Projection picture color correction method, device, projection equipment and storage medium

Abstract

The present application relates to a method, apparatus, projection device, and storage medium for projected screen color correction. The method comprises: acquiring a projected screen image; the projected screen image is an image obtained by performing image acquisition on a reference projected screen; the reference projected screen is a projected screen presented when a projection device projects a white image onto a projection surface; determining a projection area image corresponding to a reference projected screen area from the projected screen image; determining a primary color in the projected area image; determining a target gain coefficient corresponding to each color channel based on the color value of the primary color in each color channel; adjusting the current gain coefficient of the projection device in each color channel to the corresponding target gain coefficient to correct the color of the projected screen presented when the projection device projects onto the projection surface. This method can improve the color quality of the projected screen.

Description

Technical Field

[0001] The present application relates to the technical field of projection equipment, and in particular to a method and device for correcting the color of a projection image, a projection equipment, and a storage medium. Background Art

[0002] With the development of science and technology, a variety of projection devices have emerged, bringing significant convenience to people's work and lives. However, in actual use, the color of the projection surface onto which the projection device is projected may not necessarily be white, but may be other colors besides white. This can cause the color of the projected image on the projection surface to differ from the original image, reducing the color quality of the projected image. For example, when a projection device is projected onto a light red wall, the projected image on the light red wall will appear to have a color that leans towards light red. Summary of the Invention

[0003] Based on this, it is necessary to provide a projection picture color correction method, device, projection equipment, computer-readable storage medium and computer program product to improve the color quality of the projection picture in order to solve the above technical problems.

[0004] In a first aspect, the present application provides a method for color correction of a projected image. The method comprises:

[0005] Acquire a projection screen image; the projection screen image is an image obtained by capturing an image of a reference projection screen; the reference projection screen is a projection screen presented when a projection device projects a white image onto a projection surface;

[0006] Determining a projection area image corresponding to a reference projection screen area from the projection screen image;

[0007] Determining a dominant color in the projection area image;

[0008] Determining target gain coefficients corresponding to respective color channels according to the color values ​​of the primary color in the respective color channels;

[0009] The current gain coefficient of each color channel of the projection device is adjusted to the corresponding target gain coefficient to correct the color of the projection picture projected by the projection device onto the projection surface.

[0010] In a second aspect, the present application further provides a projection image color correction device. The device comprises:

[0011] An image acquisition module is used to acquire a projection screen image; the projection screen image is an image obtained by performing image acquisition on a reference projection screen; the reference projection screen is a projection screen presented when a projection device projects a white image onto a projection surface;

[0012] A projection area determination module, configured to determine a projection area image corresponding to a reference projection screen area from the projection screen image;

[0013] A main color determination module, configured to determine the main color in the projection area image;

[0014] A gain coefficient determination module, configured to determine a target gain coefficient corresponding to each color channel according to the color value of the main color in each color channel;

[0015] The gain adjustment module is used to adjust the current gain coefficient of the projection device in each color channel to the corresponding target gain coefficient, so as to correct the color of the projection picture projected by the projection device onto the projection surface.

[0016] In one embodiment, the projection area determination module is further used to binarize the projection screen image according to a target threshold to obtain a binary image; perform contour extraction on the binary image to obtain contours in the binary image; perform polygon fitting on each contour in the binary image; determine, from the fitted polygons, a target polygon that conforms to a preset shape and has the largest area as a reference projection screen area; extract the image content corresponding to the reference projection screen area from the projection screen image to obtain a projection area image.

[0017] In one embodiment, the projection area determination module is further used to determine the coordinates of each vertex of the reference projection screen area; according to the coordinates of each vertex, the image content corresponding to the reference projection screen area is extracted from the projection screen image to obtain the projection area image.

[0018] In one embodiment, the projection area determination module is further used to determine the pixel average value of the vertex area in the projection screen image and the pixel average value of the central area of ​​the projection screen image; and determine the target threshold based on the average value between the pixel average value of the vertex area and the pixel average value of the central area.

[0019] In one embodiment, the main color determination module is further used to cluster the individual pixel points in the projection area image according to their color values ​​to obtain multiple clusters; determine a target cluster with the most pixels from the multiple clusters; and determine the color value of the cluster center of the target cluster as the main color in the projection area image.

[0020] In one embodiment, the main color determination module is also used to randomly select multiple initial cluster centers from each pixel point in the projection area image as the current cluster center; divide each pixel point in the projection area image into different current initial cluster clusters according to the distance between the color value of each pixel point in the projection area image and the color value of each current cluster center; calculate the new cluster center of each current initial cluster cluster according to each pixel point in each current initial cluster cluster as the new current cluster center; return to execute the division of each pixel point in the projection area image into different current initial cluster clusters according to the distance between the color value of each pixel point in the projection area image and the color value of each current cluster center and subsequent steps until the stopping condition is met to obtain the final multiple cluster clusters.

[0021] In one embodiment, the gain coefficient determination module is further used to set the target gain coefficient corresponding to the color channel where the minimum color value is located as a regular gain coefficient; the minimum color value is the minimum value of the color values ​​of the main color in each color channel; based on the regular gain coefficient and the first difference corresponding to each color channel to be adjusted, the target gain coefficient corresponding to each color channel to be adjusted is determined; wherein, the color channel to be adjusted is a color channel other than the color channel where the minimum color value is located; the first difference corresponding to each color channel to be adjusted is the difference between the color value of the color channel to be adjusted and the minimum color value; the target gain coefficient corresponding to the color channel to be adjusted is less than the regular gain coefficient.

[0022] In one embodiment, the gain coefficient determination module is further used to determine the second difference corresponding to each color channel to be adjusted based on the first difference corresponding to each color channel to be adjusted and the preset adjustment coefficient; and determine the target gain coefficient corresponding to each color channel to be adjusted based on the conventional gain coefficient and the second difference corresponding to each color channel to be adjusted.

[0023] In a third aspect, the present application further provides a projection device. The projection device includes a memory and a processor, wherein the memory stores a computer program, and when the computer program is executed by the processor, the processor performs the steps of the projection image color correction method described in each embodiment of the present application.

[0024] In a fourth aspect, the present application further provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, causes the processor to perform the steps of the projection image color correction method described in various embodiments of the present application.

[0025] In a fifth aspect, the present application further provides a computer program product, which includes a computer program that, when executed by a processor, causes the processor to execute the steps of the projection image color correction method described in each embodiment of the present application.

[0026] The above-mentioned projection screen color correction method, device, projection device, storage medium and computer program product obtain a projection screen image obtained by capturing an image of a reference projection screen presented by the projection device projecting a white image onto the projection surface, determine the projection area image corresponding to the reference projection screen area from the projection screen image, and then determine the main color in the projection area image. According to the color value of the main color in each color channel, the target gain coefficient corresponding to each color channel is determined, and finally the current gain coefficient of the projection device in each color channel is adjusted to the corresponding target gain coefficient, thereby correcting the color of the projection screen presented by the projection device projected onto the projection surface, reducing the influence of the color of the projection surface on the color of the projection screen, and improving the color quality of the projection screen. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 A diagram illustrating an application environment of a method for color correction of a projection image in one embodiment;

[0028] Figure 2 1 is a flow chart of a method for color correction of a projection image according to an embodiment;

[0029] Figure 3 A comparison diagram of the before and after effects of color correction of a projection image in one embodiment;

[0030] Figure 4 is a schematic diagram of clustering pixels in one embodiment;

[0031] Figure 5 1 is a schematic diagram of the overall process of a method for color correction of a projection image in one embodiment;

[0032] Figure 6 is a structural block diagram of a projection image color correction device in one embodiment;

[0033] Figure 7 FIG. 4 is a diagram showing the internal structure of a projection device in one embodiment. DETAILED DESCRIPTION

[0034] In order to make the purpose, technical solutions and advantages of this application more clear, the following further describes this application in detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain this application and are not intended to limit this application.

[0035] The projection image color correction method provided in the embodiment of the present application can be applied to Figure 1 In the application environment shown, the projection device 102 can project onto a projection surface 104, and a projection image 106 can be presented on the projection surface 104. The projection device 102 can project a white image onto the projection surface 104, and a reference projection image can be presented on the projection surface. The projection device 102 can obtain a projection image obtained by performing image acquisition on the reference projection image, determine a projection area image corresponding to the reference projection area from the projection image, then determine a primary color in the projection area image, determine a target gain coefficient corresponding to each color channel based on the color value of the primary color in each color channel, and finally adjust the current gain coefficient of the projection device 102 in each color channel to the corresponding target gain coefficient to correct the color of the projection image presented by the projection device 102 on the projection surface. The projection device 102 can be any device with a projection function, such as a projector, a laser projection TV, etc. The projection surface 104 can be the surface onto which the projection device projects, such as a wall or a projection screen.

[0036] In one embodiment, Figure 2 As shown, a method for color correction of a projection image is provided, which is applied to Figure 1 Taking the projection device 102 in FIG. 1 as an example, the method includes the following steps:

[0037] Step 202 , obtaining a projection screen image; the projection screen image is an image obtained by capturing an image of a reference projection screen; the reference projection screen is a projection screen presented when the projection device projects a white image onto a projection surface.

[0038] The term "projection surface" refers to the surface onto which the projection device projects. For example, the projection surface can be a wall or a projection screen. The term "projected image" refers to the image presented when the projection device projects an image or picture onto the projection surface. It should be understood that the projected image is not the image or picture content projected by the projection device itself, but rather the image presented by the superposition of the image content projected onto the projection surface and the projection surface itself. This refers to the image that is seen by the human eye or captured by an image capture device.

[0039] In one embodiment, the white image is a pure white image, that is, the pixel value of each pixel in the white image is the maximum pixel value. For example, if the pixel value in the image ranges from 0 to 255, the pixel value of each pixel in the white image is 255.

[0040] In one embodiment, the projection device can project a white image onto the projection surface, and a reference projection picture will appear on the projection surface.

[0041] In one embodiment, the projection device can use a built-in image acquisition unit to capture an image of a reference projection screen presented on the projection surface to obtain a projection screen image. The image acquisition unit can be a unit with image acquisition functionality built into the projection device. For example, the image acquisition unit can be a camera.

[0042] In another embodiment, the terminal used by the user can capture an image of the reference projection screen presented on the projection surface to obtain a projection screen image, and then transmit the projection screen image to the projection device. The terminal used by the user can communicate with the projection device via a network or Bluetooth. The terminal used by the user can be any personal computer, laptop, smartphone, tablet computer, IoT device, or portable wearable device with image capture capabilities. IoT devices can include smart speakers, smart TVs, smart air conditioners, smart car devices, etc. Portable wearable devices can include smart watches, smart bracelets, head-mounted devices, etc.

[0043] Step 204 : determining a projection area image corresponding to the reference projection screen area from the projection screen image.

[0044] The reference projection screen area refers to the area corresponding to the reference projection screen in the projection screen image, and the projection area image refers to the image corresponding to the reference projection screen area in the projection screen image.

[0045] In one embodiment, the projection device may determine the reference projection screen area according to the projection screen image.

[0046] In one embodiment, the projection device may extract image content corresponding to the reference projection screen area from the projection screen image to obtain a projection area image.

[0047] In another embodiment, the projection device can determine the image content corresponding to the reference projection screen area in the projection screen image as the projection area image, that is, the image content corresponding to the reference projection screen area is not extracted from the projection screen image, but step 206 and subsequent steps are directly executed for the image content corresponding to the reference projection screen area in the projection screen image.

[0048] Step 206: Determine the main color in the projection area image.

[0049] Among them, the main color is the color with the largest area in the projection area image.

[0050] Step 208 : Determine the target gain coefficient corresponding to each color channel according to the color value of the main color in each color channel.

[0051] In one embodiment, the color channels may include a red channel (R channel), a green channel (G channel), and a blue channel (B channel).

[0052] In one embodiment, the projection device may decompose the three-channel pixel values ​​of the main color to obtain the color values ​​(ie, pixel values) of the main color in each color channel.

[0053] In one embodiment, the projection device may set the target gain coefficient corresponding to the color channel containing the minimum color value as a normal gain coefficient, and set the target gain coefficient corresponding to each color value to be adjusted to a coefficient smaller than the normal gain coefficient. The minimum color value is the minimum value of the primary color in each color channel. The color channel to be adjusted is the color channel other than the color channel containing the minimum color value. The normal gain coefficient is the gain coefficient commonly used when the projection device is factory-set.

[0054] For example, if the RGB value of the main color is [138, 36, 23], that is, the color value of the main color in the red channel is 138, the color value in the green channel is 36, and the color value in the blue channel is 23. The color channel with the minimum color value 23 is the blue channel. Therefore, the target gain coefficient corresponding to the blue channel can be set to the normal gain coefficient, and the target gain coefficients corresponding to the red and green channels can be set to coefficients smaller than the normal gain coefficient.

[0055] In step 210 , the current gain coefficient of each color channel of the projection device is adjusted to the corresponding target gain coefficient to correct the color of the projection image projected by the projection device onto the projection surface.

[0056] In one embodiment, the projection device can adjust the current gain coefficient of the projection device in each color channel to the corresponding target gain coefficient, and perform projection according to the target gain coefficient of each color channel to correct the color of the projection image projected by the projection device onto the projection surface.

[0057] like Figure 3 As shown, (a) is a schematic diagram of the effect of the projection screen before color correction, and (b) is a schematic diagram of the effect of the projection screen after color correction. It can be seen that before color correction, the color of the projection screen is greatly affected by the color of the projection surface, resulting in the color of the projection screen being almost close to the color on the projection surface outside the projection screen. After color correction, the color of the projection screen is less affected by the color of the projection surface, and presents the color of the projection content itself.

[0058] The above-mentioned projection screen color correction method obtains a projection screen image obtained by capturing an image of a reference projection screen presented by a projection device projecting a white image onto a projection surface, determines a projection area image corresponding to the reference projection screen area from the projection screen image, and then determines the main color in the projection area image. According to the color value of the main color in each color channel, the target gain coefficient corresponding to each color channel is determined. Finally, the current gain coefficient of the projection device in each color channel is adjusted to the corresponding target gain coefficient, thereby correcting the color of the projection screen presented by the projection device projected onto the projection surface, reducing the influence of the color of the projection surface on the color of the projection screen, and improving the color quality of the projection screen.

[0059] In one embodiment, determining the projection area image corresponding to the reference projection screen area from the projection screen image includes: binarizing the projection screen image according to a target threshold to obtain a binarized image; extracting contours from the binarized image to obtain contours in the binarized image; performing polygon fitting on each contour in the binarized image; determining, from the polygons obtained by fitting, a target polygon that conforms to a preset shape and has the largest area as the reference projection screen area; and extracting image content corresponding to the reference projection screen area from the projection screen image to obtain the projection area image.

[0060] In one embodiment, the projection device may first convert the projection screen image into a grayscale image, and then perform binarization processing on the projection screen image converted into the grayscale image according to a target threshold value to obtain a binarized image.

[0061] In one embodiment, the projection device may call the adaptiveThreshold function in opencv (a computer vision software library) to perform binarization processing according to a target threshold to obtain a binarized image.

[0062] In one embodiment, the projection device can set the pixel values ​​of pixels in the projected screen image whose pixel values ​​are greater than or equal to the target threshold to the maximum pixel value, and set the pixel values ​​of pixels whose pixel values ​​are less than the target threshold to the minimum pixel value, thereby obtaining a binary image. It can be understood that the color corresponding to the maximum pixel value is white, and the color corresponding to the minimum pixel value is black, which is equivalent to changing the pixel values ​​of pixels in the projected screen image whose pixel values ​​are greater than or equal to the target threshold to white, and changing the pixel values ​​of pixels whose pixel values ​​are less than the target threshold to black. For example, for a projected screen image with 256 grayscale levels, the pixel value range is 0 to 255. In this case, the pixel values ​​of pixels in the projected screen image whose pixel values ​​are greater than or equal to the target threshold can be set to 255, and the pixel values ​​of pixels whose pixel values ​​are less than the target threshold can be set to 0.

[0063] In one embodiment, the target threshold value may be pre-set. In another embodiment, the target threshold value may be determined based on the projection screen image.

[0064] In one embodiment, before performing contour extraction on the binary image to obtain contours in the binary image, the projection device may perform noise reduction processing on the binary image to obtain a de-noised binary image, and then perform contour extraction on the de-noised binary image to obtain contours in the binary image. In one embodiment, the noise reduction processing may be Gaussian filtering, etc. In one embodiment, the projection device may call the GaussianBlur function in OpenCV (a computer vision software library) to perform Gaussian filtering on the binary image.

[0065] In one embodiment, performing contour extraction on a binary image to obtain contours in the binary image includes: performing edge detection on the binary image to obtain edge detection results, and then performing contour search on the edge detection results to obtain contours in the binary image. In one embodiment, the projection device can call the Canny function in opencv (a computer vision software library) to perform edge detection on the binary image to obtain edge detection results. In one embodiment, the projection device can call the findContours function in opencv (a computer vision software library) to perform contour search on the edge detection results to obtain contours in the binary image. Contour search is the process of finding contours in an image.

[0066] In one embodiment, the projection device can traverse each contour and perform polygon fitting on each contour to obtain multiple polygons. In one embodiment, the projection device can call the approxPolyDP function in opencv (computer vision software library) to perform polygon fitting.

[0067] In one embodiment, the preset shape is the shape of a reference projection screen. In one embodiment, when the reference projection screen is a rectangle, the preset shape is a rectangle, and the projection device can determine, from among the polygons obtained by fitting, a target polygon with a rectangular shape and the largest area as the reference projection screen area. In one embodiment, when the preset shape is a rectangle, the projection device can determine, from among the polygons obtained by fitting, a target polygon with four sides and the largest area as the reference projection screen area.

[0068] In the above embodiment, since the reference projection screen area is obtained by projecting a white image, the pixel values ​​in this area in the projection screen image must be larger than the pixel values ​​in other areas. Therefore, the projection screen image is binarized, and then the contours in the binarized image are extracted. Then, polygon fitting is performed on each contour. From the polygons obtained by fitting, the target polygon that meets the preset shape and has the largest area is determined as the reference projection screen area. The area corresponding to the reference projection screen can be accurately determined, and then the image content corresponding to the reference projection screen area can be accurately extracted from the projection screen image to obtain the projection area image, thereby improving the accuracy of the projection area image.

[0069] In one embodiment, extracting image content corresponding to the reference projection screen area from the projection screen image to obtain the projection area image includes: determining the coordinates of each vertex of the reference projection screen area; and extracting image content corresponding to the reference projection screen area from the projection screen image according to the coordinates of each vertex to obtain the projection area image.

[0070] In one embodiment, when the shape of the reference projection screen area is a rectangle, the projection device can determine the coordinates of the four vertices of the reference projection screen area, and then extract the image content corresponding to the reference projection screen area from the projection screen image based on the coordinates of the four vertices to obtain the projection area image.

[0071] In the above embodiment, the coordinates of each vertex of the reference projection screen area are determined, and the image content corresponding to the reference projection screen area is extracted from the projection screen image according to the coordinates of each vertex to obtain the projection area image, which can accurately obtain the projection area image.

[0072] In one embodiment, before binarizing the projection screen image according to the target threshold to obtain the binarized image, the method also includes: determining the pixel average value of the vertex area in the projection screen image and the pixel average value of the central area of ​​the projection screen image; determining the target threshold based on the average value between the pixel average value of the vertex area and the pixel average value of the central area.

[0073] The vertex region is the region at the vertex of the projected image. The center region is the region at the center of the projected image. The pixel average is the average value of the pixel values ​​of each pixel in the region.

[0074] In one embodiment, the sizes of the vertex region and the center region can be preset. The sizes of the vertex region and the center region can be the same or different.

[0075] In one embodiment, the projection device may determine the average pixel value of each vertex region in the projection screen image, and determine the target threshold value according to the average value between the average pixel value of each vertex region and the average pixel value of the central region.

[0076] In the above embodiment, the target threshold is determined based on the average value between the pixel average values ​​of the vertex area and the pixel average values ​​of the center area. This allows the target threshold to be accurately determined, thereby enabling the projection screen image to be binarized based on the accurate target threshold.

[0077] In one embodiment, determining the main color in the projection area image includes: clustering each pixel point according to the color value of each pixel point in the projection area image to obtain multiple clusters; determining a target cluster with the most pixels from the multiple clusters; and determining the color value of the cluster center of the target cluster cluster as the main color in the projection area image.

[0078] Each cluster contains at least one pixel. Each cluster has a cluster center. The cluster center is a pixel in the cluster. The target cluster is the cluster with the most pixels among the multiple clusters obtained by clustering.

[0079] In one embodiment, the projection device may cluster each pixel point using any clustering algorithm such as a Kmeans clustering algorithm, a hierarchical clustering algorithm, or a DBSCAN clustering algorithm.

[0080] In one embodiment, the color value of a pixel includes color values ​​of the pixel in multiple channels. The projection device may cluster the pixels according to the distances between the color values ​​of the pixels in the projection area image in each channel.

[0081] In one embodiment, the projection device may determine the number of pixels in each cluster, and determine a target cluster with the most pixels from the multiple clusters according to the number of pixels in each cluster.

[0082] In the above embodiment, since there may be multiple colors on the projection surface, there may be multiple colors in the projection area image. Therefore, according to the color value of each pixel point in the projection area image, each pixel point is clustered to obtain multiple clusters, and the target cluster with the most pixels is determined from the multiple clusters. The color value of the cluster center of the target cluster is determined as the main color in the projection area image, which can accurately determine the main color with the largest area in the projection area image.

[0083] In one embodiment, clustering is performed on each pixel point in the projection area image according to its color value to obtain multiple clusters, including: randomly selecting multiple initial cluster centers from each pixel point in the projection area image as current cluster centers; dividing each pixel point in the projection area image into different current initial cluster clusters according to the distance between the color value of each pixel point in the projection area image and the color value of each current cluster center; calculating a new cluster center of each current initial cluster cluster according to each pixel point in each current initial cluster cluster as a new current cluster center; returning to execute the step of dividing each pixel point in the projection area image into different current initial cluster clusters according to the distance between the color value of each pixel point in the projection area image and the color value of each current cluster center and subsequent steps until a stopping condition is met to obtain multiple final clusters.

[0084] In one embodiment, the number of initial cluster centers may be pre-set, for example, the number of initial cluster centers may be greater than or equal to 3 and less than or equal to 5.

[0085] In one embodiment, for each pixel in the projection area image, the projection device may calculate the distance between the color value of the pixel and the color value of each current cluster center, and divide the pixel into the initial cluster corresponding to the cluster center with the smallest distance.

[0086] In one embodiment, the stopping condition may be that the positions of the current cluster centers remain unchanged. In another embodiment, the stopping condition may be that the number of iterations is greater than or equal to a preset number threshold.

[0087] In one embodiment, the projection device may use the multiple current initial clusters when the stop condition is satisfied as the final multiple clusters.

[0088] like Figure 4 As shown in , it is a schematic diagram of clustering each pixel point. First, as Figure 4 As shown in A in , multiple initial cluster centers are randomly selected. In the figure, three cluster centers, C1, C2 and C3, are selected. Then, as Figure 4 As shown in B in , each pixel point is divided into different initial clusters. Then, as Figure 4 As shown in C in , calculate the new cluster center of each initial cluster, such as Figure 4 As shown in D in the figure, the initial clusters corresponding to each new cluster center are obtained, and then the execution is returned. Figure 4 Follow the steps in C.

[0089] In the above embodiment, each pixel point in the projection area image is iteratively clustered until the current cluster center remains unchanged, thereby obtaining multiple clusters. Multiple clusters can be accurately determined, thereby accurately determining the main color in the projection area image.

[0090] In one embodiment, determining the target gain coefficients corresponding to the respective color channels according to the color values ​​of the main color in the respective color channels includes: setting the target gain coefficient corresponding to the color channel where the minimum color value is located to a regular gain coefficient; the minimum color value is the minimum value among the color values ​​of the main color in the respective color channels; determining the target gain coefficients corresponding to the respective color channels to be adjusted according to the regular gain coefficients and the first differences corresponding to the respective color channels to be adjusted; wherein the color channels to be adjusted are color channels other than the color channel where the minimum color value is located; the first difference corresponding to each color channel to be adjusted is the difference between the color value of the color channel to be adjusted and the minimum color value; and the target gain coefficient corresponding to the color channel to be adjusted is smaller than the regular gain coefficient.

[0091] For example, if the normal gain coefficient is 1024 and the RGB value of the primary color is [138, 36, 23], that is, the primary color has a color value of 138 in the red channel, 36 in the green channel, and 23 in the blue channel, then the color channel with the minimum color value of 23 is the blue channel, and the color channels to be adjusted are the red and green channels. The projection device can set the target gain coefficient for the blue channel to 1024. The first difference value for the red channel is 138-23=115, and the first difference value for the green channel is 36-23=13. The projection device can determine the target gain coefficient for the red channel based on the first difference value of 115 for the red channel and the normal gain coefficient of 1024, and determine the target gain coefficient for the green channel based on the first difference value of 13 for the green channel and the normal gain coefficient of 1024, with the target gain coefficients for the red and green channels respectively being less than 1024.

[0092] In one embodiment, the projection device may determine a second difference value corresponding to the color channel to be adjusted based on the first difference value corresponding to the color channel to be adjusted, and then determine a target gain coefficient corresponding to the color channel to be adjusted based on the difference between the conventional gain coefficient and the second difference value corresponding to the color channel to be adjusted. In one embodiment, the projection device may determine the difference between the conventional gain coefficient and the second difference value corresponding to the color channel to be adjusted as the target gain coefficient corresponding to the color channel to be adjusted.

[0093] In one embodiment, the second difference may be positively correlated with the first difference, that is, the larger the first difference is, the larger the second difference is; and the smaller the first difference is, the smaller the second difference is.

[0094] In one embodiment, the second difference may be linearly positively correlated with the first difference. In another embodiment, the second difference may be nonlinearly positively correlated with the first difference.

[0095] In the above embodiment, the target gain coefficient corresponding to the color channel where the minimum color value is located is set as the conventional gain coefficient, and the target gain coefficient corresponding to each color channel to be adjusted is determined based on the first difference between the conventional gain coefficient and each color channel to be adjusted, and the target gain coefficient corresponding to the color channel to be adjusted is smaller than the conventional gain coefficient, so that the main color in the projection area image can be reduced, thereby avoiding the influence of the color of the projection surface on the color of the projection picture, and improving the color quality of the projection picture.

[0096] In one embodiment, determining the target gain coefficient corresponding to each color channel to be adjusted based on the conventional gain coefficient and the first difference corresponding to each color channel to be adjusted includes: determining the second difference corresponding to each color channel to be adjusted based on the first difference corresponding to each color channel to be adjusted and the preset adjustment coefficient; and determining the target gain coefficient corresponding to each color channel to be adjusted based on the conventional gain coefficient and the second difference corresponding to each color channel to be adjusted.

[0097] In one embodiment, the projection device may multiply the first difference value corresponding to each color channel to be adjusted by a preset adjustment coefficient to obtain the second difference value corresponding to each color channel to be adjusted.

[0098] In one embodiment, the projection device may determine the target gain coefficient corresponding to each color channel to be adjusted based on the difference between the conventional gain coefficient and the second difference value corresponding to each color channel to be adjusted. In one embodiment, the projection device determines the target gain coefficient corresponding to each color channel to be adjusted as the difference between the conventional gain coefficient and the second difference value corresponding to each color channel to be adjusted.

[0099] For example, if the preset adjustment coefficient is 3, the normal gain coefficient is 1024, and the primary color's RGB values ​​are [138, 36, 23], then the primary color has a red channel value of 138, a green channel value of 36, and a blue channel value of 23. The color channel with the minimum color value of 23 is the blue channel, and the channels to be adjusted are the red and green channels. The first difference for the red channel is 138 - 23 = 115, and the first difference for the green channel is 36 - 23 = 13. The second difference for the red channel is 115 * 3, and the second difference for the green channel is 13 * 3. Therefore, the target gain coefficients for the red channel are 1024 - 115 * 3 = 679, and the target gain coefficients for the green channel are 1024 - 13 * 3 = 985.

[0100] In the above embodiment, the second difference corresponding to each color channel to be adjusted is determined based on the first difference corresponding to each color channel to be adjusted and the preset adjustment coefficient, and then the target gain coefficient corresponding to each color channel to be adjusted is determined based on the conventional gain coefficient and the second difference corresponding to each color channel to be adjusted. The target gain coefficient corresponding to the color channel to be adjusted can be accurately determined, so that the main color in the projection area image can be reduced to an appropriate level, thereby avoiding the influence of the color of the projection surface on the color of the projection picture, and improving the color quality of the projection picture.

[0101] like Figure 5 As shown, it is a schematic diagram of the overall process of the present application. First, the image acquisition unit of the projection device can perform image acquisition to obtain a projection screen image, and then determine the projection area image from the projection screen image, and then determine the main color in the projection area image, and then decompose the main color into the pixel value of the B channel (i.e., color value), the pixel value of the G channel and the pixel value of the R channel, and determine the target gain coefficient corresponding to each color channel according to the pixel value of the B channel, the pixel value of the G channel and the pixel value of the R channel.

[0102] It should be understood that, although the steps in the flowcharts of the above embodiments are shown in sequence as indicated by the arrows, these steps are not necessarily performed in the order indicated by the arrows. Unless otherwise specified herein, there is no strict order restriction on the execution of these steps, and these steps can be performed in other orders. Moreover, at least a portion of the steps in the flowcharts of the above embodiments may include multiple steps or multiple stages, and these steps or stages are not necessarily performed at the same time, but can be performed at different times. The execution order of these steps or stages is not necessarily to be performed in sequence, but can be performed in turn or alternately with other steps or at least a portion of steps or stages in other steps.

[0103] Based on the same inventive concept, embodiments of the present application also provide a projection screen color correction device for implementing the projection screen color correction method described above. The solution provided by this device is similar to the solution described in the method described above. Therefore, the specific limitations of one or more projection screen color correction device embodiments provided below can be found in the limitations of the projection screen color correction method described above and will not be further elaborated here.

[0104] In one embodiment, Figure 6 As shown, a projection image color correction device 600 is provided, comprising: an image acquisition module 602, a projection area determination module 604, a main color determination module 606, a gain coefficient determination module 608 and a gain adjustment module 610, wherein:

[0105] The image acquisition module 602 is used to acquire a projection screen image; the projection screen image is an image obtained by capturing an image of a reference projection screen; the reference projection screen is a projection screen presented when the projection device projects a white image onto a projection surface.

[0106] The projection area determination module 604 is configured to determine a projection area image corresponding to a reference projection screen area from the projection screen image.

[0107] The main color determination module 606 is configured to determine the main color in the projection area image.

[0108] The gain coefficient determination module 608 is configured to determine a target gain coefficient corresponding to each color channel according to the color value of the main color in each color channel.

[0109] The gain adjustment module 610 is used to adjust the current gain coefficient of each color channel of the projection device to the corresponding target gain coefficient, so as to correct the color of the projection image projected by the projection device onto the projection surface.

[0110] In one embodiment, the projection area determination module 604 is further used to binarize the projection screen image according to a target threshold value to obtain a binary image; perform contour extraction on the binary image to obtain contours in the binary image; perform polygon fitting on each contour in the binary image; determine, from the fitted polygons, a target polygon that conforms to a preset shape and has the largest area as a reference projection screen area; extract image content corresponding to the reference projection screen area from the projection screen image to obtain a projection area image.

[0111] In one embodiment, the projection area determination module 604 is further configured to determine the coordinates of each vertex of the reference projection screen area; and extract image content corresponding to the reference projection screen area from the projection screen image according to the coordinates of each vertex to obtain the projection area image.

[0112] In one embodiment, the projection area determination module 604 is also used to determine the pixel average value of the vertex area in the projection screen image and the pixel average value of the central area of ​​the projection screen image; and determine the target threshold value based on the average value between the pixel average value of the vertex area and the pixel average value of the central area.

[0113] In one embodiment, the main color determination module 606 is also used to cluster each pixel point according to the color value of each pixel point in the projection area image to obtain multiple clusters; determine the target cluster cluster with the most pixels from the multiple clusters; and determine the color value of the cluster center of the target cluster cluster as the main color in the projection area image.

[0114] In one embodiment, the main color determination module 606 is also used to randomly select multiple initial cluster centers from each pixel point in the projection area image as the current cluster center; divide each pixel point in the projection area image into different current initial cluster clusters according to the distance between the color value of each pixel point in the projection area image and the color value of each current cluster center; calculate the new cluster center of each current initial cluster cluster according to each pixel point in each current initial cluster cluster as the new current cluster center; return to execute the division of each pixel point in the projection area image into different current initial cluster clusters according to the distance between the color value of each pixel point in the projection area image and the color value of each current cluster center and subsequent steps until the stopping condition is met to obtain the final multiple cluster clusters.

[0115] In one embodiment, the gain coefficient determination module 608 is further used to set the target gain coefficient corresponding to the color channel where the minimum color value is located as a regular gain coefficient; the minimum color value is the minimum value of the color values ​​of the main color in each color channel; based on the regular gain coefficient and the first difference corresponding to each color channel to be adjusted, the target gain coefficient corresponding to each color channel to be adjusted is determined; wherein, the color channel to be adjusted is the color channel other than the color channel where the minimum color value is located; the first difference corresponding to each color channel to be adjusted is the difference between the color value of the color channel to be adjusted and the minimum color value; the target gain coefficient corresponding to the color channel to be adjusted is less than the regular gain coefficient.

[0116] In one embodiment, the gain coefficient determination module 608 is further used to determine the second difference corresponding to each color channel to be adjusted based on the first difference corresponding to each color channel to be adjusted and the preset adjustment coefficient; and to determine the target gain coefficient corresponding to each color channel to be adjusted based on the conventional gain coefficient and the second difference corresponding to each color channel to be adjusted.

[0117] The above-mentioned projection screen color correction device obtains a projection screen image obtained by capturing an image of a reference projection screen presented by a projection device projecting a white image onto a projection surface, determines a projection area image corresponding to the reference projection screen area from the projection screen image, and then determines the main color in the projection area image. According to the color value of the main color in each color channel, the target gain coefficient corresponding to each color channel is determined, and finally the current gain coefficient of the projection device in each color channel is adjusted to the corresponding target gain coefficient, thereby correcting the color of the projection screen presented by the projection device projecting onto the projection surface, reducing the influence of the color of the projection surface on the color of the projection screen, and improving the color quality of the projection screen.

[0118] Each module in the aforementioned projection image color correction device can be implemented in whole or in part through software, hardware, or a combination thereof. Each module can be embedded in or independent of a processor within the projection device as hardware, or stored in a memory within the projection device as software, allowing the processor to call and execute the corresponding operations of each module.

[0119] In one embodiment, a projection device is provided, whose internal structure diagram can be as follows: Figure 7 As shown. The projection device includes a processor, memory, and a network interface connected via a system bus. The processor of the projection device is used to provide computing and control capabilities. The memory of the projection device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system and a computer program. The internal memory provides an environment for the operation of the operating system and computer program in the non-volatile storage medium. The network interface of the projection device is used to communicate with an external terminal via a network connection. When executed by the processor, the computer program implements a method for color correction of a projected image.

[0120] Those skilled in the art will understand that Figure 7 The structure shown in the figure is only a block diagram of a part of the structure related to the solution of the present application, and does not constitute a limitation on the projection device to which the solution of the present application is applied. The specific projection device may include more or fewer components than shown in the figure, or combine certain components, or have a different component arrangement.

[0121] In one embodiment, a projection device is provided, including a memory and a processor. The memory stores a computer program, and the processor implements the steps in the above method embodiments when executing the computer program.

[0122] In one embodiment, a computer-readable storage medium is provided, on which a computer program is stored. When the computer program is executed by a processor, the steps in the above-mentioned method embodiments are implemented.

[0123] In one embodiment, a computer program product is provided, including a computer program, which implements the steps in the above method embodiments when executed by a processor.

[0124] It should be noted that the user information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data used for analysis, stored data, displayed data, etc.) involved in this application are all information and data authorized by the user or fully authorized by all parties.

[0125] Those skilled in the art will appreciate that all or part of the processes in the above-mentioned embodiment methods can be implemented by instructing the relevant hardware through a computer program, and the computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to memory, database or other media used in the embodiments provided in this application may include at least one of non-volatile and volatile memory. Non-volatile memory may include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetic random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory may include random access memory (RAM) or external cache memory, etc. By way of illustration and not limitation, RAM can be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM). The database involved in the various embodiments provided herein may include at least one of a relational database and a non-relational database. Non-relational databases may include, but are not limited to, distributed databases based on blockchains. The processor involved in the various embodiments provided herein may be, but are not limited to, a general-purpose processor, a central processing unit, a graphics processing unit, a digital signal processor, a programmable logic unit, a data processing logic unit based on quantum computing, and the like.

[0126] The technical features of the above embodiments can be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0127] The above-described embodiments merely represent several implementation methods of the present application. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present application. It should be noted that a person of ordinary skill in the art may make various modifications and improvements without departing from the spirit of the present application, and these modifications and improvements fall within the scope of protection of the present application. Therefore, the scope of protection of the present application shall be determined by the appended claims.

Claims

1. A method for color correction of a projection image, characterized in that: The method comprises: Acquire a projection screen image; the projection screen image is an image obtained by capturing an image of a reference projection screen; the reference projection screen is a projection screen presented when a projection device projects a white image onto a projection surface; Determining a projection area image corresponding to a reference projection screen area from the projection screen image; Determining a dominant color in the projection area image; The target gain coefficient corresponding to the color channel where the minimum color value is located is set as a regular gain coefficient; the minimum color value is the minimum value of the color values ​​of the main color in each color channel; according to the first difference value corresponding to each color channel to be adjusted and the preset adjustment coefficient, the second difference value corresponding to each color channel to be adjusted is determined; according to the regular gain coefficient and the second difference value corresponding to each color channel to be adjusted, the target gain coefficient corresponding to each color channel to be adjusted is determined; the color channel to be adjusted is a color channel other than the color channel where the minimum color value is located; the first difference value corresponding to each color channel to be adjusted is the difference between the color value of the color channel to be adjusted and the minimum color value; the target gain coefficient corresponding to the color channel to be adjusted is less than the regular gain coefficient; The current gain coefficient of each color channel of the projection device is adjusted to the corresponding target gain coefficient to correct the color of the projection picture projected by the projection device onto the projection surface.

2. The method according to claim 1, characterized in that The determining of the projection area image corresponding to the reference projection screen area from the projection screen image comprises: Binarizing the projection image according to a target threshold to obtain a binary image; Performing contour extraction on the binary image to obtain a contour in the binary image; Performing polygon fitting on each contour in the binary image; From the polygons obtained by fitting, a target polygon that meets the preset shape and has the largest area is determined as the reference projection screen area; The image content corresponding to the reference projection screen area is extracted from the projection screen image to obtain a projection area image.

3. The method according to claim 2, characterized in that Extracting the image content corresponding to the reference projection screen area from the projection screen image to obtain the projection area image includes: Determining the coordinates of each vertex of the reference projection image area; According to the coordinates of each vertex, the image content corresponding to the reference projection screen area is extracted from the projection screen image to obtain a projection area image.

4. The method according to claim 2, characterized in that Before performing binarization processing on the projection screen image according to the target threshold to obtain a binarized image, the method further includes: Determining an average pixel value of a vertex region in the projection screen image and an average pixel value of a central region of the projection screen image; A target threshold is determined according to an average value between an average value of pixels in the vertex area and an average value of pixels in the central area.

5. The method according to claim 1, characterized in that Determining the main color in the projection area image includes: Clustering each pixel point according to the color value of each pixel point in the projection area image to obtain a plurality of clusters; Determine a target cluster with the most pixels from the multiple clusters; The color value of the cluster center of the target cluster is determined as the main color in the projection area image.

6. The method according to claim 5, characterized in that Clustering the pixels according to the color values ​​of the pixels in the projection area image to obtain a plurality of clusters includes: Randomly selecting multiple initial cluster centers from each pixel point in the projection area image as current cluster centers; Dividing each pixel point in the projection area image into different current initial cluster clusters according to the distance between the color value of each pixel point in the projection area image and the color value of each current cluster center; Calculating a new cluster center of each of the current initial clusters according to each pixel point in each of the current initial clusters as a new current cluster center; Return to executing the step of dividing each pixel in the projection area image into different current initial clusters according to the distance between the color value of each pixel in the projection area image and the color value of each current cluster center and subsequent steps until the stopping condition is met to obtain the final multiple clusters.

7. A projection image color correction device, characterized in that: The device comprises: An image acquisition module is used to acquire a projection screen image; the projection screen image is an image obtained by performing image acquisition on a reference projection screen; the reference projection screen is a projection screen presented when a projection device projects a white image onto a projection surface; A projection area determination module, configured to determine a projection area image corresponding to a reference projection screen area from the projection screen image; A main color determination module, configured to determine the main color in the projection area image; A gain coefficient determination module, configured to set a target gain coefficient corresponding to a color channel where a minimum color value is located as a regular gain coefficient; the minimum color value is the minimum value of the color values ​​of the main color in each color channel; determining a second difference value corresponding to each color channel to be adjusted based on a first difference value corresponding to each color channel to be adjusted and a preset adjustment coefficient; determining a target gain coefficient corresponding to each color channel to be adjusted based on the regular gain coefficient and the second difference value corresponding to each color channel to be adjusted; the color channel to be adjusted is a color channel other than the color channel where the minimum color value is located; the first difference value corresponding to each color channel to be adjusted is the difference between the color value of the color channel to be adjusted and the minimum color value; the target gain coefficient corresponding to the color channel to be adjusted is less than the regular gain coefficient; The gain adjustment module is used to adjust the current gain coefficient of the projection device in each color channel to the corresponding target gain coefficient, so as to correct the color of the projection picture projected by the projection device onto the projection surface.

8. A projection device comprising a memory and a processor, wherein the memory stores a computer program, wherein: When the processor executes the computer program, the steps of the method according to any one of claims 1 to 6 are implemented.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 6 are implemented.

10. A computer program product comprising a computer program, characterized in that When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 6 are implemented.

Images