image signals and At least one frame of the third image signal. For example, 1 second includes 25 frame periods, and the image sensor 81 performs multiple exposures in each frame period, thereby generating at least one frame of second image signals and at least one frame of third image signals, and combining the images generated in one frame period The second image signal and the third image signal are called a group of image signals, so 25 groups of image signals will be generated within 25 frame periods. Wherein, the second exposure parameter and the third exposure parameter may be the exposure parameters of two adjacent exposures within one frame period, or may be the exposure parameters of two non-adjacent exposures among multiple exposures within one frame period. The embodiment of the application does not limit this.

Through the above settings, in the daytime or when the light intensity is good, the camera 80 can be in the first working mode, the image sensor 81 generates the first image signal under the first exposure parameter, and the processing chip 82 processes the first image signal. Black level adjustment is performed to obtain a first adjustment signal.

In the case of dark night or other poor light intensity, the camera 80 can be in the second working mode, the image sensor 81 generates the second image signal under the second exposure parameter, and generates the third image signal under the third exposure parameter, In the part of the time period under the second exposure parameter, the visible light is supplemented by the light supplement 84, and in the part of the time period under the third exposure parameter, the near-infrared supplement is performed by the light supplement 84, so as to improve the imaging under extremely low illuminance quality. Wherein, the image sensor 81 alternately generates and outputs the second image signal and the third image signal to the processing chip 82 through multiple exposures in the second operation mode, and the processing chip 82 performs the second image signal and the third image signal in the second operation mode. The black levels of the image signals are respectively adjusted, and the second adjustment signal and the third adjustment signal are alternately generated and output.

9 is a schematic diagram of the exposure sequence of the image sensor in the first working mode provided by the embodiment of the present application. As shown in FIG. 9 , in the first working mode, the image sensor adopts the first exposure parameters to generate multiple frames of the first image signal, Then the multiple frames of first image signals are sent to the processing chip, and the processing chip sequentially processes the multiple frames of first image signals. When processing the first image signal of multiple frames, for each first image signal of the current frame, the processing chip will, according to the black level of the black pixel area corresponding to the first image signal of the current frame, and the first image signal of the current frame The black level information of the black pixel area corresponding to the first image signal of the previous frame is used to adjust the black level of the first image signal of the current frame.

FIG. 10 is a first schematic diagram of the exposure sequence of the image sensor in the second working mode provided by the embodiment of the present application, and FIG. 11 is a second schematic diagram of the exposure sequence of the image sensor in the second working mode provided by the embodiment of the present application, as shown in FIGS. 10 and 11 As shown, in the second working mode, the image sensor generates multiple frames of second image signals by using the second exposure parameters, and generates multiple frames of third image signals by using the third exposure parameters. In FIG. 10 , the image sensor performs exposure alternately under the second exposure parameter and the third exposure parameter, and outputs the second image signal and the third image signal alternately. In FIG. 11 , the image sensor is exposed twice according to the second exposure parameters to output two frames of second image signals, and then exposed according to the third exposure parameters to output one frame of third image signals, and this exposure process is repeated.

The two exposure methods in FIG. 10 and FIG. 11 are just examples, and the image sensor may also adopt other combination methods for exposure. For example, multiple exposures may include odd-numbered exposures and even-numbered exposures. In this way, exposures corresponding to the second exposure parameter and the third exposure parameter may include but are not limited to the following methods:

In a first possible implementation manner, the exposure corresponding to the second exposure parameter is one exposure in the odd number of exposures, and the exposure corresponding to the third exposure parameter is one exposure in the even number of exposures. In this way, multiple exposures may include exposures corresponding to the second exposure parameters and exposures corresponding to the third exposure parameters arranged in odd-even order. For example, odd-numbered exposures such as the first exposure, the third exposure, and the fifth exposure in the multiple exposures are the exposures corresponding to the second exposure parameters, and the second exposure, the fourth exposure, the sixth exposure, etc. Even exposures are exposures corresponding to the third exposure parameter.

In the second possible implementation, the exposure corresponding to the second exposure parameter is one of the even-numbered exposures, and the exposure corresponding to the third exposure parameter is one of the odd-numbered exposures. In this way, multiple exposures can include The exposure corresponding to the second exposure parameter and the exposure corresponding to the third exposure parameter are arranged. For example, the odd-numbered exposures such as the first exposure, the third exposure, and the fifth exposure in the multiple exposures are the exposures corresponding to the third exposure parameters, and the second exposure, the fourth exposure, the sixth exposure, etc. Even exposures are exposures corresponding to the second exposure parameter.

In a third possible implementation, the exposure corresponding to the second exposure parameter is one of the specified odd-numbered exposures, and the exposure corresponding to the third exposure parameter is one of the exposures other than the specified odd-numbered exposures, That is, the exposure corresponding to the third exposure parameter may be an odd-numbered exposure in the multiple exposures, or may be an even-numbered exposure in the multiple exposures.

In a fourth possible implementation, the exposure corresponding to the second exposure parameter is one of the specified even-numbered exposures, and the exposure corresponding to the third exposure parameter is one of the exposures other than the specified even-numbered exposures, That is, the exposure corresponding to the third exposure parameter may be an odd-numbered exposure in the multiple exposures, or may be an even-numbered exposure in the multiple exposures.

In a fifth possible implementation manner, the exposure corresponding to the second exposure parameter is one exposure in the first exposure sequence, and the exposure corresponding to the third exposure parameter is one exposure in the second exposure sequence.

In a sixth possible implementation manner, the exposure corresponding to the second exposure parameter is one exposure in the second exposure sequence, and the exposure corresponding to the third exposure parameter is one exposure in the first exposure sequence.

Wherein, the above multiple exposures include multiple exposure sequences, the first exposure sequence and the second exposure sequence are the same exposure sequence or two different exposure sequences in the multiple exposure sequences, each exposure sequence includes N exposures, The N exposures include 1 exposure corresponding to the second exposure parameter and N-1 exposures corresponding to the third exposure parameter, or, the N exposures include 1 exposure corresponding to the third exposure parameter and N-1 exposures corresponding to the second exposure parameter The exposure corresponding to the exposure parameter, N is a positive integer greater than 2.

For example, each exposure sequence includes 3 exposures, and these 3 exposures may include 1 exposure corresponding to the second exposure parameter and 2 exposures corresponding to the third exposure parameter, so that the first exposure of each exposure sequence can be The exposure corresponding to the second exposure parameter, and the second and third exposures are exposures corresponding to the third exposure parameter. That is, each exposure sequence may be expressed as: exposure corresponding to the second exposure parameter, exposure corresponding to the third exposure parameter, and exposure corresponding to the third exposure parameter. Alternatively, the three exposures may include one exposure corresponding to the third exposure parameter and two exposures corresponding to the second exposure parameter. In this way, the first exposure of each exposure sequence may be the exposure corresponding to the third exposure parameter, and the second exposure corresponding to the third exposure parameter. The second exposure and the third exposure are exposures corresponding to the second exposure parameter. That is, each exposure sequence may be expressed as: exposure corresponding to the third exposure parameter, exposure corresponding to the second exposure parameter, and exposure corresponding to the second exposure parameter.

The above only provides six possible implementations of the exposure corresponding to the second exposure parameter and the exposure corresponding to the third exposure parameter. In practical applications, it is not limited to the above six possible implementations, which are not limited in the embodiment of the present application. .

The exposure parameter refers to the exposure parameter used when capturing the image. When the image sensor is in the second working mode, the second exposure parameter is different from at least one of the third exposure parameters, wherein at least one of the exposure parameters is exposure time, One or more of exposure gain and aperture size, the exposure gain includes analog gain, and/or digital gain. The exposure time refers to the photosensitive time of each pixel of the image sensor. For example, if the image sensor is a camera, the exposure time refers to the time interval from opening to closing of the shutter of the camera. The length of exposure time affects the amount of incoming light. When the light is strong, the exposure time can be set shorter. When the light is dark, the exposure time can be appropriately extended to increase the amount of incoming light.

The gain is divided into analog gain and digital gain. The analog gain refers to amplifying the electrical signal output by the image sensor, and the digital gain refers to amplifying the obtained digital signal after the analog-to-digital conversion is completed. When adjusting the gain, you can adjust the brightness of the output image. The larger the gain, the higher the brightness of the image, but at the same time, the noise will increase, resulting in increased particles and blurred output images. The size of the aperture can also control the amount of light entering. When the aperture is larger, the amount of light entering is more, and vice versa, the amount of light entering is less.

At least one of the exposure parameters in the second exposure parameter and the third exposure parameter condition is different, and one or more exposure parameters may also be the same. The first exposure parameter condition and the second exposure parameter condition may be the same or different, and the first exposure parameter and the third exposure parameter may be the same or different.

After the first image signal, the second image signal, and the third image signal are obtained, black level adjustment processing needs to be performed on them, and the process will be described below with reference to FIGS. 12-15 .

When the camera is in the first working mode, the first adjustment method is specifically:

Determine the black level value of the first image signal of the current frame according to the received black level statistical value of the first image signal of the current frame and the received black level value information of the first image signal of the historical frame, wherein , the first image signal of the historical frame is the first image signal of the previous frame of the first image signal of the current frame;

determining the black level offset of the first image signal of the current frame according to the black level value of the first image signal of the current frame and the first target black level value;

Adjusting the black level of the first image signal of the current frame according to the black level offset of the first image signal of the current frame to obtain a first adjustment signal corresponding to the first image signal of the current frame.

The following will take the image sensor as an RGBW sensor as an example, and take the first adjustment method as an example to describe the black level adjustment process. The RGBW sensor includes four light-sensitive channels, which are R light-sensitive channel, G light-sensitive channel, and B light-sensitive channel. channel and W photosensitive channel.

Figure 12 is a schematic diagram of black level adjustment processing in the first working mode provided by the embodiment of the present application, as shown in Figure 12, the specific steps are:

S1: For the input first image signal of the current frame, respectively count the black level of the black pixel area corresponding to each photosensitive channel, and obtain the black level statistical value of each photosensitive channel of the first image signal of the current frame.

Among them, the statistics may use one or more combinations of average, median, weighted average or similar processing.

S2: Take out the black level value of each photosensitive channel of the first image signal of the historical frame from the memory. If the first image signal of the current frame is the first frame, store the preset black level value in the memory. Among them, the historical frame The first image signal is the first image signal of the previous frame of the first image signal of the current frame, and the first image signal of the current frame is the first image signal being processed by the processing chip.

S3: According to the preset conditions, the black level statistical value of each photosensitive channel of the first image signal of the current frame is mixed with the black level value of each photosensitive channel of the first image signal of the historical frame to obtain the first image signal of the current frame The black level value of each photosensitive channel of the camera is stored in the memory for use by the first image signal of the next frame.

Among them, the preset condition can be one or more combinations of weighting coefficient, selection signal, sensor analog gain, digital gain, exposure time, temperature, deviation from the previous frame, etc., and the mixing process can be weighted average or selection.

S4: Calculate the black level offset of each photosensitive channel of the first image signal of the current frame according to the first target black level value and the black level value of each photosensitive channel of the first image signal of the current frame.

Wherein, the first target black level value is a preset parameter, not less than 0, which is used to adjust the black level of the overall image signal to this target value, and calculate the black level of each photosensitive channel of the first image signal of the current frame. The level offset may be subtracted from the first target black level value by the black level value of each photosensitive channel of the first image signal of the current frame.

S5: applying the black level offset of each photosensitive channel of the first image signal of the current frame to the first image signal of the current frame, so as to correct the black level offset.

Applying the black level offset of each photosensitive channel of the first image signal of the current frame to the first image signal of the current frame refers to adding or subtracting the black level offset to the black level value of the first image signal of the current frame displacement.

Let's take an example to illustrate.

First, for the black pixel area in the input first image signal, the average value is calculated for the data values of the four RGBW channels respectively (you can also perform median filtering and other denoising processing on the black pixel area before calculating the average value), to obtain the current The black level statistical value corresponding to each photosensitive channel of the first image signal of the frame, wherein, the black level statistical value of the R photosensitive channel of the first image signal of the current frame is hist_R, and the black level of the G photosensitive channel of the first image signal of the current frame is hist_R. The level statistical value is hist_G, the black level statistical value of the B photosensitive channel of the first image signal of the current frame is hist_B, and the black level statistical value of the W photosensitive channel of the first image signal of the current frame is hist_W.

Secondly, the black level value of each photosensitive channel of the first image signal of the historical frame is taken out from the memory, wherein, the black level value of the R photosensitive channel of the first image signal of the historical frame is blc_pre_R, and the G value of the first image signal of the historical frame is blc_pre_R. The black level value of the photosensitive channel is blc_pre_G, the black level value of the photosensitive channel B of the first image signal of the historical frame is blc_pre_B, and the black level value of the W photosensitive channel of the first image signal of the historical frame is blc_pre_W, if the current frame No. An image signal is the first frame, and a set of black level values is preset in the memory.

Again, according to the preconfigured weight value weight, the black level statistical value corresponding to each photosensitive channel of the first image signal of the current frame and the black level value of each photosensitive channel of the first image signal of the historical frame are weighted to obtain the current frame No. The black level value of each photosensitive channel of an image signal, and store the black level value of each photosensitive channel of the first image signal of the current frame into the memory.

blc_cur_R=(1-weight)*blc_pre_R+weight*hist_R,

blc_cur_G=(1-weight)*blc_pre_G+weight*hist_G,

blc_cur_B=(1-weight)*blc_pre_W+weight*hist_B,

blc_cur_W=(1-weight)*blc_pre_W+weight*hist_W,

Among them, blc_cur_R is the black level of the R photosensitive channel of the first image signal of the current frame, blc_cur_G is the black level of the G photosensitive channel of the first image signal of the current frame, blc_cur_B is the black level of the B photosensitive channel of the first image signal of the current frame Level, blc_cur_W is the black level of the W photosensitive channel of the first image signal of the current frame.

Again, calculate the black level offset of each photosensitive channel of the first image signal of the current frame according to the first target black level value dst_R, dst_G, dst_B, dst_W and the black level value of each photosensitive channel of the first image signal of the current frame quantity.

blc_offset_cur_R=blc_cur_R-dst_R,

blc_offset_cur_G=blc_cur_G-dst_G,

blc_offset_cur_B=blc_cur_B-dst_B,

blc_offset_cur_W=blc_cur_W-dst_W,

Among them, blc_offset_cur_R is the black level offset of the R photosensitive channel of the first image signal of the current frame;

blc_offset_cur_G is the black level offset of the G photosensitive channel of the first image signal of the current frame;

blc_offset_cur_B is the black level offset of the B photosensitive channel of the first image signal of the current frame;

blc_offset_cur_W is the black level offset of the W photosensitive channel of the first image signal of the current frame.

Finally, the calculated black level offset of each photosensitive channel of the first image signal of the current frame is applied to the data value of the effective pixel area of the first image signal of the current frame. The specific method is to use each photosensitive channel of the effective pixel area The data value is subtracted from the black level offset of the corresponding photosensitive channel, and when the result is less than 0, it is set to 0 to obtain the first adjustment signal corresponding to the first image signal of the current frame.

If the camera is in the second working mode, the processing chip needs to process the second image signal and the third image signal respectively.

First, the processing chip needs to distinguish the second image signal from the third image signal. Figure 13 is a schematic diagram of the distinction between the second image signal and the third image signal provided by the embodiment of the present application. As shown in Figure 13, the image sensor according to the second exposure The alternate exposure under the parameter and the third exposure parameter alternately generates the second image signal and the third image signal, and then the processing chip logically distinguishes the image sequence generated by the image sensor to obtain the second image sequence and the third image sequence, wherein, the first The second image sequence includes multiple frames of the second image signal, and the third image sequence includes multiple frames of the third image signal, and then the processing chip processes the second image signal and the third image signal respectively. Among them, the second adjustment method is specifically:

Determine the black level value of the second image signal of the current frame according to the received black level statistical value of the second image signal of the current frame and the received black level value information of the second image signal of the historical frame, wherein , the second image signal of the historical frame is the second image signal of the previous frame of the second image signal of the current frame;

determining the black level offset of the second image signal of the current frame according to the black level value of the second image signal of the current frame and the second target black level value;

Adjusting the black level of the second image signal of the current frame according to the black level offset of the second image signal of the current frame to obtain a second adjustment signal corresponding to the second image signal of the current frame.

The third adjustment method is specifically:

Determine the black level value of the third image signal of the current frame according to the received black level statistical value of the third image signal of the current frame and the received black level information of the third image signal of the historical frame, wherein, The third image signal of the historical frame is the third image signal of the previous frame of the third image signal of the current frame;

determining the black level offset of the third image signal of the current frame according to the black level value of the third image signal of the current frame and the third target black level value;

Performing black level adjustment on the third image signal of the current frame according to the black level offset of the third image signal of the current frame to obtain a third adjustment signal corresponding to the third image signal of the current frame.

The black level information of the second image signal of the historical frame can be the black level value of the second image signal of the historical frame, or the black level offset of the second image signal of the historical frame. The following two cases will be addressed for example.

FIG. 14 is a first schematic diagram of black level adjustment processing in the second working mode provided by the embodiment of the present application. As shown in FIG. 14 , the processing chip processes the second image signal and the third image signal similarly.

For example, for the second image signal, the black level of the black pixel area corresponding to each photosensitive channel of the second image signal of the current frame is firstly counted to obtain the statistical value of the black level of each photosensitive channel of the second image signal of the current frame.

Among them, the statistics may use one or more combinations of average, median, weighted average or similar processing.

Then, the black level value of each photosensitive channel of the second image signal of the historical frame is fetched from the memory, and if the second image signal of the current frame is the first frame, the preset black level value is stored in the memory.

Secondly, according to the preset conditions, the black level statistical value of each photosensitive channel of the second image signal of the current frame is mixed with the black level value of each photosensitive channel of the second image signal of the historical frame to obtain the second image signal of the current frame The black level value of each photosensitive channel of the camera is stored in the memory for use by the second image signal of the next frame.

Among them, the preset condition can be one or more combinations of weighting coefficient, selection signal, sensor analog gain, digital gain, exposure time, temperature, deviation from the previous frame, etc., and the mixing process can be weighted average or selection.

Again, according to the second target black level value and the black level value of each photosensitive channel of the second image signal of the current frame, calculate the black level offset of each photosensitive channel of the second image signal of the current frame, the second target black The level value is a preset parameter, not less than 0, which is used to adjust the black level of the overall image signal to this target value, and calculate the black level offset of each photosensitive channel of the second image signal of the current frame, It may be that the black level value of each photosensitive channel of the second image signal of the current frame is subtracted from the second target black level value.

Finally, the black level offset of each photosensitive channel of the second image signal of the current frame is applied to the second image signal of the current frame to achieve the effect of correcting the offset of the black level.

The processing process for the third image signal is similar and will not be repeated here. It should be noted that when the second image signal is processed, the black level value of the black pixel area corresponding to the second image signal of the previous frame of the second image signal of the current frame and the second target black level value are combined, When processing the third image signal, the black level value of the black pixel region corresponding to the third image signal of the previous frame of the current frame of the third image signal and the third target black level value are combined.

The black level information of the black pixel area corresponding to the second image signal may not only be the black level value of each photosensitive channel of the second image signal, but also the black level offset of each photosensitive channel of the second image signal , correspondingly, the processing process of the processing chip will change accordingly.

FIG. 15 is a second schematic diagram of black level adjustment processing in the second working mode provided by the embodiment of the present application. As shown in FIG. 15 , for the second image signal, the black level information of the second image signal in the historical frame is The black level offset of the second image signal, the processing process specifically includes the following steps:

First, for the black pixel area corresponding to each photosensitive channel of the second image signal of the current frame that is input, the median values of the RGBW four channel data values are respectively calculated to obtain the black level corresponding to each photosensitive channel of the second image signal of the current frame Statistical value, wherein, the black level statistical value of the R photosensitive channel of the second image signal of the current frame is hist_R, the black level statistical value of the G photosensitive channel of the second image signal of the current frame is hist_G, and the black level statistical value of the second image signal of the current frame is hist_G. The black level statistical value of the photosensitive channel B is hist_B, and the black level statistical value of the W photosensitive channel of the second image signal of the current frame is hist_W;

Then, calculate the black level of each photosensitive channel of the second image signal of the current frame according to the second target black level values dst_R, dst_G, dst_B, dst_W and the black level statistics corresponding to each photosensitive channel of the second image signal of the current frame Offset;

blc_offset_R=hist_R-dst_R,

blc_offset_G=hist_G-dst_G,

blc_offset_B=hist_B-dst_B,

blc_offset_W=hist_W−dst_W.

Secondly, take out the black level offsets blc_offset_pre_R, blc_offset_pre_G, blc_offset_pre_B, blc_offset_pre_W of each photosensitive channel of the second image signal of the historical frame from the memory, if the second image signal of the current frame is the first frame, then a group is preset in the memory black level offset;

Again, calculate the difference between the black level offset of each photosensitive channel of the second image signal of the current frame and the black level offset of each photosensitive channel of the second image signal of the previous frame, and obtain the photosensitive channels of the second image signal channel difference offset;

dif_offset_R＝|blc_offset_R-blc_offset_pre_R|,

dif_offset_G＝|blc_offset_G-blc_offset_pre_G|,

dif_offset_B＝|blc_offset_B-blc_offset_pre_B|,

dif_offset_W＝|blc_offset_W-blc_offset_pre_W|,

max_dif_offset=max(dif_offset_R, dif_offset_G, dif_offset_B, dif_offset_W)

Among them, || means to find the absolute value, and max means to find the maximum value.

Then, the black level offset is calculated according to the difference offset of each photosensitive channel of the second image signal of the current frame and the preset difference offset threshold dif_thr, and the black level offset of each photosensitive channel of the second image signal of the current frame is obtained. level offset;

In this step, in addition to obtaining the black level offset of each photosensitive channel of the second image signal of the current frame through this method, weighting or selection can also be performed according to conditions such as analog gain, digital gain, exposure time, and temperature.

Finally, the calculated black level offset of each photosensitive channel of the second image signal of the current frame is applied to the effective pixel area data value of the second image signal of the current frame. The current frame black level offset of the corresponding channel is subtracted from the data value of each channel in the effective pixel area, and when the result is less than 0, it is set to 0 to obtain the second adjustment signal.

For the third image signal, the above-mentioned steps can also be used for processing, wherein the image signal of the previous frame of the third image signal of the current frame is the third image signal of the historical frame, and when the black level of the third image signal is adjusted, the corresponding first frame The second target black level value needs to be replaced with the third target black level value, by obtaining the black level of the black pixel area corresponding to each photosensitive channel of the third image signal of the current frame and the first frame of the previous frame of the third image signal of the current frame The black level offset of each photosensitive channel of the three image signals performs black level adjustment processing on the third image signal of the current frame, which will not be repeated here.

After the black level is adjusted according to the above steps, the first adjustment signal is obtained in the first working mode, and the second adjustment signal and the third adjustment signal are obtained in the second working mode. Further, the processing chip may include a black level adjustment unit and a first image processing unit, wherein the black level adjustment unit is used to adjust the black level of the image signal to obtain a corresponding adjustment signal, and the first image processing unit is used to Correspondingly adjusted signals result in correspondingly processed signals.

Figure 16 is a first schematic diagram of camera processing provided by the embodiment of the present application. As shown in Figure 16, when the camera is in the first working mode, the image sensor collects and generates the first image signal, and sends the first image signal to the black level adjustment unit, the black level adjustment unit processes the first image signal to generate a first adjustment signal, and sends the first adjustment signal to the first image processing unit, and the first image processing unit processes the first adjustment signal to obtain the first adjustment signal For image processing, the processing of the first adjustment signal by the first image processing unit includes but not limited to one or more of noise reduction, gain, dead point correction, black level correction, color correction, brightness mapping, sharpening, etc.

When the camera is in the second working mode, the image sensor collects and generates the second image signal and the third image signal, and sends the second image signal and the third image signal to the black level adjustment unit, and the black level adjustment unit controls the second The image signal is processed to generate a second adjustment signal, the third image signal is processed to generate a third adjustment signal, and the second adjustment signal and the third adjustment signal are sent to the first image processing unit, and the first image processing unit will The second adjustment signal is processed to obtain a second processed image, and the third adjustment signal is processed to obtain a third processed image. The processing of the second and third adjustment signals by the first image processing unit includes but is not limited to noise reduction, gain One or more of , dead pixel correction, black level correction, color correction, brightness mapping, sharpening, etc.

The image processing unit is also used for:

In the second working mode, fusion processing is performed on the second adjustment signal and the third adjustment signal to obtain and output a processed image.

Figure 17 is the second schematic diagram of camera processing provided by the embodiment of the present application. As shown in Figure 17, when the camera is in the second working mode, the first image processing unit is also used to perform fusion processing on the second processed image and the third processed image , get the processed image.

Fig. 18 is a schematic diagram of the third camera processing provided by the embodiment of the present application. As shown in Fig. 18, further, the processing chip may further include a second image processing unit. When the camera is in the first working mode, the second image processing unit is used to Process the first image signal to obtain a first processed signal, and send the first processed signal to a black level adjustment unit, and the black level adjustment unit is used to perform black level adjustment processing on the first processed signal to obtain a first adjust the signal, and send the first adjusted signal to the first image processing unit, and the first image processing unit is used to process the first adjusted signal to obtain a first processed image.

When the camera is in the second working mode, the second image processing unit is used to process the second image signal to obtain a second processed signal, process the third image signal to obtain a third processed signal, and convert the second processed signal to and the third processed signal are sent to the black level adjustment unit. The black level adjustment unit is used to perform black level adjustment processing on the second processed signal to obtain a second adjustment signal, perform black level adjustment processing on the third processed signal to obtain a third adjustment signal, and combine the second adjustment signal and The third adjustment signal is sent to the first image processing unit. The first image processing unit is configured to process the second adjustment signal to obtain a second processed image, and process the third adjustment signal to obtain a third processed image. The processing of the image signal by the second image processing unit includes, but is not limited to, one or more of noise reduction, gain, and the like.

Fig. 19 is a fourth schematic diagram of camera processing provided by the embodiment of the present application. As shown in Fig. 19, when the camera is in the second working mode, the second image processing unit processes the second image signal to obtain the second processed signal, and the second image processing unit processes the second image signal. The three image signals are processed to obtain the third processed signal, and then the second adjusted signal and the third adjusted signal are respectively obtained through the black level adjustment unit, and the first image processing unit is also used to perform processing on the second adjusted signal and the third adjusted signal Fusion processing to obtain a processed image.

The camera provided by the embodiment of the present application includes a single image sensor and a processing chip, the output terminal of the image sensor is connected to the processing chip, and the camera includes two working modes. output the first image signal to the processing chip, and when the processing chip receives the first image signal, adjust the black level of the first image signal according to the first adjustment method to obtain the first adjustment signal; in the second working mode , the image sensor generates and outputs the second image signal to the processing chip according to the second exposure parameter, generates and outputs the third image signal to the processing chip according to the third exposure parameter; when the processing chip receives the second image signal, adjusts the signal according to the second adjust the black level of the second image signal to obtain the second adjustment signal; when receiving the third image signal, adjust the black level of the third image signal according to the third adjustment method to obtain the third adjustment signal. The camera provided by the embodiment of the present application can adjust the working mode of the camera accordingly under different conditions. The black level adjustment is performed on the image signal. When the camera is in the second working mode, when the black level adjustment is performed, the second image signal and the third image signal are firstly distinguished, and then the second image signal and the third image signal are respectively adjusted. The black level adjustment process is performed on the signal according to different adjustment methods, wherein the black level adjustment is performed on the second image signal of the current frame according to the second image signal of the historical frame, and the third image signal of the current frame is adjusted according to the third image signal of the historical frame To adjust the black level, when processing each frame of image signal, the black level information of the previous frame image signal is fully utilized, and the multi-frame image signals are related to each other, so that the image signal between frames The black level adjustment has correlation, which avoids the serious image jumping problem that is easy to occur when adjusting the black level of multi-frame image signals, and solves the instability when adjusting the black level of multi-frame image signals.

FIG. 20 is a schematic flowchart of a method for adjusting a black level provided by an embodiment of the present application. The method is applied to a camera, and the camera includes a single image sensor and a processing chip, and the output terminal of the image sensor is connected to the processing chip. As shown in Figure 20, the method includes:

S201. Using the image sensor to generate a first image signal according to a first exposure parameter in a first working mode, and using the processing chip to adjust the black level of the first image signal according to a first adjustment method, to obtain a second an adjustment signal;

S202. Using the image sensor to alternately generate a second image signal and a third image signal through multiple exposures in the second working mode, wherein the second image signal is generated according to the second exposure parameter, and the third image signal is generated according to the third exposure Parameter generation; adjust the black level of the second image signal by the processing chip according to the second adjustment method to obtain a second adjustment signal; adjusting the black level to obtain a third adjustment signal; and alternately outputting the second adjustment signal and the third adjustment signal through the processing chip.

In a possible implementation manner, the camera further includes an exposure parameter control unit, and the method further includes:

In the second working mode, the exposure parameter control unit alternately outputs the second exposure parameter and the third exposure parameter to the image sensor.

In a possible implementation manner, the black level adjustment of the first image signal by the processing chip according to the first adjustment method to obtain the first adjustment signal includes:

Determine the black level value of the first image signal of the current frame according to the received black level statistical value of the first image signal of the current frame and the received black level information of the first image signal of the historical frame, wherein, The first image signal of the historical frame is the first image signal of the previous frame of the first image signal of the current frame;

determining the black level offset of the first image signal of the current frame according to the black level value of the first image signal of the current frame and the first target black level value;

Adjusting the black level of the first image signal of the current frame according to the black level offset of the first image signal of the current frame to obtain a first adjustment signal corresponding to the first image signal of the current frame.

In a possible implementation manner, the black level adjustment of the second image signal by the processing chip according to the second adjustment method to obtain the second adjustment signal includes:

Determine the black level value of the second image signal of the current frame according to the received black level statistical value of the second image signal of the current frame and the received black level value information of the second image signal of the historical frame, wherein , the second image signal of the historical frame is the second image signal of the previous frame of the second image signal of the current frame;

determining the black level offset of the second image signal of the current frame according to the black level value of the second image signal of the current frame and the second target black level value;

Adjusting the black level of the second image signal of the current frame according to the black level offset of the second image signal of the current frame to obtain a second adjustment signal corresponding to the second image signal of the current frame.

In a possible implementation manner, the black level adjustment of the third image signal by the processing chip according to a third adjustment method to obtain a third adjustment signal includes:

Determine the black level value of the third image signal of the current frame according to the received black level statistical value of the third image signal of the current frame and the received black level information of the third image signal of the historical frame, wherein, The third image signal of the historical frame is the third image signal of the previous frame of the third image signal of the current frame;

determining the black level offset of the third image signal of the current frame according to the black level value of the third image signal of the current frame and the third target black level value;

Performing black level adjustment on the third image signal of the current frame according to the black level offset of the third image signal of the current frame to obtain a third adjustment signal corresponding to the third image signal of the current frame.

In a possible implementation, the method further includes:

Process the first adjustment signal by the processing chip in the first working mode to obtain and output a first processed image;

Processing the second adjustment signal by the processing chip in the second working mode to obtain and output a second processed image, and processing the third adjustment signal to obtain and output a third processed image; Alternatively, in the second working mode, fusion processing is performed on the second adjustment signal and the third adjustment signal to obtain and output a processed image.

FIG. 21 is a schematic structural diagram of a black level adjustment device provided in an embodiment of the present application. As shown in FIG. 21 , it includes a first processing module 211 and a second processing module 212, wherein:

The first processing module 211 is configured to receive a first image signal when the image sensor is in the first working mode, and adjust the black level of the first image signal according to a first adjustment method to obtain a first adjustment signal;

The second processing module 212 is configured to alternately receive the second image signal and the third image signal when the image sensor is in the second working mode, and adjust the performing black level adjustment on the second image signal to obtain a second adjustment signal, and performing black level adjustment on the third adjustment signal according to a third adjustment method when receiving the third image signal to obtain a third adjustment signal, And alternately output the second adjustment signal and the third adjustment signal.

In a possible implementation manner, the first processing module 211 is specifically configured to:

Determine the black level value of the first image signal of the current frame according to the received black level statistical value of the first image signal of the current frame and the received black level information of the first image signal of the historical frame, wherein, The first image signal of the historical frame is the first image signal of the previous frame of the first image signal of the current frame;

determining the black level offset of the first image signal of the current frame according to the black level value of the first image signal of the current frame and the first target black level value;

Adjusting the black level of the first image signal of the current frame according to the black level offset of the first image signal of the current frame to obtain a first adjustment signal corresponding to the first image signal of the current frame.

In a possible implementation manner, the second processing module 212 is specifically configured to:

Determine the black level value of the second image signal of the current frame according to the received black level statistical value of the second image signal of the current frame and the received black level value information of the second image signal of the historical frame, wherein , the second image signal of the historical frame is the second image signal of the previous frame of the second image signal of the current frame;

determining the black level offset of the second image signal of the current frame according to the black level value of the second image signal of the current frame and the second target black level value;

Adjusting the black level of the second image signal of the current frame according to the black level offset of the second image signal of the current frame to obtain a second adjustment signal corresponding to the second image signal of the current frame.

In a possible implementation manner, the second processing module 212 is specifically configured to:

Determine the black level value of the third image signal of the current frame according to the received black level statistical value of the third image signal of the current frame and the received black level information of the third image signal of the historical frame, wherein, The third image signal of the historical frame is the third image signal of the previous frame of the third image signal of the current frame;

determining the black level offset of the third image signal of the current frame according to the black level value of the third image signal of the current frame and the third target black level value;

Performing black level adjustment on the third image signal of the current frame according to the black level offset of the third image signal of the current frame to obtain a third adjustment signal corresponding to the third image signal of the current frame.

In a possible implementation manner, a third processing module is also included, and the third processing module is configured to:

Processing the first adjustment signal in the first working mode to obtain and output a first processed image;

In the second working mode, the second adjustment signal is processed to obtain and output a second processed image, and the third adjustment signal is processed to obtain and output a third processed image; or, in the In the second working mode, fusion processing is performed on the second adjustment signal and the third adjustment signal to obtain and output a processed image.

The device provided in the embodiment of the present application can be used to implement the technical solution of the above method embodiment, and its implementation principle and technical effect are similar, and will not be repeated here.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present application, rather than limiting them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: It is still possible to modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the technical solutions of the various embodiments of the present application. scope.

Claims (14)

1. A camera, characterized in that, comprises a single image sensor and a processing chip, the output end of the image sensor is connected with the processing chip, wherein: The image sensor is used to generate and output a first image signal to the processing chip according to a first exposure parameter in a first working mode; The processing chip is configured to, when receiving the first image signal, adjust the black level of the first image signal according to a first adjustment method to obtain a first adjustment signal; The image sensor is also used to alternately generate and output a second image signal and a third image signal to the processing chip through multiple exposures in the second working mode, wherein the second image signal is based on the second exposure parameter generating, the third image signal is generated according to a third exposure parameter; The processing chip is further configured to, when receiving the second image signal, adjust the black level of the second image signal according to a second adjustment method to obtain a second adjustment signal; For an image signal, adjust the black level of the third image signal according to a third adjustment method to obtain a third adjustment signal; alternately output the second adjustment signal and the third adjustment signal. 2. The camera according to claim 1, further comprising an exposure parameter control unit, wherein: The exposure parameter control unit is configured to alternately output the second exposure parameter and the third exposure parameter to the image sensor in the second working mode. 3. The camera according to claim 1, wherein the second exposure parameter is different from at least one exposure parameter in the third exposure parameter, and the at least one exposure parameter is exposure time, exposure gain, aperture size One or more of them, the exposure gain includes an analog gain, and/or a digital gain. 4. The camera according to any one of claims 1-3, wherein the first adjustment method is specifically: Determine the black level value of the first image signal of the current frame according to the received black level statistical value of the first image signal of the current frame and the received black level information of the first image signal of the historical frame, wherein, The first image signal of the historical frame is the first image signal of the previous frame of the first image signal of the current frame; determining the black level offset of the first image signal of the current frame according to the black level value of the first image signal of the current frame and the first target black level value; Adjusting the black level of the first image signal of the current frame according to the black level offset of the first image signal of the current frame to obtain a first adjustment signal corresponding to the first image signal of the current frame. 5. The camera according to any one of claims 1-3, wherein the second adjustment method is specifically: Determine the black level value of the second image signal of the current frame according to the received black level statistical value of the second image signal of the current frame and the received black level information of the second image signal of the historical frame, wherein, The second image signal of the historical frame is the second image signal of the previous frame of the second image signal of the current frame; determining the black level offset of the second image signal of the current frame according to the black level value of the second image signal of the current frame and the second target black level value; Adjusting the black level of the second image signal of the current frame according to the black level offset of the second image signal of the current frame to obtain a second adjustment signal corresponding to the second image signal of the current frame. 6. The camera according to any one of claims 1-3, wherein the third adjustment method is specifically: Determine the black level value of the third image signal of the current frame according to the received black level statistical value of the third image signal of the current frame and the received black level information of the third image signal of the historical frame, wherein, The third image signal of the historical frame is the third image signal of the previous frame of the third image signal of the current frame; determining the black level offset of the third image signal of the current frame according to the black level value of the third image signal of the current frame and the third target black level value; Performing black level adjustment on the third image signal of the current frame according to the black level offset of the third image signal of the current frame to obtain a third adjustment signal corresponding to the third image signal of the current frame. 7. The camera according to claim 1, wherein the processing chip is further used for: Processing the first adjustment signal in the first working mode to obtain and output a first processed image; In the second working mode, the second adjustment signal is processed to obtain and output a second processed image, and the third adjustment signal is processed to obtain and output a third processed image; or, in the In the second working mode, fusion processing is performed on the second adjustment signal and the third adjustment signal to obtain and output a processed image. 8. A black level adjustment method applied to a camera, the camera comprising a single image sensor and a processing chip, the output end of the image sensor is connected to the processing chip, it is characterized in that the method comprises: The first image signal is generated by the image sensor according to the first exposure parameter in the first working mode, and the black level of the first image signal is adjusted by the processing chip according to the first adjustment method to obtain the first adjustment Signal; The second image signal and the third image signal are alternately generated by the image sensor through multiple exposures in the second working mode, wherein the second image signal is generated according to the second exposure parameter, and the third image signal is generated according to the third exposure parameter ; adjust the black level of the second image signal by the processing chip according to the second adjustment method to obtain a second adjustment signal; perform black level adjustment on the third image signal by the processing chip according to the third adjustment method level adjustment to obtain a third adjustment signal; and alternately output the second adjustment signal and the third adjustment signal through the processing chip. 9. The method according to claim 8, wherein the camera further comprises an exposure parameter control unit, and the method further comprises: In the second working mode, the exposure parameter control unit alternately outputs the second exposure parameter and the third exposure parameter to the image sensor. 10. The method according to claim 8 or 9, wherein the black level adjustment of the first image signal by the processing chip according to the first adjustment method to obtain the first adjustment signal comprises: Determine the black level value of the first image signal of the current frame according to the received black level statistical value of the first image signal of the current frame and the received black level information of the first image signal of the historical frame, wherein, The first image signal of the historical frame is the first image signal of the previous frame of the first image signal of the current frame; determining the black level offset of the first image signal of the current frame according to the black level value of the first image signal of the current frame and the first target black level value; Adjusting the black level of the first image signal of the current frame according to the black level offset of the first image signal of the current frame to obtain a first adjustment signal corresponding to the first image signal of the current frame. 11. The method according to claim 8 or 9, wherein the black level adjustment of the second image signal by the processing chip according to the second adjustment method to obtain the second adjustment signal comprises: Determine the black level value of the second image signal of the current frame according to the received black level statistical value of the second image signal of the current frame and the received black level value information of the second image signal of the historical frame, wherein , the second image signal of the historical frame is the second image signal of the previous frame of the second image signal of the current frame; determining the black level offset of the second image signal of the current frame according to the black level value of the second image signal of the current frame and the second target black level value; Adjusting the black level of the second image signal of the current frame according to the black level offset of the second image signal of the current frame to obtain a second adjustment signal corresponding to the second image signal of the current frame. 12. The method according to claim 8 or 9, wherein the black level adjustment of the third image signal by the processing chip according to a third adjustment method to obtain a third adjustment signal comprises: Determine the black level value of the third image signal of the current frame according to the received black level statistical value of the third image signal of the current frame and the received black level information of the third image signal of the historical frame, wherein, The third image signal of the historical frame is the third image signal of the previous frame of the third image signal of the current frame; determining the black level offset of the third image signal of the current frame according to the black level value of the third image signal of the current frame and the third target black level value; Performing black level adjustment on the third image signal of the current frame according to the black level offset of the third image signal of the current frame to obtain a third adjustment signal corresponding to the third image signal of the current frame. 13. The method of claim 8, further comprising: Process the first adjustment signal by the processing chip in the first working mode to obtain and output a first processed image; Processing the second adjustment signal by the processing chip in the second working mode to obtain and output a second processed image, and processing the third adjustment signal to obtain and output a third processed image; Alternatively, in the second working mode, fusion processing is performed on the second adjustment signal and the third adjustment signal to obtain and output a processed image. 14. A black level adjustment device, characterized in that it comprises: The first processing module is configured to receive a first image signal when the image sensor is in the first working mode, and adjust the black level of the first image signal according to a first adjustment method to obtain a first adjustment signal; The second processing module is configured to alternately receive the second image signal and the third image signal when the image sensor is in the second working mode, and adjust the performing black level adjustment on the second image signal to obtain a second adjustment signal, and performing black level adjustment on the third adjustment signal according to a third adjustment method when receiving the third image signal to obtain a third adjustment signal, And alternately output the second adjustment signal and the third adjustment signal.