CN1171190C - Brightness compensation method and device for plasma display - Google Patents

Abstract

A brightness compensation method and apparatus for a plasma display, the brightness compensation method comprising the steps of: first, the luminance value of each pixel data in the pixel data column is read. Then, the load of the pixel data column is calculated. The load is the number of pixel data in the pixel data column whose brightness value exceeds the preset brightness critical value. Then, a main brightness compensation value is obtained according to the load, and a plurality of secondary brightness compensation values are obtained according to the main brightness compensation value. Then, the brightness compensation is performed on the pixel data in sequence. When the brightness value is larger than or equal to the preset low brightness decision value, the main brightness compensation value is subtracted from the brightness value. Otherwise, the corresponding sub-brightness compensation value is subtracted according to the brightness value. Finally, the pixel data column is output.

Description

Brightness compensation method and device for plasma display

technical field

The present invention relates to a brightness compensation method and device, and the brightness compensation method particularly relates to a brightness compensation method suitable for a plasma display.

Background technique

In the foreseeable future, people's requirements for sound and light services will increase with the development of audio-visual equipment manufacturing technology and the innovation of display methods. Taking the display as an example, the known cathode ray tube (Cathode Ray Tube, CRT) display has the disadvantages of bulky size and serious radiation, and the image displayed on the edge of the fluorescent screen will also have serious image distortion in the large size of the cathode ray tube display. The problem of distortion and distortion will inevitably fail to meet people's requirements for high-quality audio-visual enjoyment in the future. After the broadcasting of digital television, the cathode ray tube fluorescent screen known to display images in an analog manner will gradually be eliminated. Instead, it will be a plasma display (Plasma Display Panel, PDP) with low radiation, low power consumption, and both large size and small volume.

Please refer to FIG. 1 , which shows a schematic diagram of the loading effect of the fluorescent screen of a plasma display. The so-called load effect means that the brightness displayed by each pixel (pixel) on the fluorescent screen of the plasma display will be affected by the brightness of other pixels on the same row (row), resulting in a gap between the actual display brightness and the normal display brightness. phenomena that cause differences. As shown in Figure 1, three pixel rows (pixel row) 102, 104, 105 on the fluorescent screen, wherein the pixel row 102 is made up of pixel areas (pixel area) 106 and 110; Pixel areas 108 and 112; the pixel row 105 includes pixel areas 109 and 113. The pixel area 106 has a low gray scale value, the pixel area 108 has a middle gray scale value, and the pixel area 109 has a high gray scale value. In addition, the pixel areas 110, 112, 113 have the same gray scale value. Judging by common sense, the pixel areas 110, 112, 113 should display the same brightness. But in fact, the magnitude relationship of the individual luminances L110, L112, 113 of the pixel regions 110, 112, 113 is L110>L112>L113. That is to say, although the grayscale value of the pixel in the pixel region 110 in the pixel row 102, the pixel in the pixel region 112 in the pixel row 104 and the pixel in the pixel region 113 in the pixel row 105 are the same, But because pixel region 106 on pixel row 102 is a darker data point, pixel region 108 in pixel row 104 is a brighter data point than pixel region 106, and pixel region 105 in pixel row 105 is a brighter data point. 109 is a brighter data point than the pixel area 108, so the brightness displayed by the pixels in the pixel area 112 is darker than the brightness displayed by the pixels in the pixel area 110, and the pixels in the pixel area 113 display The brightness of the pixel area 112 is darker than the brightness displayed by the pixels in the pixel area 112. If the brightness of the pixels on the same column of the plasma display fluorescent screen is brighter, the brightness displayed by the pixels in this column is compared with the brightness to be displayed in theory, and the actual display brightness of the pixels is weakened. This situation is called the loading effect. It should be noted that the load effect usually only occurs on the pixels in the same column, that is, the brightness of a certain pixel is only related to the brightness of other pixels in the same column, and is not affected by the brightness of other pixels in the same row (column). Impact. That is, no loading effect occurs in the vertical direction.

Image data (image data) is composed of a plurality of pixel data rows (pixel data row). Taking a plasma display with a panel resolution of 800×600 (that is, the entire fluorescent screen has 800 pixels in each column and 600 pixels in each row) as an example, one image data contains 600 pixels. A pixel data column, and a pixel data column contains 800 pixel data (pixel data). Please refer to FIG. 2 , which is a schematic diagram of a known brightness compensation device 200 . The known brightness compensation device 200 includes a programmable gate array (Field Programmable Gate Array, FPGA) 202 and two memory banks 204 coupled with it. First, the image data input to the plasma display will first enter a brightness compensation device 200 . The brightness compensation device 200 reads one pixel data row at a time, and first determines whether the pixel data row needs brightness compensation. If it is determined that brightness compensation is needed, the brightness compensation device 200 will perform brightness compensation on the pixel data row. Afterwards, the brightness compensation device 200 will output the data of the brightness-compensated pixel data row, and each pixel of the pixel row will be displayed according to the corresponding compensated pixel data, so that each pixel row The actual display brightness of the pixels can be close to the color and brightness that should be displayed by the original display data, without distortion of the brightness and color.

Please refer to FIG. 3 , which is a flow chart of a known method for solving the load effect. The known brightness compensation method of the plasma display is described as follows: firstly, in step 302, the brightness compensation device reads the pixel data column sequentially. Wherein, each pixel data row contains a plurality of pixel data, and each pixel data contains a brightness value.

As mentioned above, the brighter the pixel brightness of a certain pixel column on the phosphor screen of a plasma display, the greater the load effect of this pixel column. In other words, when the actual brightness displayed by the pixel row is compared with the theoretical brightness to be displayed, the degree of reduction in brightness is greater. Therefore, when the brightness compensation device judges whether to perform brightness compensation on a pixel data row, the criterion it is based on is the magnitude of the brightness value of each pixel data in the pixel data row. In pixel data, the size of the brightness value is usually represented by an eight-bit binary format data, which is called the gray level value of the pixel data (gravellevel value). Generally, the gray scale value ranges from (00000000) ₂ to (11111111) ₂ , expressed in decimal format from 0 to 255, where 0 represents all black and 255 represents all white. In this way, there are 256 types of brightness values in total, and the larger the brightness value, the brighter the brightness. A known method is to preset a brightness threshold to determine whether the brightness value of a certain pixel data will cause a load effect on the pixel row. If the luminance value of a certain pixel data is greater than or equal to the luminance critical value, then on the fluorescent screen of the plasma display, the pixels displayed according to the pixel data row will cause the pixel row where it is located to produce a load effect. Wherein, the magnitude of the brightness critical value is preset. In terms of eight-bit binary format grayscale values, the higher the grayscale value data, the greater the weight of the brightness. Therefore, generally, when setting the brightness threshold value, only the high bit of the gray scale value needs to be considered. A known method is to define the threshold value of brightness as the upper three bits of the grayscale value equal to 101. If the upper three bits of the grayscale value of a pixel data are greater than or equal to 101, the pixel data is considered to increase the loading effect of the pixel row on the fluorescent screen of the plasma display. Conversely, if the upper three bits of the gray scale value of the pixel data are less than 101, the pixel data is considered not to increase the loading effect of the pixel column on the fluorescent screen of the plasma display.

After the brightness compensation device reads the pixel data column sequentially. Then enter step 304, the brightness compensation device calculates the load of the pixel data row. The load is defined here as the number of pixel data whose luminance exceeds a preset low luminance decision value in the pixel data row. The greater the load of the pixel data row, the greater the number of pixel data in the pixel data row whose luminance value exceeds the low brightness critical value. In this way, the loading effect of the pixel data on the pixel columns of the phosphor screen of the plasma display will be more serious.

Afterwards, enter step 306, and determine whether the pixel data row needs brightness compensation. As mentioned above, the greater the load of the pixel column on the screen of the plasma display, the more serious the loading effect of the pixel column on the phosphor screen of the plasma display. At this time, it is more necessary for the brightness compensation device to perform brightness compensation. In the known method, when judging whether the pixel data row needs brightness compensation, a load threshold is preset. If the loading of the pixel data row is greater than or equal to the loading threshold, the pixel data row is considered to have a large loading effect and needs to perform brightness compensation. On the contrary, if the load is less than the load threshold value, the pixel data row will be directly output without brightness compensation.

As mentioned above, when the load of the pixel data row is larger, it means that when a certain pixel row of the plasma display phosphor screen is displayed according to the pixel data row, the actual display brightness of the pixel will be weakened more. The known brightness compensation method is to add the gray scale value of each pixel to a brightness compensation value, and increase the brightness of the pixel data row to reduce the influence of the load effect and achieve the effect of brightness compensation.

Furthermore, it has to be considered that the addition of brightness compensation values can of course reduce the loading effect of the pixel columns of the phosphor screen of the plasma display. However, if the brightness compensation value added to a certain pixel data row is too large, the pixel row displayed according to this pixel data row will appear particularly bright compared with other pixel rows. In this way, the continuity of the brightness of the entire image will be affected and the displayed image will be distorted. Therefore, it is necessary to select an appropriate brightness compensation value without affecting the output quality of the image.

A known method for determining an appropriate brightness compensation value for a pixel data row is to pre-build a brightness compensation table in the brightness compensation device. The brightness compensation table is composed of a group of brightness compensation values, and the group of brightness compensation values is arranged in descending order according to the size. That is to say, in the brightness compensation table, the brightness compensation value at the front is larger than the brightness compensation value at the rear. When the pixel data row needs brightness compensation, the brightness compensation device will select an appropriate brightness compensation value according to the brightness compensation table. When step 308 is executed to select the brightness compensation value, the brightness compensation device first selects the first brightness compensation value in the brightness compensation table. That is, the preset maximum brightness compensation value in the brightness compensation table. Afterwards, step 310 is executed to add the brightness compensation value to the brightness value of each pixel in the pixel data column to perform brightness compensation. It can be known from the foregoing that an increase in the grayscale value represents an increase in the brightness of the pixel, so that the effect of brightness compensation can be achieved by increasing the brightness displayed by the pixels on the fluorescent screen. Herein, the pixel data column to which the brightness compensation value has been added is defined as a compensated pixel data column.

Next, enter step 312, calculate the load of the compensated pixel data column. It is calculated in the same way as calculating the load of the original pixel data column. Then, enter step 314 to compare whether the load of the compensated pixel data column is the same as that of the original pixel data column. It can be seen from the foregoing that when performing brightness compensation, adding the brightness compensation value must be based on the premise that the quality of the image output will not be affected. In other words, the added brightness compensation value cannot be too large. The known method for judging whether the added brightness compensation value is too large when performing brightness compensation is: the load of the compensated pixel data row after brightness compensation must be the same as the load of the original pixel data row. If the load of the compensated pixel data column is greater than the load of the original pixel data column, then it is considered that the added brightness compensation value is too large, enough to affect the quality of the output image, and the next step will repeat the action of step 308, by brightness In the compensation table, select the next brightness compensation value. From the foregoing, the relationship between the position and the magnitude of the brightness compensation value in the brightness compensation table shows that the newly selected brightness compensation value will be smaller than the originally selected brightness compensation value. Then, repeat the actions from step 310 to step 314, and judge again whether the added brightness compensation value is too large, and whether it will affect the output quality of the image. If the load of the compensated pixel data column is still greater than the load of the original pixel data column, it will return to step 308, and then select the next smaller brightness compensation value from the brightness compensation table to perform brightness compensation on the pixel data column , until the condition that the load of the compensated pixel data column added with the brightness compensation value is the same as that of the original pixel data column is met. Finally, step 316 is executed to output the compensated pixel data column from the brightness compensation device 200 to complete the brightness compensation.

However, the known methods for performing brightness compensation have the following problems: First, the known brightness compensation methods use a fixed low brightness decision value and a load threshold to determine whether brightness compensation is required. Moreover, when performing brightness compensation, regardless of the load of the pixel data row, the same brightness compensation table is used to determine the brightness compensation value of the pixel data row. But it does not consider the pixel data columns with different loads, and the brightness compensation value to be added must be adjusted accordingly to achieve a better brightness compensation effect. In this way, the added brightness compensation value cannot meet the actual compensation requirement, resulting in distortion and reducing the brightness compensation effect.

In addition, the known practice is to add the same brightness compensation value to the brightness data of all pixels in the same column when performing brightness compensation. So even the luminance data that is completely black will be added with a luminance compensation value. In this way, the dark images that will be made will become brighter than the normal dark images, which not only affects the minimum brightness actually displayed by the fluorescent screen, but also reduces the contrast of image brightness.

On the other hand, if a column of pixel data of the fluorescent screen of the plasma display has the maximum brightness value, that is, the pixel data obtained in the column of pixel data has a gray scale value of 255. In this way, no matter how much the load of the pixels in this column is, any brightness compensation action cannot be performed, because the maximum value of the gray scale can only reach 255. Even if the luminance data of all pixels on the pixel data row are all bright, the load of the pixels in this row is the largest, and the load effect of the pixel row displaying the pixel data row is also the largest. Therefore, the brightness compensation value to be added to the pixel data column should be the largest. However, since the luminance value of the pixel data is already the maximum value, the luminance compensation cannot be performed by the known method of adding a luminance compensation value.

In addition, the known brightness compensation method is to compare the pixel data of the pixel data column before and after adding the brightness compensation value, and judge whether the number of pixels whose gray scale value is higher than three bits or equal to 101 is equal, To determine whether the added brightness compensation value is appropriate. However, if the grayscale value of a certain pixel in a column of pixel data happens to be "(10011111) ₂ ", then no matter what brightness compensation value is added, the brightness of the compensated pixel data column after adding the brightness compensation value will be The number of pixels whose upper three bits of data are greater than or equal to 101 will be greater than the number of pixels whose upper three bits of brightness data are greater than or equal to 101 in the original pixel data column. That is to say, if the grayscale value of a pixel in a certain column of pixel data is exactly "(10011111) ₂ ", then this column of pixel data will not be able to perform brightness compensation.

As can be seen from the above description, the known brightness compensation method has at least the following disadvantages:

1. The brightness compensation value cannot be adjusted according to how much the pixel brightness exceeds the low brightness decision value.

2. It will affect and increase the minimum brightness value displayed by the pixels of the fluorescent screen, and reduce the contrast of image brightness.

3. If at least one pixel in the same row of pixel data is fully bright, then these fully bright pixels cannot perform brightness compensation.

4. If the grayscale value of at least one pixel in the same column of pixel data is close to the preset brightness threshold, for example, "(10011111) ₂ ", then the pixel in this column cannot perform brightness compensation.

Contents of the invention

In view of this, the purpose of the present invention is to provide a brightness compensation method suitable for plasma displays to achieve the following purposes:

1. The brightness compensation value can be adjusted according to how much the pixel brightness exceeds the load level.

2. Brightness adjustment does not affect the minimum brightness value displayed on the fluorescent screen, nor does it reduce the contrast of image brightness.

3. It is not impossible to perform brightness compensation due to some special circumstances.

According to the object of the present invention, a brightness compensation method suitable for a plasma display is proposed. The plasma display has a brightness compensation device, and the device uses the brightness compensation method to perform brightness compensation on a pixel data row. The brightness compensation method at least includes the following steps: first, read the brightness value of each pixel data in the pixel data row; then, calculate the load of the pixel data row, wherein, the load is that the brightness value in the pixel data row exceeds a preset The number of pixel data of the brightness critical value; Next, get the corresponding main brightness compensation value according to the load; After that, get the corresponding multiple sub-brightness compensation values according to the main brightness compensation value; Then, extract each pixel in sequence The brightness value of the pixel data, and perform brightness compensation according to the brightness value of each pixel data. Subtract the primary brightness compensation value; otherwise, subtract the corresponding secondary brightness compensation value according to the brightness value; finally, output the pixel data column.

That is to say, the present invention provides a brightness compensation method for a plasma display, the plasma display includes a brightness compensation device, and the brightness compensation method is to adjust the brightness of a pixel data column input to the plasma display. Compensation, wherein, the pixel data row contains a plurality of pixel data with a brightness value, the brightness compensation method comprises the following steps:

Read the brightness value of the pixel data in the pixel data column;

calculating a load of the pixel data row, wherein the load is equal to the number of pixel data whose luminance value exceeds a preset luminance threshold;

Obtain a main brightness compensation value corresponding to the pixel data row according to the load;

A plurality of sub-luminance compensation values corresponding to the pixel data column are obtained according to the main luminance compensation value, wherein, in the pixel data column, the pixel data whose luminance value is lower than a low luminance decision value are respectively corresponding to the sub- One of the brightness compensation values;

performing brightness compensation operations on each pixel data of the pixel data row in sequence, wherein, when the brightness value of each pixel data is greater than or equal to the low brightness determination value, the brightness value is subtracted from the main brightness compensation value, Otherwise, subtracting the corresponding brightness compensation value from the brightness value; and

Output the pixel data column.

The present invention also provides a brightness compensation device for a plasma display. The brightness compensation device performs brightness compensation on a pixel data row input to the plasma display, wherein the pixel data row includes a plurality of value of pixel data, the brightness compensation means includes:

A data reading device, used to read the brightness value of the pixel data in the pixel data row;

a load calculation device, used to calculate a load of the pixel data row, wherein the load is equal to the number of pixel data whose luminance value exceeds a preset luminance critical value;

a main brightness compensation value determining device, used to obtain a main brightness compensation value corresponding to the pixel data row according to the load;

A primary brightness compensation value determining device, used to obtain a plurality of secondary brightness compensation values corresponding to the pixel data row according to the main brightness compensation value, wherein, in the pixel data row, the brightness value is lower than a low brightness determination value The pixel data of is each corresponding to one of the sub-luminance compensation values;

A pixel data compensating device, which is used to sequentially perform the brightness compensation operation on each pixel data of the pixel data row, wherein, when the brightness value of each pixel data is greater than or equal to the low brightness determination value, the subtracting the main brightness compensation value from the brightness value, otherwise, subtracting the corresponding secondary brightness compensation value from the brightness value; and

An output device is used for outputting the pixel data column.

In order to make the above objects, features, and advantages of the present invention more comprehensible, a preferred embodiment will be described in detail below in conjunction with the accompanying drawings.

Description of drawings

FIG. 1 is a schematic diagram illustrating the loading effect of a phosphor screen of a plasma display.

FIG. 2 is a schematic diagram of a known brightness compensation device.

FIG. 3 is a flow chart of a known method for solving the loading effect of a plasma display.

FIG. 4 is a flowchart of a brightness compensation method for a plasma display according to a preferred embodiment of the present invention.

FIG. 5 is a table showing the correspondence relationship between the load of the pixel data row and the main brightness compensation value built in a brightness compensation device.

FIG. 6 is a table showing the corresponding relationship between the brightness value and the secondary brightness compensation value under the condition that the primary brightness compensation value is 10 built in a brightness compensation device.

FIG. 7 is a table showing the corresponding relationship between the brightness value and the secondary brightness compensation value when the primary brightness compensation value is 20 built in a brightness compensation device.

Detailed ways

The spirit of the present invention is to determine different brightness compensation values according to the different brightness values of each pixel data in the pixel data row. And the brightness compensation is performed by subtracting the brightness compensation value from the brightness value.

Please refer to FIG. 4 , which is a flow chart of a brightness compensation method for a plasma display according to a preferred embodiment of the present invention. If a plasma display fluorescent screen with a resolution of 800×600 is taken as an example, each pixel column has 800 pixels, and each pixel has pixel data of three colors: red, blue, and green, and each The pixel data of the color has a brightness value, so that each pixel on the fluorescent screen can display an appropriate color and brightness. Therefore, the brightness compensation device performs brightness compensation on the brightness values of a pixel data column, which has a total of 800×3 and 2400 pixel data at a time.

First, step 402 is executed, and the brightness compensation device reads all the pixel data of one pixel data column at a time, totaling 2400 pixel data. Afterwards, step 404 is executed to calculate the load of the pixel data column. The method of calculating the load is the same as the known method. The brightness compensation device calculates the number of pixel data whose brightness value exceeds a preset brightness threshold to determine the load of the pixel data row. It should be noted that since the characteristics of the plasma phosphor screen of each plasma display are not the same, when the load effect occurs, the magnitude of the load effect is also different. In other words, when the same pixel data column is input to different plasma displays, the degree of loading effect on the fluorescent screens of different plasma displays is also different due to the difference in characteristics of the plasma panel of each plasma display. In order to achieve the best brightness compensation effect, the brightness threshold value preset by the brightness compensation device of each plasma display must also be properly adjusted according to the differences in the characteristics of the plasma panels of each plasma display.

After the brightness compensation device obtains the load of the pixel data column, it can execute step 406 to determine the main brightness compensation value according to the size of the load of the pixel data column by using a look-up table method. In the present invention, a brightness compensation table is built in the brightness compensation device in advance. Please refer to FIG. 5 , which shows a correspondence table between loads of pixel data rows built in the brightness compensation device and main brightness compensation values. Different from the known method, the brightness compensation table proposed by the present invention is divided into several different levels according to the size of the load of the pixel data column, and each level corresponds to a main brightness compensation value, as shown in FIG. 5 . In this way, the disadvantages of the known luminance compensation method that only decides whether to perform luminance compensation with a fixed load threshold, and the size of the luminance compensation value cannot be adjusted according to the load of the pixel data column can be improved.

As mentioned above, due to the differences in the characteristics of the plasma panel of each plasma display, the load effect caused on the fluorescent screen of different plasma displays is also different. Therefore, the corresponding relationship between the load size and the brightness compensation value is different for different plasma displays. Therefore, when performing a product test on each plasma display, the corresponding relationship between the load and the main brightness compensation value in the brightness compensation table must be preset and stored in the brightness compensation device.

The known brightness compensation method is to directly add the brightness compensation value to the brightness data. But in this way, the brighter the brightness of the pixel data row is, the larger the loading effect will be, but the more difficult it is to perform brightness compensation. In a plasma display, the greater the load effect of the pixel row, the greater the brightness reduction of the brightness displayed by the pixel is compared with the brightness to be displayed in theory. From the above, it can be seen that the higher the load of the pixel row needs to increase the brightness, but the brightness of the pixel with the larger brightness value is difficult to increase the brightness of the pixel by adding the brightness compensation value. Since the gray scale value of the pixel data with high brightness value cannot be increased, the gray scale value of the pixel data with low brightness value is reduced to reduce the brightness.

Therefore, the method adopted by the present invention is to subtract a brightness compensation value from each brightness data. Thus, when the pixels in the pixel column on the phosphor screen of the plasma display are displayed according to the pixel data, the luminance of the pixels in the same column as the pixels displaying high luminance are dimmed due to the loading effect. On the other hand, the displayed brightness of the pixels in the same column as displaying the low brightness will be darker than the original due to the appropriate subtraction of a brightness compensation value. At this time, the difference between the actual luminance displayed by the pixel displaying high luminance and the pixel displaying low luminance is similar to the difference between the two grayscale values in the original pixel data. Therefore, the impact of the load effect on the image quality and distortion displayed on the fluorescent screen of the plasma display can be alleviated.

Please refer to Fig. 5 again, as mentioned above, the greater the load of the pixel data row means that when the pixel row on the fluorescent screen is displayed according to the pixel data row, the load effect is greater, that is, the pixel on the pixel row displays The more the brightness of the display is attenuated than it should be. Conversely, for a pixel with a smaller load effect, the displayed brightness is less attenuated from the originally displayed brightness. If brightness compensation is to be performed according to the method proposed by the present invention, the brightness compensation value to be subtracted should be smaller for the pixel data column with a larger load. The smaller the load of the pixel data column, the larger the brightness compensation value to be subtracted. In other words, as the load of the pixel data column decreases, the main brightness compensation value to be subtracted increases. It should be noted that since the magnitude of the load effect generated by the plasma fluorescent screen panel is not directly proportional to the magnitude of the load of the fed-in pixel data column, the corresponding relationship between the preset load and the main brightness compensation value is determined by The premise of achieving a better brightness compensation effect does not necessarily have to be a linear relationship as shown in FIG. 5 .

When performing brightness compensation according to the method proposed by the present invention, a brightness compensation value needs to be subtracted from the brightness value of the pixel data. However, in the pixel data column, the luminance value of some pixel data is already very small. If the luminance compensation value is subtracted, the luminance value of this pixel data may be reduced to zero, thus affecting the display image. image brightness contrast. In order to reduce the load effect of the fluorescent screen of the plasma display without affecting the contrast of the displayed image, it is necessary to additionally consider the pixel data with lower brightness values, and subtract the brightness compensation value when performing brightness compensation. In the present invention, a low brightness decision value is preset in the brightness compensation device. It is used to determine whether each pixel data is normal brightness pixel data or low brightness pixel data. If the luminance value of certain pixel data is greater than or equal to the low luminance decision value, the pixel data can be regarded as general luminance pixel data. If the luminance value of a certain pixel data is lower than the low-brightness decision value, this pixel data is regarded as low-brightness pixel data. Determines the brightness compensation value to subtract.

Next, step 408 is executed. In step 408, the sub-luminance compensation value to be subtracted from the low-luminance pixel data is determined according to the magnitude of the main brightness compensation value. The method adopted by the present invention is: divide the pixel data whose luminance value is lower than the low luminance decision value into several different low luminance levels according to the size of the gray scale value, and each low luminance level corresponds to a brightness compensation value. It should be noted that, for low-brightness pixel data with a larger grayscale value, the corresponding sub-brightness compensation value must be closer to the main brightness compensation value. When performing brightness compensation, the difference between the brightness compensation value subtracted from the low-brightness pixel data close to the low-brightness decision value and the normal-brightness pixel data close to the low-brightness decision value should be as small as possible. The low-brightness pixel data close to the low-brightness decision value and the general-brightness pixel data close to the low-brightness decision value have different brightness compensation effects due to the subtraction of different brightness compensation values, so the image will be displayed in this way. Unnatural levels of light and dark occur. In addition, the magnitude of the sub-brightness compensation value will gradually decrease as the corresponding gray scale value decreases. In other words, when performing brightness compensation on pixel data with a lower brightness value, the subtracted brightness compensation value will be smaller, or even 0. In this way, the low-brightness pixel data will not reduce the contrast between light and dark at low gray scales after subtracting the sub-brightness compensation value.

Please refer to FIG. 6 , which shows a corresponding relation table between a brightness value selected by the present invention and a secondary brightness compensation value under the condition that the primary brightness compensation value is 10 built in a brightness compensation device. Assume that a brightness compensation value sets the low brightness determination value to 100. Pixel data with a grayscale value greater than or equal to 100 is normal brightness pixel data, while pixel data with a grayscale value smaller than 100 is regarded as low brightness pixel data. According to the foregoing, when the main brightness compensation value is determined to be 10, the closer to 100 the low-brightness pixel data is, the closer the corresponding sub-brightness compensation value is to 10. As shown in Figure 6, set the sub-brightness compensation value corresponding to the pixel data whose brightness gray scale value is between 90 and 100 to 9, and the sub-brightness compensation value corresponding to the pixel data whose brightness is between 80 and 90 The value is 8, and so on, the set sub-brightness compensation value decreases with the decrease of the brightness. As for the brightness data whose grayscale value is lower than 10, since the grayscale value is already very small, the secondary brightness compensation value is set to 0, that is, no brightness compensation process is performed. In this way, on the one hand, brightness compensation can be performed, and on the other hand, the brightness performance of the pixels displaying low-brightness pixel data in the pixel row can also be preserved, so as to maintain the size of the brightness contrast of the displayed image.

The brightness compensation device must preset the corresponding relationship between the brightness value and the secondary brightness compensation value in the case of different primary brightness compensation values. When performing brightness compensation, the low brightness compensation can be performed with the difference of the main brightness compensation value. Please refer to FIG. 7 , which shows a corresponding relation table between the brightness value and the secondary brightness compensation value under the condition that the main brightness compensation value is 20 built in a brightness compensation device. The method for determining the sub-brightness compensation value corresponding to the low-brightness pixel data with different brightness values is the same as the above-mentioned case where the primary brightness compensation value is 10. It should be noted that the magnitude of the sub-brightness compensation value must also be properly adjusted according to the different characteristics of the plasma panel of each plasma display. In addition, the same as the above-mentioned situation of determining the main brightness compensation value corresponding to different loads, the preset corresponding relationship between low brightness pixel data and sub brightness compensation value can achieve a better brightness compensation effect while maintaining The luminance of the pixels displaying low-brightness pixel data on the fluorescent screen is a premise, and does not necessarily have a linear relationship as shown in FIGS. 6 and 7 .

After determining the primary brightness compensation value and the secondary brightness compensation value to be subtracted for performing brightness compensation, then step 410 is performed to sequentially perform brightness compensation on each pixel data. The brightness compensating device sequentially reads the brightness value of each pixel data in the pixel data column. Afterwards, step 412 is executed to determine whether the pixel data is normal brightness pixel data. If so, then execute step 414, subtract the main brightness compensation value from the brightness value of this pixel data; The size of , minus its corresponding sub-luminance compensation value. After brightness compensation is performed on the pixel data, step 418 is executed to output the pixel data. The luminance compensation means performs luminance compensation by subtracting an appropriate luminance compensation value from the pixel data and outputting the compensated pixel data. Therefore, after outputting the pixel data, step 420 is executed to check whether there is any pixel data in the pixel data column that has not been subjected to brightness compensation. If yes, repeat step 410 to continue to sequentially perform brightness compensation on the pixel data. If not, it means that all the pixel data in the pixel data row have been brightness compensated. In this way, it means that the brightness compensation device has completed the brightness compensation work for a pixel data row and the process ends.

The brightness compensation method and device for plasma displays disclosed in the above embodiments of the present invention can achieve the following effects:

1. The present invention determines different main brightness compensation values according to the load of each pixel data column, and selects an appropriate secondary brightness compensation value for low brightness pixel data according to the brightness value. When performing brightness compensation, the size of the brightness compensation value can be properly adjusted according to the size of the load of the pixel data column and its own brightness value. In this way, a better effect of brightness compensation can be achieved, and the known brightness compensation method can be improved. Only a fixed brightness compensation table is used to determine the brightness compensation value that needs to be added to the pixel data columns of different loads, and cannot follow the pixel data. The disadvantage of determining the brightness compensation value is the load size of the column.

2. The present invention performs brightness compensation by subtracting the brightness compensation value from the brightness value. In this way, the known brightness compensation method will be improved, and the brightness value is directly added to the brightness compensation value, resulting in the disadvantage that it is more difficult to perform brightness compensation when the load effect is greater. If there is a pixel in the pixel data row whose brightness is fully bright, or a pixel in the pixel data row whose brightness grayscale value is "(10011111) ₂ ", brightness compensation can be performed.

3. In the present invention, in addition to subtracting the brightness compensation value from the brightness value of the pixel data, the low brightness pixel data performs brightness compensation according to the brightness value minus an appropriate sub-brightness compensation value. In this way, on the one hand, brightness compensation can be performed, and on the other hand, the brightness performance of pixels displaying low-brightness pixel data on the fluorescent screen of the plasma display can also be maintained, so that the brightness compensation does not affect the minimum brightness value displayed on the fluorescent screen, nor The amount of brightness contrast that reduces image brightness.

In summary, although the present invention has been disclosed above with a preferred embodiment, it is not intended to limit the present invention. Any person skilled in the art may make various modifications without departing from the spirit and scope of the present invention. Therefore, the scope of patent protection of the present invention should be as defined by the appended claims.

Claims (7)

1. luminance compensation method that is used for plasma scope, this plasma display comprises a luminance compensating mechanism, this luminance compensation method is that the pixel data row that input to this plasma display are carried out luminance compensation, wherein, these pixel data row comprise a plurality of pixel datas with a brightness value, and this luminance compensation method may further comprise the steps:

Read the brightness value of pixel data in these pixel data row;

Calculate a load of these pixel data row, wherein, this load is to equal the number that this brightness value surpasses the pixel data of a default brightness critical values;

Obtain this pixel data according to this load and be listed as a pairing subjective brightness offset;

Obtain this pixel data according to this subjective brightness offset and be listed as pairing a plurality of luminance compensation values, wherein, in these pixel data row, the pixel data that brightness value is lower than a low-light level signals is respectively to correspond to one of time luminance compensation value;

Each pixel data to these pixel data row carries out the luminance compensation action in regular turn, wherein, when the brightness value of each pixel data more than or equal to this low-light level signals, then this brightness value is deducted this subjective brightness offset, otherwise, then this brightness value is deducted its pairing this time luminance compensation value; And

Export this pixel data row.

2. luminance compensation method according to claim 1 is characterized in that, this subjective brightness offset is to obtain by look-up table according to this load.

3. luminance compensation method according to claim 1 is characterized in that, this time luminance compensation value is to obtain by look-up table according to this subjective brightness offset.

4. luminance compensation method according to claim 1 is characterized in that, each pixel data that brightness value is lower than this low-light level signals is that the size according to the brightness value of each pixel data obtains pairing luminance compensation value of this pixel data by look-up table.

5. luminance compensation method according to claim 1 is characterized in that, more little when the load of these pixel data row, its pairing subjective brightness offset is then big more.

6. luminance compensation method according to claim 1 is characterized in that, the brightness value of each pixel data that brightness value is lower than this low-light level signals is big more, and pairing time the luminance compensation value is then big more.

7. the luminance compensating mechanism of a plasma scope, this luminance compensating mechanism is that the pixel data row that input to this plasma display are carried out luminance compensation, wherein, these pixel data row comprise a plurality of pixel datas with a brightness value, and this luminance compensating mechanism comprises:

One data fetch device is in order to read the brightness value of pixel data in these pixel data row;

One load calculation device, in order to calculate a load of these pixel data row, wherein, this load is to equal the number that this brightness value surpasses the pixel data of a default brightness critical values;

One subjective brightness offset determination device is listed as a pairing subjective brightness offset in order to obtain this pixel data according to this load;

A luminance compensation value determining device, be listed as pairing a plurality of luminance compensation values in order to obtain this pixel data according to this subjective brightness offset, wherein, in these pixel data row, the pixel data that brightness value is lower than a low-light level signals is respectively to correspond to one of time luminance compensation value;

One pixel data compensation system, carry out this luminance compensation action in order to each pixel data that in regular turn this pixel data is listed as, wherein, when the brightness value of each pixel data more than or equal to this low-light level signals, then this brightness value is deducted this subjective brightness offset, otherwise, then this brightness value is deducted its pairing this time luminance compensation value; And

One output unit is in order to export this pixel data row.

Images