CN101295474A - Image processing method for display device and related device thereof - Google Patents

Abstract

An image processing method for a display device for improving image quality includes receiving a video signal; sequentially generating a plurality of image data according to the video signal, wherein each of the plurality of image data includes a frame of data and a low grayscale picture data, which respectively correspond to a frame output time and a vertical blanking time in the timing of the video signal; and sequentially displaying the plurality of image data on a display panel of the display device.

Description

Image processing method for display device and related device

technical field

The present invention relates to an image processing method used in a display device and a related device, in particular to an image processing method and a related device that can achieve the effect of black insertion technology without performing frequency doubling processing on frame data.

Background technique

Liquid crystal displays have the characteristics of light and thin appearance, low power consumption, and no radiation pollution, and have been widely used in information products such as computer systems, mobile phones, and personal digital assistants (PDAs). The working principle of the liquid crystal display is to use the liquid crystal molecules in different alignment states to have different polarization or refraction effects on light, so the penetration of light can be controlled through liquid crystal molecules in different alignment states, and output light of different intensities can be further generated. And red, green, blue light with different grayscale intensities.

Please refer to FIG. 1 , which is a schematic diagram of a conventional thin film transistor (Thin Film Transistor, TFT) liquid crystal display 10 . The liquid crystal display 10 includes a liquid crystal display panel (LCD Panel) 100 , a control circuit 102 , a data line signal output circuit 104 , a scan line signal output circuit 106 and a voltage generator 108 . The liquid crystal display panel 100 is composed of two substrates (Substrate), and a liquid crystal material (Liquid Crystal) is filled between the two substrates. A plurality of data lines (Data Line) 110, a plurality of scan lines (Scan Line, or gate line, Gate Line) 112 and a plurality of thin film transistors 114 perpendicular to the data lines 110 are arranged on one substrate, while on another A common electrode (Common Electrode) is disposed on the substrate for providing a common voltage (Vcom) via the voltage generator 108 . For ease of description, only four thin film transistors 114 are shown in FIG. Distributed on the liquid crystal display panel 100 in a matrix, each data line 110 corresponds to a row (Column) of the thin film transistor liquid crystal display 10, and the scanning line 112 corresponds to a column (Row) of the thin film transistor liquid crystal display 10, and each The thin film transistor 114 corresponds to a pixel (Pixel). In addition, the characteristics of the circuit formed by the two substrates of the liquid crystal display panel 100 can be regarded as an equivalent capacitance 116 .

The driving principle of the existing thin film transistor liquid crystal display 10 is described in detail as follows. When the control circuit 102 receives the horizontal synchronization signal (Horizontal Synchronization) 118 and the vertical synchronization signal (Vertical Synchronization) 120, the control circuit 102 will generate corresponding control signals respectively Input to the data line signal output circuit 104 and the scan line signal output circuit 106, and then the data line signal output circuit 104 and the scan line signal output circuit 106 will generate input signals to different data lines 110 and scan lines 112 according to the control signal, Therefore, the conduction of the thin film transistor 114 and the potential difference between the two ends of the equivalent capacitor 116 are controlled, and the arrangement of the liquid crystal molecules and the corresponding light penetration amount are further changed to display the display data 122 on the panel. For example, the scan line signal output circuit 106 inputs a pulse to the scan line 112 to turn on the thin film transistor 114, so the signal input to the data line 110 by the data line signal output circuit 104 can be input to the equivalent capacitor 116 through the thin film transistor 114, Therefore, the gray level (Gray Level) state of the corresponding pixel is controlled. In addition, by controlling the magnitude of the signal input from the data line signal output circuit 104 to the data line 110 , different gray scales can be generated.

Because the physical characteristics of liquid crystals are similar to those of capacitors, the liquid crystals have the problem of slow response; on the other hand, compared with the pulse-type drive mode of the picture tube display, the drive mode of the liquid crystal display voltage continuous maintenance (Hold Type) will cause The image edge of the moving object (Moving Subject) produces the phenomenon of motion blur (Motion Blur). In order to reduce the degree of motion blur, the prior art provides a black insertion technology, which shortens the frame data (that is, multiplies the frequency of the frame data) and inserts pure black or low grayscale values between frames. Sub-frame, to shorten the image data pulse, also known as pulse-like liquid crystal display technology. In simple terms, the black insertion technology refers to the fixed insertion of subframes with a grayscale value of 0 or a relatively low grayscale value between adjacent frames.

Please refer to FIG. 2 and FIG. 3 , FIG. 2 is a schematic diagram of a conventional black insertion technology implemented in a pixel, and FIG. 3 is a schematic diagram of light intensity generated by the pixel. Among them, the slash part indicates the driving data P0, P1, P2... received by the pixel at each frame time (Frame Time), and the driving data P0, P1, P2... correspond to the frames F0, F1, F2 respectively … Therefore, it can be seen from FIG. 2 that before the next driving data is input, the (gray scale) value of the driving data will return to 0 (or a relatively low value). In this case, the pixel exhibits a change in light intensity that resembles a pulsed output.

Although the existing black insertion technology can reduce the degree of motion blur, it needs to multiply the frame rate. In addition to consuming system resources, it is easy to cause problems such as electromagnetic interference and other electromagnetic radiation. In addition, the existing black insertion technology makes the pixels correctly display grayscale data only in half of the frame time, while the other half of the frame time is a black picture with a grayscale value of 0. In other words, the black insertion technology will halve the average brightness of the overall screen and affect the image effect.

Contents of the invention

Therefore, the main objective of the present invention is to provide an image processing method for a display device and related devices.

The present invention discloses an image processing method for a display device to improve image quality, including receiving a video signal; generating a plurality of image data sequentially according to the video signal, and each image of the plurality of image data The data includes one frame data and one low-gray-scale picture data, respectively corresponding to one frame output time and one vertical blanking time in the timing of the video signal; and displaying the plurality of images sequentially on a display panel of the display device data.

The present invention discloses a display device capable of improving image quality, which includes a receiving end for receiving a video signal; a display panel; and a video processing unit coupled to the receiving end for sequentially receiving the video signal Generate a plurality of image data, each image data of the plurality of image data includes a frame data and a low-grayscale image data, respectively corresponding to a frame output time and a vertical blanking time in the timing of the video signal; and a The output unit, coupled to the video processing unit, is used to sequentially display the plurality of image data on the display panel.

Description of drawings

FIG. 1 is a schematic diagram of a conventional thin film transistor liquid crystal display.

FIG. 2 is a schematic diagram of an existing black insertion technology.

FIG. 3 is a schematic diagram of light intensity corresponding to FIG. 2 .

FIG. 4 is a schematic diagram of an image processing flow for a display device according to an embodiment of the present invention.

FIG. 5 is a schematic diagram of image data output corresponding to an embodiment of the present invention.

FIG. 6 is a schematic diagram of a display device according to an embodiment of the present invention.

Description of reference symbols

10 thin film transistor liquid crystal display

100 LCD display panel

102 control circuit

104 Data line signal output circuit

106 Scanning line signal output circuit

108 voltage generator

110 data cable

112 scan lines

114 Thin Film Transistor

116 Equivalent capacitance

118 Horizontal synchronization signal

120 Vertical sync signal

122 Display data

40 Process

400, 402, 404, 406, 408 steps

FD1, FD2, FD3 Frame data

BD1, BD2, BD3 Low grayscale picture data

T _VO1 , T _VO2 , T _VO3 frame display time

T _BO1 , T _BO2 , T _BO3 vertical blanking time

T _GF1 , T _GF2 , T _GF3 , T _GB1 , T _GB2 , T _GB3 time slots

Detailed ways

Please refer to FIG. 4 , which is a schematic diagram of an image processing flow 40 for a display device according to an embodiment of the present invention. The image processing flow 40 can improve image quality, and it includes the following steps:

Step 400: start.

Step 402: Receive a video signal.

Step 404: According to the video signal, generate a plurality of image data sequentially, each image data of the plurality of image data includes a frame data and a low-grayscale image data, respectively corresponding to a frame output in the timing sequence of the video signal Time and a Vertical Blanking Duration.

Step 406: Display the plurality of image data sequentially on a display panel of the display device.

Step 408: end.

According to the image processing flow 40, the present invention sequentially displays frame data and low-grayscale image data at the frame output time and the vertical blanking time. Wherein, the grayscale value of the low grayscale image data is 0 or a relatively low value. Since the present invention only displays low-gray-scale picture data during the vertical blanking time, the frame data does not need to undergo frequency doubling processing. In addition to reducing required resources, the average brightness of the picture is maintained to enhance image quality.

In order to clearly illustrate the present invention, the meaning of the vertical blanking time is briefly described below. The earliest dynamic image display device is the cathode ray display, which uses the characteristics of the image persistence of the human eye to segment the image signal, pass through the cathode ray tube, and scan each horizontal line column by column, so that the entire image is displayed on the display panel superior. CRT scans from one end of a horizontal line to the other, and then moves to the next horizontal line to start the next scan. The process of moving requires a period of time sufficient for the cathode ray tube to be positioned at the start of the next horizontal line to start scanning the next horizontal line. Therefore, in the video timing mechanism of a cathode ray display, the video signal is divided into horizontal and vertical parts. In addition to the image data of each horizontal line in the horizontal part, a blanking signal (Blanking Signal) is inserted between the image data of each segment. Each blanking signal can be sequentially divided into a front porch signal (Front Porch), a horizontal synchronization signal (Hsync) and a back porch signal (BackPorch). The front porch and back porch signals do not contain any data and are used to give the CRT enough time to move to the start of the scan, while the horizontal sync signal is used to tell the CRT when to start scanning. In addition, after scanning a whole frame, the cathode ray tube needs to return to the upper left of the display panel to re-scan a new frame. Therefore, the vertical part also provides a front porch signal, a vertical synchronous signal (Vsync) and a back porch signal. Its function is the same as that of the horizontal part. To start the scanning action, the relevant timing specifications can refer to the Generalized Timing Formula (GTF) of the Video Electronics Standards Association (VESA).

When the display is developed from the traditional cathode ray tube to the liquid crystal display, for compatibility and other factors, the image timing technology of the liquid crystal display still follows the specification of the traditional cathode ray display, while the horizontal and vertical blanking time is evolved to control the horizontal and vertical The direction pixels are enabled, and during the horizontal and vertical blanking times, the video signal has no content.

The present invention utilizes the characteristics of the vertical blanking time to insert low gray scale picture data (that is, black picture) in the vertical blanking time. In this way, the effect of black insertion technology can be achieved without frequency doubling processing of frame data. At the same time, since the frame data has not been multiplied, the average brightness of the overall picture can be improved. In contrast, in the existing black insertion technology, the frame data needs to be multiplied first. In addition to consuming system resources, the average brightness of the overall screen is thus halved, which affects the image effect.

On the other hand, in order to avoid the problem of uneven brightness caused by inserting black screens, the present invention can sequentially use two different scanning methods (from top to bottom and bottom to top) when displaying image data (ie, step 406) to display image data. In this case, the output situation of the image data is as shown in FIG. 5 . In Fig. 5, the upper part represents a sequence of image data, the lower part represents the picture displayed on the display panel, FD1, FD2, FD3... represent frame data, BD1, BD2, BD3... represent low gray scale pictures Data, T _VO1 , T _VO2 , T _VO3 ... represent the frame display time, T _BO1 , T _BO2 , T _BO3 ... represent the vertical blanking time, T _GF1 , T _GF2 , T _GF3 ... represent the image data interval The gap (Gap) time, and T _GB1 , T _GB2 , T _GB3 . In addition, the arrows in the vertical direction indicate that the scanning sequence is from top to bottom or from bottom to top. The data BD2 is scanned from bottom to top. In this case, since the adjacent image data are scanned in different order, uneven brightness can be avoided.

The image processing flow 40 is to insert low-gray-scale picture data during the vertical blanking time, so that the frame data does not need to be frequency multiplied, so that the average brightness of the overall picture can be improved, and adjacent frame data are scanned in different order, which can avoid brightness Uneven situations occur. Regarding the actual implementation of the image processing flow 40, those skilled in the art can realize it with specific software and hardware according to the above description.

For example, please refer to FIG. 6 , which is a schematic diagram of a display device 60 according to an embodiment of the present invention. The display device 60 can improve image quality, and includes a receiving end 600 , a display panel 602 , a video processing unit 604 and an output unit 606 . The video processing unit 604 can receive the video signal through the receiving end 600, and generate a plurality of image data accordingly; each image data includes a frame data and a low-gray-scale image data, corresponding to a frame output time and a vertical blanking time respectively . The output unit 606 can sequentially display the image data on the display panel 602 , and preferably outputs adjacent image data in different scan modes. Therefore, the display device 60 inserts the low-grayscale image data (black image) during the vertical blanking time, and the video processing unit 604 does not need to perform frequency doubling processing on the frame data to achieve the effect of the black insertion technique. At the same time, since the frame data has not been multiplied, the average brightness of the overall picture can be improved. In addition, since the adjacent image data is scanned in a different order, uneven brightness can be avoided. The output of related image data is shown in FIG. 5 , which will not be repeated here.

To sum up, the present invention uses the characteristics of the vertical blanking time to insert low-gray-scale image data during the vertical blanking time, so that the frame data does not need to be frequency-multiplied, so that the image quality and the average brightness of the image are improved. At the same time, since the adjacent image data is scanned in different order, uneven brightness can be avoided and the image quality can be further enhanced. Therefore, the present invention can insert low-gray-scale image data without doubling the frame rate. In addition to improving the image quality, it can also save system resources and prevent electromagnetic radiation such as electromagnetic interference.

The above descriptions are only preferred embodiments of the present invention, and all equivalent changes and modifications made according to the scope of the patent application of the present invention shall fall within the scope of the present invention.

Claims (20)

1. An image processing method for a display device to improve image quality, comprising: receiving a video signal; According to the video signal, a plurality of image data is sequentially generated, and each image data of the plurality of image data includes a frame of data and a low-grayscale image data, respectively corresponding to a frame output time and a frame in the timing sequence of the video signal. vertical blanking time; and The multiple image data are displayed sequentially on a display panel of the display device. 2. The image processing method according to claim 1, wherein the timing of the timing of the video signal conforms to the generalized timing formula of the Image Electronics Standards Association. 3. The image processing method as claimed in claim 1, wherein the grayscale value of each low grayscale frame data is approximately 0. 4. The image processing method as claimed in claim 1, wherein the grayscale value of each low grayscale picture data is smaller than an average result of the grayscale values of all the picture data. 5. The image processing method according to claim 1 , wherein sequentially displaying the plurality of image data alternately displays the plurality of images on the display panel of the display device in a first scanning order and a second scanning order data. 6. The image processing method according to claim 5 , wherein the first scan sequence is from above the display panel to the bottom of the display panel, and the second scan sequence is from below the display panel to the display panel above. 7. The image processing method as claimed in claim 1, wherein the display device is a liquid crystal display device. 8. The image processing method as claimed in claim 1, wherein the frame data of each image data of the plurality of image data is not subjected to frequency doubling processing. 9. The image processing method as claimed in claim 1, wherein a time slot is included between adjacent image data of the plurality of image data. 10. The image processing method as claimed in claim 1, wherein there is a time gap between the frame data and the low-grayscale frame data of each image data. 11. A display device capable of improving image quality, comprising: a receiving end, used to receive a video signal; a display panel; A video processing unit, coupled to the receiving end, is used to sequentially generate a plurality of image data according to the video signal, and each image data of the plurality of image data includes a frame data and a low gray scale image data, respectively A frame output time and a vertical blanking time corresponding to the timing of the video signal; and An output unit, coupled to the video processing unit, is used to sequentially display the plurality of image data on the display panel. 12. The display device according to claim 11, wherein the timing of the timing of the video signal conforms to the generalized timing formula of the Video Electronics Standards Association. 13. The display device as claimed in claim 11, wherein the grayscale value of each low grayscale frame data is approximately 0. 14. The display device as claimed in claim 11, wherein a grayscale value of each low grayscale picture data is smaller than an average result of grayscale values of all the picture data. 15. The display device as claimed in claim 11, wherein the output unit displays the plurality of image data on the display panel in a first scanning sequence and a second scanning sequence alternately. 16. The display device according to claim 15 , wherein the first scan sequence is from above the display panel to the bottom of the display panel, and the second scan sequence is from below the display panel to the display panel above. 17. The display device as claimed in claim 11, wherein the display device is a liquid crystal display device. 18. The display device according to claim 11, wherein the video processing unit does not perform frequency doubling processing on the frame data of each image data of the plurality of image data. 19. The image processing method as claimed in claim 11, wherein a time slot is included between adjacent image data of the plurality of image data. 20. The image processing method as claimed in claim 11, wherein a time slot is included between the frame data and the low-grayscale frame data of each image data.

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