Color correction device, color correction method, and correction table generation method

Abstract

The present application provides a color correction device, a color correction method and a correction table generating method. The color correction device includes a correction table circuit, a proportion circuit and an image processing circuit. The correction table circuit provides a selected correction table including a plurality of zone correction parameters. Each zone correction parameter corresponds to a corresponding zone of a plurality of zones of a display panel. The proportion circuit calculates a sub-pixel correction parameter corresponding to a current sub-pixel according to at least one of the zone correction parameters of the selected correction table. The image processing circuit corrects original sub-pixel data of the current sub-pixel according to the sub-pixel correction parameter to generate corrected sub-pixel data of the current sub-pixel.

Description

Technical Field

[0001] This invention relates to a display device, and more particularly to a color correction device, a color correction method, and a method for generating a correction table. Background Technology

[0002] Many display devices use self-emissive panels, such as Organic Light-Emitting Diode (OLED) panels. OLED panels are now widely used in various display devices. Due to process drift and / or differences in environmental conditions, OLED panels are prone to inconsistent red, green, and blue brightness ratios in different areas of pixels, resulting in native color shift. The color shift area can be irregular and widespread. Summary of the Invention

[0003] This invention provides a color correction device, a color correction method, and a correction table generation method for color correction of a display panel.

[0004] In an embodiment of the present invention, the color correction device described above includes a correction table circuit, a scaling circuit, and an image processing circuit. The correction table circuit provides a selected correction table. The selected correction table includes a plurality of area correction parameters. Each of these area correction parameters corresponds to a corresponding area among a plurality of areas of the display panel. The scaling circuit is coupled to the correction table circuit to receive the selected correction table. The scaling circuit calculates a subpixel correction parameter corresponding to the current subpixel based on at least one of the area correction parameters in the selected correction table. The image processing circuit is coupled to the scaling circuit to receive the subpixel correction parameters. The image processing circuit corrects the original subpixel data of the current subpixel based on the subpixel correction parameters to generate corrected subpixel data of the current subpixel.

[0005] In an embodiment of the present invention, the color correction method described above includes: providing a selected correction table by a correction table circuit, wherein the selected correction table includes a plurality of area correction parameters, and each of these area correction parameters corresponds to a corresponding area in a plurality of areas of a display panel; calculating a subpixel correction parameter corresponding to the current subpixel by a scaling circuit based on at least one of these area correction parameters in the selected correction table; and correcting the original subpixel data of the current subpixel based on the subpixel correction parameters by an image processing circuit to generate corrected subpixel data of the current subpixel.

[0006] In an embodiment of the present invention, the above-described calibration table generation method includes: dividing a display panel into multiple zones; measuring the color space value of each of these zones, wherein each of these zones has a conversion function to convert the original pixel data into a color space value; calculating Mt = TFi(Di*Pi) to obtain the zone calibration parameter Pi of the current zone, wherein Mt is the color space value of the target zone in these zones, TFi() is the conversion function corresponding to the current zone in these zones, and Di is the original pixel data of the current zone; and filling the zone calibration parameter corresponding to each of these zones into a calibration table.

[0007] Based on the above, the calibration table generation method described in the embodiments of the present invention can measure the color space value of each of multiple zones of a display panel, and then obtain the zone calibration parameters of these zones based on the color space values ​​of these zones. These zone calibration parameters can be filled into a calibration table. During normal display, the color calibration device can calculate the sub-pixel calibration parameters corresponding to the current sub-pixel based on the calibration table, and correct the original sub-pixel data of the current sub-pixel based on the sub-pixel calibration parameters. Therefore, the color calibration device can perform color calibration of the display panel (e.g., correcting native color shift). Attached Figure Description

[0008] Figure 1 This is a flowchart illustrating a method for generating a calibration table according to an embodiment of the present invention.

[0009] Figure 2 This is a schematic diagram of a circuit block of a display device according to an embodiment of the present invention.

[0010] Figure 3 This is a circuit block diagram of a color correction device according to an embodiment of the present invention.

[0011] Figure 4 This is a schematic flowchart of a color correction method according to an embodiment of the present invention.

[0012] Explanation of reference numerals in the attached figures

[0013] 200: Display device

[0014] 210, 300: Color correction device

[0015] 220: Drive circuit

[0016] 230: Display panel

[0017] 310: Calibration circuit

[0018] 320: Proportional Circuit

[0019] 330: Image processing circuit

[0020] Dsp1: Raw subpixel data

[0021] Dsp2: Corrected subpixel data

[0022] OP: Operating conditions

[0023] Rt: Subpixel correction parameters

[0024] S110~S140, S410~S430: Steps

[0025] Tb: Selected Correction Table Detailed Implementation

[0026] Reference will now be made in detail to exemplary embodiments of the invention, examples of which are illustrated in the accompanying drawings. Wherever possible, the same component reference numerals are used in the drawings and description to denote the same or similar parts.

[0027] The term "coupled (or connected)" as used throughout this application (including the claims) may refer to any direct or indirect means of connection. For example, if the text describes a first device coupled (or connected) to a second device, it should be interpreted as the first device being directly connected to the second device, or the first device being indirectly connected to the second device through other devices or some means of connection. The terms "first," "second," etc., used throughout this application (including the claims) are used to name components, and are not intended to limit the upper or lower limit of the number of components, nor to limit the order of components. Furthermore, wherever possible, components / components / steps using the same reference numerals in the drawings and embodiments represent the same or similar parts. Components / components / steps using the same reference numerals or the same terms in different embodiments can be referred to mutually in the relevant descriptions.

[0028] Figure 1 This is a schematic flowchart of a correction table generation method according to an embodiment of the present invention. Depending on the actual application, Figure 1 The calibration table generation method shown can be implemented in the manufacturing process of a display device. The generated calibration table can be stored in the display device. For example, in the manufacturing process, the display device can operate under one or more operating conditions to facilitate the preparation of one or more calibration tables corresponding to one or more operating conditions. During normal display, the color calibration device can select at least one calibration table from a plurality of candidate calibration tables according to the operating conditions, and then correct the original sub-pixel data of the current sub-pixel according to the selected calibration table.

[0029] exist Figure 1In step S110, the display panel can be divided into multiple zones. Depending on the actual design, the display panel can be an Organic Light-Emitting Diode (OLED) display panel, a Micro Light-Emitting Diode (Micro LED) display panel, or other self-emissive panels. In other embodiments, the display panel can be a non-self-emissive panel. The number of zones on the display panel is determined according to the actual design.

[0030] In step S120, a testing machine (not shown) can measure the color space value of each zone of the display panel. For example, the testing machine can measure the color space value Mi of the i-th zone of the display panel. One of these zones of the display panel can be designated as the target zone (reference zone). For example, in some embodiments, a central zone (or other zone) of the display panel can be designated as the target zone.

[0031] Each zone of the display panel has a dedicated conversion function. This conversion function converts the original pixel data into color space values. For the i-th zone of the display panel, the relationship between its color space value Mi, the conversion function TFi(), and the original pixel data Di can be Mi = TFi(Di). For example, in some embodiments, the color space value Mi can be the coordinates [X, Y, Z] in the XYZ color space. Wi Y Wi Z Wi The original pixel data Di may include different color grayscale values ​​(e.g., red value R, green value G, and blue value B), and the transformation function TFi() may include a transformation matrix. However, the applied color space is not limited to the XYZ color space. In other embodiments, the color space value Mi may be coordinates of the xyY color space, Lab color space, YUV color space, HSV color space, or other color spaces. For the i-th region of the display panel, the relationship between its color space value Mi, transformation function TFi(), and original pixel data Di can be referred to Equation 1 below.

[0032]

[0033] Equation 1 shows the white chromaticity [X] Wi Y Wi Z Wi [ ] can be the color space value Mi of the i-th region measured in step S120. White chromaticity [X Wi Y Wi Z WiThis can be obtained through a measuring device (testing machine, not shown). The measuring device can measure the white chromaticity of each area of ​​this display panel as the color space value measured in step S120. For example, taking the i-th area of ​​the display panel as an example, when the display panel displays a white screen, the measuring device can measure the XYZ color space coordinates (white chromaticity [X...]) of the i-th area of ​​the white screen. Wi Y Wi Z Wi Mi is the color space value of the i-th region.

[0034] Equation 1 shows a 3x3 transformation matrix where the chromaticity of the three primary colors (X) is... R Y R Z R ), (X G Y G Z G ) and (X B Y B Z B This can be obtained through a measuring device (testing machine, not shown). The measuring device can measure the different chromaticity of each zone of this display panel, as different element rows in the transformation matrix. For example, taking the i-th zone of the display panel as an example, when the display panel displays a red image, the measuring device can measure the XYZ color space coordinates (red chromaticity (X...) of the i-th zone of this red image). Ri Y Ri Z Ri This is the first element row in the transformation matrix shown in Equation 1. When the display panel shows a green screen, the measuring device can measure the XYZ color space coordinates (green chromaticity (X...) of the i-th region of this green screen. Gi Y Gi Z Gi This is the second element row in the transformation matrix shown in Equation 1. When the display panel shows a blue screen, the measuring device can measure the XYZ color space coordinates (blue chromaticity (X...) of the i-th region of this blue screen. Bi Y Bi Z Bi This is the third element row in the transformation matrix shown in Equation 1. Therefore, different areas of the display panel have their own dedicated transformation matrix (transformation function).

[0035] Similarly, for the target area (reference area) of the display panel, the relationship between its color space value Mt, the conversion function TFt(), and the original pixel data Dt, Mt=TFt(Dt), can be expressed as Equation 2 below. That is, the color space value Mt can include the coordinates [X, Y, Z] of the XYZ color space shown in Equation 2. Wt Y Wt Z WtThe original pixel data Dt may include the red value R, green value G and blue value B as shown in Equation 2, and the transformation function TFt() may include the 3*3 transformation matrix shown in Equation 2.

[0036]

[0037] In step S130, the testing equipment (not shown) can calculate Mt = TFi(Di*Pi) to obtain the area correction parameter Pi of a current area (e.g., the i-th area of ​​the display panel) among multiple areas. Here, Mt is the color space value of a target area (reference area) among multiple areas of the display panel, TFi() is the transformation function corresponding to the current area, and Di is the original pixel data of the current area. In some embodiments, "Mt = TFi(Di*Pi)" can be expressed as Equation 3 below. Based on Equation 3, the testing equipment can calculate the area correction parameter Pi of the i-th area, which is also the red correction parameter Ratio. Ri Green correction parameter Ratio Gi With blue correction parameter Ratio Bi However, the implementation examples of the zone correction parameter Pi are not limited to Ratio. Ri Ratio Gi With Ratio Bi In other embodiments, the region correction parameter Pi can be a one-dimensional parameter (vector), a two-dimensional parameter (matrix), a multi-dimensional parameter (tensor), or other parameter forms.

[0038]

[0039] In step S140, the testing equipment (not shown) can fill the area correction parameters corresponding to each area of ​​the display panel into a correction table. Based on the actual design, the display panel can operate under various operating conditions, and the testing equipment prepares multiple correction tables corresponding to different operating conditions. According to the actual design, these operating conditions may include the current sub-pixel grayscale, temperature, humidity, environmental color temperature, ambient brightness, and / or other operating conditions. During normal display, the display device configured with this display panel can select at least one correction table from the pre-prepared candidate correction tables based on the current operating conditions, and then correct the original sub-pixel data of the current sub-pixel according to the selected correction table.

[0040] Figure 2 This is a schematic diagram of a circuit block of a display device 200 according to an embodiment of the present invention. Figure 2The display device 200 shown includes a color correction device 210, a driving circuit 220, and a display panel 230. Depending on the actual design, the display panel 230 may be an OLED display panel, a micro-light-emitting diode display panel, or other display panels. The number of partitions in the display panel 230 can be determined according to the actual design. The color correction device 210 can correct the original sub-pixel data Dsp1 of the current sub-pixel to generate corrected sub-pixel data Dsp2 for the driving circuit 220. Based on the corrected sub-pixel data Dsp2, the driving circuit 220 can drive the corresponding sub-pixel (not shown) in the display panel 230. Therefore, the display panel 230 can display an image based on the driving operation of the driving circuit 220. This embodiment does not limit the implementation details of the driving circuit 220. For example, in some embodiments, the driving circuit 220 may be a known display panel driving circuit or other driving circuit.

[0041] Figure 3 This is a circuit block diagram of a color correction device 300 according to an embodiment of the present invention. Figure 3 The color correction device 300 shown can be used as Figure 2 This is one of many embodiments of the color correction device 210 shown. Figure 3 The color correction device 300 shown can be referenced. Figure 2 Description of the color correction device 210 shown. Figure 3 The color correction device 300 shown includes a calibration meter circuit 310, a scaling circuit 320, and an image processing circuit 330. Depending on different design requirements, the calibration meter circuit 310, the scaling circuit 320, and / or the image processing circuit 330 can be implemented in hardware, firmware, software, or a combination of the above three.

[0042] In hardware form, the aforementioned calibration table circuit 310, scaling circuit 320, and / or image processing circuit 330 can be implemented as logic circuits on an integrated circuit. The functions of the aforementioned calibration table circuit 310, scaling circuit 320, and / or image processing circuit 330 can be implemented as hardware using hardware description languages ​​(such as Verilog HDL or VHDL) or other suitable programming languages. For example, the functions of the aforementioned calibration table circuit 310, scaling circuit 320, and / or image processing circuit 330 can be implemented as various logic blocks, modules, and circuits in one or more controllers, microcontrollers, microprocessors, application-specific integrated circuits (ASICs), digital signal processors (DSPs), field-programmable gate arrays (FPGAs), and / or other processing units.

[0043] In software and / or firmware form, the functions of the calibration circuit 310, the scaling circuit 320, and / or the image processing circuit 330 can be implemented as programming codes. For example, the calibration circuit 310, the scaling circuit 320, and / or the image processing circuit 330 can be implemented using general programming languages ​​(such as C, C++, or assembly language) or other suitable programming languages. The programming codes can be recorded / stored in a non-transitory computer-readable medium. In some embodiments, the non-transitory computer-readable medium includes, for example, read-only memory (ROM), semiconductor memory, programmable logic circuits, and / or storage devices. A central processing unit (CPU), controller, microcontroller, or microprocessor can read and execute the programming codes from the non-transitory computer-readable medium to implement the functions of the calibration circuit 310, the scaling circuit 320, and / or the image processing circuit 330.

[0044] Figure 4 This is a schematic flowchart of a color correction method according to an embodiment of the present invention. Please refer to... Figure 3 and Figure 4In step S410, the calibration table circuit 310 can provide a selected calibration table Tb to the scaling circuit 320. The selected calibration table Tb includes multiple area calibration parameters, each of which corresponds to a corresponding area among multiple areas of the display panel 230. For example, in some embodiments, the calibration table circuit 310 can select one of multiple candidate calibration tables as the selected calibration table Tb based on at least one operating condition OP. Depending on the actual design, the at least one operating condition OP includes: current subpixel grayscale, temperature, humidity, ambient color temperature, ambient brightness, and / or other operating conditions. Details of the fabrication of these candidate calibration tables of the calibration table circuit 310 can be found in [reference needed]. Figure 1 The relevant explanation is provided below. In some other embodiments, the calibration table circuit 310 may select multiple tables from multiple candidate calibration tables according to the at least one operating condition OP, and then use the multiple tables to perform interpolation calculations to generate the selected calibration table Tb.

[0045] The scaling circuit 320 is coupled to the calibration table circuit 310 to receive the selected calibration table Tb. In step S420, the scaling circuit 320 can calculate the sub-pixel correction parameter Rt corresponding to the current sub-pixel based on at least one of the multiple area correction parameters of the selected calibration table Tb. For example, the scaling circuit 320 can generate the sub-pixel correction parameter Rt corresponding to the current sub-pixel by performing interpolation calculations using at least one of these area correction parameters of the selected calibration table Tb.

[0046] Assume that the sub-pixel is currently located in the i-th region of the display panel 230, and the adjacent region of the i-th region is the (i+1)-th region of the display panel 230. The scaling circuit 320 can use the region correction parameter Pi of the i-th region and the region correction parameter Pi+1 of the (i+1)-th region. Taking Equation 3 as an example, the region correction parameter Pi can include the red correction parameter Ratio. Ri Green correction parameter Ratio Gi With blue correction parameter Ratio Bi The area correction parameter Pi+1 can be deduced by referring to the relevant description of the area correction parameter Pi. The scaling circuit 320 can use the area correction parameter Pi and Pi+1 to perform interpolation calculations to generate the sub-pixel correction parameter Rt corresponding to the current sub-pixel.

[0047] Image processing circuit 330 is coupled to scaling circuit 320 to receive subpixel correction parameter Rt. In step S430, image processing circuit 330 can correct the original subpixel data Dsp1 of the current subpixel according to the subpixel correction parameter Rt to generate corrected subpixel data Dsp2 of the current subpixel. For example (but not limited to), image processing circuit 330 can multiply the original subpixel data Dsp1 by the subpixel correction parameter Rt to generate corrected subpixel data Dsp2. Assume that the original subpixel data Dsp1 includes red value R1, green value G1, and blue value B1, and the subpixel correction parameter Rt includes red correction parameter Ratio. R Green correction parameter Ratio G With blue correction parameter Ratio B The image processing circuit 330 can calculate "R2 = R1 * Ratio". R “G2 = G1 * Ratio” G "and "B2=B1*Ratio B This is used to generate the red value R2, green value G2, and blue value B2 of the corrected subpixel data Dsp2.

[0048] In summary, Figure 1 The calibration table generation method measures the color space value of each of multiple areas of the display panel 230, and then calculates the area calibration parameters of these areas based on the color space values. These area calibration parameters can be filled into a candidate calibration table. Multiple candidate calibration tables can be prepared in advance for different operating conditions OP (e.g., current subpixel grayscale, temperature, humidity, ambient color temperature, ambient brightness, and / or other operating conditions), and these candidate calibration tables are recorded in the calibration table circuit 310. During normal display, the calibration table circuit 310 selects one from the multiple candidate calibration tables as the selected calibration table Tb based on at least one operating condition OP, or selects multiple tables from the multiple candidate calibration tables to generate the selected calibration table Tb. The scaling circuit 320 can calculate the subpixel calibration parameter Rt corresponding to the current subpixel based on at least one of the multiple area calibration parameters of the selected calibration table Tb. The image processing circuit 330 can correct the original subpixel data Dsp1 of the current subpixel based on the subpixel calibration parameter Rt to generate the corrected subpixel data Dsp2 of the current subpixel. Therefore, the color correction device 210 (or 300) can calculate the sub-pixel correction parameter Rt corresponding to the current sub-pixel according to the correction table, and correct the original sub-pixel data Dsp1 of the current sub-pixel according to the sub-pixel correction parameter Rt. Therefore, the color correction device 210 (or 300) can perform color correction of the display panel 230 (e.g., correct native color shift).

[0049] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A color correction device, characterized in that, The color correction device includes: A calibration meter circuit for providing a selected calibration meter, wherein the selected calibration meter includes a plurality of zone calibration parameters, and each of the plurality of zone calibration parameters corresponds to a corresponding zone among a plurality of zones of a display panel; A scaling circuit, coupled to the calibration table circuit, receives the selected calibration table and calculates the sub-pixel calibration parameter corresponding to the current sub-pixel based on at least one of the plurality of region calibration parameters in the selected calibration table; and An image processing circuit, coupled to the scaling circuit, receives the sub-pixel correction parameters and uses them to correct the original sub-pixel data of the current sub-pixel based on the sub-pixel correction parameters to generate corrected sub-pixel data of the current sub-pixel. The methods for generating the selected correction table include: The color space value of each of the plurality of regions is measured, wherein each of the plurality of regions has a transformation function to convert the original pixel data into the color space value; calculate To obtain the region correction parameter Pi of the current region among the plurality of regions, where Mt is the known color space value of the target region among the plurality of regions, TFi() is the transformation function corresponding to the current region among the plurality of regions, and Di is the original pixel data of the current region; and Fill the selected correction table with the correction parameters corresponding to each of the plurality of regions.

2. The color correction device according to claim 1, characterized in that, The image processing circuit multiplies the original subpixel data by the subpixel correction parameter to generate the corrected subpixel data.

3. The color correction device according to claim 1, characterized in that, The scaling circuit generates the sub-pixel correction parameters corresponding to the current sub-pixel by performing interpolation calculations using at least one of the plurality of region correction parameters.

4. The color correction device according to claim 1, characterized in that, The calibration table circuit selects one of a plurality of candidate calibration tables as the selected calibration table based on at least one operating condition.

5. The color correction device according to claim 4, characterized in that, The at least one operating condition includes the current subpixel grayscale, temperature, humidity, ambient color temperature, or ambient brightness.

6. The color correction device according to claim 1, characterized in that, The calibration table circuit selects multiple tables from multiple candidate calibration tables based on at least one operating condition, and performs interpolation calculations using the multiple tables to generate the selected calibration table.

7. A color correction method, characterized in that, The color correction method includes: A selective calibration table is provided by a calibration table circuit, wherein the selective calibration table includes multiple zone calibration parameters, and each of the multiple zone calibration parameters corresponds to a corresponding zone among multiple zones of the display panel; The proportional circuit calculates the sub-pixel correction parameter corresponding to the current sub-pixel based on at least one of the plurality of area correction parameters in the selected correction table; and The image processing circuit corrects the original sub-pixel data of the current sub-pixel according to the sub-pixel correction parameters to generate the corrected sub-pixel data of the current sub-pixel. The methods for generating the selected correction table include: The color space value of each of the plurality of regions is measured, wherein each of the plurality of regions has a transformation function to convert the original pixel data into the color space value; calculate To obtain the region correction parameter Pi of the current region among the plurality of regions, where Mt is the known color space value of the target region among the plurality of regions, TFi() is the transformation function corresponding to the current region among the plurality of regions, and Di is the original pixel data of the current region; and Fill the selected correction table with the correction parameters corresponding to each of the plurality of regions.

8. The color correction method according to claim 7, characterized in that, The operation of generating the corrected sub-pixel data of the current sub-pixel includes: The original subpixel data is multiplied by the subpixel correction parameter to generate the corrected subpixel data.

9. The color correction method according to claim 7, characterized in that, The operation of calculating the sub-pixel correction parameter corresponding to the current sub-pixel includes: The sub-pixel correction parameters corresponding to the current sub-pixel are generated by interpolation calculation using at least one of the plurality of region correction parameters.

10. The color correction method according to claim 7, characterized in that, The color correction method further includes: The selected correction table is chosen from a plurality of candidate correction tables based on at least one operating condition.

11. The color correction method according to claim 10, characterized in that, The at least one operating condition includes the current subpixel grayscale, temperature, humidity, ambient color temperature, or ambient brightness.

12. The color correction method according to claim 7, characterized in that, The color correction method further includes: Selecting multiple tables from multiple candidate correction tables based on at least one operating condition; and Interpolation calculations are performed using the multiple tables to generate the selected correction table.

13. A method for generating a calibration table, characterized in that, The method for generating the calibration table includes: The display panel is divided into multiple areas; The color space value of each of the plurality of regions is measured, wherein each of the plurality of regions has a transformation function to convert the original pixel data into the color space value; calculate To obtain the region correction parameter Pi of the current region among the plurality of regions, where Mt is the known color space value of the target region among the plurality of regions, TFi() is the transformation function corresponding to the current region among the plurality of regions, and Di is the original pixel data of the current region; and Fill the calibration table with the calibration parameters corresponding to each of the plurality of regions.

14. The calibration table generation method according to claim 13, characterized in that, The color space values ​​are coordinates in the XYZ color space, the original pixel data includes red, green and blue values, and the transformation function includes a transformation matrix.

15. The calibration table generation method according to claim 14, characterized in that, The operation of measuring the color space value of each of the plurality of regions includes: A white screen is displayed on the display panel; and The XYZ color space coordinates of each of the plurality of regions of the white image are measured as the color space value.

16. The calibration table generation method according to claim 14, characterized in that, The method for generating the calibration table further includes: The red image is displayed on the display panel; Measure the XYZ color space coordinates of each of the plurality of regions of the red image, and use them as the first element row in the transformation matrix; A green screen is displayed on the display panel; Measure the XYZ color space coordinates of each of the plurality of regions of the green screen, and use them as the second element row in the transformation matrix; The blue screen is displayed on the display panel; and The XYZ color space coordinates of each of the plurality of regions of the blueprint are measured and used as the third element row in the transformation matrix.

Images