KR102153567B1 - Apparatus and method for compensating of brightness deviation - Google Patents

Abstract

A luminance deviation compensating device and a compensation method for compensating for luminance deviation due to various types of display irregularities at the entire gray level according to the gamma deviation of the display device are provided.

Description

Apparatus and method for compensating of brightness deviation}

The present invention relates to a luminance deviation compensating device for a display device, and in particular, a luminance deviation compensating device and a compensation method for compensating for luminance deviation due to various types of display irregularities with respect to the entire gray level according to the gamma deviation of the display device. It is about.

Recently, flat panel displays such as Liquid Crystal Display (LCD), Plasma Display Panel (PDP), and Organic Light Emitting Diode Display (OLED) are mainly used as image display devices. .

In such a flat panel display, after completing a display panel displaying an image, an inspection process for detecting spots on a display panel such as a mura or the like is performed. In the inspection process, the display panel in which the display spot is detected performs a repair process on the defective part.

Display spots are mainly caused by variations in exposure amount by exposure equipment used in the thin film pattern formation process of a display device. The width of the thin film pattern is varied due to the variation in exposure amount, resulting in variations in parasitic capacitance of the thin film transistor, variation in height of column spacers maintaining the cell gap, variation in parasitic capacitance between signal lines, and the like. These deviations cause luminance deviation, and display stains in the form of vertical or horizontal lines appear on the display panel.

Meanwhile, as display stains that cannot be solved through the above-described repair process exist, recently, a method of compensating for a luminance deviation in a region where the display stain is generated using a data compensation method is considered.

The luminance deviation compensation method includes a manual method in which the display stain is detected and compensated by an operator, and an automatic method in which the display stain is detected and compensated using a camera. The manual method is mainly used because the accuracy is poor and the compensation time is longer.

However, the conventional automatic method of compensating for luminance deviation compensates for the luminance deviation by detecting only representative display spots that appear in a specific area of the display device, for example, display spots of a large size at least in block units. Accordingly, compensation for luminance deviation by the conventional automatic method cannot compensate for display stains that appear in various forms on a display panel such as a sharp mura.

Also, the conventional luminance deviation compensation method does not take into account the gamma characteristic of the display device. Accordingly, a luminance deviation is overcompensated by a gamma characteristic that may appear differently for each display device, resulting in a problem such as deterioration of image quality.

An object of the present invention is to provide a luminance deviation compensating device and a compensation method capable of compensating for display spots in various forms in the entire gray scale area of the display device in consideration of different gamma characteristics for each display device.

In order to achieve the above object, an apparatus for compensating for luminance deviation according to an embodiment of the present invention includes: a pattern output unit for outputting one of a dot pattern signal and a gray pattern signal to a display device; A camera that photographs the entire surface of the display device and outputs a first image based on the dot pattern signal and a second image based on the gray pattern signal; A first compensator for generating first compensating data for one gradation level of the display device from the first image; And calculating a gamma deviation for all gradation levels of the display device from the second image, generating second compensation data for a plurality of gradation levels of the display device from the second image, and generating first compensation data and a second compensation data. And a second compensating unit for generating luminance deviation compensation data for all gradation levels of the display device from the 2 compensation data.

A method for compensating a luminance deviation according to an embodiment of the present invention for achieving the above object includes: extracting camera noise; Removing the camera noise from the first image captured of the dot pattern signal displayed on the display device, and calculating a specific pixel luminance value from the first image from which the noise has been removed; Removing the camera noise from a second image photographed of the gray pattern signal displayed on the display device, and calculating a gamma deviation with respect to the entire gray level of the display device from the noise-removed second image; Generating first compensation data for one gradation level of the display device from the specific pixel luminance value according to the gamma deviation; Calculating a plurality of gradation level luminance values of the display device from the second image from which noise has been removed, and generating second compensation data from the plurality of gradation level luminance values according to the gamma deviation; And generating luminance deviation compensation data for all gradation levels of the display device from the first compensation data and the second compensation data.

In the luminance deviation compensation apparatus and compensation method according to the present invention, compensation data for display stains is generated at one gray level level of the display device, and compensation data is generated at all gray level levels of the display device by using the data. It has various shapes and characteristics at the entire gray level, and can compensate for luminance deviations for display spots.

In addition, by generating compensation data in consideration of different gamma characteristics for each display device, it is possible to prevent the image quality of the display device from deteriorating due to overcompensation by the compensation data.

1 is a block diagram of a compensation system including a luminance deviation compensation device according to an embodiment of the present invention.
2 is a flowchart of the operation of the compensation system.
3A is a diagram illustrating an example of a dot pattern signal output by a pattern output unit.
3B is a diagram illustrating an example of a gray pattern signal output by a pattern output unit.
4 is an operation flowchart showing the operation of the camera.
5 is a flowchart illustrating an operation of the camera compensation unit.
6 is a configuration diagram of a first compensation unit.
7 is a flowchart illustrating an operation of the first compensation unit.
8 is a diagram illustrating a process of generating first compensation data by a first compensation unit.
9 is a configuration diagram of a second compensation unit.
10 is a flowchart illustrating an operation of a second compensation unit.
11 is a diagram illustrating a process of generating second compensation data by a second compensation unit.

Hereinafter, a luminance deviation compensation apparatus and a compensation method according to the present invention will be described in detail with reference to the accompanying drawings.

1 is a configuration diagram of a compensation system including a luminance deviation compensation device according to an embodiment of the present invention, and FIG. 2 is a flowchart illustrating an operation of the compensation system.

1 and 2, the compensation system according to the present embodiment may include a display device 200 and a luminance deviation compensation device 100.

The display device 200 may be a variety of flat panel display devices such as a liquid crystal display device and an organic light emitting display device. The display device 200 may include a display panel (not shown) in which an image is displayed and a driving circuit (not shown) for driving the display panel. The display device 200 may correct a luminance deviation of a display image due to display stains generated in the display panel according to the luminance deviation compensation data LC provided from the luminance deviation compensation apparatus 100. For example, the display device 200 may store the luminance deviation compensation data LC in the driving circuit. In addition, when the display device 200 is driven according to the image signal input from the outside, the image signal displayed on the display panel is corrected according to the stored luminance deviation compensation data LC, thereby reducing the luminance deviation of the image due to display stains. You can compensate.

The luminance deviation compensation device 100 may include a pattern output unit 110, a camera 120, and a compensation module 130.

The pattern output unit 110 may generate and output one of the dot pattern signal PS1 and the gray pattern signal PS2 to the display device 200 (S20).

3A is a diagram illustrating an example of a dot pattern signal output by the pattern output unit, and FIG. 3B is a diagram illustrating an example of a gray pattern signal output by the pattern output unit.

Referring to FIG. 3A, a dot pattern signal PS1 output from the pattern output unit 110 may include a plurality of dot patterns D_PTN.

Each dot pattern D_PTN may be formed as a dot area having a size of N*M (N and M are natural numbers). In the dot area, a plurality of dots including a first dot D1 of a specific gray level and the remaining dots of a gray level different from the first dot D1 may be provided. Each of the plurality of dots may correspond to each pixel of the display device 200.

For example, each dot pattern D_PTN may be formed as a 4*4 dot area. The first dot D1 of 128 gray level and the remaining dots of 0 gray level may be provided in the dot area. The zero gradation level may be the black gradation of the display device 200.

The dot pattern signal PS1 may be output to be displayed on the entire display panel of the display device 200. Accordingly, the number of dot patterns D_PTN included in the dot pattern signal PS1 may vary according to the resolution of the display device 200. For example, suppose that the display device 200 displays Full HD (FHD), a plurality of 480*270 dot patterns D_PTN may be included in the dot pattern signal PS1.

That is, according to the dot pattern signal PS1 composed of a plurality of dot patterns D_PTN, the display device 200 displays a pixel corresponding to the first dot D1 of each of the plurality of dot patterns D_PTN among all pixels, such as FHD. In the case of the display device 200, 480*270 pixels may be displayed at a 128 gradation level, and the remaining pixels of the display device 200 may be displayed at a 0 gradation level. Here, one pixel of the display device 200 may include R, G, and B subpixels.

In addition, the pattern output unit 110 may output a plurality of dot pattern signals PS1 to the display device 200. Each of the plurality of dot pattern signals PS1 may be signals having different positions of the first dots D1 of the plurality of dot patterns D_PTN. For example, the pattern output unit 110 may output a plurality of dot pattern signals PS1 while shifting the first dot D1 in one direction within the dot area in the plurality of dot patterns D_PTN.

Referring to FIG. 3B, the gray pattern signal PS2 output from the pattern output unit 110 may include a gray pattern G_PTN such that all pixels of the display device 200 have the same gray level. The gray pattern G_PTN may be a pattern of 0, 32, 64, 128, 192, and 255 gray levels. Accordingly, the pattern output unit 110 may output the gray pattern signal PS2 for each of the gray patterns G_PTN of 0, 32, 64, 128, 192 and 255 gray levels to the display panel 200.

For example, as shown in FIG. 3B, when the pattern output unit 110 outputs the gray pattern signal PS2 including the gray pattern G_PTN of 128 gray level (128G) to the display device 200, the display device All pixels of 200 can display 128 gray levels.

Referring back to FIGS. 1 and 2, the camera 120 photographs the front surface of the display device 200 when the display device 200 displays one of the dot pattern signal PS1 and the gray pattern signal PS2. Thus, an image signal can be output (S30).

For example, the display device 200 may display the dot pattern signal PS1 output from the pattern output unit 110. The camera 120 may photograph the entire surface of the display device 200 and output the first image signal IS1 based on the dot pattern signal PS1. Here, when the pattern output unit 110 outputs a plurality of dot pattern signals PS1, the camera 120 outputs a plurality of first image signals IS1 corresponding to each of the plurality of dot pattern signals PS1. can do.

Further, the display device 200 may display the gray pattern signal PS2 output from the pattern output unit 110. The camera 120 may photograph the entire surface of the display device 200 and output a second image signal IS2 based on the gray pattern signal PS2. Here, when the pattern output unit 110 outputs a plurality of gray pattern signals PS2, the camera 120 outputs a plurality of second image signals IS2 corresponding to each of the plurality of gray pattern signals PS2. can do.

The first image signal IS1 may be output to the first compensation unit 150 of the compensation module 130, and the second image signal IS2 is output to the second compensation unit 160 of the compensation module 130. Can be.

4 is an operation flowchart showing the operation of the camera.

1, 3A, and 4, the pattern output unit 110 may output an initial dot pattern signal, that is, a first dot pattern signal PS1 to the display device 200 (S101 ). The first dot pattern signal PS1 may be a signal in which a first dot D1 provided in each of the plurality of dot patterns D_PTN is disposed at the top left of the N*M dot region, that is, in the first region.

The camera 120 may photograph the front side of the display device 200 (S102) and output the first image signal IS1 (S103).

Subsequently, the pattern output unit 110 may shift the position of the first dot D1 in each of the plurality of dot patterns D_PTN of the first dot pattern signal PS1 in one direction (S104). For example, the pattern output unit 110 may move the first dot D1 of each dot pattern D_PTN in a first direction, such as a horizontal direction, a vertical direction, or a diagonal direction within the N*M dot area.

Subsequently, the pattern output unit 110 may determine whether the shifted first dot D1 is located in the last area of the dot area (S105). For example, the pattern output unit 110 may determine whether the shifted first dot D1 is located in the lower right corner of the N*M dot area, that is, the N*M-th area.

If the shifted first dot D1 is not located in the last area of the N*M dot area (N), the pattern output unit 110 generates a new dot pattern signal according to the shifted first dot D1, that is, the second dot pattern. The dot pattern signal PS1 may be output to the display device 200 (S101). Then, the camera 120 may capture the second dot pattern signal PS1 (S102) and output a new first image signal IS1 (S103).

However, when the shifted first dot D1 is located in the last area of the N*M dot area (Y), the pattern output unit 110 does not output the dot pattern signal PS1 to the display device 200, Photography by the camera 120 is also ended (S106).

That is, the pattern output unit 110 of the present embodiment generates a plurality of dot pattern signals PS1 while moving the first dot D1 of each dot pattern D_PTN in one direction in the first dot pattern signal PS1. Can be printed. At this time, the pattern output unit 110 moves the first dot D1 until the first dot D1 shifted from each dot pattern D_PTN is located in the last area of the dot area, and thus a plurality of dot pattern signals ( PS1) can be created and printed. Accordingly, the camera 120 may output a plurality of first image signals IS1 corresponding to each of the plurality of dot pattern signals PS1 output from the pattern output unit 110.

For example, in the dot pattern signal PS1, each dot pattern D_PTN has a 4*4 dot area, and the first dot D1 may be located at the first of the 4*4 dot area, that is, in the upper left area. The pattern output unit 110 may sequentially move the first dot D1 of each dot pattern D_PTN in a diagonal direction in a 4*4 dot area. Accordingly, the pattern output unit 110 may output four dot pattern signals PS1 according to the shifted first dot D1. Further, the camera 120 may output four first image signals IS1 corresponding to the four dot pattern signals PS1.

Meanwhile, the pattern output unit 110 may sequentially move the first dot D1 in a 4*4 dot area in a horizontal or vertical direction in each dot pattern D_PTN of the dot pattern signal PS1. Accordingly, the pattern output unit 110 may output 16 dot pattern signals PS1 according to the shifted first dot D1. In addition, the camera 120 may output 16 first image signals IS1 corresponding to the 16 dot pattern signals PS1.

In addition, when the pattern output unit 110 outputs the gray pattern signal PS2 to the display device 200, the camera 120 may capture the image and output the second image signal IS2. As described above, the gray pattern signal PS2 includes a gray pattern G_PTN of 0, 32, 64, 128, 192, and 255 gray levels, so the pattern output unit 110 receives six gray pattern signals PS2. It can be output to the display device 200. In addition, the camera 120 may output six second image signals IS2 corresponding to six gray pattern signals PS2.

Referring back to FIGS. 1 and 2, the compensation module 130 may include a camera compensation unit 140, a first compensation unit 150, and a second compensation unit 160.

The camera compensation unit 140 may extract noise CC by the camera 120 before the first image signal IS1 or the second image signal IS2 is output from the camera 120 (S10). The extracted noise CC may be output to the first compensation unit 150 and the second compensation unit 160 to be described later.

In addition, the camera compensation unit 140 is a background image signal (BG) from the image signal captured by the display device 200 that displays a specific image signal output from the camera 120, for example, a gray pattern signal PS2 of 0 gradation level. ) Can be created. The background image signal BG may be output to the first compensator 150.

5 is a flowchart illustrating an operation of the camera compensation unit.

Referring to FIGS. 1 and 5, an initial photographing of the camera 120 may be performed (S111 ). The initial photographing is taken while the lens of the camera 120 is covered, and the focus between the camera 120 and the display device 200 is excluded.

Subsequently, camera noise CC may be extracted from the initial photographed image signal output from the camera 120 (S113). The extracted camera noise CC may be output to the first compensation unit 150 and the second compensation unit 160, respectively.

Subsequently, the pattern output unit 110 may output a gray pattern signal PS2 of a specific grayscale, for example, a gray pattern signal PS2 including a gray pattern of a 0 grayscale level, to the display device 200. The camera 120 may output the second image signal IS2 by photographing the gray pattern signal PS2 of the 0 gradation level displayed on the display device 200 (S115).

Subsequently, the camera compensation unit 140 may generate a background image signal BG by performing a pre-processing of removing the previously extracted camera noise CC from the second image signal IS2 (S117). The background image signal BG may be output to the first compensator 150.

Meanwhile, in the present embodiment, it has been described as an example that the camera compensator 140 generates a background image signal BG from the second image signal IS2 according to the gray pattern signal PS2 of the 0 gray level. However, the background image signal BG may be generated through the same process in the second compensator 160 to be described later.

Referring again to FIGS. 1 and 2, the first compensation unit 150 of the compensation module 130 displays compensation data of the display device 200, that is, from the first image signal IS1 output from the camera 120. The first compensation data LC1 for a specific gray level of the device 200 may be generated (S40). Here, the first compensation data LC1 may be luminance deviation compensation data for 128 grayscale levels of the display device 200.

6 is a configuration diagram of a first compensator, and FIG. 7 is a flowchart illustrating an operation of the first compensator.

1, 6, and 7, the first compensation unit 150 includes a preprocessor 151, a position detection unit 153, a luminance value calculation unit 155, and a compensation data generation unit 157. I can.

The preprocessor 151 may process the first image signal IS1 to output a first image signal from which noise has been removed (S121).

The preprocessor 151 may convert the first image signal IS1 by bit and normalize it to a predetermined bit (S122). For example, when the first image signal IS1 is input in the form of a 16-bit integer, the preprocessor 151 converts the type of the first image signal IS1 into a 16-bit double. After that, it can be normalized again in the form of an 8-bit integer.

The preprocessor 151 may extract a region of interest (ROI) from the normalized first image signal IS1 (S123). The region of interest is a portion in which an image is mainly displayed on the display device 200 and may be, for example, an active area of the display panel excluding the bezel of the display device 200. Here, the ROI may be extracted with a size larger than that of the active region.

The preprocessor 151 may remove camera noise CC from the extracted image of the ROI (S124). Camera noise CC may be previously generated from the camera compensation unit 140.

Subsequently, the preprocessor 151 may perform correction in consideration of the characteristics of the camera 120 in the first image signal IS1 from which noise has been removed. For example, the camera 120 has a lower amount of light in the outer area compared to the central area of the lens. Accordingly, the preprocessor 151 may perform correction to equalize the luminance of the outer portion and the center of the first image signal IS1.

The position detection unit 153 may detect the position of a specific pixel in the first image signal IS1 output from the preprocessor 151 (S125).

As described above, the first image signal IS1 is an image signal by the dot pattern signal PS1 composed of a plurality of dot patterns D_PTN each having a first dot D1 of a specific gray level. Accordingly, the specific pixel of the first image signal IS1 may mean a pixel corresponding to the first dot D1 of the dot pattern signal PS1. The specific pixel may mean a pixel located in the region of interest extracted by the preprocessor 151 previously.

Meanwhile, the dot pattern signal PS1 includes a plurality of first dots D1. Accordingly, a plurality of specific pixels are included in the first image signal IS1, and the position detection unit 153 may detect a position for each of a plurality of specific pixels, for example, coordinates of a specific pixel.

The position detection unit 153 may detect and output a position of each of a plurality of specific pixels and simultaneously store it as pixel position information. The location detector 153 may accumulate the stored pixel location information and store the entire specific pixel location information PM. The stored total specific pixel location information PM may be output to the second compensator 160 to be described later.

The luminance value calculation unit 155 may calculate a luminance level for a specific pixel detected by the position detection unit 153 (S127).

First, the luminance value calculator 155 may uniformly correct the level of an image for a specific pixel, for example, an image of an area in which the specific pixel is located in the first image signal IS1 output from the camera 120. This is to eliminate a phenomenon in which an image for a specific pixel is spread by pixels of the camera 120 and the pixels of the display device 200 having different sizes. For example, since the pixel of the camera 120 is smaller than the pixel of the display device 200, an actual image of a detected specific pixel may be composed of a plurality of camera pixels. At this time, since the levels of the plurality of camera pixels are not the same, the image for a specific pixel is blurred. Accordingly, the luminance value calculating unit 155 corrects the levels of the plurality of camera pixels using one of an average value, a minimum value, or a maximum value, so that an image for a specific pixel composed of a plurality of camera pixels can have a uniform level. Can be corrected to be.

Here, the luminance value calculator 155 may correct a plurality of camera pixel levels by using a background image signal generated by the camera compensation unit 140, that is, a background image signal BG of a 0 gray level.

After the camera pixel level is corrected, the luminance value calculator 155 may calculate a luminance value of a specific pixel, for example, a gray level level of a specific pixel from the corrected image.

The compensation data generation unit 157 is a first compensation for compensating for a luminance deviation at one gradation level of the display device 200, for example, 128 gradation levels from the luminance value of a specific pixel output from the luminance value calculation unit 155. Data LC1 may be generated (S129).

The compensation data generation unit 157 uses a gamma curve calculated by the second compensation unit 160 to be described later, that is, a gamma deviation (GMA) for the entire gray level of the display device 200, from the luminance value of a specific pixel. The first compensation data LC1 may be generated.

The display device 200 has different red, green, and blue gamma characteristics. Accordingly, red, blue, and green image data having the same gray scale in one pixel of the display device 200 may exhibit different luminances. Accordingly, the compensation data generation unit 157 of the first compensation unit 150 calculates the gamma deviation (GMA) newly calculated according to the red, green, and blue gamma characteristics of the display device 200 from the second compensation unit 160. It is provided, and the first compensation data LC1 for compensating for a difference in luminance value, that is, a luminance deviation for a specific pixel may be generated by using this.

8 is a diagram illustrating a process of generating first compensation data by a first compensation unit.

In FIG. 8, a first gamma curve GMA' is a curve according to a normal gamma deviation, for example, 2.2 gamma, and a second gamma curve GMA is a curve according to a calculated gamma deviation, such as 2.7 gamma. Further, a specific pixel detected by the first compensator 150, for example, the first pixel A1 may have a first luminance value L1.

First, the first compensator 150 includes a first luminance value L1 of a specific pixel, for example, the first pixel A1, and a first gradation level G1 corresponding thereto, from the second gamma curve GMA. Gradation levels can be extracted.

Subsequently, the first compensator 150 has a luminance value corresponding to the first gradation level G1 of the first pixel A1 from the first gamma curve GMA', that is, a second luminance value L2. Two pixels (A2) can be extracted.

Subsequently, the first compensator 150 extracts a gradation level corresponding to the second luminance value L2 of the second pixel A2 from the second gamma curve GMA, that is, the second gradation level G2. I can. The first compensator 150 may extract a third pixel A3 having a second gradation level G2 and a second luminance value L2 from the second gamma curve GMA.

In this way, the first compensator 150 selects a specific pixel having the first gray level G1 and the first luminance value L1 according to the second gamma curve GMA, that is, the first pixel A1 as the second. First compensation data LC1 for compensating to be a third pixel A3 having a gray level G2 and a second luminance value L2 may be generated.

The above-described first compensation data LC1 may be compensation data generated from one first image signal IS1 output from the camera 120. As described above, since the pattern output unit 110 outputs a plurality of dot pattern signals PS1 to the display device 200, the camera 120 also outputs a plurality of first image signals IS1. Accordingly, the first compensator 150 performs preprocessing, specific pixel position detection, luminance value calculation, and compensation data generation for each of the plurality of first image signals IS1 output from the camera 120 to make the final first compensation. Data LC1 can be generated. The final first compensation data LC1 may be compensation data for compensating for luminance deviations for all pixels at the 128 gray level of the display device 200. Here, the final first compensation data LC1 may include a low frequency component and a high frequency component.

Again, referring to FIGS. 1 and 2, the second compensating unit 160 of the compensation module 130 is based on the second image signal IS2 output from the camera 120, the total gray level of the display device 200, For example, a gamma deviation (GMA) for 0 to 255 gray levels of the display device 200 may be calculated (S50).

In addition, the second compensator 160 uses the calculated gamma deviation (GMA) to provide a plurality of grayscale levels of the display device 200, for example, the luminance for 32, 64, 128, and 192 grayscale levels of the display device 200. Deviation compensation data, that is, second compensation data may be generated (S60).

In addition, the second compensating unit 160 generates luminance deviation compensation data LC for all gradation levels of the display device 200 from the first compensation data LC1 and the second compensation data. ) Can be output (S70).

9 is a configuration diagram of a second compensating unit, and FIG. 10 is a flowchart illustrating an operation of the second compensating unit.

1, 9, and 10, the second compensation unit 160 includes a preprocessor 161, a luminance value calculation unit 163, a compensation data generation unit 165, and a data synthesis unit 167. can do.

The preprocessor 161 may preprocess the second image signal IS2 to output a second image signal from which noise has been removed (S131). The preprocessor 161 has the same configuration and operation as the preprocessor 151 of the first compensation unit 150 described above, and a detailed description thereof will be omitted.

The luminance value calculator 163 may calculate luminance values for a plurality of gradation levels of the display device 200 from the second image signal from which noise has been removed (S132).

The luminance value calculation unit 163 may calculate luminance values for 0, 32, 64, 128, 192, and 255 gray levels of the display device 200. The luminance value calculation unit 163 receives all the specific pixel position information PM from the first compensation unit 150 and applies the information to the entire specific pixel for each of the plurality of gray levels of the display device 200. The luminance value can be calculated.

The luminance value calculation unit 163 may calculate a gamma deviation (GMA) for all gradation levels of the display device 200 from luminance values calculated at each of the plurality of gradation levels (S133). The luminance value calculation unit 163 calculates luminance values for six gradation levels of the display device 200, and the total gradation of the display device 200 from the luminance values of the six gradation levels calculated through interpolation. The gamma deviation (GMA) for the level can be calculated.

The compensation data generation unit 167 is configured from the gamma deviation (GMA) calculated by the luminance value calculation unit 163 and the luminance values of a plurality of gradation levels, that is, 0, 32, 64, and Second compensation data LC2 for compensating for luminance deviations for 128, 192, and 255 gray levels may be generated (S134).

11 is a diagram illustrating a process of generating second compensation data by a second compensation unit.

In FIG. 11, a first gamma curve GMA' is a gamma deviation curve according to a conventional 2.2 gamma, and a second gamma curve GMA is a gamma deviation curve according to a calculated 2.7 gamma. In addition, one pixel, that is, the first pixel A1 may have a first luminance value L1 according to the pixel position information PM provided from the first compensator 150.

First, the second compensating unit 160 includes a first luminance value L1 of a specific pixel, for example, the first pixel A1, and a first gradation level G1 corresponding thereto, from the second gamma curve GMA. Gradation levels can be extracted.

Subsequently, the second compensator 160 has a luminance value corresponding to the first gradation level G1 of the first pixel A1 from the first gamma curve GMA', that is, the second luminance value L2. Two pixels (A2) can be extracted.

Subsequently, the second compensator 160 extracts a gradation level corresponding to the second luminance value L2 of the second pixel A2, that is, the second gradation level G2 from the second gamma curve GMA. I can. The second compensator 160 may extract a third pixel A3 having a second gradation level G2 and a second luminance value L2 from the second gamma curve GMA.

In this way, the second compensator 150 selects one pixel having the first gradation level G1 and the first luminance value L1, that is, the first pixel A1 according to the second gamma curve GMA. The second compensation data LC2 for compensating to be the third pixel A3 having the second gradation level G2 and the second luminance value L2 may be generated.

The second compensation data LC2 described above may be compensation data generated from one second image signal IS2 output from the camera 120. As described above, since the pattern output unit 110 outputs a plurality of gray pattern signals PS2, the camera 120 also outputs a plurality of second image signals IS2. Accordingly, the second compensation unit 160 performs pre-processing, luminance value calculation, and compensation data generation for each of the plurality of second image signals IS2 output from the camera 120 to generate a plurality of second compensation data LC2. Can be created. The plurality of second compensation data LC2 is compensation data for compensating for luminance deviations for all pixels at the remaining gradation levels excluding 0 and 255 gradation levels of the display device 200, that is, 32, 64, 128, and 192 gradation levels. I can. Here, each of the plurality of second compensation data LC2 may include only a low frequency component.

The data synthesis unit 167 transfers the display device 200 from the first compensation data LC1 generated by the first compensation unit 150 and the second compensation data LC2 generated by the second compensation unit 160. The luminance deviation compensation data LC for the gradation level may be generated.

The data synthesis unit 167 may extract a high frequency component from the first compensation data LC1 (S135). The first compensation data LC1 may be compensation data for 128 gray levels of the display device 200.

The data synthesizing unit 167 applies a gain parameter to the high frequency component of the extracted first compensation data LC1 to apply a gain parameter to a plurality of gray levels of the display device 200, that is, 32, 64 and 192 gray levels. It can generate high-frequency components. The gain parameter may have different values for each of a plurality of gray levels.

The data synthesizing unit 167 may synthesize the generated high-frequency components of the plurality of grayscale levels into each of the corresponding plurality of second compensation data LC2 (S136). Accordingly, each of the plurality of second compensation data LC2 may include both a low frequency component and a high frequency component.

Subsequently, the data synthesizing unit 167 may generate luminance deviation compensation data LC for all gray levels of the display device 200 from the plurality of second compensation data LC2 through interpolation (S137).

The luminance deviation compensation data LC is output to and stored in the display device 200, and the display device 200 may operate by correcting an image signal input from the outside using the stored luminance deviation compensation data LC.

As described above, the luminance deviation compensation device 100 generates compensation data for all pixels of the display device 200 by using a dot pattern shifted at a specific gray level of the display device 200, and displays the data using the dot pattern. The luminance deviation compensation data LC for all grayscale levels of the device 200 may be generated.

Also, the luminance deviation compensation data LC may be generated according to a gamma characteristic of the display device 200, that is, a gamma deviation GMA. Here, the present invention may generate the luminance deviation compensation data LC in consideration of different gamma characteristics for each display device 200, and further, the luminance deviation compensation data ( LC) can also be produced.

Accordingly, the luminance deviation compensation device 100 of the present invention provides luminance deviation compensation data capable of compensating for luminance deviation due to display spots appearing in various forms for the entire grayscale level according to the gamma deviation (GMA) of the display device 200. (LC) can be produced.

Although many items are specifically described in the above description, this should be interpreted as an example of a preferred embodiment rather than limiting the scope of the invention. Therefore, the invention should not be determined by the described embodiments, but should be determined by the claims and equivalents to the claims.

100: luminance deviation compensation device 110: pattern output unit
120: camera 130: compensation module
140: camera compensation unit 150: first compensation unit
160: second compensation unit 200: display device

Claims (17)

A pattern output unit that outputs one of a dot pattern signal and a gray pattern signal to the display device;
A camera that photographs the entire surface of the display device and outputs a first image based on the dot pattern signal and a second image based on the gray pattern signal;
A first compensator for generating first compensating data for one gradation level of the display device from the first image; And
Calculates a gamma deviation for all gradation levels of the display device from the second image, generates second compensation data for a plurality of gradation levels of the display device from the second image, and generates first compensation data and second compensation data A luminance deviation compensating device comprising a second compensating unit for generating luminance deviation compensation data for all gradation levels of the display device from the compensation data. The method of claim 1,
The dot pattern signal includes a plurality of dots corresponding to each of a plurality of pixels of the display device in a dot area having a size of N*M (N, M is a natural number), and a first dot among the plurality of dots is A luminance deviation compensating device including a plurality of dot patterns having gradation levels. The method of claim 2,
The first dot has a luminance deviation compensation device having a gradation level of 128. The method of claim 1,
The gray pattern signal is a luminance deviation compensation device including a gray pattern such that all pixels of the display device have one of a plurality of gray scale levels. The method of claim 1, wherein the first compensation unit,
A preprocessor for removing camera noise from the first image;
A location detector for extracting location information of a specific pixel from the first image from which noise has been removed;
A luminance level calculator that calculates a luminance value of the specific pixel; And
A luminance deviation compensation apparatus comprising a compensation data generator configured to generate the first compensation data from a luminance value of the specific pixel according to the gamma deviation. The method of claim 1, wherein the second compensation unit,
A preprocessor for removing camera noise from the second image;
A luminance level calculator for calculating luminance values for a plurality of gradation levels of the display device in the second image from which the noise has been removed;
A gamma deviation calculating unit for calculating the gamma deviation for all gradation levels of the display device from luminance values for the plurality of gradation levels; And
A compensation data generator for generating second compensation data from each of luminance values for the plurality of gray levels according to the gamma deviation; And
And a data synthesizing unit for generating the luminance deviation compensation data for all gradation levels of the display device from the first compensation data and the second compensation data. The method of claim 6,
The gamma deviation calculating unit calculates the gamma deviation for all gradation levels of the display device by interpolating luminance values for a plurality of gradation levels of the display device. The method of claim 6,
The data synthesizing unit synthesizes the high frequency component extracted from the first compensation data with the second compensation data to generate the brightness difference compensation data. The method of claim 1,
Luminance deviation compensation apparatus further comprising a camera compensation unit for extracting the camera noise by the camera. Extracting camera noise;
Removing the camera noise from the first image captured of the dot pattern signal displayed on the display device, and calculating a specific pixel luminance value from the first image from which the noise has been removed;
Removing the camera noise from a second image photographed of the gray pattern signal displayed on the display device, and calculating a gamma deviation with respect to the entire gray level of the display device from the noise-removed second image;
Generating first compensation data for one gradation level of the display device from the specific pixel luminance value according to the gamma deviation;
Calculating a plurality of gradation level luminance values of the display device from the second image from which noise has been removed, and generating second compensation data from the plurality of gradation level luminance values according to the gamma deviation; And
And generating luminance deviation compensation data for all gradation levels of the display device from the first compensation data and the second compensation data. The method of claim 10,
The extracting of the camera noise may include extracting the camera noise from an initial image photographed while the camera lens is covered. The method of claim 10,
The dot pattern signal includes a plurality of dots corresponding to each of a plurality of pixels of the display device in a dot area having a size of N*M (N, M is a natural number), and a first dot among the plurality of dots is Includes a plurality of dot patterns having gradation levels,
The step of calculating the specific pixel luminance value,
Shifting the first dot of the dot pattern signal in one direction within the dot area and outputting a plurality of dot pattern signals;
Capturing each of the plurality of dot pattern signals and outputting a plurality of first images;
Extracting an ROI from each of the plurality of first images and removing the camera noise from the extracted ROIs;
Generating specific pixel position information by detecting a position of a specific pixel corresponding to the first dot of each of the plurality of dot pattern signals in each of the plurality of first images from which noise has been removed; And
And calculating the specific pixel luminance value from each of the plurality of first images from which the noise has been removed according to the specific pixel position information. The method of claim 10,
The gray pattern signal includes a gray pattern such that all pixels of the display device have one of a plurality of gray levels,
The step of calculating the gamma deviation,
Outputting a plurality of gray pattern signals corresponding to a plurality of gray level levels of the display device;
Photographing each of the plurality of gray pattern signals and outputting a plurality of second images;
Extracting an ROI from each of the plurality of second images and removing the camera noise from the extracted ROIs;
Calculating a plurality of gradation level luminance values of the display device from each of the plurality of second images from which noise has been removed;
And calculating the gamma deviation for all gradation levels of the display device by interpolating the plurality of gradation level luminance values. The method of claim 13, wherein generating the first compensation data comprises:
Extracting a first gradation level corresponding to the specific pixel luminance value from the calculated gamma deviation;
Extracting a first luminance value of a pixel corresponding to the first gradation level from the normal gamma deviation;
Extracting a second gradation level of a pixel corresponding to the first luminance value from the gamma deviation; And
And generating the first compensation data for compensating a first grayscale level corresponding to the specific pixel luminance value from the gamma deviation to the second grayscale level. The method of claim 13, wherein generating the second compensation data comprises:
Extracting a first gradation level corresponding to a luminance value of one pixel from the calculated gamma deviation;
Extracting a first luminance value of a pixel corresponding to the first gradation level from the normal gamma deviation;
Extracting a second gradation level of a pixel corresponding to the first luminance value from the gamma deviation; And
And generating the second compensation data for compensating a first gradation level corresponding to a luminance value of the one pixel from the gamma deviation to the second gradation level. The method of claim 10, wherein generating the luminance deviation compensation data comprises:
Extracting a high frequency component from the first compensation data;
Generating a high frequency component of the second compensation data by applying a gain corresponding to the second compensation data to the extracted high frequency component; And
And generating the luminance deviation compensation data for all gradation levels of the display device by interpolating the second compensation data. The method of claim 10, after extracting the camera noise,
Further comprising the step of generating a background image by removing the camera noise from the captured image by outputting the gray pattern signal of a specific gray level to the display device,
The calculating of the specific pixel luminance value comprises calculating the specific pixel luminance value from the first image from which the noise has been removed according to the background image.

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