Test device

Abstract

The present application relates to a test device. The test device includes a color difference detection filter configured to detect a color difference region based on a detected image signal and output position information of the color difference region and a filtered image signal, an image enhancement processor configured to perform deblurring on the filtered image signal based on the position information and output a deblurred image signal, a color difference corrector configured to generate first compensation data for the color difference region based on the deblurred image signal, a sampling corrector configured to generate second compensation data for a non-color difference region based on the detected image signal, and a compensator configured to output compensation data based on the first compensation data and the second compensation data.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to and the benefit of Korean Patent Application No. 10-2020-0076019, filed on June 22, 2020, which is hereby incorporated by reference for all purposes as if fully set forth herein. Technical Field

[0003] The present disclosure herein relates to a display device and a testing apparatus for testing the display device. Background Art

[0004] Multimedia electronic devices such as televisions, mobile phones, tablet computers, navigation devices, and game consoles have displays that include multiple pixels that display images. Due to variations in the manufacturing process, pixels formed using the same manufacturing process may have different optical properties. As a result, pixels supplied with image data signals of the same grayscale may output light with different brightness levels due to variations in their optical properties. Summary of the Invention

[0005] The present disclosure provides a testing apparatus for detecting characteristic deviation of pixels and a display device capable of performing color difference (mura) compensation.

[0006] According to an embodiment of the present invention, a testing device includes: a chromatic aberration detection filter configured to detect a chromatic aberration area based on a detected image signal and output position information of the chromatic aberration area and a filtered image signal; an image enhancement processor configured to perform deblurring on the filtered image signal based on the position information and output a deblurred image signal; a chromatic aberration corrector configured to generate first compensation data for the chromatic aberration area based on the deblurred image signal; a sampling corrector configured to generate second compensation data for a non-chromatic aberration area based on the detected image signal; and a compensator configured to output compensation data based on the first compensation data and the second compensation data.

[0007] In an embodiment, the color difference detection filter may detect the color difference area by performing an erosion operation and a dilation operation on the detected image signal.

[0008] In an embodiment, the color difference detection filter may perform an erosion operation and a dilation operation based on a variable filter size and filter shape.

[0009] In an embodiment, the color difference detection filter can group a plurality of pixels corresponding to the detected image signal into a plurality of regions; calculate a score of each of the plurality of regions based on a portion of the filtered image signal corresponding to each of the plurality of regions; and set a region of the plurality of regions in which the score is higher than a threshold value as a color difference region.

[0010] In an embodiment, the color difference detection filter can calculate the filtered image signal by performing an erosion operation and a dilation operation on the detected image signal; calculate a difference between the detected image signal and the filtered image signal; and calculate a score of each of the plurality of regions based on a deviation between the difference corresponding to each of the plurality of regions and a reference value.

[0011] In an embodiment, the reference value can include a first reference value and a second reference value, the first reference value can be m+kσ, the second reference value can be m-kσ, m can be an average luminance of the filtered image signal, k can be a detection coefficient, and σ can be a standard deviation.

[0012] In an embodiment, the image enhancement processor performs deblurring on the filtered image signal in a region of the plurality of regions corresponding to the position information.

[0013] In an embodiment, the image enhancement processor can perform deblurring on the filtered image signal using an equation as follows:

[0014]

[0015] Here, f(x, y) can be the filtered image signal, I t (f(x, y)) can be a t-th deblurred image signal, and I t-1 (f(x, y)) can be a (t-1)-th deblurred image signal.

[0016] In an embodiment, the image enhancement processor can iteratively calculate the equation until a difference ratio between the t-th deblurred image signal and the (t-1)-th deblurred image signal is equal to or less than a predetermined value.

[0017] In an embodiment, the color difference corrector can group a plurality of pixels corresponding to the detected image signal into a plurality of compensation blocks; and generate first compensation data corresponding to a first compensation block of the plurality of compensation blocks, the first compensation block corresponding to the color difference region, wherein the first compensation block includes a×b pixels (where each of a and b is a natural number) of the plurality of pixels, and the color difference corrector generates 2×a pieces of the first compensation data for the first compensation block.

[0018] In an embodiment, the sampling corrector can generate four second compensation data for a second compensation block of the plurality of compensation blocks, the second compensation block corresponding to the non-chromatic aberration region.

[0019] According to an embodiment of the inventive concept, a display apparatus includes a display panel including a plurality of pixels respectively connected to a plurality of data lines and a plurality of scan lines, a data driving circuit configured to drive the plurality of data lines, a scan driving circuit configured to drive the plurality of scan lines, a memory configured to store compensation data including first compensation data and second compensation data, and a driving controller configured to receive a control signal and an image signal, control the data driving circuit and the scan driving circuit to display the image on the display panel based on the control signal, and provide an image data signal obtained by correcting the image signal based on the compensation data to the data driving circuit. The driving controller can correct a first image signal corresponding to a chromatic aberration region of the display panel based on the first compensation data, provide a first corrected image signal as a first part of the image data signal, correct a second image signal corresponding to a non-chromatic aberration region of the display panel based on the second compensation data, and provide a second corrected image signal as a second part of the image data signal.

[0020] In an embodiment, the plurality of pixels can be grouped into a plurality of compensation blocks, each of the plurality of compensation blocks can include a×b pixels of the plurality of pixels (where each of a and b is a natural number), and the first compensation data can include 2×a compensation data corresponding to the chromatic aberration region of the display panel.

[0021] In an embodiment, the driving controller can generate a×b compensation data corresponding to the a×b pixels by linear interpolation based on 2×a compensation data corresponding to the chromatic aberration region in the first compensation data, and the driving controller can correct the first image signal corresponding to the chromatic aberration region of the display panel based on the a×b compensation data and output the first part of the image data signal.

[0022] In an embodiment, the plurality of pixels can be grouped into a plurality of compensation blocks, each of the plurality of compensation blocks can include a×b pixels of the plurality of pixels (where each of a and b is a natural number), and the second compensation data can include four compensation data corresponding to the non-chromatic aberration region of the display panel.

[0023] In an embodiment, the driving controller can generate a×b compensation data corresponding to the a×b pixels by spatial interpolation based on four compensation data corresponding to the non-chromatic aberration region in the second compensation data, and the driving controller can correct the second image signal corresponding to the non-chromatic aberration region of the display panel based on the a×b compensation data and output the second part of the image data signal.

[0024] According to an embodiment of the inventive concept, a color difference compensation method includes generating a detected image signal based on an image displayed by a display panel; detecting a color difference area of the display panel based on the detected image signal, and outputting position information of the color difference area and a filtered image signal; performing deblurring on the filtered image signal based on the position information, and outputting a deblurred image signal; generating first compensation data for the color difference area based on the deblurred image signal; generating second compensation data for a non-color difference area of the display panel based on the detected image signal; storing the first compensation data and the second compensation data in a memory; correcting a first detected image signal of the detected image signal corresponding to the color difference area of the display panel based on the first compensation data stored in the memory; providing the first corrected image signal as a first portion of an image data signal; correcting a second detected image signal of the detected image signal corresponding to the non-color difference area of the display panel based on the second compensation data; providing the second corrected image signal as a second portion of the image data signal; and displaying the image data signal on the display panel based on the first corrected image signal and the second corrected image signal.

[0025] In an embodiment, the method can further include performing the erosion operation and the dilation operation based on a variable filter size and a filter shape.

[0026] In an embodiment, the method can further include grouping a plurality of pixels corresponding to the detected image signal into a plurality of areas; calculating a score for each of the plurality of areas based on a portion of the filtered image signal; and setting an area of the plurality of areas having a score higher than a threshold value as the color difference area.

[0027] In an embodiment, generating the first compensation data can include grouping a plurality of pixels corresponding to the detected image signal into a plurality of compensation blocks; and generating the first compensation data corresponding to a first compensation block of the plurality of compensation blocks, the first compensation block corresponding to the color difference area, wherein each of the plurality of compensation blocks can include a×b pixels (wherein each of a and b is a natural number) of the plurality of pixels, and the color difference corrector generates 2×a pieces of the first compensation data for the first compensation block. BRIEF DESCRIPTION OF DRAWINGS

[0028] The accompanying drawings are included to provide a further understanding of the inventive concept, and are incorporated in and constitute a part of this disclosure. The drawings illustrate exemplary embodiments of the present disclosure and, together with the specification, serve to describe the principles of the inventive concept. In the drawings:

[0029] Figure 1 A test system for testing a display panel according to an embodiment is illustrated;

[0030] Figure 2An exemplary color difference displayed on a display device is illustrated;

[0031] Figure 3 is a block diagram of a test device according to an embodiment;

[0032] Figure 4A and Figure 4B An exemplary operation of a color difference detection filter according to an embodiment is illustrated;

[0033] Figure 5 is a normal distribution graph illustrating a filtered image signal output from a color difference detection filter;

[0034] Figure 6 An exemplary filtered image signal output from a color difference detection filter is illustrated;

[0035] Figure 7 An exemplary operation of a color difference detection filter for detecting a general vertical line-shaped color difference displayed on a display device is illustrated;

[0036] Figure 8 An exemplary operation of a color difference detection filter for detecting a step-shaped vertical line-shaped color difference displayed on a display device is illustrated;

[0037] Figure 9 An exemplary method for detecting a region including a step-shaped vertical line-shaped color difference is illustrated;

[0038] Figure 10 is a graph illustrating scores of each of the first to ninth regions shown in Figure 9

[0039] Figure 11A , Figure 11B and Figure 11C An operation of an image enhancement processor according to an embodiment is described;

[0040] Figure 12 An exemplary compensation data generated in a compensator according to an embodiment is illustrated;

[0041] Figure 13 An exemplary display device according to an embodiment is illustrated;

[0042] Figure 14 A method for interpolating compensation data for a color difference region according to an embodiment is illustrated;

[0043] Figure 15 A method for interpolating compensation data for a non-color difference region according to an embodiment is illustrated; and

[0044] Figure 16 A method for interpolating a gray scale according to an embodiment is illustrated.​ DETAILED DESCRIPTION

[0045] It will be understood that when an element or layer is referred to as being "on" or "connected to" or "coupled to" another element or layer, it can be directly on, connected or coupled to the other element or layer, or one or more intervening elements or layers can be present.

[0046] Throughout the disclosure, like reference numerals refer to like elements throughout. In the drawings, the thickness, ratio, and size of elements are exaggerated for effective description and technical explanation. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items.

[0047] It will be understood that, although the terms first, second, etc. can be used herein to describe various elements, components, regions, layers and / or sections, these elements, components, regions, layers and / or sections should not be limited by these terms. These terms are only used to distinguish one element, component, region, layer or section from another element, component, region, layer or section. Thus, a first element, component, region, layer or section discussed below could be termed a second element, component, region, layer or section without departing from the teachings of the present disclosure. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise.

[0048] Spatially relative terms such as "beneath", "below", "lower", "above", "upper" and the like can be used herein for ease of description to describe one element or feature's relationship to another element(s) or feature(s) as illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientations depicted in the figures.

[0049] It will also be understood that the terms "comprises" or "comprising", or "includes" or "including" when used in this disclosure specify the presence of stated features, integers, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof.

[0050] Unless specifically stated otherwise, and as apparent from the previous discussion, it is appreciated that, throughout the description, the use of terms such as "comprising" or "comprises" or "including" or "includes" or the like, means "including but not limited to" or "comprising but not limited to". Likewise, the term "comprising" is used herein to mean including at least the recited element, that which is meant by the term "comprising" is "including, but not limited to".

[0051] Hereinafter, the present disclosure will be described in detail with reference to the accompanying drawings.

[0052] Figure 1 A test system for testing a display panel according to an embodiment is illustrated.

[0053] Referring to Figure 1 , the test system includes a display device DD, a camera CAM, and a test device TD. Although Figure 1 A television is illustrated as an example of the display device DD, but the present disclosure is not limited thereto. The display device DD can be used not only in large electronic devices such as televisions and outdoor digital signage, but also in small and medium electronic devices such as personal computers, laptop computers, self-service terminals, car navigation devices, cameras, tablet PCs, smart phones, personal digital assistants (PDAs), portable multimedia players (PMPs), game consoles, and wristwatch-type electronic devices.

[0054] As Figure 1 illustrated in the middle, the camera CAM captures an image displayed on the display device DD and provides an image signal IM (a detected image signal) to the test device TD. The test device TD determines a color difference region of the display device DD based on the image signal IM received from the camera CAM and generates compensation data CP_DATA for the color difference region. The compensation data CP_DATA can be provided to the display device DD. The display device DD can correct an image data signal based on the compensation data CP_DATA and display a corrected image.

[0055] Figure 2 A color difference displayed on the display device DD is exemplarily illustrated.

[0056] Referring to Figure 2 , the display device DD displays an image on a surface defined by a first direction DR1 and a second direction DR2. The display device DD can include a circuit pattern formed by a stepper in a manufacturing process. If an area processed at a time by the stepper is less than a surface area of the display device DD, a deviation in an exposure amount can occur due to overlapping exposure, aberration of a plurality of lenses, or the like. The deviation in the exposure amount can change a width of the circuit pattern, and cause a deviation in pixel brightness due to a deviation in parasitic capacitance between thin film transistors, between signal wirings, or the like. The deviation in brightness can occur as a stepped color difference on the display device DD. The stepped color difference can have a shape of a horizontal line-shaped color difference or a vertical line-shaped color difference. Figure 2 The display device DD illustrated in the middle displays an example of a vertical line-shaped color difference VM extending in the second direction DR2 and repeatedly occurring in the first direction DR1.

[0057] Figure 3 is a block diagram of the test device TD according to an embodiment.

[0058] Referring to Figure 3The test device TD includes a color difference region corrector 100, a sampling corrector 140, and a compensator 150.

[0059] The color difference region corrector 100 can detect a color difference region based on an image signal IM (a detected image signal) received from a camera CAM (see Figure 1 ), and generate first compensation data CP1 with respect to the color difference region. The color difference region corrector 100 can include a color difference detection filter 110, an image enhancement processor 120, and a color difference corrector 130.

[0060] The color difference detection filter 110 can detect a stepped vertical line-shaped color difference region based on the image signal IM, and output position information DET_P of a position of the detected stepped vertical line-shaped color difference region. In addition, the color difference detection filter 110 can perform filtering on the image signal IM, and output a filtered image signal F_IM.

[0061] The image enhancement processor 120 can receive the position information DET_P and the filtered image signal F_IM from the color difference detection filter 110. The image enhancement processor 120 can perform deblurring on the filtered image signal F_IM based on the position information DET_P, generate a deblurred image signal DB_IM, and provide the deblurred image signal DB_IM to the color difference corrector 130.

[0062] The color difference corrector 130 can generate the first compensation data CP1 based on the deblurred image signal DB_IM received from the image enhancement processor 120.

[0063] The sampling corrector 140 can generate second compensation data CP2 with respect to the image signal IM.

[0064] The compensator 150 can receive the first compensation data CP1 from the color difference region corrector 100 and the second compensation data CP2 from the sampling corrector 140, and generate compensation data CP_DATA.

[0065] The color difference detection filter 110, the image enhancement processor 120, and the color difference corrector 130 will be described in greater detail below.

[0066] Figure 4A and Figure 4B The operation of the color difference detection filter 110 (see Figure 3 ) according to an embodiment is exemplarily illustrated. The Figure 3 will be described below in conjunction with Figure 4A and Figure 4B .

[0067] Referring to Figure 4A and Figure 4BThe color difference detection filter 110 can detect a color difference region using a morphological pair. The morphological pair can include an erosion operation and a dilation operation.

[0068] Equation 1 represents the erosion operation, and Equation 2 represents the dilation operation.

[0069] [Equation 1]

[0070]

[0071] [Equation 2]

[0072]

[0073] In Equations 1 and 2, x refers to a position of a pixel in a first direction DR1 (see FIG. 1), y refers to luminance (brightness), μ is a filter size, and Figure 2 is a filter shape.

[0074] Referring to Figure 4A , when μ = 8, i.e., the filter size μ is equal to eight pixels, a bright stitch BS and a dark stitch DS can be detected after the erosion operation and the dilation operation are performed.

[0075] Referring to Figure 4B , when μ = 16, i.e., the filter size μ is equal to 16 pixels, a stepped color difference can not be detected because the bright stitch BS and the dark stitch DS are removed after the erosion operation and the dilation operation are performed.

[0076] If the filter size is fixed, the color difference detection filter 110 in Figure 3 may not detect a stepped color difference. According to one embodiment, the color difference detection filter 110 can change the filter size (μ) to be able to detect a stepped color difference.

[0077] Figure 5 and Figure 6 are example graphs for describing operations of the color difference detection filter 110 (see FIG. 1). will be described below in conjunction with Figure 3 . Figure 3 Figure 5 and Figure 6 .

[0078] Figure 5 is a normal distribution graph showing a filtered image signal F_IM output from the color difference detection filter 110. In Figure 5 ​​In the example shown, the portion of the filtered image signal F_IM having a luminance value greater than the first reference value m+kσ can be classified as a bright seam BS. Further, the portion of the filtered image signal F_IM having a luminance value less than the second reference value m-kσ can be classified as a dark seam DS. Here, m is the average luminance or mean luminance, σ is the standard deviation, and k is a detection coefficient.

[0079] Figure 6 The filtered image signal F_IM output from the color difference detection filter 110 is exemplarily shown.

[0080] In the graph of Figure 6 , the abscissa represents the position x of a pixel in the first direction DR1 (see Figure 2 ) of the display device DD (see Figure 2 ), and the ordinate represents the filtered image signal F_IM, also referred to as a response signal.

[0081] In the example shown in Figure 6 , the bright seam BS and the dark seam DS occur in the vicinity of the 1920th pixel in the first direction DR1. The bright seam BS and the dark seam DS can occur as a vertical line-shaped color difference VM on the display device DD, as shown in Figure 2 .

[0082] Figure 7 The operation of the color difference detection filter 110 (see Figure 3 ) for detecting a general vertical line-shaped color difference displayed on the display device DD (see Figure 1 ) is exemplarily shown. The Figure 1 and Figure 3 will be described below in conjunction with Figure 7 .

[0083] Referring to Figure 1 , Figure 3 and Figure 7 , the camera CAM (see Figure 1 ) can capture a first image displayed on the display device DD (see Figure 1 ), generate a first image signal IM1 corresponding to the first image, and provide the first image signal IM1 as an image signal IM to the color difference detection filter 110. The color difference detection filter 110 can perform filtering on the first image signal IM1 using the modalities of Equation 1 and Equation 2, and output a first filtered image signal F_IM1 as the filtered image signal F_IM.

[0084] As shown in Figure 7 , the display device DD (see Figure 1) includes a generally vertical linear color difference, but when the first difference D_IM1 between the first image signal IM1 and the first filtered image signal F_IM1 is calculated on a pixel-by-pixel basis, the first difference D_IM1 may not have a large deviation. That is, the color difference detection filter 110 may not be as Figure 6 The first filtered image signal F_IM1 is classified as including bright slits and dark slits, like the bright slits BS and dark slits DS shown in FIG.

[0085] Figure 8 The color difference detection filter 110 is shown as an example (see Figure 3 ) for detecting the display device DD (see Figure 1 ) on the vertical color difference of the ladder. Figure 1 and Figure 3 To describe Figure 8 .

[0086] Reference Figure 1 、 Figure 3 and Figure 8 , Camera CAM (see Figure 1 ) can capture the display device DD (see Figure 1 ), generates a second image signal IM2 corresponding to the second image, and provides the second image signal IM2 as the image signal IM to the color difference detection filter 110. The color difference detection filter 110 may perform filtering on the second image signal IM2 using the forms of Equations 1 and 2, and output a second filtered image signal F_IM2 as the filtered image signal F_IM.

[0087] like Figure 8 As shown in FIG, the display device DD (see Figure 1 ) includes a stepped vertical line color difference VM, and when a second difference D_IM2 between the second image signal IM2 and the second filtered image signal F_IM2 is calculated according to the pixel, the second difference D_IM2 may have a large deviation. That is, the color difference detection filter 110 may classify the second difference D_IM2 as including the color difference corresponding to Figure 6 The difference between the bright slits BS shown in the figure corresponds to Figure 6 The difference between the dark gap DS shown in .

[0088] Figure 9 and Figure 10 The method for detecting an area including a stepped vertical linear chromatic aberration is exemplarily shown. For ease of description, Figure 9 Shown Figure 8 The enlarged view of the second difference D_IM2 shown in FIG. Figure 2 and Figure 3 To describeFigure 9 and Figure 10 .

[0089] Reference Figure 9 The horizontal axis represents the pixel on the display device DD (see Figure 2 ) in the first direction DR1, and the ordinate represents the image signal IM (ie, Figure 8 The second image signal IM2) and the filtered image signal F_IM (ie, Figure 8 The difference D_IM (ie, the second filtered image signal F_IM2) between Figure 8 The second difference D_IM2).

[0090] exist Figure 9 In the display device DD (see Figure 2 ) are grouped into first to ninth areas A1 to A9, and each of the first to ninth areas A1 to A9 includes eight pixels.

[0091] Figure 10 It shows Figure 9 Graph of the score of each of the first to ninth areas A1 to A9 shown in FIG.

[0092] According to one embodiment, the scores of the first to ninth regions A1 to A9 can be calculated using the deviation between the average luminance m and the difference value D_IM of the pixels included in the first to ninth regions A1 to A9. In an embodiment, regions with scores above a threshold can be determined as color difference regions. The color difference score SC for each of the first to ninth regions A1 to A9 can be calculated using Equation 3.

[0093] [Equation 3]

[0094]

[0095] exist Figure 9 and Figure 10 In the example shown in , the filter size μ is equal to 8.

[0096] The deviation between the second reference value m-kσ and the difference value D_IM of the pixels arranged in columns 1912 to 1919 in seventh area A7 is the largest, and the color difference score SC of seventh area A7 has the highest color difference score of 112.30. Next, the deviation between the second reference value m-kσ and the difference value D_IM of the pixels arranged in columns 1872 to 1879 in second area A2 is the second largest, and the color difference score SC of second area A2 has the second highest color difference score of 100.16. In an embodiment, the threshold value may be, for example, 100.0, and therefore seventh area A7 and second area A2 may be determined as color difference areas.

[0097] The color difference detection filter 110 can provide the filtered image signal F_IM and the position information DET_P of the two regions A7 and A2 having the two highest color difference scores to the image enhancement processor 120.

[0098] Figure 11A Figure 11B Figure 11C are graphs for describing operations of the image enhancement processor 120 (see Figure 3 ) according to an embodiment. The Figure 11A Figure 11B Figure 11C are presented as examples for describing operations of the image enhancement processor 120, and the present disclosure is not limited thereto. The Figure 1 Figure 3 Figure 11A Figure 11B Figure 11C are described below in conjunction with

[0099] Referring to Figure 1 Figure 11A , the image signal IM generated by the camera CAM (see Figure 1 ) based on the image displayed on the display device DD can have a blurred outline, for example, a blurred boundary between black and white.

[0100] Referring to Figure 3 , the filtered image signal F_IM output from the color difference detection filter 110 can also have a blurred outline as shown in Figure 11A .

[0101] The image enhancement processor 120 can deblur the filtered image signal F_IM received from the color difference detection filter 110 to correct the filtered image signal F_IM by reducing or removing the blurred outline, and output a deblurred image signal DB_IM.

[0102] Figure 11B The deblurred image signal DB_IM output from the image enhancement processor 120 is exemplarily shown.

[0103] Figure 11C is a graph showing a comparison of the filtered image signal F_IM output from the color difference detection filter 110 and the deblurred image signal DB_IM output from the image enhancement processor 120.

[0104] As shown in Figure 11C , the gray scale values can be clearly distinguished at the boundary between black and white in the deblurred image signal DB_IM compared to the filtered image signal F_IM.

[0105] ​​​​​​​​​According to one embodiment, the image enhancement processor 120 can obtain the deblurred image signal DB_IM by calculating a first derivative and a second derivative of the filtered image signal F_IM.

[0106] The deblurred image signal DB_IM output by the deblurring operation of the image enhancement processor 120 can be obtained by Equation 4.

[0107] [Equation 4]

[0108]

[0109] In Equation 4, f(x, y) denotes the filtered image signal F_IM, and I t (f(x, y)) denotes the deblurred image signal DB_IM. According to Equation 4, a Laplacian operation Δ and a gradient operation can detect and clarify a boundary (edge) in the filtered image signal F_IM.

[0110] Figure 11A The image shown in FIG. 1A can not be converted into the deblurred image shown in FIG. 1B by a single operation according to Equation 4, but can achieve the conversion by iteratively operating Equation 4. Figure 11B

[0111] For example, the image enhancement processor 120 can iteratively perform the operation of Equation 4 until a difference ratio DR between an t-th deblurred image signal I t (f(x, y)) and an (t-1)-th deblurred image signal I t-1 (f(x, y)) is equal to or less than a predetermined value (e.g., about 0.03).

[0112] The difference ratio DR can be calculated by Equation 5.

[0113] [Equation 5]

[0114]

[0115] Referring back to Figure 3 , the image enhancement processor 120 can provide the deblurred image signal DB_IM to the color difference corrector 130 and the position information DET_P received from the color difference detection filter 110.

[0116] The color difference corrector 130 can generate the first compensation data CP1 based on the deblurred image signal DB_IM received from the image enhancement processor 120. The color difference corrector 130 can sufficiently remove a color difference from the deblurred image signal DB_IM and generate the first compensation data CP1.

[0117] ​The color difference corrector 130 can calculate the first compensation data CP1 by Equation 6.

[0118] [Equation 6]

[0119] CP1 = G T - G C

[0120] G T = I M (I T (G C )) -1

[0121]

[0122]

[0123] In Equation 6, G T is a compensation target gray scale, G C is a compensation gray scale, I T and I M are gray scale to luminance conversion formulas for the compensation target gray scale G T and the image signal IM including a vertical line-shaped color difference, respectively, max gray is a maximum gray scale, and max Intensity is a maximum luminance at full white.

[0124] The sampling corrector 140 can generate second compensation data CP2 with respect to the image signal IM. The sampling corrector 140 can generate the second compensation data CP2 based on a difference between a gray scale (also referred to as a target gray scale) of a test image and a gray scale of the image signal IM.

[0125] The compensator 150 can add the first compensation data CP1 received from the color difference corrector 130 and the second compensation data CP2 received from the sampling corrector 140 to generate compensation data CP_DATA.

[0126] Figure 12 The compensation data CP_DATA (see Figure 3 ) generated in the compensator 150 (see Figure 3 ) according to the embodiment is exemplarily illustrated. The compensation data CP_DATA (see Figure 3 ) will be described below in connection with Figure 3 . Figure 12 .

[0127] Figure 12 The illustrated cells respectively represent pixels PX. A pixel group in a matrix form including "a" number of pixels in a first direction DR1 and "b" number of pixels in a second direction DR2 (here, each of a and b is a natural number) in the pixels PX can form one compensation block. In Figure 12In this embodiment, the compensation blocks CB11 to CB13 and CB21 to CB23 are shown as an example. Each of the compensation blocks CB11 to CB13 and CB21 to CB23 includes a x b pixels. In an embodiment, each of a and b is equal to 8 (a = b = 8).

[0128] As described above with reference to Figure 10 The second area A2 including the pixels disposed in the first direction DR1 from the 1872nd column to the 1879th column can be determined as a color difference area because its color difference score SC has a value higher than the threshold value.

[0129] With reference to Figure 12 , it is assumed that the pixels disposed in the first direction DR1 from the 1872nd column to the 1879th column are included in the compensation blocks CB12 and CB22. That is, each of the compensation blocks CB12 and CB22 is a color difference area in which a stepped vertical line-shaped color difference can be displayed. Further, the color difference corrector 130 can generate the first compensation data CP1 with respect to the compensation blocks CB12 and CB22.

[0130] In this example, the color difference corrector 130 can generate 2 x a pieces (i.e., 16 pieces) of the first compensation data CP1 with respect to one of the compensation blocks CB12 and CB22. For example, the compensation block CB12 can include 16 pieces of the first compensation data CP1-1 to CP1-16.

[0131] The pixels disposed in the first direction DR1 from the 1864th column to the 1871st column are included in the compensation blocks CB11 and CB21. The pixels disposed in the first direction DR1 from the 1880th column to the 1887th column are included in the compensation blocks CB13 and CB23. That is, the compensation blocks CB11, CB21, CB13, and CB23 correspond to non-color difference areas which can not include a stepped vertical line-shaped color difference. That is, the sampling corrector 140 can generate the second compensation data CP2 with respect to the compensation blocks CB11, CB21, CB13, and CB23.

[0132] In this example, the sampling corrector 140 can generate four pieces of the second compensation data CP2 with respect to one of the compensation blocks CB11, CB21, CB13, and CB23. For example, the compensation block CB11 can include four pieces of the second compensation data CP2-1 to CP2-4.

[0133] The area (i.e., the compensation blocks CB12 and CB22) which displays a stepped vertical line-shaped color difference corresponds to more pieces of the compensation data CP_DATA compared to the other compensation blocks CB11, CB21, CB13, and CB23 which do not display a stepped vertical line-shaped color difference. The method of compensating an image using the compensation data CP_DATA will be described in more detail below.

[0134] Figure 13 A display device DD according to an embodiment is exemplarily illustrated.

[0135] Referring to Figure 13 The display device DD includes a display panel 200, a driving controller 210, a data driving circuit 220, and a memory 250.

[0136] The display panel 200 includes a scan driving circuit 240, a plurality of pixels PX, a plurality of data lines DL1 to DLm, and a plurality of scan lines SL1 to SLn. Each of the plurality of pixels PX is connected to a corresponding data line among the plurality of data lines DL1 to DLm and a corresponding scan line among the plurality of scan lines SL1 to SLn.

[0137] The display panel 200 displaying an image can be one of various types of display panels including, but not limited to, a liquid crystal display (LCD) panel, an electrophoretic display panel, an organic light emitting diode (OLED) panel, a light emitting diode (LED) panel, an inorganic electroluminescent (EL) display panel, a field emission display (FED) panel, a surface-conduction electron-emitter display (SED) panel, a plasma display panel (PDP), and a cathode ray tube (CRT) display panel.

[0138] The driving controller 210 receives an input image signal RGB and a control signal CTRL. The control signal CTRL can include, but is not limited to, a synchronization signal and a clock signal. The driving controller 210 provides an image data signal DAS to the data driving circuit 220, which is generated by processing the input image signal RGB according to an operating condition of the display panel 200. Based on the control signal CTRL, the driving controller 210 provides a first control signal DCS to the data driving circuit 220 and a second control signal SCS to the scan driving circuit 240. The first control signal DCS can include, but is not limited to, a horizontal synchronization start signal, a clock signal, and a line latch signal, and the second control signal SCS can include, but is not limited to, a vertical synchronization start signal and an output enable signal.

[0139] The data driving circuit 220 can output grayscale voltages for driving the plurality of data lines DL1 to DLm in response to the first control signal DCS and the image data signal DAS received from the driving controller 210. In an exemplary embodiment, the data driving circuit 220 can be implemented as an integrated circuit (IC) directly mounted on a predetermined area of the display panel 200, or can be mounted on a separate printed circuit board in a form of a chip on film (COF) to be electrically connected to the display panel 200. In another embodiment, the data driving circuit 220 can be formed on the display panel 200 in the same process as a driving circuit of the pixels PX.

[0140] The scan driving circuit 240 can drive the plurality of scan lines SL1 to SLn in response to a second control signal SCS received from the driving controller 210. In an exemplary embodiment, the scan driving circuit 240 can be formed on the display panel 200 in the same process as the driving circuit of the pixel PX, but the present disclosure is not limited thereto. For example, the scan driving circuit 240 can be implemented as an integrated circuit (IC) mounted directly on a predetermined area of the display panel 200, or can be mounted on a separate printed circuit board in the form of a chip on film (COF) to be electrically connected to the display panel 200.

[0141] The memory 250 stores compensation data CP_DATA. The compensation data CP_DATA stored in the memory 250 can be provided by a test device TD shown in FIG. 1. Figure 3 The compensation data CP_DATA can include first compensation data CP1 and second compensation data CP2.

[0142] The driving controller 210 can correct the input image signal RGB based on the compensation data CP_DATA stored in the memory 250, and can provide the corrected image data signal DAS to the data driving circuit 220.

[0143] Figure 14 A method for interpolating compensation data for a color difference region according to an embodiment is illustrated.

[0144] Referring to Figure 12 , Figure 13 and Figure 14 , each of the compensation blocks CB12 and CB22 corresponding to the color difference region includes 16 pieces of first compensation data CP1-1 to CP1-16. The driving controller 210 can use the 16 pieces of first compensation data CP1-1 to CP1-16 to generate compensation data CP_DATA corresponding to 8x8 pixels (i.e., 64 pixels) by linear interpolation.

[0145] For example, the driving controller 210 can calculate one piece of compensation data CP_DATA corresponding to the pixel PX at the position (r3, c1) using Equation 7.

[0146] [Equation 7]

[0147]

[0148] Based on the compensation data corresponding to the pixels PX at the positions (r1, c1) and (r2, c1), the compensation data corresponding to the pixel PX at the position (r3, c1) is interpolated according to a linear distance between the position (r3, c1) and the positions (r1, c1) and (r2, c1).

[0149] Figure 15 A method for interpolating compensation data for non-chromatic aberration regions according to an embodiment is shown.

[0150] Referring to Figure 12 , Figure 13 and Figure 15 , each of the compensation blocks CB11, CB21, CB13, and CB23 corresponding to the non-chromatic aberration regions includes four pieces of second compensation data CP2-1 to CP2-4. The drive controller 210 uses the four pieces of second compensation data CP2-1 to CP2-4 to generate compensation data CP_DATA corresponding to 8x8 pixels (i.e., 64 pixels) by spatial interpolation.

[0151] For example, the drive controller 210 can calculate one piece of compensation data CP_DATA corresponding to the pixel PX at the position (r3, c1) using Equation 8 based on the four pieces of second compensation data CP2-1 to CP2-4.

[0152] [Equation 8]

[0153]

[0154] First, four intermediate compensation data corresponding to the pixels PX at the positions (r1, c1), (r2, c1), (r3, c2), and (r3, c3) are interpolated based on the four pieces of second compensation data CP2-1 to CP2-4, and the compensation data corresponding to the pixel PX at the position (r3, c1) is interpolated according to the distances between the pixel PX at the position (r3, c1) and the positions (r1, c1), (r2, c1), (r3, c2), and (r3, c3) based on the four intermediate compensation data corresponding to the pixels PX at the positions (r1, c1), (r2, c1), (r3, c2), and (r3, c3).

[0155] Figure 16 A method for interpolating gray scales according to an embodiment is shown.

[0156] Figure 1 The test device TD shown in FIG. 11 can test vertical linear color aberration for some of the gray scales, not all of the gray scales, and the drive controller 210 (see FIG. 1) can calculate compensation data CP_DATA for the remaining gray scales with a linear interpolation method. Figure 13

[0157] The drive controller 210 can generate compensation data for the nth gray scale using compensation data for the nth gray scale and compensation data for the (n+1)th gray scale and the (n+1)th gray scale​​​ grayscale between estimated compensation data Est Comp .

[0158] The drive controller 210 can calculate the estimated compensation data Est Comp .

[0159] [Equation 9]

[0160]

[0161] Referring Figure 1 , the test device TD described herein can detect a deviation in the characteristics of the pixels and generate compensation data CP_DATA for a region having a color difference within the display region of the display apparatus DD. In particular, the test device TD can generate compensation data CP_DATA by more accurately detecting a color difference region through a morphology filter and performing deblurring on the color difference region. Further, the test device TD can improve the color difference compensation performance of the display apparatus DD by increasing the number of compensation data CP_DATA corresponding to the color difference region compared to a non-color difference region.

[0162] Although exemplary embodiments of the inventive concept have been described herein, it should be understood that various changes and modifications can be made by those skilled in the art which include the spirit and scope of the inventive concept including the appended claims or equivalents. The exemplary embodiments described herein are not intended to limit the technical spirit and scope of the disclosure, and the technical spirit within the scope of the appended claims or equivalents will be interpreted as included within the scope of the disclosure.

Claims

1. A testing device comprising: a color difference detection filter configured to detect a color difference area based on the detected image signal and output position information of the color difference area and a filtered image signal; an image enhancement processor configured to perform deblurring on the filtered image signal based on the position information and output a deblurred image signal; a chromatic aberration corrector configured to generate first compensation data for the chromatic aberration region based on the deblurred image signal; a sampling corrector configured to generate second compensation data for a non-color difference area based on the detected image signal; as well as The compensator is configured to output compensation data based on the first compensation data and the second compensation data.

2. The testing device according to claim 1, wherein: The color difference detection filter detects the color difference area by performing an erosion operation and a dilation operation on the detected image signal.

3. The testing device according to claim 2, wherein: The color difference detection filter performs the erosion operation and the dilation operation based on a variable filter size and filter shape.

4. The testing device according to claim 1, wherein: The color difference detection filter is further configured as: grouping a plurality of pixels corresponding to the detected image signal into a plurality of regions; calculating a score for each of the plurality of regions based on a portion of the filtered image signal corresponding to each of the plurality of regions; as well as A region among the plurality of regions having a score higher than a threshold is set as the color difference region.

5. The testing device according to claim 4, wherein: The color difference detection filter is further configured as: calculating the filtered image signal by performing an erosion operation and a dilation operation on the detected image signal; calculating a difference between the detected image signal and the filtered image signal; A score for each of the plurality of areas is calculated based on a deviation between the difference value corresponding to each of the plurality of areas and a reference value.

6. The testing device according to claim 5, wherein The reference value includes a first reference value and a second reference value, The first reference value is m+kσ, and the second reference value is m-kσ, and m is the mean brightness of the filtered image signal, k is the detection coefficient, and σ is the standard deviation.

7. The testing device according to claim 4, wherein: The image enhancement processor performs the deblurring on the filtered image signal in a region corresponding to the position information among the plurality of regions.

8. The testing device according to claim 1, wherein: The image enhancement processor performs the deblurring on the filtered image signal using the following equation: as well as Wherein, f(x, y) is the filtered image signal, I t(f(x，y)) is the tth deblurred image signal, and I t -1(f(x，y)) is the (t-1)th deblurred image signal.

9. The testing device according to claim 8, wherein: The image enhancement processor iteratively calculates the equation until a difference ratio between the tth deblurred image signal and the (t-1)th deblurred image signal is equal to or smaller than a predetermined value.

10. The testing device according to claim 1, wherein: The chromatic aberration corrector is further configured as: grouping a plurality of pixels corresponding to the detected image signal into a plurality of compensation blocks; and generating the first compensation data corresponding to a first compensation block among the plurality of compensation blocks, the first compensation block corresponding to the color difference area, wherein the first compensation block includes a×b pixels among the plurality of pixels, wherein each of a and b is a natural number, and The chromatic aberration corrector generates 2×a pieces of the first compensation data for the first compensation block.

Images