Image display system

Abstract

An image display system includes a motion detection device for detecting the motion of an object in an input image and a black data insertion device for inserting black data into a frame of the input image to generate an output image. The duty cycle of the black data inserted into the frame is changed according to the result of the motion detection device.

Description

Technical Field

[0001] The present invention relates to an image display system, and in particular to an image display system based on motion detection and black data insertion based on average pixel level (APL). Background Art

[0002] Organic light-emitting diode (OLED) displays are composed of organic light-emitting diodes, whose light-emitting layer between electrodes contains organic compounds that can emit light in response to an electric current.

[0003] Compared to LCDs, OLED displays have better power efficiency and thinner thickness because they do not require a backlight. OLED pixels emit light directly, so they have a higher contrast ratio and a wider viewing angle. OLED displays do not emit light when displaying black, so they can provide deeper black levels. In addition, OLED displays have faster response than LCDs.

[0004] However, some OLED displays will produce motion blur due to the sample-and-hold effect, even if the panel has a very fast response time. The sample-and-hold effect causes the frame to be displayed in a statistical manner before the next refresh, but the human eye continues to move when tracking a moving object. Therefore, the human eye is in a different position at the beginning and end of the refresh, and the retina will perceive motion blur.

[0005] Therefore, it is urgent to propose a novel mechanism to overcome the deficiencies of traditional organic light emitting diode displays. Summary of the invention

[0006] In view of the above, one of the objectives of the embodiments of the present invention is to provide an image display system that can effectively suppress the afterimage caused by movement and maintain the brightness of static images.

[0007] According to an embodiment of the present invention, an image display system includes a motion detection device and a black data insertion device. The motion detection device detects the motion of an object of an input image. The black data insertion device inserts black data into a frame of the input image, thereby generating an output image. The duty cycle of the black data inserted into the frame is changed according to the result of the motion detection device. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1 The block diagram of the image display system according to the embodiment of the present invention is shown, which can be applied to an organic light emitting diode (OLED) display.

[0009] Figure 2The flowchart of the motion detection method according to the first embodiment of the present invention can be executed by a motion detection device.

[0010] Figure 3 The flowchart of the motion detection method according to the second embodiment of the present invention can be executed by a motion detection device.

[0011] Figure 4 A block diagram showing an image display system according to another embodiment of the present invention.

[0012] The reference numerals are described as follows:

[0013] 100: Image display system

[0014] 11: Mobile detection device

[0015] 12: Black data insertion device

[0016] 200: Mobile Detection Method

[0017] 21: Downsample even and odd rows

[0018] 22: Get the average pixel level

[0019] 23: Get the difference

[0020] 24: Hysteresis

[0021] 25: Determine whether the difference is greater than the critical value

[0022] 300: Mobile Detection Method

[0023] 31: Split the input image into multiple regions

[0024] 32: Downsample even and odd rows for each region

[0025] 33: Get the average pixel level for each area

[0026] 34: Get the difference

[0027] 35: Determine whether the difference is greater than the first threshold

[0028] 36: Determine whether all regions have been executed

[0029] 37: Determine whether the number of motion detection areas is greater than the second threshold

[0030] 400: Image display system

[0031] 41: Defect correction device

[0032] 42: Overdrive

[0033] 43: Digital gamma correction device

[0034] 44: Dithering device Detailed implementation manner

[0035] Figure 1 The block diagram showing the image display system 100 according to an embodiment of the present invention is applicable to an organic light emitting diode (OLED) display. The constituent blocks of the image display system 100 can be implemented by hardware, software, or a combination thereof, such as being executed in a digital image processor.

[0036] In this embodiment, the image display system 100 may include a motion detection device 11 for detecting a change in the position (i.e., motion) of an object in the input image, and the input image may include red (R), green (G), and blue (B) signals.

[0037] According to one of the features of this embodiment, the motion detection device 11 can detect motion based on the average pixel level (APL) of the input image, so in this embodiment, it is called a motion detection device based on the average pixel level. Figure 2 The flowchart showing the motion detection method 200 according to the first embodiment of the present invention can be executed by the motion detection device 11.

[0038] In step 21, the even lines and odd lines of the input image are respectively downsampled. Among them, the downsampling of the even lines takes even pixels, and the color signal has the maximum brightness (i.e., Max(R, G, B)). The downsampling of the odd lines takes odd pixels, and the color signal has the minimum brightness (i.e., Min(R, G, B)).

[0039] In step 22, the average value (i.e., the average pixel level (APL)) or the sum value of the downsampled (input image's) even lines and odd lines is obtained. Then, in step 23, the (positive) difference in the average pixel level between the current frame and the previous frame is obtained, where the previous frame can be temporarily stored in a storage device, such as a double data rate (DDR) synchronous dynamic random access memory (SDRAM).

[0040] When the difference is greater than a preset (first) threshold, it indicates that motion is detected (step 25), otherwise, no motion is detected. In this embodiment, before or after comparing the difference with the threshold, a hysteresis mechanism (step 24) can be executed to protect transitional motion.

[0041] Figure 3 The flowchart showing the motion detection method 300 according to the second embodiment of the present invention can be executed by the motion detection device 11.

[0042] In step 31, the input image (or frame) is divided into a plurality of regions. In one embodiment, the input image is divided into four regions. Figure 2 Process of uncut input images, Figure 3 The process shown can achieve better accuracy and fewer missed detections.

[0043] In step 32, for each region, the even-numbered rows and odd-numbered rows of the input image are downsampled respectively. The downsampling of the even-numbered rows is performed at intervals of two pixels and in turn by color. For example, the second row can be downsampled to obtain R(2, 2), G(4, 2), B(6, 2), R(8, 2), G(10, 2), B(12, 2)... The downsampling of the odd-numbered rows is performed at intervals of three pixels and in turn by color. For example, the first row can be downsampled to obtain R(1, 1), G(4, 1), B(7, 1), R(10, 1), G(13, 1), B(16, 1)... In this way, the dithering effect can be effectively reduced.

[0044] In step 33, for each region, in the even and odd rows of the downsampled (input image), every two adjacent downsampled pixels are averaged to obtain a middle value. Then, the average value (i.e., average pixel level (APL)) or the sum value of the middle values ​​is obtained. For example, R(2,2) and G(4,2) are averaged to obtain a middle value, and B(6,2) and R(8,2) are averaged to obtain another middle value. Then, in step 34, for each region, the (positive) difference of the average pixel level between the current frame and the previous frame is obtained, wherein the previous frame can be temporarily stored in a storage device, such as a double data rate (DDR) synchronous dynamic random access memory (SDRAM).

[0045] When the difference is greater than the preset (first) threshold value, the corresponding area is a motion detection area (step 35), otherwise the corresponding area is not a motion detection area. Steps 32 to 35 are repeated until all areas are executed (step 36).

[0046] When the number of motion detection areas is greater than a preset (second) threshold value, it indicates that motion is detected (step 37 ), otherwise, no motion is detected.

[0047] Back to Figure 1The image display system 100 of the present embodiment may include a black data insertion device 12, which inserts black data into the frame of the input image, thereby generating an output image. According to another feature of the present embodiment, the duty cycle (which may be expressed as a percentage or ratio) of the black data inserted into the frame may be changed according to the result of the motion detection device 11. When the motion detection device 11 detects motion, the duty cycle of the inserted black data may be gradually increased frame by frame (within a preset range). Conversely, when the motion detection device 11 does not detect motion, the duty cycle of the inserted black data may be gradually reduced frame by frame. The insertion position of the black data may be changed according to a preset pattern.

[0048] Figure 4 A block diagram showing an image display system 400 according to another embodiment of the present invention is shown. Figure 4 The image display system 400 is similar to Figure 1 The differences of the image display system 100 are described as follows: The image display system 400 may include a de-mura device 41 disposed before or after the motion detection device 11 to adjust the luminance and / or chromaticity of each OLED pixel to obtain a uniform display.

[0049] The image display system 400 may include an overdrive device 42, disposed after the defect correction device 41 or the black data insertion device 12, to compensate for the slower temporal response of the organic light emitting diode display. The image display system 400 may include a digital gamma correction device 43, disposed after the overdrive device 42, to perform non-linear operations to encode and decode the luminance or tristimulus values ​​of the output image. The image display system 400 may include a dithering device 44, disposed after the digital gamma correction device 43, which may be a deliberately applied noise form to randomize the quantization error to prevent large-size patterns in the output image. The above-mentioned defect correction device 41, overdrive device 42, digital gamma correction device 43 and dithering device 44 can be implemented using conventional techniques, and the details thereof are not repeated.

[0050] The above description is only a preferred embodiment of the present invention and is not intended to limit the claims of the present invention; any other equivalent changes or modifications that do not deviate from the spirit disclosed in the present invention should be included in the following claims.

Claims

1. An image display system, comprising: a motion detection device for detecting the motion of an object in an input image; and a black data inserting device for inserting black data into the frame of the input image, thereby generating an output image; The duty cycle of the black data inserted into the frame is changed according to the result of the motion detection device, in, The mobile detection device performs the following steps: downsampling the input image; obtaining an average or sum value of the downsampled input image; and Determine the difference between the average or sum of the current frame and the previous frame; When the difference is greater than a preset critical value, it indicates that movement is detected, otherwise no movement is detected. And wherein the downsampling of the input image comprises the following steps: Downsampling the even-numbered lines and the odd-numbered lines of the input image respectively; The downsampling of even-numbered lines is to take even-numbered pixels, whose color signals have maximum brightness, and the downsampling of odd-numbered lines is to take odd-numbered pixels, whose color signals have minimum brightness.

2. The image display system according to claim 1, in, The motion detection device detects motion according to the average pixel level of the input image.

3. An image display system, comprising: a motion detection device for detecting the motion of an object in an input image; and a black data inserting device for inserting black data into the frame of the input image, thereby generating an output image; The duty cycle of the black data inserted into the frame is changed according to the result of the motion detection device, The mobile detection device performs the following steps: Cut the input image into multiple regions; downsampling the region of the input image; For each region, every two adjacent downsampled pixels are averaged to obtain a plurality of intermediate values; Obtaining an average or sum of the median values ​​for each region; and For each area, determine the difference between the average value or the sum value of the current frame and the previous frame, and when the difference is greater than a preset first threshold value, the corresponding area is a motion detection area; When the number of the motion detection areas is greater than a preset second critical value, it indicates that motion is detected; otherwise, no motion is detected. And wherein the downsampling of the input image comprises the following steps: Downsampling the even-numbered rows and the odd-numbered rows of the region of the input image respectively; The downsampling of even-numbered lines is performed by sampling at intervals of multiple pixels and in turn by color, and the downsampling of odd-numbered lines is performed by sampling at intervals of multiple pixels and in turn by color.

4. The image display system according to claim 3, in, The downsampling of the even-numbered lines is every other pixel sampling, and the downsampling of the odd-numbered lines is every other three pixel sampling.

5. The image display system according to claim 1 or 3, in, When the motion detection device detects motion, the duty cycle of inserting black data is gradually increased frame by frame.

6. The image display system according to claim 1 or 3, in, When the motion detection device detects no motion, the duty cycle of inserting black data is gradually reduced frame by frame.

7. The image display system according to claim 1 or 3, in, The insertion position of the black data is changed according to the preset mode.

8. The image display system according to claim 1 or 3, further comprising: A defect correction device is arranged before or after the motion detection device to adjust the brightness or chromaticity of each pixel of the display to obtain a uniform display of the display.

9. The image display system as claimed in claim 8, further comprising: An overdriving device is arranged after the defect correction device or the black data insertion device to compensate for the slower temporal response of the display.

10. The image display system as claimed in claim 9, further comprising: A digital gamma correction device is arranged after the over-driving device and is used to perform non-linear operation to encode and decode the brightness or three-color values ​​of the output image.

11. The image display system according to claim 10, further comprising: A dithering device is arranged after the digital gamma correction device and is in the form of noise, and is used to randomize the quantization error.

12. The image display system according to claim 1 or 3, in, The image display system is suitable for an organic light emitting diode display.

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