TWI236656B - Method and device of compensating brightness for LCD - Google Patents

Abstract

A method of compensating brightness for LCD includes measuring the original gamma curve of LCD panel, predeterminating a target gamma curve, inputting an initial gray level to figure out the brightness matching on the target gamma curve, finding out an adjusted gray level performing the brightness by the original gamma curve, and repeating above steps to result a lookup table having a plurality of proportion arrays. Thereafter the method further includes calculating the amount distribution of the input gray levels of the image, selecting a matching proportion array from the lookup table according proportion of the dark region and the bright region, substituting the adjusted gray levels for the input gray levels, and outputting the adjusted gray levels to adjust the signal strength and improve image performance. A device is also claimed. The method and device of compensating brightness for LCD are applicable to image adjustment of various LCD or similar displays.

Description

^ 36656 V. Description of the invention 0) Γ The technical field to which the invention belongs 4 &% refers to the method and device method and device for adjusting the input signal strength and the degree compensation, which are suitable for the better image quality Bright y image adjustment. Various liquid display or similar displays [Prior technology] _The popularity of LCD 1-person display and the advantages of high image quality.芏 If it has a low power consumption and a thin computer screen, it will gradually take the mainstream that can be applied to the digital TV, notebook computer or display industry ', then = traditional cathode ray tube (c R τ) becomes a coefficient and dielectric constant And & text is limited to the characteristics of liquid crystal molecules, such as the long coefficient of stickiness and the residual coefficient of afterimage phenomenon, etc., the liquid crystal display will respond to the image of the timer. If the image is a night scene, the problem of = is displayed. If the input screen is darker, the viewer cannot see the image ^ f The degree of acceptance or contrast generated by f appears insufficient, making the scene 'image, such as backlight, ,, and festival. The diurnal surface has too many grayscale values with too much contrast, so that the diurnal surface is more bright and darker than the diurnal image. The diurnal surface of the two areas is dark, and the darker areas are darker and brighter. On the upper side of the area, there will be a brightness contrast adjustment ^ ^ to display a delicate layering sense. Usually, the display and contrast make the image clearer.> The viewer can manually adjust the brightness of the image. It is not rich in color shirts for dynamic image viewing However this hand The dynamic adjustment pairs are fast and diverse, with single brightness and & trouble, because the day-to-day switching of dynamic images must be difficult to adapt to various scene images through the internal two-scale ratio of the display, and the level of the day-and-day is more obvious. ° Early adjustment, strengthen the contrast of the image, make

Page 1236656, description of the invention (2) Please refer to Figure 1. In order to enhance the image, the conventional technology adjusts the method of “setting the gray level brightness control on the LCD display :: ;; on the driver, when the system judges the image Insufficient brightness or contrast i The original gamma line is adjusted to adjust the gamma curve, which also increases the A s inch, and the brightness of the display is also increased, which makes the image: "Production is improved, but this technology has the following disadvantages ： Obtained σ redundancy, another control device needs to be set up inside the display to control the increase of power consumption and resource consumption inside the display. The characteristics of each display surface are different, and the method of controlling f is set for different panel characteristics. The adjustment is not flexible enough for the characteristics of the image. Controlling this force seems to be in view of this. The inventor of the present case provides one, and its device, to improve the above-mentioned disadvantages. A novel exemption compensator. SUMMARY OF THE INVENTION In order to provide a method to consider the characteristics of the LCD panel and use the Kc method, the image quality of the π device. The other purpose is to provide a simple and fast correspondence using the comparison table. The gray scale value of the tolerance compensation method of 3 is fast. Get the adjustment of the appropriate brightness performance quickly, and use it to provide a novel brightness compensation. Device ;; Indicator day-surface method can be used to change the gray scale value. 仏 Various types of liquid crystal display panels Page 10 1236656 V. Description of the invention (3) In order to achieve the above-mentioned invention purpose, the method of this case includes: (1) measurement The original gamma curve of the panel; (2) Set a target gamma curve; (3) Enter an initial grayscale value to obtain the brightness corresponding to the target gamma curve, and find the adjusted gray that represents the brightness on the original gamma curve The step value j (4) repeats the steps (2) to (3) above to generate the initial gray scale value of the complex array and the adjusted gray scale value of the complex array, and summarizes the adjusted gray scale value of the complex array into a proportional array;

(5) Repeat the above steps (2) to (4) to generate a complex array proportional array under different target curves to make a comparison table; (6) Calculate the number distribution of the input grayscale values of the image; (7) Calculate the dark Scale ratio and light scale ratio; (8) Select a corresponding scale array from the dark scale comparison table according to the size of the dark scale ratio, and replace the input gray scale value with the adjusted gray scale value in the scale array;

(9) Select a corresponding scale array from the brightness comparison table according to the size of the brightness scale, and replace the input gray scale value with the adjusted gray scale value in the scale array; and (1 0) change the adjusted gray scale value Output to adjust signal strength to improve image quality. In the present invention, the device for performing the above method includes: a color gradation distribution analysis unit for receiving an image signal and counting the number of distributions of each input gray level value to obtain a color gradation distribution state;

Page 11 l236656 & Description of the invention (4) Two comparison table storage unit for storing the comparison table; and two-magnitude second-order arithmetic unit for calculating the gradation ratio, and substituted into the ± proportional matrix two U U intensity Replace the input grayscale value with the adjusted grayscale value corresponding to the proportional array conversion function #] in the comparison table and rotate it to adjust the intensity of the input signal source to obtain better ^. In order to have a deeper understanding of the present invention, the details are as follows. Also detailed description [Embodiment] Please refer to FIG. 2 for a liquid crystal display of 10 bt.

An image screen has 10 2 4 gray scale values, which will exist in the image: 'Each number of each gray scale value is calculated and calculated, and a color gradation distribution map is obtained. = The range below one ratio of the total gray scale range is set. The dark level region 2} is set to a range above one percentage of the total gray level range as the light level region 2 2. In the preferred embodiment of the present invention, the range of the dark level region is set to be a quarter of the total gray level range. A gray scale range, that is, the gray scale value is 0 to 2 5 6, and the range of the bright scale area is set to a quarter of the gray scale range after the total gray scale range, that is, the gray scale value is 7 6

8 to 1 0 2 4, and then define the dark level ratio as the dark level area 2 1 the number of gray levels 2 3 in the total gray level number; the light level ratio refers to the light level area 2 2 the gray level number 2 4 accounts for the total The ratio of the number of gray levels. Referring to FIG. 3, a preferred embodiment is used to explain how to establish a comparison table on which the brightness of a liquid crystal display panel is improved. The method is as follows: (1) First measure the panel of the liquid crystal display to obtain an original gamma curve 10 ;

1236656 on page 12 5. Description of the invention (5) (2) Set a target gamma curve 1 1; (3) Enter an initial gray level value X i (label 1 2) to obtain the brightness corresponding to the target gamma curve 11 1 Y i (label 1 3), find the adjusted grayscale value X 2 (label 14) representing the brightness on the original gamma curve 10; (4) repeat the steps (2) to (3) above to generate a complex array initial The gray level value X i and the complex array adjustment gray level value X 2, and the complex array adjustment gray level value is summarized into a proportional array; and

(5) Repeat steps (2) to (4) above to generate a complex array proportional array under different target curves to make a comparison table. As shown in Figure 4, in terms of the display resolution of 10 bits, the dark level comparison table 41 and the light level comparison table 4 2 are respectively designed according to the dark level and the light level region, and the dark level control table 41 is selected. 8 sets of initial gray scale values 4 3 and a proportional array group 4 4 containing 6 sets of proportional arrays, and a light level comparison table 4 2 Selects 8 sets of initial gray scale values 4 3 ′ and a proportional array group containing 7 sets of proportional arrays 4 4 ′ Each scale array group 4 4 and 4 4 ′ includes adjusted gray scale values 4 6 and 4 6 ′ corresponding to the initial gray scale values 4 3 and 4 3 ′.

After the image data is input, calculate the number distribution of the input grayscale values of the image to obtain the color gradation distribution map as shown in Figure 2. Calculate the dark scale ratio and the bright scale ratio, respectively. Select a corresponding proportional array in the proportional array group 1 of 4. If the dark scale ratio is higher, Bei 1J selects the stronger proportional array in the dark scale comparison table 4 1 of the dark scale comparison table 4 1 as shown by reference number 4 5 It is shown that the corresponding method of the dark scale ratio and the dark scale ratio table in Table 41 is to substitute the dark scale ratio into a dark scale conversion function to obtain a

Page 13 1236656 V. Description of the invention (6) Dark LUT intensity, that is, the dark level conversion function is one, u T intensity = f 丄 (dark level ratio), the greater the LUT intensity, this = 2 function, that is, dark The higher the scale ratio is, the stronger the scale array in the dark scale 44 is. The intensity of the 9th-order LU corresponds to the scale array group 6 instead of inputting the gray scale value; the same gray scale value is adjusted by the scale array 4 according to Table 4 2 The proportion array group 4 is based on the size of the brightness ratio. From the brightness ratio to the higher brightness ratio, select a corresponding ratio array in the brightness ratio ratio 4, and select the stronger ratio matrix in ^^ See Table 4 for the ratio of 2 The array group 4 4 and the brightness level comparison table 4 2 scale matrix = label 4 5. As shown in the figure, the brightness level ratio and a brightness level conversion function to obtain a corresponding ratio method is to substitute the brightness level ratio = F 2 (brightness level Ratio), "y are all intensities, that is, bright order LU, Ding Qiang, that is, the higher the ratio of the bright order, the 70-order conversion function of the bright order is an increasing function, and the intensity corresponds to the proportional array = 4 The adjusted gray scale value of LU Ding Proportional Array is stronger than 4 and is output with the adjusted gray scale value. In Chile tone generation input grayscale value J, finally, if the - surface of the dark image day; = whiteness improving image quality. The gray scale value between the scale array 4 7 and the light level comparison table 41 1 to the dark level comparison table 41 1 can be interpolated = the scale array 4 7. The schematic diagram of each tone and output is shown in Figure 5. If ^ is obtained differently, the input and output curves of the input area of the grayscale value are as follows: 5 1. The dark adjusted area after the adjustment and the bright output curve 5 1 will be higher than the slope of the slope 丄, 5 2, and dark. The input gray scale value of the input area is equal to the gray scale value of the output, Friend 2 5 3. The straight line 5 3 indicates that it will be lower than the straight line 5 3 of the slope 1. The input and output curves of the U ^ area are 5 2 5 4, 5 5 The critical point 'curve 5', 5 2 and the straight line will be connected to the technical curve 5 1, 5 2 by a straight line 5 6

Page 14 1236656 V. Description of the invention (7) 5 6 constitutes a new image signal adjustment input and output relationship. It can be seen that if the dark level comparison table is provided with P group dark level ratio arrays, and the light level comparison table is provided with Q Group bright-level proportional array. After the combination and arrangement, the combination method of PXQ group proportional array can be obtained, that is, there will be input and output curves for PXQ adjustment, so there are many choices and application flexibility. In addition, the level of the lookup table can be set according to the requirements of the resolution of the display. If the input gray level value is 10 bit and the scale array is set to 12 bit display value, the output gray level value is 1 2 bit, so Only the order of the lookup table needs to be changed to apply to different displays, which is extremely industrially applicable.

Please refer to FIG. 6. The device for performing the above method in the present invention includes: a color level distribution analysis unit 6 1 for receiving image signals and counting the number of distributions of each input gray level value to obtain a color level distribution state ; A lookup table storage unit 6 2 for storing the lookup table; and a color scale operation unit 6 3 for calculating the color scale ratio, and substituting the conversion function into the LUT intensity to correspond to the ratio array in the lookup table, so as to Adjust the grayscale value in the scale array instead of the input grayscale value and output it; to adjust the intensity of the input signal source to obtain better image quality

〇 Therefore, the present invention has the following advantages: 1. Improves the disadvantages of the brightness and contrast of the traditional liquid crystal display. After the image is strengthened, it becomes more contrasty and colorful. 2. The application of the method of the present invention is not limited to the characteristics of a single panel. The gamma curve characteristics of different panels can be measured to make a special comparison table.

Page 15 1236656 V. Description of the invention (8) The image adjusted according to this comparison table can better express the color level. 3. Utilizing the characteristics of the comparison table, the calculation is simple and fast, regardless of the corresponding or interpolated grayscale values. The time for correcting the image signal is greatly shortened, which makes the image appear to be corrected to the target brightness more quickly. * 4. The number of proportional arrays in the comparison table can be set according to requirements. If the number of groups is larger, the more gray scale values can be adjusted. Therefore, the choice is diverse and the application flexibility. 5. The order of the comparison table can be set according to the requirements of the resolution of the display. It can be applied to a variety of displays with different gray levels, which is widely used. In summary, the present invention can indeed achieve the intended purpose, and provide a novel brightness compensation method and device for a liquid crystal display, which is of great industrial use value, and filed a patent application in accordance with the law.

Page 16 1236656 Schematic description 『Schematic Explanation』 Figure 1 is a schematic diagram of the conventional technique of increasing the gamma voltage value to enhance the image. Figure 2 is a schematic diagram of a color gradation distribution image. FIG. 3 is a schematic diagram of the original gamma curve and the target gamma curve of the brightness compensation method and device of the liquid crystal display according to the embodiment of the present invention. FIG. 4 is a schematic diagram of a comparison table of the brightness compensation method and the device of the liquid crystal display according to the embodiment of the present invention. FIG. 5 is a schematic diagram of inputting and outputting grayscale values of the brightness compensation method and the device of the liquid crystal display according to the embodiment of the present invention. FIG. 6 is an image processing flowchart of the brightness compensation method and the device of the liquid crystal display according to the embodiment of the present invention. 『Explanation of Schematic Symbols』 2 1: Dark level region 2 2: Bright level region 2 3: Number of gray levels in dark level region 2 4: Number of gray levels in bright level region 1 0: Original gamma curve 1 1: Target gamma Mark curve 1 2: Initial gray level value X1 1 3: Brightness Y1 1 4: Adjust gray level value X 2 4 1: Dark level comparison table

Page 17 1236656 Schematic illustration 4 2: Bright level pair m $ Table 4 3, 4 3, ·· Initial gray level value 4 4, 4 4 ·· Proportion array group 4 5, 4 5, the direction of strength of the proportional array 4 6 、 4 6 • Adjust the grayscale value 4 7: Dark level pair 昭, η, scale array in the table 4 7,; Bright level scale array in the summon table 5 1, 5 2 • Dark level area and Bright step in and out curve 5 3: a straight line with a slope of 1 (the gray scale value is equal to the output gray scale value) 5 4 、 5 5 • critical point 5 6 straight line 6 1 color scale distribution analysis unit 6 2 Storage unit 6 3 Level operation unit

Page 18

Claims (1)

1236656 VI. Patent Application Range 1. A method for compensating the brightness of a liquid crystal display, including: (1) the original gamma curve of the measurement panel; (2) setting a target gamma curve; (3) entering an initial grayscale value to get the corresponding Based on the brightness of the target gamma curve, find the adjusted grayscale value representing the brightness on the original gamma curve. 1 (4) Repeat the steps (2) to (3) above to generate the complex array initial grayscale value and the complex array adjustment gray. Order value, the grayscale value of the complex array is reduced to a proportional array; (5) Repeat the above steps (2) to (4) to generate a complex array scale array under different target curves to make a comparison table; (6) Calculate the number distribution of the input grayscale values of the image; (7) Calculate the dark Scale ratio and light scale ratio; (8) Select a corresponding scale array from the dark scale comparison table according to the size of the dark scale ratio, and replace the input gray scale value with the adjusted gray scale value in the scale array; (9) Select a corresponding scale array from the brightness comparison table according to the size of the brightness scale, and replace the input gray scale value with the adjusted gray scale value in the scale array; and (1 0) change the adjusted gray scale value The output is used to adjust the signal strength to improve the image X3. It is used to adjust the strength of the input signal source to obtain better image quality. 2. The brightness compensation method of the LCD as described in item 1 of the scope of patent application Page 19, 1236656 6. The patent application range method, where the dark scale ratio refers to the ratio of the number of gray scales in the dark scale area to the total gray scale number, and the range of the dark scale area is a range below one ratio of the total gray scale range; Brightness ratio refers to the ratio of the number of gray scales in the light gray scale to the total number of gray scales, and the range of the light gray scale area is a range above one percentage of the total gray scale range. 3. The brightness compensation method for a liquid crystal display as described in item 2 of the scope of the patent application, wherein the range of the dark range is a quarter of the gray range before the total gray range; the range of the bright range is four after the total gray range. One-half gray scale range. 4. The brightness compensation method for a liquid crystal display as described in item 1 of the scope of the patent application, wherein the dark level comparison table is an array composed of a plurality of input grayscale values and a complex array proportional array, and each input grayscale value may be proportional to The array corresponds to an adjusted grayscale value; the light level comparison table is an array composed of a plurality of input grayscale values and a complex array proportional array. Each input grayscale value can be mapped to an adjusted grayscale value in the proportional array. . 5. The brightness compensation method for a liquid crystal display as described in item 1 of the scope of the patent application, wherein the corresponding method of the dark step ratio and the proportional array is to substitute the dark step ratio into a dark step conversion function to obtain a dark step LUT intensity, that is, a dark step LUT. Intensity = F i (dark scale ratio), the intensity of this dark scale LUT is mapped to the scale array in the dark scale comparison table, and the adjusted gray scale value in the scale array is used instead of the input gray scale value; The corresponding method is to substitute the brightness level ratio into a brightness level conversion function to obtain a brightness level LUT intensity, that is, brightness level LUT intensity = F 2 (brightness ratio), and corresponding this brightness level LUT intensity to the brightness level comparison table. Page 20 1236656 VI. Patent Application Proportional Array. Use this to adjust the grayscale value in the proportional array instead of inputting the grayscale value. 6. The brightness compensation method for a liquid crystal display as described in item 5 of the scope of patent application, wherein the dark-level and bright-level conversion functions are an increasing function, that is, the higher the dark-level and bright-level ratios, the greater the dark-level and bright-level LUT intensity. . 7. The brightness compensation method for a liquid crystal display as described in item 1 of the scope of patent application, wherein the grayscale values between the grayscale values are obtained by interpolation. 8. A brightness compensation method for a liquid crystal display, comprising: (1) calculating a number distribution of an input gray level value of an image; (2) Calculate the dark scale ratio and the light scale ratio separately; (3) Select a corresponding scale array from the dark scale comparison table according to the size of the dark scale ratio, and replace the input gray scale value with the adjusted gray scale value in the scale array. ; (4) select a corresponding scale array from the brightness comparison table according to the size of the brightness scale, and replace the input gray scale value with the adjusted gray scale value in the scale array; and (5) change the adjusted gray scale value Output to adjust signal strength to improve image quality; This adjusts the strength of the input signal source to obtain better image quality. 9. The brightness compensation method for a liquid crystal display as described in item 8 of the scope of the patent application, wherein the dark level ratio refers to the ratio of the number of gray levels in the dark level area to the total number of gray levels, and the range of the dark level area is the total gray level range A range below one scale; the light scale ratio refers to the number of gray scales in the light scale area to the total gray scale Page 21 1236656 VI. The scope of the number of patent applications, and the range of the bright level area is more than one ratio of the total gray level range. 10. The brightness compensation method for a liquid crystal display as described in item 9 of the scope of the patent application, wherein the range of the dark range is a quarter of the gray range before the total gray range; the range of the bright range is after the total gray range. Quarter gray scale range. 1 1 、 The brightness compensation of LCD as described in item 8 of the scope of patent application Method, wherein the dark-level comparison table is an array composed of a plurality of input gray-level values and a complex array proportional array, and each input gray-level value can correspond to an adjusted gray-level value in the proportional array; the light-level comparison table is composed of An array of a plurality of input grayscale values and a complex array of proportional arrays. Each input grayscale value can correspond to an adjusted grayscale value in the proportional array. 12. The brightness compensation method for a liquid crystal display as described in item 8 of the scope of patent application, wherein the corresponding method of the dark step ratio and the proportional array is to substitute the dark step ratio into a dark step conversion function to obtain a dark step LUT intensity, that is, the dark step. LUT intensity = F: (dark scale ratio), this darker LUT intensity corresponds to the scale array in the dark scale comparison table, and the gray scale value in the scale array is used instead of the input gray scale value; the light scale ratio and ratio The corresponding method of the array is to substitute the light-level ratio into a light-level conversion function to obtain a light-level LU Ding intensity, that is, the light-level LUT intensity = F 2 (light-level ratio), and map this light-level LUT intensity to the light-level comparison table. Scaled array. Use the adjusted grayscale value in this scaled array to replace the input grayscale value. Page 22 1236656 VI. Patent application range 1 3, as described in the patent application range item 12, brightness compensation method, wherein the dark level and light level conversion function is an increasing function, that is, the dark level and the light level ratio The higher the dark level and the bright level LUT intensity, the more the brightness compensation method of the liquid crystal display according to item 8 of the scope of the patent application, wherein the gray scale values between the gray scale values are adjusted by interpolation to obtain 0. 5. A liquid crystal A display brightness compensation method includes: (1) the original gamma curve of the measurement panel; (2) setting a target gamma curve; (3) inputting an initial grayscale value to obtain the brightness corresponding to the target gamma curve, and finding an adjusted grayscale value representing the brightness on the original gamma curve; (4) repeating the steps (2) to (3) above to generate the initial grayscale value of the complex array and adjust the grayscale value of the complex array, and summarize the adjusted grayscale value of the complex array into a proportional array; and (5) repeat the above (2) Steps) to (4) generate complex array proportional arrays under different target curves to make a comparison table; thereby adjusting the intensity of the input signal source to obtain better image quality. 16. A brightness compensation device for a liquid crystal display, comprising: a color scale distribution analysis unit for receiving image signals and counting the number of distributions of each input gray scale value to obtain a color scale distribution state Page 23 1236656 VI. Patent application scope A comparison table storage unit to store the comparison table; and a color scale operation unit to calculate the color scale ratio, which is substituted into the conversion function and converted to the LUT intensity to correspond to the ratio in the comparison table. Array, which replaces the input grayscale value with the adjusted grayscale value in this proportional array and outputs it; thereby adjusting the intensity of the input signal source to obtain better image quality. 17. The brightness compensation device for a liquid crystal display as described in item 16 of the scope of the patent application, wherein the conversion function is an increasing function, that is, the higher the ratio of the dark level and the bright level, the greater the intensity of LU T. 18. The brightness compensation device for a liquid crystal display according to item 16 of the scope of patent application, wherein the grayscale values between the grayscale values are adjusted to obtain 0 by interpolation. Page 24