Patent Publication Number: US-9898998-B2

Title: Apparatus and method for generating correction data, and image quality correction system thereof

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims priority from Korean Patent Application No. 10-2013-0146058, filed in the Korean Intellectual Property Office on Nov. 28, 2013, and Korean Patent Application No. 10-2014-0043722, filed in the Korean Intellectual Property Office on Apr. 11, 2014, the entire disclosures of which are incorporated herein by reference in their entirety. 
     BACKGROUND 
     1. Field 
     Aspects of the exemplary embodiments relate to an apparatus and a method for generating correction data, and an image quality correction system thereof, and more particularly, to an apparatus and a method for generating correction data to correct the non-uniformity of a display panel, and an image quality correction system thereof. 
     2. Description of the Related Art 
     A display panel may have non-uniform image quality due to many factors that occur during the manufacturing process. For example, a specific area of the display panel may appear to be brighter or darker than other areas, or the color temperature of the display panel may be reddish or bluish overall. 
     In particular, as current display panels become larger and thinner, various types of non-uniform image quality occur. For example, non-uniformity of image quality may appear only in a specific gradation section or a specific area of the display panel. 
     In a related art display panel, the non-uniformity in the display panel can be corrected in a limited form with reference only to brightness, or only a predetermined gradation can be corrected. However, such a limited method of correction cannot be applied to a display panel which is provided in various types and colors. In addition, a panel for which a correction is applied in a limited manner or conversely, is applied in an excessive manner may occur, thereby affecting productivity of the panel. 
     SUMMARY 
     An aspect of the exemplary embodiments relates to an apparatus and a method of generating correction data to improve non-uniform image quality of a display panel by generating and providing correction data with respect to the non-uniform area of the display panel, and an image quality correction system thereof. 
     A method of generating correction data according to an exemplary embodiment, the method includes detecting brightness of a display panel of a display apparatus, determining a non-uniform area of the display panel for each red, green, and blue (RGB) color based on the detected brightness, generating correction data regarding the non-uniform area by determining a screen split size and a correction section for correcting an image quality of the display panel based on the non-uniform area, storing the generated correction data in a storage of the display apparatus, and correcting, by the display apparatus, an image quality of the display panel based on the correction data. 
     The generating may include determining whether to correct each RGB color based the non-uniform area determined for each RGB color. 
     The generating may include, when a correction for a plurality of colors is required, determining a correction section for each color where the correction is required. 
     The generating may further include calculating a correction value for each correction section based on the determined screen split size and generating correction data including the calculated correction value and correction information, and the correction information may include at least one of the correction section information, the information regarding whether to correct each RGB color, and the screen split size information. 
     The number of data of the correction data may be calculated by adding the number of correction value data and the number of correction information data. 
     The generating may include assigning a separate address so as to distinguish the correction section information, the information regarding whether to correct each RGB color, and the screen split size information from the calculated correction value. 
     The display apparatus may process the correction data using one of a timing controller, a frame rate controller, a scaler, and separate hardware. 
     A correction data generating apparatus according to an exemplary embodiment includes a detector configured to detect brightness of a display panel of a display apparatus, a determination device configured to determine a non-uniform area of the display panel for each RGB color based on the detected brightness, a correction data generator configured to generate correction data regarding the non-uniform area by determining a screen split size and a correction section for correcting an image quality of the display panel based on the non-uniform area, and a storage configured to store the generated correction data in a storage of the display apparatus, wherein the display apparatus corrects an image quality of the display panel based on the correction data. 
     The correction data generator is configured to determine whether to correct each RGB color based the non-uniform area determined for each RGB color. 
     The correction data generator is configured to determine a correction section for each color where the correction is required when a correction for a plurality of colors is required. 
     The correction data generator is configured to calculate a correction value for each correction section based on the determined screen split size, and generate correction data including the calculated correction value and correction information, and the correction information may include at least one of the correction section information, the information regarding whether to correct each RGB color, and the screen split size information. 
     The number of data of the correction data may be calculated by adding the number of correction value data and the number of correction information data. 
     The correction data generator may assign a separate address so as to distinguish the correction section information, the information regarding whether to correct each RGB color, and the screen split size information from the calculated correction value. 
     The display apparatus may process the correction data using one of a timing controller, a frame rate controller, a scaler, and separate hardware. 
     An image quality correction system according to an exemplary embodiment includes a correction data generating apparatus configured to detect brightness of a display panel, determine a non-uniform area of the display panel for each RGB color based on the detected brightness, determine a screen split size and a correction section to correct image quality of the display panel based on the non-uniform area, and generate correction data regarding the non-uniform area and a display apparatus configured to store the generated correction data and process an image of the non-uniform area from among input images based on the correction data. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above and/or other aspects of the present exemplary embodiments will be more apparent by describing certain exemplary embodiments with reference to the accompanying drawings, in which: 
         FIG. 1  is a block diagram illustrating configuration of a correction data generating apparatus briefly according to an exemplary embodiment; 
         FIGS. 2A to 2D  are views illustrating a non-uniform area of a display panel according to various exemplary embodiments; 
         FIGS. 3A to 3C  are views illustrating configuration of a display apparatus to correct an non-uniform area according to various exemplary embodiments; 
         FIG. 4  is a flowchart provided to explain a method of generating correction data according to an exemplary embodiment; 
         FIG. 5  is a flowchart provided to explain a method of generating correction data regarding an non-uniform area in detail according to an exemplary embodiment; and 
         FIGS. 6A to 6C  are views illustrating the configuration of a display apparatus to correct a non-uniform area according to other exemplary embodiments. 
     
    
    
     DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENTS 
     Hereinafter, an exemplary embodiment will be described in detail with reference to accompanying drawings. In the following description, same reference numerals are used for analogous elements when they are depicted in different drawings. The matters defined in the description, such as detailed construction and elements, are provided to assist in a comprehensive understanding of exemplary embodiments. Thus, it is apparent that exemplary embodiments can be carried out without those specifically defined matters. Also, functions or elements known in the related art are not described in detail since they would obscure the exemplary embodiments with unnecessary detail. 
     In the present disclosure, relational terms such as first and second, and the like, may be used to distinguish one entity from another entity, without necessarily implying any actual relationship or order between such entities. 
       FIG. 1  is a block diagram illustrating the configuration of a correction data generating apparatus  100  according to an exemplary embodiment. As illustrated in  FIG. 1 , the correction data generating apparatus  100  includes a detector  110 , a determination device  120 , a correction data generator  130 , and a storage  140 . 
     The detector  110  detects brightness of a display panel included in a display apparatus. In particular, the detector  110  may detect brightness by changing an input image of a display panel from a low gradation to a high gradation or from a high gradation to a low gradation with reference to a white color. In addition, the detector  110  may detect brightness regarding an input image having a plurality of colors (for example, red, green, blue, etc.) of a display panel. 
     The determination device  120  may detect a non-uniform area of the display panel based on the detected brightness. In this case, the determination device  120  may determine a non-uniform area regarding a single color (for example, white), but this is only an example. The determination device  120  may determine a non-uniform area regarding each of a plurality of RGB colors. 
     The non-uniform area of a display panel refers to an area where an image which is different from what is to be represented by the display panel is output. For example, the non-uniform area of a display panel may be a pixel line  210  which is output in different brightness from that of other pixel lines as illustrated in  FIG. 2A . In another example, the non-uniform area of a display panel may be an area  220  in the form of a block in a longitudinal direction where an image is output in different brightness from that of pixels in other areas with respect to a specific color as illustrated in  FIG. 2B . Alternatively, the non-uniform area of a display panel may be areas  230 - 1  and  230 - 2  in the form of block in a forward direction where an image is output in different brightness from that of pixels in other areas as illustrated in  FIG. 2C . In this case, the first area  230 - 1  and the second area  230 - 2  may be non-uniform areas with respect to different colors. For example, the first area  230 - 1  may be n non-uniform area regarding green, and the second area  230 - 2  may be n non-uniform area regarding red. In another example, the non-uniform area of a display panel may be the entire area of a display panel of which color is inclined to a specific color (for example, red) as illustrated in  FIG. 2D . 
     The correction data generator  130  generates correction data regarding the non-uniform area determined by the determination unit  120 . 
     Specifically, the correction data generator  130  may determine whether to correct n non-uniform area for each of a plurality of colors. In this case, if a display panel outputs an image in a single color (for example, a white image), the correction data generator  130  may determine whether the display panel outputs colors other than the single color, and determine whether to make a correction for each of a plurality of colors. For example, if a display panel outputs a white image, the first area of the display panel outputs green color, and the second area of the display panel outputs red color, the correction data generator  130  may determine that a correction regarding the green color is required in the first area of the display panel, and a correction regarding the red color is required in the second area of the display panel. 
     In addition, if a display panel outputs each RGB image, the correction data generator  130  may determine whether a non-uniform area exists in the image where each color is output, and determine whether to make a correction for a plurality of colors. For example, if a display panel outputs a red image, and another color is output in the red image, the correction data generator  130  may determine that a correction is required. 
     Further, the correction data generator  130  may determine a screen split size for screen correction to improve the image quality of the display panel. Specifically, the correction data generator  130  may determine a screen split size based on the size and shape of a non-uniform area. More specifically, the correction data generator  130  may determine a maximum area where a non-uniform area can be divided as a screen split size. For example, as illustrated in  FIG. 2B , if there is a non-uniform area  220 , the correction data generator  130  may determine a (1×3) size as the screen split size for screen correction. In another example, as illustrated in  FIG. 2C , if there are non-uniform areas  230 - 1 ,  230 - 2 , the correction data generator  130  may determine a (2×2) size as the screen split size for screen correction. As described above, by determining a maximum area where a non-uniform area can be divided based on the size and shape of the non-uniform area as the screen split size for screen correction, correction data having the least amount of data can be generated. 
     The correction data generator  130  may also determine a correction section regarding a non-uniform area. In this case, the correction data generator  130  may determine a correction section having constant intervals. For example, the correction data generator  130  may determine a correction section having 8 sections with respect to 256 gradation. Alternatively, the correction data generator  130  may determine a correction section having inconsistent intervals. In this case, the correction data generator  130  may have a narrow correction section near the gradation where a non-uniform area occurs, and a wide correction section near the gradation where a non-uniform area does not occur. For example, if a non-uniform area occurs between 25 gradation and 230 gradation, the correction data generator  130  may set the intervals such that a narrow correction exists near 25 gradation and 230 gradation, and a wide correction section exists near the remaining gradations. 
     The correction data generator  130  may determine a correction value regarding a non-uniform area for each color and correction section. Specifically, if a correction regarding a single color is required, the correction data generator  130  may determine a correction value regarding a non-uniform area according to the correction section of the single color. For example, if a non-uniform area occurs in the second correction section (for example, 20 graduation˜40 gradation) and the sixth correction section (for example, 100 gradation˜120 gradation) with regard to a white image, the correction data generator  130  may determine a correction value regarding the second correction section and the sixth correction section. 
     If a correction with regard to a plurality of colors is required, the correction data generator  130  may determine a correction value regarding a non-uniform area according to the correction section for each color where a correction is required. For example, if a non-uniform area occurs in the first correction section (for example, 0 gradation˜15 gradation) and the seventh correction section (205 gradation˜215 gradation) with regard to a red image, and a non-uniform area occurs in the third correction section (55 gradation˜70 gradation) with regard to a green image, the correction data generator  130  may determine a correction value with regard to the first correction and the seventh correction section of the red image, and determine a correction value with regard to the third correction section of the green image. 
     In particular, the correction data generator  130  may determine a correction value such that the brightness and color of a non-uniform area becomes the same as the brightness and color of other areas. For example, if the output brightness of a non-uniform area in the first correction section is higher than the general brightness, the correction data generator  130  may determine a correction value to lower the output brightness of the first correction section. In another example, if a non-uniform area of the second correction section with regard to a white image is output in red color, the correction data generator  130  may determine a correction value so that the second correction section regarding the white image is output in white color. 
     In addition, the correction data generator  130  determines whether an output screen is even by applying a correction value. If the screen output by applying a correction value is even, the correction data generator  130  may generate correction data including the correction value and correction information. In this case, the correction information may include at least one of a correction section, whether a correction is performed for each RGB color, and a screen split size. If the screen output by applying a correction value is not even, the correction data generator  130  may generate a correction value again by performing the above-described operations. In this case, the correction data generator  130  may repeat the above-described operations until an even screen is output. 
     The storage  140  stores generated correction data. In this case, the generated correction data may include a correction value and correction information as described above. Accordingly, the number of data stored in the correction data may be calculated by adding the number of correction value data and the number of correction information data. 
     In this case, the number of correction value data can be calculated by Equation 1 as shown below. 
     
       
         
           
             
               
                 
                   
                     
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     In this case, Hp and Vp refer to the number of horizontal pixels and vertical pixels of the display panel, respectively, Hblocksize and Vblocksize refer to the number of horizontal pixels and vertical pixels of the screen split area for correction, Pn refers to the number of correction sections, and whether to R correct , G correct  and B correct  may be whether to correct each RGB color. 
     The number of correction information data may be calculated by Equation 2 as shown below.
 
(Number of information of  H   blocksize  and  V   blocksize )+(Number of  R   whether to correct   , G   whether to correct  and  B   whether to correct )+(Number of correction sections and Number of correction section information)  [Equation 2]
 
     In this case, the correction information data included in the correction data is stored in a predetermined specific address to be distinguished from the correction value data, and the number of correction data and the address for each correction section may be set to correspond to the correction information data. 
     As described above, the generated correction data may be stored in a display apparatus controlling the display panel, and the display apparatus may correct and output the RGB colors of an image using the correction data. In this case, the display apparatus may process correction data using one of a timing controller, a frame rate controller, a scaler, and separate hardware, which will be described with reference to  FIGS. 3A to 3C . 
       FIG. 3A  is a view provided to explain an exemplary embodiment where a timing controller processes correction data according to the first exemplary embodiment. 
     The first storage  311  stores correction data. In this case, the first storage  311  may be realized as a permanent storage apparatus. For example, the first storage  311  may be realized as one of a flash memory and EEPROM. 
     If the display apparatus  300  operates, a data loader  312  of a timing controller  310  may load correction data, and classify the correction data as correction value data and correction information data based on a predetermined address. In addition, the data loader  312  may output the correction value data to the second storage  313 , and output the correction information data to a correction information decoder  315 . The second storage  313  may be realized as a temporary storage apparatus. For example, the second storage  313  may be realized as double data rate synchronous (DDR) or EDRAM. The second storage  313  may output the correction value data to the third storage  314  which is a storage space for operation, prior to performing operation of correction coefficient. However, as described above, the feature that the correction value data is stored in the second storage  313  temporarily and then, output to the third storage  314  is only an example. As illustrated in  FIG. 6A , the correction value data may be output to the third storage  314  directly from the data loader  312 . In addition, the correction information decoder  315  may decode the correction information data, and output information regarding a correction section, information regarding whether to make a correction for each RGB color, and information regarding a screen split size to an operation unit  316 . 
     The operation device  316  included in the timing controller  310  may calculate a correction coefficient regarding a non-uniform area using the correction value data output from the third storage  314 , information regarding the correction section output from the correction information decoder  315 , information regarding whether to make a correction for each RGB color, and information regarding the screen split size for correction. 
     A correction device  317  included in the timing controller  310  performs a correction job using the correction coefficient calculated by the operation device  316  and the RGB data processed by an external image processor. The timing controller  310  may output image data using the corrected RGB data. 
       FIG. 3B  is a view provided to explain an exemplary embodiment where the image processor  320  processes correction data according to the second exemplary embodiment. In this case, the image processor  320  may be an apparatus for image-processing, such as a Frame Rate Controller (FRC) or a scaler. 
     The first storage  321  stores correction data. In this case, the first storage  321  may be realized as a permanent storage apparatus. For example, the first storage  321  may be realized as one of a flash memory and EEPROM. 
     Once the display apparatus  300  operates, a data loader  322  of the image processor  320  may load correction data and classify it into correction value data and correction information data based on a predetermined address. In addition, the data loader  322  may output the correction value data to the second storage  323 , and output the correction information data to a correction information decoder  325 . The second storage  323  may be realized as a temporary storage apparatus. For example, the second storage  323  may be realized as DDR or EDRAM. The second storage  323  may output the correction value data to the third storage  324  which is a storage space for operation prior to performing an operation of a correction coefficient. However, as described above, the feature of storing the correction value data in the second storage  323  temporarily and outputting the data to the third storage  324  is only an example. As illustrated in  FIG. 6B , the correction value data may be output to the third storage  324  directly from the data loader  322 . The correction information decoder  325  may decode the correction information data and output information regarding a correction section, information regarding whether to make a correction for each RGB color, and information regarding a screen split size for correction to an operation device  326 , respectively. 
     The operation device  326  included in the image processor  320  may calculate a correction coefficient regarding an non-uniform area by using the correction value data output from the third storage  324 , information regarding a correction section output from the correction information decoder  325 , information regarding whether to make a correction for each RGB color, and information regarding a screen split size for correction. 
     A correction device included in the image processor  320  performs a correction by using the correction coefficient calculated by the operation device  325  and the input RGB data. The image processor  320  may output the corrected RGB data to a timing controller. 
       FIG. 3C  is a view provided to explain an exemplary embodiment where separate hardware  330  for color correction processes correction data according to the third exemplary embodiment. 
     The first storage  331  stores correction data. In this case, the first storage  331  may be realized as a permanent storage apparatus. For example, the first storage  331  may be realized as one of a flash memory and EEPROM. 
     Once the display apparatus  300  operates, a data loader  332  of the color correction hardware may load correction data and classify the data into correction value data and correction information data based on a predetermined address. In addition, the data loader  332  may output the correction value data to the second storage  333 , and output the correction information data to the correction information decoder  334 . The second storage  333  may be realized as a temporary storage apparatus. For example, the second storage  333  may be realized as DDR or EDRAM. The second storage  333  may output correction value data to the third storage  335  which is a storage space for operation prior to performing an operation of a correction coefficient. However, as described above, the feature of storing the correction value data in the second storage  333  temporarily and outputting the data to the third storage  335  is only an example. As illustrated in  FIG. 6C , the correction value data may be output to the third storage  335  directly from the data loader  332 . The correction information decoder  334  may decode the correction information data and output information regarding a correction section, information regarding whether to make a correction for each RGB color, and information regarding a screen split size for correction to the operation device  336 , respectively. 
     The operation device  336  included in the color correction hardware  330  may calculate a correction coefficient regarding a non-uniform area by using the correction value data output from the third storage  335 , information regarding a correction section output from the correction information decoder  334 , and information regarding whether to make a correction for each RGB color, and information regarding a screen split size for correction. 
     A correction device  337  included in the color correction hardware  330  performs a correction by using the correction coefficient calculated by the operation device  336  and the RGB data input from an image processor (for example, FRC or a scaler). The color correction hardware  330  may output the corrected RGB data to a timing controller. 
     As described above, according to various exemplary embodiments, the display apparatus  300  may perform a color correction regarding a non-uniform area. 
     Hereinafter, the method of generating correction data will be described with reference to  FIGS. 4 and 5 .  FIG. 4  is a flowchart provided to explain a method of generating correction data according to an exemplary embodiment. 
     First of all, the correction data generating apparatus  100  detects brightness of a display panel (operation S 410 ). Specifically, the correction data generating apparatus  100  may detect the brightness by varying an input image of the display panel from low gradation to high gradation or from high graduation to low gradation with reference to a white color. In addition, the correction data generating apparatus  100  may detect brightness regarding an input image having a plurality of colors (for example, red, green, blue, etc.) of the display panel. 
     Subsequently, the correction data generating apparatus  100  determines a non-uniform area based on the detected brightness (operation S 420 ). In this case, the correction data generating apparatus  100  may determine a non-uniform area with regard to a single color (for example, white), but this is only an example. The correction data generating apparatus  100  may determine a non-uniform area with regard to each of the plurality of RGB colors. 
     The correction data generating apparatus  100  generates correction data regarding a non-uniform area (operation S 430 ), which will be described with reference to  FIG. 5 . 
     First of all, the correction data generating apparatus  100  determines whether to make a correction for each RGB color (operation S 510 ). 
     Subsequently, the correction data generating apparatus  100  determines a screen split size for correction (operation S 520 ). In this case, the correction data generating apparatus  100  may determine a screen split size for correction to be a maximum size in which an non-uniform area is divided based on the size and shape of the non-uniform area. 
     The correction data generating apparatus  100  determines a correction section for each color (operation S 530 ). In this case, the correction data generating apparatus  100  may determine a correction section based on the number of gradation where a non-uniform area occurs. 
     Subsequently, the correction data generating apparatus  100  determines a correction value of a non-uniform area for each color and correction section (operation S 540 ). 
     In addition, the correction data generating apparatus  100  determines again whether the display panel screen which is corrected according to the correction value is even (operation S 550 ). 
     If the corrected screen is even (operation S 550 -Y), the correction data generating apparatus  100  generates correction data including a correction value and correction information (operation S 560 ). In this case, the correction information may include information regarding whether a correction is performed for each RGB color, information regarding a screen split size for correction, and information regarding a correction section. If the corrected screen is not even (operation S 550 -N), the correction data generating apparatus  100  may go back to operation S 510  and perform a correction again. 
     Referring back to  FIG. 4 , the correction data generating apparatus  100  stores the generated correction data (operation S 440 ). 
     Accordingly, the evenness of the image quality of the display panel can be improved and thus, even image quality can be achieved in any area of the display panel. In addition, a correction method can be determined in consideration of the characteristics of the display panel, thereby reducing the time for generating data for correction and thus, minimizing the production cost. 
     A program code for performing a correction data generating method according to the above-described various exemplary embodiments can be stored in a non-transitory computer readable medium. The non-transitory computer readable medium refers to a medium which may store data semi-permanently rather than storing data for a short time such as a register, a cache, and a memory and may be readable by an apparatus. Specifically, the non-transitory recordable medium may be CD, DVD, hard disk, Blu-ray disk, USB, memory card, ROM, etc. 
     The foregoing exemplary embodiments are merely exemplary and are not to be construed as limiting. The present teaching can be readily applied to other types of apparatuses. Also, the description of the exemplary embodiments is intended to be illustrative, and not to limit the scope of the claims, and many alternatives, modifications, and variations will be apparent to those skilled in the art.