TWI674570B - Screen control method and system for preventing image sticking - Google Patents

Abstract

In a screen control method and system for preventing afterimages, a motion detection module detects whether the entire display content of the screen exists based on a series of all RGB values of every two adjacent video frames of a video frame to be displayed on the screen There is dynamic content. The graphics recognition module determines whether the entire display content of the screen contains graphics according to the RGB histogram of each video frame, and the control module detects that the entire display content of the screen has a dynamic state within a predetermined period of time. Content and determine that the width and height of the smallest rectangular area where the screen displays all dynamic content are smaller than the predetermined threshold width and height, respectively, and recognize that the entire display content of the screen continues to contain graphics, reduce the brightness of the screen locally, thereby effectively preventing Afterimages appear on the screen.

Description

Screen control method and system for preventing image sticking

The present invention relates to screen content identification, and in particular, to a screen control method and system for preventing image sticking.

Currently, high-quality organic LED (OLED) panels are often used in advanced televisions. However, OLED panels suffer from so-called "image sticking" issues. If content with high brightness and saturation, such as channel logos or graphics, is displayed in an area for a long period of time, the channel logo or graphics will be portrayed on the display screen. Generally, television software is implemented to use basic detection of the entire picture motion to decide whether to perform dimming or screen saver to reduce the problem of image sticking.

With the popularity of smart TVs such as Android TVs, more and more content with highly mixed graphics and video will make image retention a more serious problem.

To solve the above problem, the existing method is based on detecting the entire screen content, that is, the motion of the full screen. In particular, the television picture of a smart TV is usually composed of (bright / saturated and little or no motion) graphics and mobile video. In this case, full-screen motion detection may incorrectly recognize the entire screen as "in motion" due to moving video and decide not to dimming (i.e., reduce screen brightness), while there may actually be still graphics areas, This still graphics area may also cause image sticking. For example, when the screen is mostly static or graphics but a small part of it is playing a dynamic video, image sticking may occur in the static or graphics area.

Therefore, there is still much room for improvement in the existing full-screen motion detection methods.

Therefore, an object of the present invention is to provide a screen control method and system for preventing image sticking, which can overcome at least one disadvantage of the prior art.

Therefore, a screen control method for preventing image sticking according to the present invention is performed by a screen control system and includes the following steps: (A) receiving a series of video frames to be displayed on a screen, and receiving each video received The frame is divided into a plurality of image blocks with the same size; (B) For each video frame, a plurality of RGB values of the image blocks corresponding to the video frame and the video information corresponding to the video frame are obtained. RGB histogram of the frame; (C) According to the RGB values of every two adjacent video frames, detect whether the screen has any dynamic content based on the entire display content of the two adjacent video frames to generate a detection Test results, and according to the RGB histogram of each video frame, identify whether the entire display content of the screen contains graphics to generate a recognition result, wherein the detection result can indicate that there is no dynamics in the entire display content Content, or one or more sub-areas corresponding to all dynamic content in the entire display area of the screen, respectively; and (D) for a predetermined time period generated in step (C) A detection result and each recognition result, when the detection result indicates a plurality of sub-areas and when it is determined that the entire display area of the screen contains the sub-areas indicated by the detection result, a smallest rectangular area having a A width smaller than a predetermined threshold width and a height smaller than a predetermined threshold height and when the recognition result indicates that the entire display content of the screen contains graphics, the entire display area of the screen is lowered except for areas where dynamic content is displayed The brightness of the remaining area.

Therefore, a screen control system for preventing image sticking according to the present invention includes a video frame division module, an RGB value calculation module, an RGB histogram measurement module, a motion detection module, a graphic recognition module, and a Control module.

The video frame division module is adapted to receive a series of video frames from the outside and to be displayed on a screen, and divide each received video frame into a plurality of image blocks having the same size.

The RGB value calculation module is connected to the video frame division module, and calculates a plurality of corresponding image areas according to the image blocks of each video frame from the video frame division module. The RGB value of the block.

The RGB histogram measurement module is adapted to receive the video frames, and obtain an RGB histogram corresponding to the video frame according to each received video frame.

The dynamic detection module is connected to the RGB value calculation module to receive the RGB values of each video frame, and detect the screen based on the two adjacent frames based on the RGB values of every two adjacent video frames. Whether there is any dynamic content in the entire display content of the video frame to generate a detection result. The detection result may indicate that there is no dynamic content in the entire display content, or one or more sub-areas corresponding to all dynamic content in the entire display area of the screen.

The graphic recognition module is connected to the RGB histogram measurement module to receive the RGB histogram of each video frame, and recognizes whether the entire display content of the screen contains graphics according to the RGB histogram to generate a recognition result.

The control module is connected to the dynamic detection module and the graphic recognition module to receive each detection result and each identification result, and for each detection result and each identification result received within a predetermined time period When the detection result indicates a plurality of sub-areas and when it is determined that the entire display area of the screen contains the sub-area indicated by the detection result, a smallest rectangular area having a width smaller than a predetermined threshold width, and A height less than a predetermined threshold height and when the recognition result indicates that the entire display content of the screen contains graphics, the brightness of the remaining area of the entire display area of the screen except for the area where dynamic content is displayed is reduced.

The effect of the present invention is that it can effectively recognize whether the entire display content of the screen contains dynamic content and / or graphics in combination with the local RGB value change and the graphic recognition processing of the entire RGB value square graph; and when it is within a predetermined time period When it is detected that the entire display content of the screen continuously has dynamic content and it is determined that the width and height of the smallest rectangular area where the screen displays all dynamic content are smaller than the predetermined threshold width and height, and it is recognized that the entire display content of the screen continues to contain graphics , Reduce the brightness of the screen locally, which can effectively prevent the phenomenon of image sticking on the screen.

Before the present invention is described in detail, it should be noted that in the following description, similar elements are represented by the same numbers.

Referring to FIG. 1, an embodiment of a screen control system 100 for preventing image sticking according to the present invention is based on a series of video frames (that is, so-called Video chain) to control the screen to prevent the image from remaining on the screen, wherein the video frames are input to the screen control system 100 at an update frequency of 50HZ or 60HZ, for example, and each video frame has 1920´ 1080 pixels, but not limited to this example. In this embodiment, the screen control system 100 may include a video frame division module 1, an RGB value calculation module 2, a motion detection module 3, an RGB histogram measurement module 4, and a pattern recognition. Module 5 and a control module 6. It is worth noting that the screen control system 100 can be integrated into, for example, a system-on-chip (SoC), and the video frame division module 1, the RGB value calculation module 2, the dynamic detection Each of the measurement module 3, the RGB histogram measurement module 4, the graphic recognition module 5 and the control module 6 can perform the following related operations in the form of software, hardware, or firmware.

The video frame division module 1 is adapted to sequentially receive the video frames, and divide each received video frame into a plurality of images having a low resolution and the same size, for example, by using a known division method. Blocks, such as a square tile grid, where each image block contains at least one pixel. For example, each video frame is divided into 32´20 image blocks.

The RGB value calculation module 2 is connected to the video frame division module 1 and uses a known RGB value calculation method according to the image blocks from each video frame of the video frame division module 1. A plurality of RGB values corresponding to the image blocks are calculated.

The motion detection module 3 is connected to the RGB value calculation module to receive the RGB values of each video frame, and detects the screen based on the two phases based on the RGB values of every two adjacent video frames. Whether there is any dynamic content in the entire display content of the adjacent video frame to generate a detection result. It is worth noting that the detection result can indicate that there is no dynamic content in the entire display content, or that one or more sub-areas in the entire display area of the screen respectively correspond to all dynamic content. More specifically, for each two adjacent video frames, the motion detection module 3 compares the RGB values of each image block of one of the two-phase neighboring video frames with the two-phase neighboring video frames. The RGB value of the image block in which the other frame corresponds. After comparing all the image blocks, the motion detection module 3 can generate, for example, a black image as the detection result without any difference, and use the black image to represent or indicate the screen's There is no dynamic content in the entire display content, and if there is any difference, the motion detection module 3 can generate a difference image frame as the detection result, and the difference image frame can be white, for example. Mode (but not limited to this) indicates all the difference image blocks that have differences in RGB values, and indicates the remaining image blocks that have no difference in RGB values in a black manner, where all the difference image blocks are used as all Sub-areas corresponding to all dynamic content, respectively. For example, the slanted area in FIG. 2 represents all the difference image blocks having a difference in RGB values, and the remaining (white) area represents all the image blocks having no difference in RGB values.

The RGB histogram measurement module 4 is suitable for receiving the video frames, and according to each video frame received, in particular, each pixel contained in the video frame is in R (red), G (green) ) And B (blue) pixel values (each of which is a value in the range of 0 to 255), using a known measurement method, an RGB histogram corresponding to the video frame is obtained. It is worth noting that the RGB histogram of an image is used to describe the occurrence probability of each RGB value, and the histogram is usually used to enhance the dynamic television picture. For example, if a video frame that is a natural scene is received by the RGB histogram measurement module 4, the RGB histogram measurement module 4 will obtain an RGB histogram as shown in FIG. 3 based on it. The plot corresponding to each of R (red), G (green), and B (blue) generally shows a relatively smooth and continuous outline; and if a limited number of artificially used When a video frame of a graphic (such as a form) generated by color shading is received by the RGB histogram measurement module 4, the RGB histogram measurement module 4 will obtain an RGB histogram as shown in FIG. 4 according to which The plots corresponding to each of R (red), G (green), and B (blue) appear to be relatively "sharp". More specifically, for the graph corresponding to each of R (red), G (green), and B (blue) in FIG. 4, the graph has a highest peak point and the highest peak point is in height Significantly higher than at least one peak point of the graph adjacent to the highest peak point (ie, the left peak point and / or the right peak point). In other words, it can be seen from FIG. 4 that the highest peak point of the graph corresponding to red is significantly higher than the adjacent left and right peak points; the highest peak point of the graph corresponding to blue is significantly higher than the adjacent left peak. Point and the right peak point; and the highest peak point corresponding to the green graph is only significantly higher than the adjacent left peak point.

The pattern recognition module 5 is connected to the RGB histogram measurement module 4 to receive the RGB histogram of each video frame, and based on the RGB histogram and using the above-mentioned natural scene and artificial graphics on the outline of the RGB histogram Characteristics, it is recognized whether the entire content displayed on the screen contains (artificial) graphics or contains natural scenes to generate a recognition result.

The control module 6 is connected to the motion detection module 3 and the graphic recognition module 5 to receive each detection result from the motion detection module 3 and each recognition result from the graphic recognition module 5 .

Hereinafter, referring to FIG. 1 and FIG. 5, an example is described to explain how the control module 6 executes a screen control procedure for the screen according to each detection result and each recognition result continuously received. The screen control program includes the following steps S51 to S62.

In step 51, first, the control module 6 confirms whether the entire display content of the screen is static according to the received detection result. In this embodiment, when the detection result is, for example, a black image (that is, the detection result indicates that the entire display content of the screen does not have any dynamic content), the control module 6 confirms the screen The entire display is rendered static. In this case, the control module 6 may use a first timer (not shown) to start counting or accumulate the entire display content of the screen for the first time that has been statically displayed (step S52).

It is worth noting that, in step S52, the control module 6 must control the first timing only after confirming that the entire display content of the screen is static at least twice in a row (that is, the previous time and this time). The device accumulates the first time. If the control module 6 has previously confirmed that the entire display of the screen is not static, the control module 6 controls the first timer to start counting the first time.

In step S53 following step S52, the control module 6 determines whether the first time reaches a predetermined time period (for example, 10 minutes, but not limited to this example). If the determination result is affirmative, the control module 6 executes a screen saver program to make the screen appear a black screen (step S54). After that, the flow returns to step S51. Otherwise, the control module 6 keeps the brightness of the screen unchanged (step S58).

When the detection result is, for example, a difference image frame indicating all the difference image blocks (that is, when the detection result indicates all sub-areas corresponding to all dynamic content in the entire display area of the screen), The control module 6 confirms in step S51 that the entire display content of the screen is not static. In this case, the control module 6 resets the first timer to reset the first time to zero (step S55).

In step S56 following step S55, the control module 6 obtains a minimum rectangular area including all sub-areas indicated by the detection result in the entire display area of the screen according to the detection result, and determines the minimum rectangle. Whether the width and height of the area are smaller than a predetermined threshold width and a predetermined threshold height, respectively. For example, as shown in FIG. 2, the predetermined threshold width W may be 40% of the width of the entire display area of the screen (for example, 1920 pixels´40% = 768 pixels) and the predetermined threshold height H is 40% of the height of the entire display area of the screen (for example, 1080 pixels´40% = 432 pixels), but not limited to this. In this case, if the detection result shown in FIG. 2 is used, the control module 6 determines that the obtained width w and height h of the smallest rectangular area A are smaller than the predetermined threshold width W and the predetermined threshold height, respectively. H.

When the control module 6 determines in step S56 that the width and height of the minimum rectangular area are not less than the predetermined threshold width and the predetermined threshold height, respectively, this indicates that there is a considerable amount of dynamic content on the screen display content. In this case, the control module 6 resets a second timer (not shown) to reset the second time calculated by the two timers to zero (step S57). On the contrary, when the determination result of the control module 6 in step S56 is positive, the flow proceeds to step S59. In particular, the second timer is a second timer used to calculate the width and height of the smallest rectangular area of the screen display area that are smaller than the predetermined threshold width and the predetermined threshold height, respectively, while the screen display content continuously contains graphics. time.

Following step S58 in step S57, the control module 6 keeps the brightness of the screen unchanged. After that, the flow returns to step S51.

In step S59, the control module 6 confirms whether the entire display content of the screen contains graphics according to the recognition result. If the result of the confirmation is that the entire display content of the screen presents a natural scene (that is, does not contain any graphics), the control module 6 executes steps S57 and S58 in sequence, and the flow returns to step S51. Conversely, if the confirmation result is affirmative, it means that the entire display content of the screen is mixed with graphics and dynamic content. In this case, the flow proceeds to step S60.

In step S60, the control module 6 starts counting or accumulating the second timer (the width and height of the smallest rectangular area of the screen display area are kept smaller than the predetermined threshold width and the predetermined threshold height, respectively) while the screen display content The second time is continued (including the graphics). It is worth noting that the control module 6 must confirm that the width and height of the smallest rectangular area of the screen display area are kept smaller than the predetermined threshold width and the predetermined value at least twice in a row (that is, the previous time and this time). When the threshold height and the screen display content contain graphics, the second timer is controlled to accumulate the first time. If the control module 6 previously confirms that at least one of the width and height of the smallest rectangular area of the screen display area is not less than one of the predetermined threshold width and the predetermined threshold height, or confirms the screen display When the content does not contain graphics, the entire display of the screen is not static, the control module 6 controls the second timer to start counting the second time.

Following step S61 in step S60, the control module 6 determines whether the second time reaches the predetermined time period. If the determination result is negative, the control module 6 executes step S58 (the screen brightness remains unchanged), and after that, the flow returns to step S51. When the control module 6 determines that the second time reaches the predetermined time period, the control module 6 makes the screen local dimming. More specifically, the control module 6 adjusts the screen down. The brightness of the remaining area (ie, the static area) other than the area in which the dynamic content is displayed in the entire display area (step S62), thereby effectively preventing the image residue of the static area of the screen caused by the continuous display of saturated brightness. After that, the flow returns to step S51.

In this way, by repeatedly executing the screen control process by the control module, the screen control system 100 can timely control the screen according to each video frame that is continuously input.

In summary, the screen control system 100 of the present invention can effectively identify whether the entire display content of the screen contains dynamic content and / or Or graphics; and when the entire display content of the screen is detected within a predetermined period of time with dynamic content and it is determined that the width and height of the smallest rectangular area where the screen displays all dynamic content are smaller than the predetermined threshold width and height, respectively, and identified When the entire display content of the screen continues to contain graphics, the brightness of the screen is partially reduced, which can effectively prevent the phenomenon of image retention on the screen. Therefore, the purpose of the invention can be achieved.

However, the above are only examples of the present invention. When the scope of implementation of the present invention cannot be limited in this way, any simple equivalent changes and modifications made in accordance with the scope of the patent application and the content of the patent specification of the present invention are still Within the scope of the invention patent.

100‧‧‧screen control system

1‧‧‧Video frame division module

2‧‧‧RGB value calculation module

3‧‧‧ Motion Detection Module

4‧‧‧RGB histogram measurement module

5‧‧‧Graphic Identification Module

6‧‧‧control module

w‧‧‧ width

h‧‧‧ height

A‧‧‧The smallest rectangular area

W‧‧‧ predetermined threshold width

H · ‧‧‧ predetermined threshold height

S51 ~ S62‧‧‧step

Other features and effects of the present invention will be clearly presented in the embodiment with reference to the drawings, in which: FIG. 1 is a block diagram exemplarily illustrating an embodiment of a screen control system for preventing image sticking according to the present invention; FIG. 2 exemplarily illustrates a difference image frame generated by a motion detection module of the embodiment; FIG. 3 exemplarily illustrates a difference image frame generated by the RGB histogram measurement module of the embodiment according to a natural scene An RGB histogram; FIG. 4 exemplarily shows an RGB histogram generated by the RGB histogram measurement module based on an image of an artificial figure; and FIG. 5 is a flowchart illustrating an example of the embodiment. A control module performs a screen control procedure for the screen.

Claims (10)

A screen control method for preventing image sticking is performed by a screen control system and includes the following steps: (A) receiving a series of video frames to be displayed on a screen, and dividing each received video frame into Multiple image blocks with the same size; (B) for each video frame, obtain multiple RGB values of the image blocks corresponding to the video frame, and RGB histograms corresponding to the video frame (C) According to the RGB values of each two adjacent video frames, detecting whether the screen has any dynamic content based on the entire display content of the two adjacent video frames to generate a detection result, and According to the RGB histogram of each video frame, identifying whether the entire display content of the screen contains graphics to generate a recognition result, wherein the detection result can indicate that the entire display content does not have any dynamic content, or indicates One or more sub-areas corresponding to all dynamic content appear in the entire display area of the screen; and (D) for each detection result generated in step (C) within a predetermined time period For each recognition result, when the detection result indicates a plurality of sub-areas and when it is determined that the entire display area of the screen contains the sub-areas indicated by the detection result, a smallest rectangular area having a width smaller than a predetermined threshold Width and a height less than a predetermined threshold height and when the recognition result indicates that the entire display content of the screen contains graphics, the entire display area of the screen is lowered except for areas where dynamic content is displayed The brightness of the remaining areas outside the domain. The screen control method for preventing image sticking according to claim 1, after step (C), includes the following steps: (E) when it is determined that all detection results generated in the predetermined time period in step (C) When it is indicated that the entire display content of the screen does not contain any dynamic content, a screen saver is executed. The screen control method for preventing image sticking according to claim 1, wherein in step (A), each image block is square and contains at least one pixel. The screen control method for preventing image sticking according to any one of claims 1 to 3, wherein in step (C): for each two adjacent video frames, the screen control system compares the two adjacent video frames with each other. The RGB value of each image block in one of the frames and the RGB value of the image block corresponding to the other of the two adjacent video frames in position, and the screen controls without any difference The detection result generated by the system indicates that the entire display content of the screen has no dynamic content, and in the case of any difference, the detection result generated by the screen control system is an indication of the RGB value The difference image frames of all the difference image blocks with differences, and all the difference image blocks indicated by the difference image frames are all sub-areas corresponding to all dynamic content; and for each video frame, when The screen control system determines that each of the three graphics corresponding to the red, green, and blue in the RGB histogram of the video frame has a highest peak point and the highest peak point is in height Significantly higher than the at least one pattern to the adjacent peak point At the peak point, the recognition result indicates that the entire display content of the screen contains graphics. The screen control method for preventing image sticking according to claim 1, wherein in step (D), the predetermined threshold width is 40% of the width of the entire display area of the screen, and the predetermined threshold height is the screen's 40% of the height of the entire display area. A screen control system for preventing image sticking includes a video frame division module adapted to receive a series of video frames from the outside and to be displayed on a screen, and divide each received video frame into multiple An image block of the same size; an RGB value calculation module connected to the video frame division module, and calculating based on the image blocks of each video frame from the video frame division module A plurality of RGB values corresponding to the image blocks; an RGB histogram measurement module is adapted to receive the video frames, and according to each received video frame, obtain a corresponding video frame RGB histogram; a motion detection module connected to the RGB value calculation module to receive the RGB values of each video frame, and detect the RGB values based on the RGB values of every two adjacent video frames The screen generates a detection result based on whether there is any dynamic content in the entire display content of the two adjacent video frames, and the detection result may indicate that there is no dynamic content in the entire display content, or indicates that On-screen A pattern recognition module connected to the module to receive the measured RGB histogram; one or a plurality of regions within the sub-regions respectively corresponding to all of the display dynamic content The RGB histogram of each video frame, and identifying whether the entire display content of the screen contains graphics according to the RGB histogram to generate a recognition result; and a control module connected to the motion detection module and the graphics The identification module receives each detection result and each identification result, and for each detection result and each identification result received within a predetermined time period, when the detection result indicates multiple sub-areas and when determining A minimum rectangular area containing the sub-areas indicated by the detection result in the entire display area of the screen has a width less than a predetermined threshold width and a height less than a predetermined threshold height, and when the recognition result indicates When the entire display content of the screen contains graphics, the brightness of the remaining area of the entire display area of the screen except for the area where dynamic content is displayed is reduced. The screen control system for preventing image sticking according to claim 6, wherein, for all detection results received within the predetermined time period, when the control module determines that all detection signals received within the predetermined time period When the test results indicate that the entire display content of the screen does not contain any dynamic content, the control module protects the screen by executing a screen saver program. The screen control system for preventing image sticking according to claim 6, wherein each image block is square and contains at least one pixel. The screen control system for preventing image sticking according to any one of claims 6 to 8, wherein: for every two adjacent video frames, the motion detection module compares to one of the two adjacent video frames. The RGB value of each image block corresponds to the position of the image block corresponding to one of the two adjacent video frames. RGB value, and if there is no difference, the detection result generated by the motion detection module indicates that the entire display content of the screen has no dynamic content, and if there is any difference, the The detection result generated by the motion detection module is a difference image frame indicating all the difference image blocks having differences in RGB values, and all the difference image blocks indicated by the difference image frame are taken as all Sub-areas corresponding to all dynamic content respectively; and for each video frame, when the graphic recognition module determines that the three RGB histograms of the video frame correspond to red, green and blue graphics, respectively When each of them has a highest peak point and the highest peak point is significantly higher in height than at least one peak point adjacent to the highest peak point in the figure, the recognition result indicates that the entire display content of the screen contains Graphics. The screen control system for preventing image sticking according to claim 6, wherein the predetermined threshold width is 40% of the width of the entire display area of the screen, and the predetermined threshold height is 40% of the height of the entire display area of the screen %.