JP2000236532A - Supervisory system using high sensitivity television camera and method for selecting its sensitivity - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a supervisory system using a high sensitivity television camera giving a video image with less noise to an image processing unit by automatically revising a sensitivity adjustment method corresponding to the degree of a change in the video image. SOLUTION: A television camera 1 for a supervisory system where the sensitivity is set by means of gain or storage control is provided with a storage section 3 that converts input light into an electric signal and stores the signal, an amplifier section 4 that amplifies the electric signal received from the amplifier section, a memory section 5 that temporarily stores a video signal received from the amplifier section, and a control section 6 that controls the above operations, an image processing unit 2 receives a video signal output of the memory section 5 and outputs a control signal to the control section 6 corresponding to the state of the video signal input. The control section 6 controls the stage section 3, the amplifier section 4 and the memory section 5 on the basis of the output signal from the amplifier section 4 and the control signal from the image processing unit 2 to switch over the sensitivity of the television camera and the sensitivity adjustment method.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a high-sensitivity television camera, and more particularly to a monitoring system using the high-sensitivity television camera and a sensitivity switching method.

[0002]

2. Description of the Related Art In recent years, surveillance systems using television cameras have been rapidly increasing due to an increase in demand for security. In general, in a monitoring system using a television camera, a dim place is often photographed, and a high-sensitivity television camera having an automatic sensitivity switching function is used. As a method of adjusting the sensitivity, a method of improving the sensitivity by making the charge storage time of the CCD image sensor longer than one frame period, a method of electrically amplifying a small signal by a high gain amplifier circuit, and the like are used. I have.

[0003]

However, in the method of increasing the sensitivity by accumulation, although the noise is not amplified by amplification, the image becomes an intermittent image according to the accumulation time, and therefore, the image is smooth for an object having many changes. In the method of increasing the sensitivity by gain amplification, a smooth image can be obtained even for a subject having many changes, but noise is also amplified, and the image becomes difficult to see. Therefore, a method of increasing the sensitivity by gain amplification is desirable for a subject with many changes, and a method of increasing the sensitivity by accumulation is desirable for a subject with little change. However, the conventional automatic sensitivity switching function adjusts the total sensitivity. Since it is decided whether to prioritize the increase in sensitivity by accumulation or the increase in gain by gain amplification, it is possible to adjust the total sensitivity even if the target image has a lot of change and the target image with little change. There has been a problem that a suitable sensitivity setting cannot be automatically performed.

An object of the present invention is to provide a surveillance system using a high-sensitivity television camera that automatically changes a sensitivity adjustment method according to the degree of change of an image and provides an image processing apparatus with less noise. It is in.

[0005]

SUMMARY OF THE INVENTION A sensitivity switching method for a monitoring system using a high-sensitivity television camera according to the present invention adjusts the sensitivity by processing pixels in a storage unit for converting incident light of the high-sensitivity television camera into an electric signal. The video signal is output from the high-sensitivity television camera to the image processing device with the desired total sensitivity by combining the adjustment of the sensitivity of the electric signal converted by the accumulation unit with the gain of the amplification unit, and the normal imaging target is stopped. In the state, the sensitivity is adjusted mainly depending on the processing of the pixels in the storage unit, and in the operation state of the imaging target, the ratio of the sensitivity adjustment by the processing of the pixels in the storage unit is automatically reduced, and The video signal is output from the high-sensitivity television camera to the image processing device with the desired total sensitivity by increasing the sensitivity adjustment ratio by the gain.

The adjustment of the sensitivity by the processing of the pixels of the storage unit for converting the light of the high-sensitivity television camera into an electric signal may be the adjustment of the storage time for storing the pixels. The adjustment may be the adjustment of the number of additions of pixels close to the pixel, or a combination of the adjustment of the accumulation time for accumulation of pixels and the adjustment of the number of additions of pixels adjacent to the pixel.

Also, a combination of sensitivity adjustment by processing pixels of a storage unit for converting light of a high-sensitivity television camera into an electric signal and sensitivity adjustment by gain of an amplification unit for the electric signal converted by the storage unit. The video signal is output from the high-sensitivity television camera to the image processing device with the desired total sensitivity, and in the normal state where the imaging target is stationary, the sensitivity adjustment is mainly performed by accumulating the pixels of the accumulation unit, and the operation state of the imaging target In, the sensitivity adjustment by the accumulation of the pixels in the accumulation unit is automatically switched to the pixel addition by the addition of the neighboring pixels, and the video signal with the desired total sensitivity is combined with the sensitivity adjustment by the gain of the amplification unit. You may output from a camera to an image processing apparatus.

A surveillance system using a high-sensitivity television camera according to the present invention includes a high-sensitivity television camera and an image processing device. The television camera converts input light into an electric signal, stores the electric signal, and outputs the electric signal in a predetermined procedure. A storage unit, an amplification unit that amplifies an electric signal input from the storage unit with a predetermined gain, and a memory unit that temporarily stores a video signal input from the amplification unit and outputs the video signal to the image processing apparatus in a predetermined procedure. The amplification unit is controlled so as to output a video signal with a predetermined total sensitivity from the amplification unit, and in a stationary state of the normal imaging target, the sensitivity is adjusted mainly by processing pixels of the storage unit, and the sensitivity of the imaging target is adjusted. In the operating state, a control unit is provided for performing adjustment so as to reduce the rate of sensitivity adjustment by processing the pixels of the storage unit.

In a surveillance system using a high-sensitivity television camera in which sensitivity is set by a method such as gain and accumulation, it is preferable that the television camera provides an image processing device with an image having less noise. The present invention provides a method of automatically changing a sensitivity adjustment method according to a change in an image, and constantly providing an image processing apparatus with an image having less noise to the image processing apparatus. This facilitates various image processing on the image processing apparatus side.

[0010]

Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a schematic block diagram of a first embodiment of a monitoring system using a high-sensitivity television camera of the present invention.

Referring to FIG. 1, the monitoring system according to the present embodiment includes a television camera 1 and an image processing device 2.

The television camera 1 has a storage unit 3 for converting input light into an electric signal, an amplification unit 4 for amplifying the electric signal input from the storage unit 3, and a temporary storage of a video signal input from the amplification unit 4. And a control unit 6 for controlling their operations.

The video signal output of the memory unit 5 is input to the image processing device 2. The image processing device 2 outputs a control signal to the control unit 6 according to the state of the video signal input. The control unit 6 controls the output signal of the amplification unit 4 and the image processing device 2
The control unit 3 controls the storage unit 3, the amplification unit 4, and the memory unit 5 in accordance with the control signal, and switches the sensitivity of the television camera and the sensitivity adjustment method.

Next, the operation of the embodiment of the present invention will be described in detail with reference to FIGS. FIG. 2 is a schematic image change diagram showing a change in the image output when the gain is quadrupled and the total sensitivity is quadrupled in the amplifier 4, where (a) is an output image of the storage unit, (B) is an output image of the amplifying unit, and (c) is an output image of the memory unit. In the television camera 1, the output images of the storage unit 3, the amplification unit 4, and the memory unit 5 are A1 → A2 → A3 →
A4 → A5, B1 → B2 → B3 → B4 → B5, C1 → C
The order changes from 2 to C3 to C4 to C5. The output video of the storage unit 3 is output by the amplification unit 4 with the gain quadrupled.

FIG. 3 is a schematic image change diagram showing a change in image when the accumulation time is quadrupled and the total sensitivity is quadrupled in the accumulating section 3, and FIG. , (B) is the output video of the amplifier, and (c) is the output video of the memory. In the television camera 1, the output images of the storage unit 3, the amplification unit 4, and the memory unit 5 are respectively A'1 →.
・ → ・ → A'5, B'1 → ・ →→→→ B'5, C'1
→ C′1 → C′1 → C′1 → C′5 The output images of the accumulation unit 3 and the amplification unit 4 are intermittent images according to the accumulation time. The video level of the video A′5 can be regarded as equivalent to the sum of the video levels of the video A1, the video A2, the video A3, and the video A4 in FIG. The memory unit 5 outputs the same video during the accumulation time so that the output to the image processing apparatus 2 does not become an intermittent video.

FIG. 4 is a schematic image change diagram showing a change in the image level of one line in the image of FIG.
(A) is the output video level of the storage unit, (b) is the output video level of the amplification unit, and (c) is the output video level of the memory unit. It is assumed that the output video levels a1 to a5 of the storage unit 3 have low levels and include noise. In the output video levels b1 to b5 of the amplifying unit 4, since the video signal is also amplified, but the noise is also amplified, the noise is more conspicuous than at the standard sensitivity. As with the output video levels b1 to b5 of the amplifying unit 4, noise is more conspicuous in the output video level of the memory unit 5 than in the standard sensitivity.

FIG. 5 is a schematic image change diagram showing a change in the image level of one line in the image of FIG.
(A) is the output video level of the storage unit, (b) is the output video level of the amplification unit, and (c) is the output video level of the memory unit. In the output video levels a′1 and a′5 of the storage unit 3, since the noise is not amplified, the noise is less noticeable than at the time of the standard sensitivity. Video levels b'1, b'5,
Similarly, noise of c'1 and c'5 is less noticeable than at the time of standard sensitivity.

The total sensitivity of the TV camera is determined by the storage unit 3
Is multiplied by the sensitivity ratio in the amplifier 4.
The total sensitivity is automatically set by the control unit 6 upon receiving the output signal of the amplification unit 4. As described above, when the accumulation time is long, the S / N is improved for a stationary object, but the image is blurred for a moving object.

In the sensitivity switching method according to the first embodiment of the monitoring system using the high-sensitivity television camera of the present invention, normally, the control unit 6 increases the accumulation time in the accumulation unit 3 and increases the gain in the amplification unit 4. A video signal having a total sensitivity as shown in FIG. Therefore, the image processing device 2 determines the state of the input video, and if it determines that there is a motion in the video, outputs a control signal for setting the upper limit of the storage time in the storage unit 3 to the control unit 6 according to the motion. Control unit 6 receiving the control signal
Controls the storage unit 3 to reduce the storage time to its upper limit, and controls the amplification unit 4 to increase the gain by that amount so as to output a video signal with the same total sensitivity.

By controlling in this manner, the television camera 1 can give an image processing apparatus 2 with less noise to the image processing apparatus 2 by increasing the sensitivity in the storage unit 3 as much as possible, and the motion of the object can be reduced. In some cases, in accordance with an instruction from the image processing apparatus 2, a video signal having a short accumulation time corresponding to the movement of the target is output with the same total sensitivity.

Next, a description will be given of a second embodiment of the monitoring system using the high sensitivity television camera according to the present invention. In the second embodiment, the output of the pixel added pixel is used instead of the temporal accumulation of the individual pixels in the accumulation unit 3 of the first embodiment.

The pixel addition includes horizontal addition in which outputs of pixels adjacent or adjacent in the horizontal direction are added and output, and vertical pixel addition in which pixels adjacent in the vertical direction are added using a memory and output. The output video of the storage unit 3 in FIG. 2A is a set of outputs of individual pixels. When pixel addition is performed, the output video of the storage unit 3 in FIG. Output set. Therefore, the sensitivity of the output image of the storage unit 3 is improved by the number of added pixels, so that the gain magnification in the amplification unit 4 can be reduced.
Unlike the method based on accumulation, intermittent video is not generated, so that the continuity of video is improved but the resolution is reduced.

In the sensitivity switching method according to the second embodiment of the monitoring system using the high-sensitivity television camera of the present invention, the control unit 6 normally outputs the pixels to which the pixel addition has been performed in the storage unit 3 to reduce the sensitivity. The image signal is output to the image processing apparatus 2 by increasing the gain in the amplifying unit and reducing the gain in the amplifying unit and having a high S / N and a total sensitivity. Therefore, when the image processing device 2 determines that there is a motion in the video from the state of the input video, it outputs a control signal for setting the upper limit of the pixel addition number in the storage unit 3 to the control unit 6 according to the change. Upon receiving the control signal, the control unit 6 controls to reduce the pixel addition number of the storage unit 3 to the upper limit, and increases the gain in the amplification unit 4 by that amount so as to output the video signal with the same total sensitivity. Control.

By controlling in this manner, the television camera 1 can give an image processing device 2 with less noise to the image processing device 2 by increasing the sensitivity in the storage unit 3 as much as possible. In some cases, in accordance with an instruction from the image processing apparatus 2, a video signal without intermittent video corresponding to the motion of the target is output with the same total sensitivity.

Next, a third embodiment of the monitoring system using the high-sensitivity television camera of the present invention will be described. In the third embodiment, it is possible to switch between the temporal accumulation of the individual pixels in the accumulation unit 3 of the first embodiment and the output of the pixel added pixel of the second embodiment.

In the sensitivity switching method according to the third embodiment of the monitoring system using the high-sensitivity television camera of the present invention, the control unit 6 normally makes the accumulation time in the accumulation unit 3 longer and reduces the gain in the amplification unit. Then, a video signal having a total sensitivity with a good S / N is output to the image processing apparatus 2. Therefore, when the image processing apparatus 2 determines that there is a motion in the video from the state of the input video, the control unit 6 switches the output of the storage unit 3 to pixel addition according to the change and sets a control signal for setting the upper limit of the number of pixel additions. Output to Upon receiving the control signal, the control unit 6 controls to stop the accumulation of the accumulation unit 3 and switch to the pixel addition, and increases the gain in the amplification unit 4 by that much so that the video signal is output with the same total sensitivity. Control.

By controlling in this manner, the camera 1 can give an image with less noise to the image processing device 2 by increasing the sensitivity in the storage unit 3 as much as possible, and the camera 1 In the case where there is an image, the image of the pixel addition corresponding to the movement of the target is output by the instruction of the image processing apparatus 2, thereby outputting a video signal corresponding to the movement of the target and having little noise with the same total sensitivity.

In the third embodiment, it is possible to switch between the temporal accumulation of the individual pixels in the accumulation unit 3 and the output of the pixel obtained by adding the pixels. However, a method of obtaining a desired sensitivity by combining them may be used. Although the resolution is slightly reduced, the interval between the intermittent images can be reduced, and the responsiveness to motion is improved.

[0029]

As described above, in the sensitivity switching method of the surveillance system having the high-sensitivity television camera of the present invention, the image processing is facilitated by always providing the image processing apparatus with a low noise image to the image processing apparatus. When there is a motion, there is an effect that the image is automatically switched to a video corresponding to the motion.

[Brief description of the drawings]

FIG. 1 is a schematic block diagram of a first embodiment of a monitoring system using a high-sensitivity television camera of the present invention.

FIG. 2 is a schematic video change diagram showing a change in a video output when a gain is quadrupled and a total sensitivity is quadrupled in an amplification unit 4; (A) is an output image of the storage unit. (B) is an output image of the amplifier. (C) is an output image of the memory unit.

FIG. 3 is a schematic video change diagram showing a video change when a storage time is quadrupled and a total sensitivity is quadrupled in a storage unit 3; (A) is an output image of the storage unit.
(B) is an output image of the amplifier. (C) is an output image of the memory unit.

4 is a schematic video change diagram showing a change in video level of one line in the video of FIG. 2; (A) is the output video level of the storage unit. (B) is the output video level of the amplifier. (C) is the output video level of the memory unit.

FIG. 5 is a schematic video change diagram showing a change in video level of one line in the video of FIG. 3; (A) is the output video level of the storage unit. (B) is the output video level of the amplifier. (C) is the output video level of the memory unit.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Television camera 2 Image processing apparatus 3 Storage part 4 Amplification part 5 Memory part 6 Control part A1-A5, B1-B5, C1-C5, A'1, A '
5, B'1, B'5, C'1, C'5 Output video a1 to a5, b1 to b5, c1 to c5, a'1, a '
5, b'1, b'5, c'1, c'5 output video level

Claims (8)

[Claims] 1. A sensitivity switching method for a monitoring system using a high-sensitivity television camera, comprising: adjusting sensitivity by processing pixels in a storage unit that converts incident light of the high-sensitivity television camera into an electric signal; The video signal is output from the high-sensitivity television camera to the image processing device with a desired total sensitivity in combination with the adjustment of the sensitivity by the gain of the amplifying section of the electric signal converted by the section, and the normal stationary state of the imaging target In, the sensitivity is adjusted mainly depending on the processing of the pixels in the storage unit, and in the operation state of the imaging target, the ratio of the sensitivity adjustment by the processing of the pixels in the storage unit is automatically reduced, and the amplification is performed. A video signal having a desired total sensitivity is output from the high-sensitivity television camera to an image processing device by increasing a sensitivity adjustment ratio by a gain of the section. Sensitivity switching method of monitoring system using Bikamera. 2. The high sensitivity according to claim 1, wherein the adjustment of the sensitivity by the processing of the pixels of the storage unit for converting the light of the high sensitivity television camera into an electric signal is the adjustment of the storage time for storing the pixels. A sensitivity switching method for a monitoring system using a television camera. 3. The adjustment of the sensitivity by processing a pixel of a storage unit that converts light of the high-sensitivity television camera into an electric signal is an adjustment of an addition number of a pixel adjacent to the pixel to be added to the pixel. A sensitivity switching method for a monitoring system using the high-sensitivity television camera according to claim 1. 4. Adjustment of sensitivity by processing of a pixel of a storage unit for converting light of the high-sensitivity television camera into an electric signal includes adjusting a storage time for storing a pixel and adding a pixel adjacent to the pixel. The sensitivity switching method for a monitoring system using a high-sensitivity television camera according to claim 1, wherein the method is a combination with a number adjustment. 5. A sensitivity switching method for a monitoring system using a high-sensitivity television camera, comprising: adjusting sensitivity by processing a pixel of a storage unit that converts light of the high-sensitivity television camera into an electric signal; The video signal is output from the high-sensitivity television camera to the image processing device with a desired total sensitivity in combination with the adjustment of the sensitivity by the gain of the amplification unit of the electric signal converted in the above-described manner. The sensitivity adjustment is mainly performed by accumulating the pixels of the accumulation unit, and in the operation state of the imaging target, the sensitivity adjustment by the accumulation of the pixels of the accumulation unit is automatically switched to the pixel addition by the addition of the neighboring pixels. Outputting a video signal from the high-sensitivity television camera to an image processing device with a desired total sensitivity in combination with sensitivity adjustment by the gain of the amplification unit. Sensitivity switching method of monitoring system using a high-sensitivity TV camera for. 6. A high-sensitivity television camera and an image processing apparatus, wherein the high-sensitivity television camera converts an input light into an electric signal, accumulates the electric signal, and outputs the electric signal according to a predetermined procedure. An amplification unit for amplifying the electric signal with a predetermined gain,
A memory unit that temporarily stores the video signal input from the amplifying unit and outputs the video signal to the image processing apparatus in a predetermined procedure, and the amplifying unit to output the video signal from the amplifying unit with a predetermined total sensitivity. In the stationary state of the normal imaging target, the sensitivity is adjusted mainly by the processing of the pixels of the storage unit. In the operation state of the imaging target, the sensitivity adjustment ratio by the processing of the pixels of the storage unit is adjusted. A monitoring system using a high-sensitivity television camera, comprising: a control unit that performs adjustment so as to lower the height. 7. The surveillance system using a high-sensitivity television camera according to claim 5, wherein the adjustment of the sensitivity by the processing of the pixels in the storage unit is an adjustment of an accumulation time for accumulating the pixels. 8. The surveillance system using a high-sensitivity television camera according to claim 5, wherein the adjustment of the sensitivity by the processing of the pixel of the storage unit is an adjustment of the number of additions of pixels adjacent to the pixel.