Detailed Description
For the purpose of making the objects, technical solutions and advantages of the present application more apparent, the embodiments of the present application will be described in further detail below with reference to the accompanying drawings.
Fig. 1 is a schematic structural diagram of a projection device according to an embodiment of the present application, and referring to fig. 1, the projection device may include a control circuit 10, a light source 20, a light valve 30, and a projection lens 40.
Referring to fig. 1, the control circuit 10 is connected to a light source 20 and a light valve 30, respectively. The control circuit 10 is configured to receive image data of a projection image to be projected and displayed, and to process the image data of the initial projection image. Thereafter, the control circuit 10 can transmit the processed image data to the light valve 30 and output a driving signal to the light source 20 based on the processed image data. The control circuit 10 may include, among other things, a system on chip (SoC) and a digital light processing (digital light processing, DLP) chip.
The light source 20 is configured to emit light under the drive of a drive signal output from the control circuit 10. The light valve 30 is used for modulating the light beam emitted by the light source 20 based on the image data output by the control circuit 10, so as to obtain a projection image to be projected and displayed. The projection lens 40 can then project the projected image to be projected to a projection screen. The light source 20 may be a laser light source or another type of light source such as a light-emitting diode (LED). The light valve 30 may include a digital micromirror device (digital micromirror device, DMD), for example, two DMDs may be included in the light valve 30. One of the DMDs acts as a random mirror for reflecting light beams from the light source along different angles. The other DMD serves as a light modulation device for modulating the light beam emitted from the light source 20 based on the image data output from the control circuit 10.
It will be appreciated that the projection device is movable relative to the projection screen. That is, the projection distance of the projection image projected by the projection apparatus varies. In the related art, a projection apparatus is capable of determining a projection size of a projection image by acquiring a projection distance of the projection image, and adjusting brightness of the projection image to be projected and displayed based on the projection size.
By way of example, fig. 2 is a schematic diagram of a projection device in the related art projecting a projected image, and as shown in fig. 2, the projection device may include a ranging sensor. The distance measuring sensor can measure the distance between the projection device and the projection screen, namely the projection distance of the projection image.
However, the above-described display method of the projection image can be applied only to a projection apparatus in which the focal length of the projection lens 40 is fixed. For the projection device with the variable focal length of the projection lens 40, the projection device cannot determine the projection size of the projection image based on the projection distance, and the projection device cannot adjust the brightness of the projection image to be projected and displayed, so that the display effect of the projection image is poor.
It will also be appreciated that the smaller the projected size of the projected image, the higher the brightness of the projected image, provided that the brightness of the light beam projected by the light source 20 of the projection device is constant. When the projection size of the projection image is smaller than a certain threshold, the brightness of the projection image may be too high, resulting in serious influence on the viewing effect.
Fig. 3 is a flowchart of a method for displaying a projection image according to an embodiment of the present application, where the method may be applied to a projection device, for example, the projection device shown in fig. 1. As shown in fig. 1, the projection device includes a projection lens 40. Referring to fig. 3, the method includes:
step 101, determining the projection size of the initial projection image based on the projection parameters of the projection lens.
In the embodiment of the present application, during the working process of the projection device, the projection parameters of the projection lens 40 can be obtained, and based on the projection parameters, the projection size of the initial projection image to be projected is determined. The projection parameters of the projection lens 40 may include at least a focal length and an image distance of the projection lens 40, and may further include an object distance of the projection lens 40 and an imaging size of the light valve 30 in the projection device. The object distance is the distance between the light valve 30 and the projection lens 40 in the projection device, and the image distance is the distance between the projection lens 40 and the projection screen. The projection size refers to the size of the projection image when projected onto the projection screen.
It will be appreciated that the projected size of the initial projected image to be projected is related to the focal length and object distance of the projection lens 40, and therefore the projection device can accurately determine the projected size of the initial projected image based on the current focal length and object distance of the projection lens 40.
It is further understood that the focal length of the projection lens 40 may be fixed or adjustable. If the focal length of the projection lens 40 is adjustable, the projection device may acquire the projection parameters of the projection lens 40 when detecting that the focal length of the projection lens 40 changes, and determine the projection size of the initial projection image to be projected based on the projection parameters.
And 102, if the projection size of the initial projection image is smaller than or equal to the size threshold, processing the initial projection image to obtain a target projection image.
In this embodiment of the present application, after determining the projection size of the initial projection image, if the projection size is detected to be smaller than or equal to the size threshold, the projection device may determine that the brightness of the initial projection image needs to be adjusted, and then may process the initial projection image to obtain the target projection image. If the projection device detects that the projection size is greater than the size threshold, it may determine that adjustment of the brightness of the initial projected image is not required, and therefore, processing of the initial projected image is not required.
The target projection image comprises a plurality of first pixels and a plurality of second pixels in the initial projection image. The pixel values of the plurality of first pixels are all target values, and the target values are smaller than a pixel value threshold. For example, the pixel value threshold may be 1 and the target value may be 0. That is, the plurality of first pixels may be black.
It will be appreciated that the size threshold may be determined based on the brightness of the light source 20 in the projection device, as well as the brightness range of the projected image suitable for viewing by the user. For example, the projection size of the projection image projected by the projection apparatus may be gradually increased on the premise that the luminance of the light source 20 in the projection apparatus is unchanged, and the first projection size that can bring the luminance of the projection image within the luminance range is determined as the size threshold.
It is also understood that the projection device can make the pixel values of the first pixels in the target projection image obtained after the processing be the target value by processing the initial projection image. Since the brightness of the plurality of first pixels is low, it is possible to ensure that the brightness of the target projection image is lower than the brightness of the initial projection image.
Step 103, projecting the target projection image to a projection screen through a projection lens.
In the embodiment of the present application, after the projection device obtains the target projection image, the target projection image can be projected onto the projection screen through the projection lens 40. Wherein, when the projection parameters of the projection lens 40 in the projection device are changed such that the projection size of the initial projected image is changed, the projection device can perform both of the above steps 101 and 102. Therefore, the brightness of the projection image projected by the projection device can be ensured not to be greatly different along with the change of the projection distance, and the display effect of the projection image is ensured to be better.
In summary, the embodiment of the application provides a method for displaying a projection image. The projection device can process the initial projection image to obtain a target projection image when detecting that the projection size of the initial projection image is smaller than or equal to a size threshold. Since the pixel values of the first pixels in the target projection image are all target values, and the target values are smaller than the pixel value threshold, the brightness of the target projection image can be ensured to be smaller than the brightness of the initial projection image. This ensures that the brightness of the projected image is not excessively high when the projected image having a small projection size is projected. That is, it is possible to ensure that the brightness of the projected image does not vary greatly with the variation of the projection distance, and further ensure that the display effect of the projected image is good.
Fig. 4 is a flowchart of another method for displaying a projection image according to an embodiment of the present application, where the method may be applied to a projection device, for example, the projection device shown in fig. 1. As shown in fig. 1, the projection apparatus includes a projection lens 40 and a control circuit 10. Referring to fig. 4, the method includes:
step 201, determining an image distance of a projection lens based on the focal length and the object distance.
In the embodiment of the present application, if the projection parameters of the projection lens 40 are changed during the operation of the projection apparatus, the projection size of the projection image projected by the projection lens 40 is also changed. The projection parameters may include at least a focal length and an object distance of the projection lens 40, and may further include an image distance of the projection lens 40. The control circuit 10 in the projection device can acquire the projection parameters of the projection lens 40 in real time. If the control circuit 10 determines that the projection parameter is changed, the image distance of the projection lens 40 can be determined based on the focal length and the object distance in the changed projection parameter. The image distance v, focal length f, and object distance u of the projection lens 40 may satisfy:
it is understood that the adjustment of the projection parameters of the projection lens 40 by the user can be classified into Zoom (Zoom) adjustment and Focus (Focus) adjustment. The zoom adjustment is to adjust the focal length f of the projection lens 40. The focus adjustment is to adjust the image distance v of the projection lens 40.
For a fixed focal length projection lens 40, the focal length is fixed, i.e., the user cannot zoom the projection lens 40. Referring to the above formula (1), when the fixed focal length projection lens 40 is adjusted in focus, the object distance of the projection lens 40 will change along with the change of the image distance, and the control circuit 10 can obtain the change of the object distance during the focusing process. Based on the amount of change in the object distance and the object distance of the projection lens 40 before focus adjustment stored in advance in the control circuit 10, the control circuit 10 can determine the object distance of the projection lens 40 after focus adjustment. Then, the control circuit 10 may determine the image distance of the focus-adjusted projection lens 40 through the above formula (1) based on the pre-stored fixed focal length.
With respect to the variable focal length projection lens 40, the user changes the focal length when making a zoom adjustment to the projection lens 40. Referring to the above formula (1), when the focal length of the projection lens 40 is changed, the object distance and the image distance of the projection lens 40 are also changed. The control circuit 10 can obtain the change amount of the object distance in the zooming process, and determine the image distance of the front projection lens 40 after zooming adjustment based on the pre-stored object distance of the front projection lens 40 after zooming adjustment. Then, the control circuit 10 can obtain the focal length of the projection lens 40 after the zoom adjustment, and determine the image distance of the projection lens 40 after the zoom adjustment based on the above formula (1).
When the user performs focus adjustment on the variable focal length projection lens 40, the focal length of the projection lens 40 may or may not be changed. This focus-invariant focus adjustment may be referred to the description of the focus process above for a fixed focus. For the focal length variable adjustment process, the control circuit 10 can determine the focal length after the focus adjustment based on the focal length before the focus adjustment stored in advance and the amount of change in the focal length during the focus process, and further can determine the image distance after the focus adjustment based on the above formula (1).
For example, referring to fig. 5, the projection device may further include a lens driving circuit 50 and an encoding circuit 60. The control circuit 10 performs focus adjustment or zoom adjustment on the projection lens 40 through the lens driving circuit 50. The encoding circuit 60 can feed back parameters (e.g., an amount of change in the object distance and an amount of change in the focal length) during focus adjustment or zoom adjustment to the control circuit 10.
Step 202, determining the projection size of the initial projection image based on the image distance and the object distance.
In the present embodiment, the projection parameters of the projection lens 40 may also include the imaging size of the light valve 30 in the projection device. After the control circuit 10 of the projection device determines the image distance of the projection lens 40 based on the object distance and the focal length of the projection lens 40, the projection size of the initial projection image can be determined based on the image distance and the object distance of the projection lens 40 and the imaging size of the light valve 30. The projection size is the size of the projection image when the projection image is projected onto the projection screen.
Wherein the projection size S of the initial projection image 1 Image distance v and object distance u from projection lens 40, and imaging dimension S of light valve 30 2 Can satisfy the following conditions:
referring to the above formula (2), the projection size S of the initial projection image 1 Positively correlated with the object distance u and negatively correlated with the image distance v. And the projection size S 1 Imaging dimension S with light valve 30 2 And also positively correlated.
Step 203, detecting whether the projection size of the initial projection image is larger than a size threshold.
In the embodiment of the present application, after the control circuit 10 of the projection device determines the projection size of the initial projection image, it may detect whether the projection size of the initial projection image is greater than the size threshold. If the control circuit 10 detects that the projection size is less than or equal to the size threshold, it may determine that the brightness of the initial projection image needs to be adjusted, and then the following step 204 may be performed. If the control circuit 10 detects that the projection size is larger than the size threshold, it may determine that adjustment of the brightness of the initial projection image is not required, and further, the following step 207 may be performed.
It will be appreciated that the size threshold may be determined based on the brightness of the light source 20 in the projection device, as well as the brightness range of the projected image suitable for viewing by the user. For example, the projection size of the projection image projected by the projection apparatus may be gradually increased on the premise that the luminance of the light source 20 in the projection apparatus is unchanged, and the first projection size that can bring the luminance of the projection image within the luminance range is determined as the size threshold. For example, the size threshold may be 70 inches.
Step 204, determining the number of the plurality of first pixels based on the projection size of the initial projection image.
It will be appreciated that the smaller the projected size of the projected image, the higher the brightness of the projected image, provided that the brightness of the light beam projected by the light source 20 of the projection device is constant. To ensure that the brightness of the initial projection image is not too high when the initial projection image with a smaller projection size is projected, the projection device may process the initial projection image such that the processed target projection image comprises a plurality of first pixels. The pixel values of the plurality of first pixels are all target values, and the target values are smaller than a pixel value threshold. For example, the pixel value threshold may be 1 and the target value may be 0. That is, the plurality of first pixels may be black. Based on this, the brightness of the target projection image projected by the projection device can be adapted to the size of the projection device.
Accordingly, in the embodiment of the present application, before processing the initial projection image, the projection device may determine the number of the plurality of first pixels based on the projection size of the initial projection image. Wherein the number of the plurality of first pixels is inversely related to the projected size. Referring to fig. 1, the projection device may further include a light valve 30. The number of the plurality of first pixels may also be related to the effective resolution of the initial projected image, as well as the resolution of the light valve 30. The effective resolution of the initial projection image is the number of pixels that can characterize the image content of the initial projection image.
In the embodiment of the present application, after the control circuit 10 determines the projection size of the initial projection image, the effective resolution of the initial projection image may be determined based on the projection size. Wherein the effective resolution of the initial projected image is positively correlated with the projected size of the initial projected image, and the effective resolution of the initial projected image may be less than the resolution of the light valve 30. For example, the control circuit 10 may determine the effective resolution of the initial projection image corresponding to the different projection sizes by gradually reducing the effective resolution according to a preset reduction with the effective resolution of the initial projection image corresponding to the size threshold as a reference value.
For example, if the size threshold is 70 inches, the effective resolution of the initial projection image corresponding to the size threshold is 1920×1080. An effective resolution of 1920×1080 for the initial projection image means that the initial projection image includes 1920 pixel columns each including 1080 pixels. If the projection size of the initial projection image is 60 inches, the effective resolution of the initial projection image may be 1460×780. If the projection size of the initial projection image is 40 inches, the effective resolution of the initial projection image is 960×540.
After determining the effective resolution of the initial projected image, the control circuit 10 may determine the number of the plurality of first pixels based on the effective resolution of the initial projected image and the resolution of the light valve 30. The difference between the number of pixels corresponding to the resolution of the light valve 30 and the number of pixels corresponding to the effective resolution of the initial projection image is the number of the plurality of first pixels.
For example, if the projection size of the initial projection image is 40 inches, the resolution of the light valve 30 is 1920×1080. The image resolution of the initial projection image is 960×540, the control circuit 10 may determine that the number of the plurality of first pixels satisfies: 1920×1080-960×540=3×960×540.
Step 205, processing the initial projection image to obtain a target projection image.
In this embodiment of the present application, after determining the number of the plurality of first pixels, the control circuit 10 of the projection device can process the initial projection image to obtain the target projection image. The target projection image comprises a plurality of first pixels and a plurality of second pixels in the initial projection image.
It will be appreciated that the control circuit 10, after determining the effective resolution of the initial projected image, is also capable of pre-processing the initial projected image prior to generating the target projected image such that the image resolution of the pre-processed initial projected image is the same as the resolution of the light valve 30. Alternatively, the image resolution of the preprocessed initial projection image is made to be m/1 of the resolution of the light valve 30, where m is an integer greater than 1. The control circuit 10 of the projection apparatus can perform different processing on the initial projection image based on the magnitude relation between the image resolution of the initial projection image after the preprocessing and the resolution of the light valve 30. The image resolution of the initial projection image is the number of pixels included in the initial projection image.
As a first possible implementation, if the image resolution of the preprocessed initial projection image is equal to the resolution of the light valve 30, the control circuit 10 of the projection device may update the pixel values of the pixels of the initial projection image except for the plurality of second pixels to be the target value, so as to obtain the target projection image. That is, the pixel values of the other pixels except the plurality of second pixels in the initial projection image are updated to be the first pixels.
Wherein the target value may be 0. That is, the first pixels except the plurality of second pixels in the target projection image may be black pixels.
It will be appreciated that the plurality of second pixels in the initial projected image are capable of characterizing the image content of the initial projected image because the pixel values of the plurality of second pixels do not change during processing. The number of the second pixels is the effective resolution of the initial projection image. The control circuit 10 of the projection device may determine the positions of the other pixels to be updated, except for the plurality of second pixels, in the initial projection image in an interlaced and/or a column-wise manner during processing of the initial projection image.
For example, if the initial projection image is 60 inches, referring to fig. 6, the control circuit 10 may determine a row of pixels to be updated every two rows of second pixels and determine a column of pixels to be updated every two columns of second pixels in the initial projection image. As shown in fig. 6, the filling color of the plurality of second pixels is white, and the filling color of the pixels other than the plurality of second pixels is black.
If the initial projection image is 40 inches, referring to fig. 7, the projection device may determine pixels of a row of pixels to be updated in every other row of second pixels and determine pixels of a column of pixels to be updated in every other column of second pixels in the initial projection image.
As a second possible implementation, if the image resolution of the initial projection image is smaller than the resolution of the light valve 30, the control circuit 10 may insert a plurality of first pixels into the initial projection image to obtain the target projection image. The image resolution of the target projection image is equal to the resolution of the light valve 30.
In this second implementation manner, the control circuit 10 can perform the pixel fusion processing on the plurality of second pixels in the initial projection image and the plurality of first pixels determined in the step 204, so that the plurality of first pixels can be inserted into the initial projection image to obtain the target projection image. Wherein the control circuit 10 is capable of inserting a plurality of first pixels in the initial projection image in an interlaced and/or a spaced-apart manner.
For example, referring to fig. 8, if the effective resolution of the initial projection image and the processed image resolution are both 960×540, and the resolution of the light valve 30 is 1920×1080, 3×960×540 first pixels may be inserted into the initial projection image, so as to obtain a target projection image with a resolution of 1920×1080. The control circuit 10 may insert three rows of first pixels into every second row of pixels and three columns of first pixels into every second column of pixels, so as to fuse 3×960×540 first pixels into the initial projection image.
Based on the above description, since the plurality of second pixels included in the target projection image are effective pixels, the plurality of first pixels are ineffective pixels, and the number of the plurality of second pixels included in the target projection image is the effective resolution of the target projection image, the effective resolution of the target projection image is 960×540.
Step 206, projecting the target projection image and at least one reference projection image to a projection screen through a light valve, a galvanometer and a projection lens in sequence.
Fig. 9 is a schematic structural view of another projection device provided in an embodiment of the present application, and referring to fig. 9, the projection device may further include a galvanometer 70. In the embodiment of the present application, the galvanometer 70 can deflect in different directions under the driving signal provided by the control circuit 10, so that the target projection image and the at least one reference projection image output by the light valve 30 can be projected to different positions of the projection screen through the projection lens 40. After the projection images in the different positions are overlapped and displayed on the projection screen, the resolution of the overlapped and displayed images perceived by human eyes can be obviously improved due to the temporary effect of human eyes.
Wherein the image resolution of the at least one reference projection image is equal to the resolution of the light valve 30, and the at least one reference projection image comprises a plurality of third pixels. Wherein the pixel values of the plurality of third pixels are all target values. The plurality of third pixels may also be referred to as inactive pixels.
For example, referring to fig. 9, assuming that the galvanometer 70 has four different deflection positions, the image resolution of the target projection image obtained by the processing in step 205 is 1920×1080, and the resolution of the light valve 30 and the image resolution of the 3 reference projection images are 1920×1080. That is, the 3 reference projection images each include 1920×1080 third pixels. The galvanometer 70 may project the target projection image and the three reference projection images output by the light valve 30 through the projection lens 40 to four different positions of the projection screen through the projection lens 40. Correspondingly, after the projection images at the four different positions are displayed in a superimposed manner, the image resolution of the obtained projection images is 3840×2160.
Step 207, if the image resolution of the initial projection image is greater than the resolution of the light valve 30 in the projection device, dividing the initial projection image into a plurality of sub-images.
In step 203, if the control circuit 10 detects that the projection size of the initial projection image is greater than the size threshold, it may determine that adjustment of the brightness of the initial projection image is not required. Also, the control circuit 10 may detect whether the image resolution of the initial projected image is greater than the resolution of the light valve 30 for further processing of the initial projected image. The control circuit 10 may divide the initial projected image into a plurality of sub-images if it detects that the image resolution of the initial projected image is greater than the resolution of the light valve 30 in the projection device. Wherein the image resolution of each sub-image is equal to the resolution of the light valve 30. If the control circuit 10 detects that the image resolution of the initial projected image is equal to the resolution of the light valve 30, it can determine that the initial projected image is not required to be processed, and the initial projected image is directly transmitted to the light valve 30.
It will be appreciated that when the projection size of the initial projection image is greater than the size threshold, to ensure that the image resolution of the projection image projected onto the projection screen is compatible with the projection size (i.e., to avoid a lower resolution of the projection image of a larger projection size), the control circuit 10 may process the initial projection image resolution such that the image resolution of the initial projection image is equal to the resolution of the light valve 30 or such that the image resolution of the initial projection image is k times the resolution of the light valve 30, where k is an integer greater than 1, before transmitting the initial projection image to the light valve 30 for processing.
Here, since there are no pixels set as target values and no newly inserted pixels in the initial projection image transmitted to the light valve 30, each pixel in the initial projection image is an effective pixel of the initial projection image. The process of dividing the initial projected image into a plurality of sub-images may also be referred to as the decomposition of the active pixels.
For example, referring to fig. 10, the projection size of the initial projection image may be 80 inches, the image resolution of the initial projection image is 3840×2160, and the resolution of the light valve 30 is 1920×1080, and the projection device may divide the initial projection image into 4 sub-images, and the image resolutions of the 4 sub-images are 1920×1080.
Alternatively, referring to fig. 11, the projection size of the initial projection image is 80 inches, and the image resolution of the initial projection image and the resolution of the light valve 30 are 1920×1080, so that the control circuit 10 may directly transmit the initial projection image to the light valve 30 for processing.
Step 208, the plurality of sub-images sequentially pass through the light valve, the galvanometer and the projection lens in the projection device and are projected onto the projection screen.
As will be appreciated by reference to the above, the projection device may also include a galvanometer 70. Accordingly, when the projection device further includes a galvanometer 70, in step 207 described above, the control circuit 10 may process the resolution of the initial projected image to a resolution that is a multiple of the resolution of the light valve 30. Thus, the control circuit 10 may divide the initial projection image into a plurality of sub-images. The galvanometer 70 can sequentially project the plurality of sub-images through the projection lens 40 to different positions of the projection screen as the plurality of sub-images sequentially pass through the light valve 30. The projection images at the different positions are superimposed and displayed on the projection screen, and then the projection image with the same resolution as the original projection image can be obtained.
By way of example, reference is continued to FIG. 10. If the resolution of the 4 sub-images obtained by dividing the initial projection image by the control circuit 10 is 1920×1080, when the 4 sub-images are projected onto the projection screen through the light valve 30, the galvanometer 70 and the projection lens 40 in sequence, a projection image with an image resolution of 3840×2160 can be obtained.
Alternatively, when the projection device does not include a galvanometer 70 (or the projection device includes a galvanometer 70 and the galvanometer 70 is not activated), the control circuit 10 may process the resolution of the initial projected image to the same resolution as the resolution of the light valve 30. For example, referring to fig. 11, the processed initial projection image may be projected directly onto a projection screen through the light valve 30 and the projection lens 40.
It can be understood that the sequence of the steps of the method for displaying a projection image provided in the embodiment of the present application may be appropriately adjusted, and the steps may also be increased or decreased accordingly according to the situation. For example, step 204 may be deleted as appropriate. That is, the projection device may process the initial projection image based on the preset number of first pixels to obtain the target projection image. Alternatively, steps 207 and 208 may be deleted as appropriate. That is, the projection device may set the image resolution of the initial projection image having a projection size greater than the size threshold to the same resolution as that of the light valve, whereby the initial projection image may be projected directly to the projection screen through the light valve and the projection lens. Any method that can be easily conceived by those skilled in the art within the technical scope of the present disclosure should be covered in the protection scope of the present application, and thus will not be repeated.
In summary, the embodiment of the application provides a method for displaying a projection image. The projection device can process the initial projection image to obtain a target projection image when detecting that the projection size of the initial projection image is smaller than or equal to a size threshold. Since the pixel values of the first pixels in the target projection image are all target values, and the target values are smaller than the pixel value threshold, the brightness of the target projection image can be ensured to be smaller than the brightness of the initial projection image. This ensures that the brightness of the projected image is not excessively high when the projected image having a small projection size is projected. That is, it is possible to ensure that the brightness of the projected image does not vary greatly with the variation of the projection distance, and further ensure that the display effect of the projected image is good.
Embodiments of the present application provide a projection device, as shown in fig. 1, which may include: a control circuit 10 and a projection lens 40, the control circuit 10 being configured to:
the projection size of the initial projected image is determined based on the projection parameters of the projection lens 40.
And if the projection size of the initial projection image is smaller than or equal to the size threshold value, processing the initial projection image to obtain a target projection image.
The target projection image is projected to the projection screen through the projection lens 40.
The target projection image comprises a plurality of first pixels and a plurality of second pixels in the initial projection image, wherein the pixel values of the first pixels are target values, and the target values are smaller than a pixel value threshold.
Optionally, referring to fig. 1, the projection device may further comprise a light valve 30, and the control circuit 10 is configured to, when the image resolution of the initial projected image is equal to the resolution of the light valve 30:
and updating the pixel values of other pixels except the second pixels in the initial projection image to be target values to obtain a target projection image.
Optionally, when the image resolution of the initial projected image is less than the resolution of the light valve, the control circuit 10 is configured to:
a plurality of first pixels are inserted in the initial projection image to obtain a target projection image having a resolution equal to that of the light valve 30.
Optionally, referring to fig. 9 and 10, the projection device may further include a galvanometer 70, and the control circuit 10 is configured to:
the target projection image, as well as at least one reference projection image, are projected onto the projection screen sequentially through the light valve 30, galvanometer 70 and projection lens 40.
The target projection image and the at least one reference projection image are projected to different positions of the projection screen, the resolution of the at least one reference projection image is equal to the resolution of the light valve 30, and each reference projection image includes a plurality of third pixels, and the pixel values of the plurality of third pixels are all target values.
Optionally, the control circuit 10 is further configured to:
if the projection size of the initial projection image is greater than the size threshold and the image resolution of the initial projection image is greater than the resolution of the light valve in the projection device, dividing the initial projection image into a plurality of sub-images, the image resolution of each sub-image being equal to the resolution of the light valve.
The plurality of sub-images are projected onto the projection screen sequentially through the light valve 30, the galvanometer 70 and the projection lens 40 in the projection device.
Optionally, the projection parameters include: focal length and object distance, the control circuit 10 is also configured to:
determining an image distance of the projection lens 40 based on the focal length and the object distance;
based on the image distance and the object distance, a projection size of the initial projected image is determined, the projection size being positively correlated with the object distance and negatively correlated with the image distance.
Optionally, the projection dimension S 1 The method meets the following conditions:
wherein u is the object distance of the projection lens, v is the image distance of the projection lens, S 2 Is the imaging size of the light valve in the projection device.
Optionally, the control circuit 10 is further configured to:
based on the projected size of the initial projected image, a number of first pixels is determined, the number of first pixels being inversely related to the projected size.
In summary, the embodiments of the present application provide a projection apparatus. The control circuit in the projection device can process the initial projection image to obtain the target projection image when detecting that the projection size of the initial projection image is smaller than or equal to the size threshold. Since the pixel values of the first pixels in the target projection image are all target values, and the target values are smaller than the pixel value threshold, the brightness of the target projection image can be ensured to be smaller than the brightness of the initial projection image. This ensures that the brightness of the projected image is not excessively high when the projected image having a small projection size is projected. That is, it is possible to ensure that the brightness of the projected image does not vary greatly with the variation of the projection distance, and further ensure that the display effect of the projected image is good.
It can be understood that the projection device provided in the above embodiment belongs to the same concept as the embodiment of the method for displaying the projection image of the projection device, and the detailed implementation process of the projection device is detailed in the method embodiment and will not be described herein.
The embodiment of the application provides a projection device, and a control circuit in the projection device comprises: the computer program comprises a memory, a processor and a computer program stored on the memory, wherein the processor executes the computer program to realize the method for displaying the projection image (such as the method shown in fig. 3 or fig. 4) provided by the method embodiment.
Embodiments of the present application provide a computer readable storage medium having instructions stored therein that are loaded and executed by a processor to implement a method for displaying a projected image (e.g., the method shown in fig. 3 or fig. 4) as provided by the method embodiments described above.
The present embodiments provide a computer program product containing instructions which, when run on a computer, cause the computer to perform a method of displaying a projected image (e.g., the method shown in fig. 3 or fig. 4) as provided by the method embodiments described above.
It will be understood by those skilled in the art that all or part of the steps for implementing the above embodiments may be implemented by hardware, or may be implemented by a program for instructing relevant hardware, where the program may be stored in a computer readable storage medium, and the above storage medium may be a read-only memory, a magnetic disk or an optical disk, etc.
It is understood that the term "at least one" in this application means one or more, and the meaning of "a plurality" means two or more.
The term "and/or" in this application is merely an association relation describing an associated object, and indicates that three relations may exist, for example, a and/or B may indicate: a exists alone, A and B exist together, and B exists alone.
The terms "first," "second," and the like in this application are used to distinguish between identical or similar items that have substantially the same function and function, and it should be understood that there is no logical or chronological dependency between the "first," "second," and "nth" terms, nor is it limited to the number or order of execution.
The foregoing description of the exemplary embodiments of the present application is not intended to limit the invention to the particular embodiments disclosed, but on the contrary, the intention is to cover all modifications, equivalents, alternatives, and alternatives falling within the spirit and scope of the invention.