KR101528146B1 - Driving apparatus for image display device and method for driving the same - Google Patents

Abstract

The present invention relates to a driving apparatus for a video display device and a driving method thereof for improving the chroma saturation improvement efficiency by varying the saturation improvement degree of the display image according to the hue change rate of the video data input from the outside, A display panel formed with the pixel region of the pixel; A gate and data for driving a plurality of gates and data lines provided in the display panel; An image conversion processing unit for analyzing saturation data of image data input from the outside to detect a saturation correction coefficient and setting a gain coefficient according to the detected correction coefficient and a setting coefficient from the user to convert saturation data of the image data; And a timing controller for controlling the gate and the data driver by generating a gate and a data control signal by supplying the converted data obtained by converting the saturation data to the data driver in accordance with the driving of the display panel, do.

The saturation data (U, V), luminance data (Y), correction coefficient, gain coefficient

Description

TECHNICAL FIELD [0001] The present invention relates to a driving apparatus for a video display device and a driving method thereof. BACKGROUND OF THE INVENTION [0002]

The present invention relates to a video display apparatus, and more particularly to a video display apparatus and a video display apparatus capable of improving the color improvement efficiency by varying the degree of color improvement of a display image according to a color change rate of image data input from the outside, And a driving method thereof.

2. Description of the Related Art Recently, flat panel display devices that have emerged include a liquid crystal display, a field emission display, a plasma display panel, and a light emitting display.

The flat panel display devices have excellent resolution, color display, and image quality, and are actively applied to notebook computers, desktop monitors, and mobile terminals.

In this image display apparatus, in order to improve the sharpness of the displayed image, the saturation data of the display image is collectively changed to implement the image. Specifically, conventionally, the rate of change of the saturation data is set in advance, and the saturation of the image is changed in a batch manner according to the set change rate, so that the image can be more clearly implemented. However, if the rate of change of the saturation data is previously set and changed as in the prior art, there arises a problem that the sharpness is lowered when displaying the low saturation images. In other words, if the saturation of a low-saturation image or a high saturation-rich image is changed at a predetermined rate of change, the image is blurred according to the characteristics of the image and the sharpness is further decreased to cause adverse effect.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems and it is an object of the present invention to provide an image display apparatus capable of improving color improvement efficiency by varying the degree of color improvement of a display image according to a color change rate of image data input from the outside, And an object of the present invention is to provide a device and a driving method thereof.

According to an aspect of the present invention, there is provided a display apparatus including a display panel including a plurality of pixel regions; A gate and data for driving a plurality of gates and data lines provided in the display panel; An image conversion processing unit for analyzing saturation data of image data input from the outside to detect a saturation correction coefficient and setting a gain coefficient according to the detected correction coefficient and a setting coefficient from the user to convert saturation data of the image data; And a timing controller for controlling the gate and the data driver by generating a gate and a data control signal by supplying the converted data obtained by converting the saturation data to the data driver in accordance with the driving of the display panel, do.

Wherein the image conversion processing unit comprises a luminance / chrominance separation unit for detecting and separating luminance and chroma data of the image data, histograms of the detected chroma data, detecting the correction coefficient, A chrominance correction unit that compares the set coefficients and generates the gain coefficient according to a result of the comparison and corrects the chroma data using the generated gain coefficient, And a conversion data generating unit for generating and outputting the converted data in which the saturation is converted by combining the corrected saturation data and the delayed luminance data from the color difference correcting unit .

The chroma correcting unit may include a UV correcting unit for modulating the chroma saturation degree of the saturation data so as to grasp the degree of chroma saturation through bit conversion and outputting a modulated chroma saturation value, a comparator for comparing the modulated chroma saturation values with a maximum value A histogram generator for generating histogram information by arranging the maximum chroma values corresponding to each gray level in at least one frame unit and generating histogram information and outputting information of the histogram; A correction coefficient calculating unit for calculating a correction coefficient corresponding to a maximum level among the distributed gradations and outputting the correction coefficient as the correction coefficient and selecting a coefficient having a smaller value by comparing the calculated correction coefficient with the setting coefficient, To generate a gain coefficient for generating and outputting the gain coefficient A UV delay unit for delaying and outputting the chroma data separated from the luminance / chrominance separation unit until the gain coefficient is generated, and a UV delay unit for computing the gain coefficient with the delayed input chroma data, And a UV conversion unit for generating data and supplying the generated data to the data conversion data generation unit. Further, the gain coefficient generator may set a value obtained by dividing the correction coefficient and the lower coefficient among the set coefficients by the gain coefficient in the total number of gradations displayed in the image.

According to another aspect of the present invention, there is provided a method of driving an image display apparatus for displaying an image using a display panel having a plurality of pixel regions, Driving a plurality of gates and data lines provided on the display panel; detecting saturation correction coefficients by analyzing chroma data of image data input from the outside; detecting a gain coefficient according to the detected correction coefficient and a setting coefficient from the user; And converting the saturation data of the image data; And displaying the image by arranging the converted data in which the saturation data is converted to be suitable for driving the display panel.

Wherein the step of converting the saturation data of the image data includes detecting and separating luminance and saturation data of the image data, histogramming the detected saturation data to detect the correction coefficient, Comparing the inputted setting coefficients, generating the gain coefficient according to a result of the comparison, and correcting the chroma data using the generated gain coefficient, and outputting the separated luminance data for a predetermined period of time And generating and outputting the converted data in which the saturation is converted by combining the corrected saturation data and the delayed luminance data.

The step of correcting the saturation data may include modulating the saturation degree of the saturation data so as to grasp the degree of saturation through bit conversion and outputting a modulated saturation value, comparing the modulated saturation values, and detecting a maximum saturation value And generating and outputting information of a histogram by arranging the maximum chroma values corresponding to each gradation in at least one frame unit and histograms, analyzing histogram information of the at least one frame, Selecting a coefficient having a smaller value by comparing the calculated correction coefficient with the setting coefficient, and outputting the gain coefficient < RTI ID = 0.0 > And a luminance / chrominance division unit Ridoen outputting by delaying until the gain coefficient generating saturation data, and characterized by including the step of creating the corrected saturation data by calculating the gain factor and the saturation data input to the delay mentioned above. The gain coefficient generation step is characterized in that a value obtained by dividing the correction coefficient and the lower coefficient among the set coefficients by the total number of gradations displayed in the image is set as the gain coefficient.

According to an embodiment of the present invention, there is provided a driving apparatus and a driving method thereof for varying the saturation improvement degree of a display image according to a color change rate of input image data and a setting coefficient from a user, have. Accordingly, the present invention can further improve the chroma improvement efficiency by setting the degree of chroma improvement of the display image to be suitable for the characteristics of each display image.

Hereinafter, a driving apparatus and a driving method thereof for an image display apparatus according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings. Here, the video display device of the present invention may be a liquid crystal display device, a field emission display device, a plasma display panel, a light emitting display device, and the like, but the following description will be made by way of example only for a liquid crystal display device for convenience of explanation.

1 is a block diagram showing a driving apparatus of a liquid crystal display according to an embodiment of the present invention.

The liquid crystal display device shown in FIG. 1 includes a liquid crystal panel 2 formed with a plurality of pixel regions; A data driver 4 for driving a plurality of data lines DL1 to DLm; A gate driver 6 for driving the plurality of gate lines GL1 to GLn; An image processing method comprising the steps of: detecting saturation correction coefficients by analyzing saturation data of image data (RGB) input from the outside, setting gain coefficients according to the detected correction coefficients and a setting coefficient from the user, A processing unit 10; And the conversion data (M_RGB) in which the saturation data is converted are arranged in accordance with the driving of the liquid crystal panel (2) and supplied to the data driver (4), and gate and data control signals (GCS, DCS) And a timing controller 8 for controlling the switches 6 and 4.

The liquid crystal panel 2 includes a thin film transistor (TFT) formed in each pixel region defined by a plurality of gate lines GL1 to GLn and a plurality of data lines DL1 to DLm, and a liquid crystal capacitor (Clc). The liquid crystal capacitor Clc is composed of a pixel electrode connected to the TFT, and a common electrode facing the pixel electrode and the liquid crystal. The TFT supplies a video signal from each of the data lines DL1 to DLm to the pixel electrode in response to a scan pulse from each of the gate lines GL1 to GLn. The liquid crystal capacitor Clc charges the difference voltage between the video signal supplied to the pixel electrode and the common voltage supplied to the common electrode, and adjusts the light transmittance by varying the arrangement of the liquid crystal molecules according to the difference voltage. The storage capacitor Cst is connected in parallel to the liquid crystal capacitor Clc so that the voltage charged in the liquid crystal capacitor Clc is maintained until the next data signal is supplied. The storage capacitor Cst is formed by overlapping the pixel electrode with the previous gate line and the insulating film interposed therebetween. Alternatively, the storage capacitor Cst may be formed by overlapping the pixel electrode with the storage line and the insulating film interposed therebetween.

The data driver 4 receives a data control signal DCS from the timing controller 8, for example, a source start pulse SSP, a source shift clock SSC, a source output enable SOE (Source Output Enable) signal from the timing controller 8 to an analog voltage, that is, a video signal. Specifically, the data driver 4 latches the data (Data) subjected to the gamma conversion through the timing controller 8 in accordance with the SSC, and supplies a scan pulse to each of the gate lines GL1 to GLn in response to the SOE signal And supplies a video signal for one horizontal line to each of the data lines DL1 to DLm for every one horizontal period to be supplied. At this time, the data driver 4 selects a positive or negative gamma voltage having a predetermined level according to the gradation value of the aligned data Data, and outputs the selected gamma voltage to each of the data lines DL1 to DLm Supply.

The gate driver 6 outputs a gate control signal GCS from the timing controller 8, for example, a gate start pulse GSP, a gate shift clock GSC, a gate output enable Sequentially generates a scan pulse in response to a Gate Output Enable (GOE) signal, and sequentially supplies the scan pulse to the gate lines GL1 to GLn. In other words, the gate driver 6 shifts the GSP from the timing controller 8 according to the GSC to sequentially supply a scan pulse, for example, a gate-on voltage to the gate lines GL1 to GLn. Then, the gate-off voltage is supplied during the period when the gate-on voltage is not supplied to the gate lines GL1 to GLn. Here, the gate driver 6 controls the pulse width of the scan pulse in accordance with the GOE signal.

The image conversion processing unit 10 detects the saturation data of the image data RGB input from the outside, for example, a graphics system (not shown), and histograms the detected saturation data to detect a correction coefficient for converting the saturation of the image. The detected correction coefficient is compared with a setting coefficient Gset input from the user, and a saturation conversion gain value is generated by selecting and using one of the coefficients according to the comparison result. The image conversion processing unit 10 generates the chroma-converted image data M_RGB (hereinafter referred to as conversion data) by correcting the chroma data of the input image data RGB using the gain value thus generated. The image conversion processing unit 10 of the present invention will be described in more detail below with reference to the accompanying drawings.

The timing controller 8 arranges the conversion data M_RGB inputted from the image conversion processing section 10 so as to be suitable for driving the liquid crystal panel 2 and supplies the data to the data driver 4. [ The timing controller 8 receives at least one of the synchronizing signals input through the image conversion processing unit 10, that is, the dot clock DCLK, the data enable signal DE, and the horizontal and vertical synchronizing signals Hsync and Vsync To control the gate and data drivers 6 and 4 by generating gate and data control signals GCS and DCS and supplying them to the gate and data drivers 6 and 4, respectively.

2 is a block diagram showing the image conversion processing unit shown in FIG.

The image conversion processing unit 10 shown in FIG. 2 includes a luminance / chrominance separation unit 12 for detecting and separating luminance (Y) and chroma (U, V) data of externally input image data (RGB) The gain coefficient is generated according to the result of comparison by comparing the detected correction coefficient with a setting coefficient (Gset) input from the user. A chrominance correction unit 14 for correcting the chroma data U and V by using the luminance data Y and the luminance data Y and a luminance delay unit 16 for delaying and outputting luminance data Y from the luminance / chrominance separation unit 12, ) And a conversion data generation unit (18) for generating and outputting the chroma corrected conversion data (M_RGB) by combining the chroma data (UI, VI) corrected with the gain coefficient and the delayed luminance data (DY) Respectively.

The components of the image conversion processing unit 10 perform the respective operations using at least one of the synchronizing signals DCLK, Hsync, Vsync and DE input from the outside. The synchronizing signals DCLK and Hsync , Vsync, DE can also be supplied to the timing controller 8 at the same time.

The luminance / chrominance separation unit 12 separates the image data RGB input from the outside into luminance (Y) and chroma data (U, V). The luminance data (Y) and the color difference data (U, V) are respectively converted into the luminance data (U, V) by the following equations (1) .

Y = 0.229 x R + 0.587 x G + 0.114 x B

U = 0.493 x (B-Y)

V = 0.887 x (R-Y)

As described above, the color difference corrector 14 histograms the detected saturation data U and V to detect a correction coefficient, and compares the detected correction coefficient with a setting coefficient Gset from the user. Then, a gain coefficient is generated according to the comparison result to correct the saturation data (U, V). The color difference corrector 14 will be described in more detail with reference to the accompanying drawings.

The luminance delay unit 16 corrects the luminance data Y from the luminance / chrominance separation unit 12 by correcting the chroma data U and V in the color difference correction unit 14 for a predetermined period, for example, At least one frame period. The luminance delay unit 16 supplies the converted data generation unit 18 with the luminance data DY delayed so as to be synchronized with the output timing of the corrected saturation data UI and VI.

The conversion data generation unit 18 receives the chroma data UI and VI corrected in accordance with the gain coefficient and the luminance data DY delayed by the luminance delay unit 16 and converts the chroma data M_RGB ). Here, the conversion data M_RGB is obtained by the following equations (4) to (6).

M_R = DY + 0.000 x UI + 1.140 x VI

M_G = DY - 0.396 x UI - 0.581 x VI

M_B = DY + 2.029 x UI + 0.000 x VI

FIG. 3 is a block diagram showing the color difference correction unit shown in FIG. 2 in more detail.

The color difference corrector 14 shown in FIG. 3 modulates the saturation degree of the chroma data (U, V) separated from the luminance / color difference separator 12 so that it can be grasped through bit conversion and outputs the modulated chroma saturation values UL, A maximum value calculator 22 for comparing the modulated chroma saturation values UL and VL with each other to detect a maximum chroma saturation value UM and VM for each gradation, A histogram generator (HSI) 23 for generating and outputting histogram information (HSI) by arranging the maximum chroma values (UM, VM) A correction coefficient calculator 24 for outputting a tone value corresponding to a maximum level among the tonalities in which the maximum saturation values UM and VM are distributed by setting a correction coefficient Tset, (Tset) and a preset coefficient (Gset) preset by the user A gain coefficient generation unit 25 for selecting a coefficient having a smaller value and generating and outputting a gain coefficient g_k using the selected coefficient, V) delayed until the gain coefficient g_k is generated and outputs the delayed chroma data DU and DV from the gain coefficient generator 25 And a UV converting unit 27 for calculating the gain coefficient g_k to generate corrected saturation data UI and VI and supplying the generated saturation data UI and VI to the converted data generating unit 18. [

The UV correcting unit 21 calculates the saturation values UL and V using the following Equation 7 to analyze the degree of saturation of the chroma data U and V separated from the brightness / VL). More specifically, when each of the image data RGB input from the outside is set to 8 bits so as to realize 0 to 255 gradations, the chroma data U and V separated from the luminance / 10 < / RTI > Accordingly, in order to analyze the degree of saturation of the separated chroma data U, V through bit conversion, it may be necessary to numerically modulate chroma saturation values (UL, VL) using the following Equation (7). The saturation values (UL, VL) thus modulated are supplied to the maximum value calculating section 22. [

UL = | U-512 |

VL = | V-512 |

The maximum value calculator 22 compares and analyzes the saturation values (UL, VL) corrected by the UV correcting unit 21 in units of at least one pixel and calculates the maximum saturation values UM, VM .

The histogram generator 23 divides the maximum saturation values (UM, VM) in units of frames at least in units of frames. Specifically, the histogram generator 23 arranges the maximum saturation values (UM, VM) in units of at least one frame so as to correspond to the respective gradations to obtain histogram information (HSI) as shown in FIG. 4 or FIG. At this time, by analyzing the histogram, the saturation information of the image can be grasped. For example, if the histogram is shifted to the right (high grayscale), it is judged that the screen has a high saturation brightness image or a lot of pure color, and if the histogram is shifted to the left (low grayscale), it can be judged as a low saturation dark screen.

The correction coefficient calculator 24 analyzes the histogram information (HSI) of at least one frame supplied from the histogram generator 23 and calculates a correction coefficient based on the gradation corresponding to the maximum level among the gradations in which the maximum chroma values (UM, VM) For example, in the case of FIG. 4, the tone value 200 is set to the correction coefficient Tset and output. If the histogram information HSI is generated as shown in FIG. 5, the tone value corresponding to the maximum level among the tonalities in which the maximum saturation values UM and VM are distributed is 255, and the tone value 255 is set as the correction coefficient Tset ) And outputs it.

The gain coefficient generation unit 25 compares the correction coefficient Tset calculated by the correction coefficient calculation unit 24 with a preset coefficient Gset set by the user and selects a coefficient having a smaller value. Specifically, when the histogram information (HSI) is generated as shown in FIG. 4, the calculated correction coefficient Tset becomes 180, and the setting coefficient Gset from the user can be 200, which indicates 200 gradations. In this case, the gain coefficient generation unit 25 selects the correction coefficient (Tset) 180 that is a smaller value, and then generates the gain coefficient g_k using the following equation (8).

g_k = total number of gradations / min (correction coefficient (Tset) or setting coefficient (Gset))

In other words, when the histogram information (HSI) is generated as shown in FIG. 4, since the calculated correction coefficient Tset 180 is smaller than the user's setting coefficient Gset 200, the gain coefficient g_k is corrected And may be a value obtained by dividing the coefficient (Tset) 180 by a factor. If the histogram information HSI is generated as shown in FIG. 5, since the user's setting coefficient Gset 200 is smaller than the calculated correction coefficient Tset 255, the gain coefficient g_k is set to 256, which is the total number of gradations, (Gset) divided by 200. The gain coefficient g_k thus generated and set is supplied to the UV conversion unit 27. [

Meanwhile, the UV delay unit 26 delays the chroma data (U, V) separated from the luminance / chrominance separation unit 12 until the gain coefficient g_k is generated. And supplies the delayed chroma data U and V to the UV converting unit 27 so that the gain coefficient g_k is synchronized with the timing at which the gain coefficient g_k is supplied to the UV converting unit 27. [

The UV converting unit 27 computes the saturation data DU and DV inputted with the delay and the gain coefficient g_k from the gain coefficient generating unit 25 to generate the corrected saturation data UI and VI And supplies it to the data conversion data generation unit 18 described above. At this time, the corrected saturation data UI and VI can be generated by multiplying the saturation data DU and DV with the gain coefficient g_k.

As described above with reference to Fig. 4, when the correction coefficient Tset is calculated to be lower than the user setting coefficient Gset, since the optimum gain coefficient g_k suitable for the saturation distribution characteristic of the image is calculated, It is possible to display an optimal image with improved saturation, that is, a clearer image, on the screen by the converted image data M_RGB.

However, when the user set coefficient Gset is calculated to be lower than the correction coefficient Tset as described above with reference to FIG. 5, the image data representing a higher gradation than the gradation according to the user setting coefficient Gset is converted into chroma You may see some loss in the conversion process. However, since it is possible to display a large number of image data representing grayscales lower than the grayscale according to the user setting coefficient Gset as a more optimized optimal image, that is, a clearer image, the actual display efficiency of the image can be further improved.

If the user setting coefficient Gset is not set, since the gain coefficient is 1 (i.e., 255/255) when the correction coefficient Tset is 255, which is the maximum level, the saturation of the image data RGB can be changed I will not.

As described above, the driving apparatus of the image display apparatus and the driving method thereof according to the embodiment of the present invention are configured such that the saturation change rate of the input image data calculated through the correction coefficient Tset and the setting coefficient Gset from the user The degree of saturation improvement of the display image can be changed and applied. Accordingly, the present invention can further improve the chroma improvement efficiency by setting the degree of chroma improvement of the display image to be suitable for the characteristics of each display image.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the invention. Therefore, the technical scope of the present invention should not be limited to the contents described in the detailed description of the specification, but should be defined by the claims.

1 is a block diagram showing a driving apparatus of a liquid crystal display according to an embodiment of the present invention;

2 is a block diagram showing the image conversion processing unit shown in FIG.

FIG. 3 is a block diagram showing the color difference correcting unit shown in FIG. 2 in more detail.

FIG. 4 illustrates a histogram generated by the histogram generator of FIG. 3. FIG.

FIG. 5 is another diagram showing a histogram generated through the histogram generator of FIG. 3;

BRIEF DESCRIPTION OF THE DRAWINGS FIG.

2: liquid crystal panel 4: data driver

6: Gate driver 8: Timing controller

10: image conversion processing unit 12: luminance / chrominance separation unit

14: chrominance correction unit 16: luminance delay unit

18: conversion data generating unit 21: UV correction unit

22: maximum value calculating unit 23: histogram generating unit

24: correction coefficient calculating section 25: gain coefficient generating section

26: UV delay unit 27: UV conversion unit

Claims (8)

A display panel for displaying an image; A gate and a data driver for driving a plurality of gates and data lines provided in the display panel; An image conversion processing unit for analyzing saturation data of image data input from the outside to detect a saturation correction coefficient and setting a gain coefficient according to the detected correction coefficient and a setting coefficient from the user to convert saturation data of the image data; And And a timing controller for controlling the gate and the data driver by generating the gate and data control signal while supplying the converted data, which is obtained by converting the chroma data, to the data driver in accordance with the driving of the display panel A driving device for a video display device. The method according to claim 1, The image conversion processing unit A luminance / color difference separator for detecting and separating luminance and chroma data of the image data, The detected saturation data is histogrammed to detect the correction coefficient, the detected correction coefficient is compared with the setting coefficient input from the user, the gain coefficient is generated according to the comparison result, and the generated gain A color difference corrector for correcting the saturation data using the coefficient, A luminance delay unit for delaying and outputting the luminance data from the luminance / chrominance separation unit for a predetermined period, And a conversion data generating unit for generating and outputting the converted data in which the saturation is converted by combining the corrected saturation data and the delayed luminance data from the color difference correcting unit. 3. The method of claim 2, The color- A UV correction unit for modulating the saturation degree of the saturation data so as to grasp the degree of saturation through bit conversion and outputting a modulated saturation value, A maximum value calculator for comparing and analyzing the modulated saturation values to detect a maximum saturation value for each gradation, A histogram generation unit for generating a histogram by arranging the maximum saturation values corresponding to each gradation in units of at least one frame and generating and outputting information of the histogram, A correction coefficient calculator for analyzing histogram information of the at least one frame to set a tone value corresponding to a maximum level among the tone values in which the maximum saturation values are distributed to the correction coefficient, A gain coefficient generation unit for selecting a coefficient having a smaller value by comparing the calculated correction coefficient with the setting coefficient and generating and outputting the gain coefficient using the selected coefficient, A UV delay unit for delaying and outputting the chroma data separated from the luminance / chrominance separation unit until the gain coefficient is generated, and And a UV converting unit operable to calculate the chroma data and the gain coefficient, which are input in the delayed manner, to generate the corrected chroma data and supply the generated chroma data to the data conversion data generating unit. The method of claim 3, The gain coefficient generator Wherein a value obtained by dividing the correction coefficient and a lower coefficient among the setting coefficients in the total number of gradations displayed by the image is set to the gain coefficient. A method of driving an image display apparatus for displaying an image using a display panel formed with a plurality of pixel regions, Driving a plurality of gates and data lines provided in the display panel, Detecting saturation correction coefficients by analyzing saturation data of image data input from the outside and converting the saturation data of the image data by setting a gain coefficient according to the detected correction coefficients and a setting coefficient from the user; And And displaying the image by arranging the converted data in which the saturation data is converted to be suitable for driving the display panel. 6. The method of claim 5, The step of converting the saturation data of the image data Detecting and separating luminance and chroma data of the image data, The detected saturation data is histogrammed to detect the correction coefficient, the detected correction coefficient is compared with the setting coefficient input from the user, the gain coefficient is generated according to the comparison result, and the generated gain Correcting the saturation data using a coefficient, Delaying the separated luminance data for a predetermined period of time and outputting the separated luminance data, And generating and outputting the converted data in which the saturation is converted by combining the corrected saturation data and the delayed luminance data. The method according to claim 6, The step of correcting the saturation data Modulating the saturation degree of the saturation data so as to grasp the degree of saturation through bit conversion and outputting the modulated saturation value, Comparing the modulated saturation values with each other to detect a maximum saturation value for each group, Arranging the maximum saturation values to correspond to each gradation in at least one frame unit, and histogramming and generating information of the histogram, Analyzing histogram information of the at least one frame to output a gray level value corresponding to a maximum level among the gray levels in which the maximum saturation values are distributed, Selecting a coefficient having a smaller value by comparing the calculated correction coefficient with the setting coefficient, generating and outputting the gain coefficient using the selected coefficient, Delaying and outputting the saturation data until the gain coefficient is generated, and And generating the corrected saturation data by calculating the delayed input saturation data and the gain coefficient. 8. The method of claim 7, The gain coefficient generation step Wherein a value obtained by dividing the correction coefficient and a lower coefficient among the setting coefficients in the total number of gradations displayed by the image is set to the gain coefficient.

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