CN107564493B - Color gamut compression method and device and display equipment - Google Patents
Color gamut compression method and device and display equipment Download PDFInfo
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Abstract
The application provides a color gamut compression method, a color gamut compression device and display equipment, relates to the technical field of display, and aims to solve the problem of color distortion existing in the conventional color gamut compression. The method comprises the following steps: if the color coordinates of the pixel points to be corrected are outside the color gamut range of the screen of the equipment, selecting any point in a target line segment, wherein the end points of the target line segment are the pixel points to be corrected and white points in the color gamut range respectively; taking the selected point as a starting point, if the selected point is in the color gamut range, continuing to select the point from the target line segment towards the direction of the pixel point to be corrected according to a preset step length until the selected point is out of the color gamut range; if the selected point is out of the color gamut range, continuing to select the point from the target line segment in the direction of the white point according to the preset step length until the selected point is in the color gamut range; and correcting the color coordinates of the pixel points to be corrected into the color coordinates of the last or last point selected last time.
Description
Technical Field
The present application relates to the field of display technologies, and in particular, to a color gamut compression method and apparatus, and a display device.
Background
In recent years, with rapid development of display technologies such as High-Dynamic Range (HDR) images, the bt.2020 standard has also been developed. Wherein the content of the first and second substances,
the bt.2020 standard has been located by the international telecommunication union radio communication sector (ITU-R) to a color gamut of image signals in the 4K/8K era, which is also one of the standards for ultra high definition blue light. The bt.709 standard is used in the general blu-ray standard, and the color gamut area of the bt.2020 standard is much larger than that of the bt.709 standard.
However, although the medium-high end televisions on the market basically use wide color gamut device screens, the color gamut of the display color gamut is still smaller than the color gamut of the bt.2020 standard, and in addition, the color gamut of the display screens used on the low end televisions on the market is still the color gamut of the bt.709 standard or is close to or even smaller than the color gamut of the bt.709 standard. Thus, when an input image signal with a large color gamut (e.g., bt.2020 signal) is displayed on a display screen with a small color gamut, as shown in fig. 1, the RGB area (i.e., area a in fig. 1) in fig. 1 is the color gamut of the input image signal, and the RGB area (i.e., area b in fig. 1) in fig. 1 is the color gamut of the display color gamut of the device screen, where the area of the RGB area is larger than the area of the RGB area, and at this time, if no processing is performed, the color in the input image signal exceeding the color gamut of the device screen is lost, and the effect on the screen of the normal color gamut is greatly impaired. In order to ensure that colors in the input graphics signals that are outside the gamut of the device screen are better displayed, it is necessary to perform gamut compression on these signals to compress colors that are outside the gamut as much as possible into the display gamut. However, gamut compression necessarily results in distortion of the compressed colors.
Therefore, how to perform color gamut compression while ensuring minimum color distortion is a problem to be addressed by the present application.
Content of application
The embodiment of the application provides a color gamut compression method, a color gamut compression device and display equipment, and aims to solve the problem of color distortion existing in the conventional color gamut compression.
In order to achieve the above purpose, the embodiment of the present application adopts the following technical solutions:
in a first aspect, a color gamut compression method is provided, including:
if the color coordinates of the pixel points to be corrected are outside the color gamut range of the equipment screen, selecting any point in the target line segment; the end points of the target line segment are the pixel point to be corrected and the white point in the color gamut range respectively;
taking the point selected this time as the starting point,
if the selected point is within the color gamut range, continuing to select the point from the target line segment towards the direction of the pixel point to be corrected according to the preset step length until the selected point is outside the color gamut range;
if the selected point is out of the color gamut range, continuing to select the point from the target line segment in the direction of the white point according to a preset step length until the selected point is in the color gamut range;
and correcting the color coordinates of the pixel points to be corrected into the color coordinates of the last or last point selected last time.
In a second aspect, there is provided a color gamut compression device comprising: a processor and a memory; wherein the memory is configured to store computer executable code for controlling the processor to perform the method of the first aspect.
In a third aspect, there is provided a display device comprising: the gamut compression device according to the second aspect.
In a fourth aspect, a computer storage medium is provided for storing computer software instructions for a gamut compression device, which comprises program code designed to perform the method of the first aspect.
According to the scheme provided by the embodiment of the application, if the color coordinates of the pixel points to be corrected are out of the color gamut range of the screen of the equipment, any point in the target line segment is selected; the end points of the target line segment are respectively the pixel point to be corrected and the white point in the color gamut range, then the selected point is taken as the starting point, if the selected point is in the color gamut range, the point is continuously selected from the target line segment towards the direction of the pixel point to be corrected according to the preset step length until the selected point is out of the color gamut range; and if the selected point is out of the color gamut range, continuously selecting the point from the target line segment in the direction of the white point according to the preset step length until the selected point is in the color gamut range, and finally correcting the color coordinates of the pixel point to be corrected into the color coordinates of the last or last previously selected point. Because any point in the color gamut and the point on the connecting line between the white points all belong to the same hue, the original color value of the pixel point to be corrected is compressed along the same hue, so that the point with the minimum color difference is found as the corrected point, and the color value of the pixel point can be compressed into the display color gamut of the screen of the equipment under the condition of minimum color distortion.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings needed to be used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present application, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.
Fig. 1 is a schematic color gamut diagram provided in an embodiment of the present application;
fig. 2 is a schematic flowchart of a color gamut compression method provided in an embodiment of the present application;
fig. 3 is a schematic view of another color gamut provided in an embodiment of the present application;
FIG. 4 is a schematic diagram of another color gamut provided in an embodiment of the present application;
fig. 5 is a schematic structural diagram of a color gamut compression apparatus according to an embodiment of the present application.
Detailed Description
The technical solutions provided by the embodiments of the present application will be described below with reference to the drawings of the specification of the embodiments of the present application. It is to be understood that only a few embodiments, but not all embodiments of the present application are described. It should be noted that some or all of the technical features of any of the technical solutions provided below may be combined and used to form a new technical solution without conflict.
Some of the terms referred to in this application are explained below to facilitate the understanding of the reader:
1. color Gamut (Color Gamut)
The color gamut is used to indicate a range area formed by the number of colors that can be expressed by all or part of the area in the display device, for example, a range of colors that can be expressed by various display devices, printers, or printing devices. In order to be able to visually represent color space values, the international lighting organization (CIE) has formulated a method for describing color space values: CIE-xy chromaticity diagram. In this coordinate system, the range of color space values that can be represented by various display devices can be generally represented by a triangular region composed of three points of color space connected by color, and the larger the area of the triangle, the larger the range of color space values that can be represented by such a display device. Color coordinates are the color quantization standard of the CIE organization, i.e., any color in nature can be attributed to a point (x, y) on the color coordinates.
2. Color Space (Color Space)
A color space, which is used to indicate the collection of the number of various colors that a certain display device can represent. Generally, the wider the color space, the more types of colors that can be displayed, and the larger the range of values in the color space. The color space may be divided into a device-dependent color space and a device-independent color space according to a correlation between devices.
3. Device dependent color spaces
The device-dependent color space refers to a color space in which a color specified by the color space is generated in relation to a device that generates the color, i.e., coordinates of the color space vary from image source device to image source device. Illustratively, the device-dependent color space includes: a subtractive color based color space (e.g., CMYK color space) and an additive color based color space (e.g., RGB color space), for example, when a computer display uses RGB to display a color, if the computer display displays a color of a pixel having a pixel value of (R, G, B) ═ 250,123,23, the color changes with changes in the brightness and saturation of the display.
4. Device independent color space
A device-independent color space, which means that the color space specifies the colors to be generated independently of the device that generated the colors, is generally built on the CIE standard, and when a color space is given a set of values for a certain color, the colors presented are consistent regardless of the device used for display. Illustratively, the device-independent color space includes: CIE1931XYZ color space (CIE Lxy space is a color space derived directly from XYZ space), CIE1976LAB, CIE1976 LUV. For example, the CIE LAB color space is a device-independent color space that is built on the basis of the HSV (hue, saturation, and value, Chinese) color space, and the colors generated on different devices by the colors specified in the color space are the same.
The color space irrelevant to the device in the embodiment of the present application may be any one of an XYZ color space, an LAB color space, or an LUV color space, which is not limited in the embodiment of the present application. For convenience of explanation, hereinafter, an example of "Lxy color space" will be described, where the Lxy color space is obtained by projecting a plane X + Y + Z of the XYZ color space to 1 onto an (X, Y) plane, that is, a plane Z is 0.
It should be noted that a plane formed by the x-axis and the y-axis in the Lxy coordinate system corresponding to the Lxy color space is used to represent the chromaticity value, for example, xr(i,j)，yrAnd (i, j) is used for expressing the chromatic value of the pixel point with the coordinate (i, j) in the plane formed by the x axis and the Y axis, and the Y axis is used for expressing the brightness.
5. Color coordinates refer to the coordinates of points within a color gamut. The color coordinates of the pixel points in the input image refer to coordinates of points corresponding to color values of the pixel points in a color gamut in a color space irrelevant to equipment, and each color coordinate corresponds to one color value.
6. The device screen is a screen of a display device, and is generally a display unit for displaying images or videos, the display device in the embodiment of the present application is an electronic device having a screen, and the electronic device may be a mobile terminal such as a smart television, a smart phone, a tablet Computer, a notebook Computer, an Ultra-mobile Personal Computer (UMPC), a netbook, a Personal Digital Assistant (PDA), or may be an electronic device dedicated for image display such as a projector, a display, or the like.
7. Generally, the color value of a pixel is usually expressed by using a hue value (hue value), a saturation value (purity value) and a brightness value of the color. The three primary colors of the pixel point include three primary colors, namely a red primary color, a green primary color and a blue primary color, wherein the three primary colors are independent from each other, and any color cannot be generated by mixing other two colors. According to the method and the device, the color values of the pixel points are divided into the color values in the color space related to the device and the color values in the color space unrelated to the device.
8. Other terms
The term "and/or" herein is merely an association describing an associated object, meaning that three relationships may exist, e.g., a and/or B, may mean: a exists alone, A and B exist simultaneously, and B exists alone. In addition, the character "/" herein generally indicates that the former and latter related objects are in an "or" relationship. The term "plurality" herein means two or more, unless otherwise specified.
For the convenience of clearly describing the technical solutions of the embodiments of the present application, in the embodiments of the present application, the terms "first" and "second" are used to distinguish the same items or similar items with basically the same functions or actions, and those skilled in the art can understand that the terms "first" and "second" are not limited to the quantity and execution order.
In the embodiments of the present application, words such as "exemplary" or "for example" are used to mean serving as an example, instance, or illustration. Any embodiment or design described herein as "exemplary" or "e.g.," is not necessarily to be construed as preferred or advantageous over other embodiments or designs. Rather, use of the word "exemplary" or "such as" is intended to present concepts related in a concrete fashion. In the embodiments of the present application, "of", "corresponding" and "corresponding" may be sometimes used in combination, and it should be noted that the intended meaning is consistent when the difference is not emphasized.
The execution subject of the color gamut compression method provided by the embodiment of the present application may be a color gamut compression device, or a display device for executing the color gamut compression method. The color gamut compression apparatus may be a Central Processing Unit (CPU) in the display device, or may be a control Unit or a functional module in the display device.
The scheme provided by the application is mainly directed to a scene in which the gamut range of an input image signal is larger than that of a device screen, as shown in fig. 1.
Fig. 2 is a flowchart of a method of color gamut compression provided in an embodiment of the present application, and as shown in fig. 2, the method includes the following steps:
s101, if the color coordinates of the pixel points to be corrected are outside the color gamut range of the screen of the equipment, selecting any point in the target line segment.
The end points of the target line segment are respectively a pixel point to be corrected and a white point in the color gamut range of the display color gamut of the device screen.
And S102, taking the point selected at this time as a starting point.
If the selected point is within the color gamut, step S103a is executed, and if the selected point is outside the color gamut, step S103b is executed.
S103a, continuing to select points from the target line segment towards the direction of the pixel point to be corrected according to the preset step length until the selected points are out of the color gamut range.
And S103, 103b, continuing to select points from the target line segment in the direction of the white point and according to a preset step size until the selected points are within the color gamut range.
The predetermined step size may be a value greater than or equal to 1, and generally, the smaller the predetermined step size is, the closer the finally selected point is to the real color gamut boundary. Of course, the recursive convergence method described above is only an example, and in a specific implementation, the final gamut boundary point may also be found by fast convergence using a halving method, that is, the value of the predetermined step size is not fixed, for example, the predetermined step size is M when the point is selected for the first time, and the predetermined step size may be M/2 when the point is selected for the second time. The manner of finding the boundary point of the color gamut is not limited here.
In one example, in order to increase the convergence speed and thus find the final gamut boundary point quickly, the present application may set the starting point as the intersection point of the target line segment and the target gamut boundary. As shown in fig. 1, the generally ideal gamut region can be regarded as a triangular region (e.g., RGB region and RGB region in fig. 1), and therefore, the present application takes a line connecting two vertices within the gamut range of the device screen as a target gamut boundary.
For example, as shown in fig. 3, if point a in fig. 3 is a position where a pixel point to be corrected is located, point W is a position of a white point in a display gamut, a connecting line between point a and point W intersects with a target gamut boundary gb, an intersection point is point P, and point P is an initial point. For example, with the point P as a starting point, if the point P is outside the color gamut, the points P and W are sequentially selected along the direction until the selected point is within the color gamut, and if the point P is within the color gamut, the point a is selected along the point P until the selected point is outside the color gamut, at which time, the last selected point or the last point of the point is the final point to be found.
In one example, a white point or a pixel point to be corrected within a display gamut of a device screen may be directly taken as a starting point. For example, as shown in fig. 4, point a in fig. 4 is a position where a pixel point to be corrected is located, point W is a position of a white point in a display gamut, and point a may be used as a starting point to select in sequence along point a to point W until the selected point is within the gamut range, or may be used as a starting point to search for point a along point W until the selected point is outside the gamut range. At this time, the point selected last time or the last point of the point is the point to be found finally.
And S104, correcting the color coordinates of the pixel points to be corrected into the color coordinates of the last or last point selected last time.
For example, after S104 is executed, since the color value corresponding to the color coordinate is a color value (e.g., Lxy or XYZ) in the device-independent color space, and cannot be directly displayed on the device screen, a spatial conversion is required to convert the color value in the device-independent color space into a color value (e.g., RGB) in the device-dependent color space, so that the color value can be displayed on the device screen.
Before implementing step S101, the method further includes:
and A1, acquiring the original color value of the pixel point to be corrected in the color space irrelevant to the equipment.
A2, judging whether the color coordinates of the pixel point to be corrected are outside the color gamut range of the device screen.
For example, when the original color value of a pixel to be corrected is obtained from an input image signal, since the color value is usually an RGB value, the color value of the pixel in a color space that is not related to a device (e.g., XYZ value) needs to be obtained after the pixel is subjected to spatial conversion. For example, currently, there are many algorithms for implementing color space conversion, and the algorithms are mainly classified into a polynomial regression method, a model method, a 3D _ LUT table look-up method, a BP neural network method, and the like.
In an example, when original RGB values of a pixel point to be corrected before being displayed on a device screen are converted into XYZ values, the application may use a model method for conversion.
Specifically, when the RGB values of the pixel point a to be corrected are converted into XYZ values, a model formula (formula 1) when the RGB values of the pixel point a are converted into XYZ values may be used for the conversion.
Wherein the matrix is
The matrix a, which is a gamut range coefficient of the input gamut of the input image signal, for characterizing the gamut range of the display gamut of the input image signal, may be determined from the chromaticity coordinates of the gamut of the input image signal.
For example, if the color gamut of the input image signal is bt.2020 color gamut, the matrix a can be obtained from CIE, 1931 bt.2020(Recommendation ITU-R bt.2020-22015-10) chromaticity coordinate table (table 1 below) and the conversion relationship between Lxy color space and XYZ color space.
Wherein, the conversion relationship between the Lxy color space and the XYZ color space is as follows formula 2:
| chromaticity coordinate | x | y |
| R | 0.708 | 0.292 |
| G | 0.17 | 0.797 |
| B | 0.131 | 0.046 |
| W(D65) | 0.3127 | 0.329 |
TABLE 1
W (D65) in table 1 indicates the color coordinates of the white point when the color temperatures of the display gamut of the device screen and the input gamut of the input graphics signal are both 6500. Note that the white point positions of the color gamut are different for different color temperatures.
Specifically, the process of obtaining the matrix a according to table 1 and the conversion relationship between the Lxy color space and the XYZ color space specifically includes the following processes:
1) y (luminance) of the device D65 white point is equal to a constant value, assuming Yw is 100.
2) Xw and Zw were obtained.
Substituting Yw into 100 in equation 2 yields:
among these, Xw and yw are known amounts, and Xw and Zw can be obtained.
3) Xr, Yr, Xg, Yg, Xb, Yb are known quantities, and Xr, Xg, Xb, Yr, Yg, Yb, Zr, Zg, Zb are determined.
By substituting the known amounts Xr, Yr, Xg, Yg, Xb, Yb into the above equations 4 and 5, Xr, Xg, Xb, Yr, Yg, Yb, Zr, Zg, Zb can be obtained, and the above matrix a can be obtained.
Wherein the matrix is
It may be configured according to a data bit width (e.g., 8bit, 10bit, 12bit, etc.) of RGB of the input image.
Example 1, if the data bit width of RGB of the input image is 10 bits, and the corresponding R, G, and B primaries range from 0 to 1023, then L in the corresponding matrix Br、LgAnd LbRespectively as follows:
example 2, if the data bit width of RGB of the input image is 12 bits, and the corresponding R, G, and B primaries range from 0 to 4095, at this time, L in the corresponding matrix Br、LgAnd LbRespectively as follows:
wherein, L isr、Lg、LbIs in the range of 0 to 1.
Optionally, a1 specifically includes the following steps:
b1, calculating at least one primary color component value corresponding to the color coordinates of the pixel point to be corrected by using the color gamut range coefficient of the device screen.
B2, if at least one primary color component value in the color coordinates of the pixel point to be corrected is judged to be larger than 1, the pixel point to be corrected is judged to be out of the color gamut range.
Optionally, the process of determining whether the color coordinate of the selected point is outside the color gamut range of the device screen according to the application specifically includes the following steps:
and C1, calculating at least one primary color component value corresponding to the color coordinates of the selected point by using the color gamut range coefficient of the device screen.
C2, if at least one primary color component value in the color coordinates of the selected point is judged to be larger than 1, the selected point is judged to be out of the color gamut range; and if the component values of all the primary colors in the color coordinates of the selected point are judged to be less than or equal to 1, judging that the selected point is in the color gamut range.
The color gamut range coefficient is used for representing the color gamut range of the display color gamut of the device screen, and the primary color component values are used for representing the positions of the corresponding primary colors in the color gamut range.
For example, since the color gamut range of the display color gamut of the device screen may be affected by the brightness of the device screen, for example, when the brightness is middle or low, the color gamut range of the corresponding display color gamut may be correspondingly reduced. That is, in an actual scene, the display color gamut of the device screen at different gray scales has different color gamut ranges. However, the gamut range of the display gamut determined by the conventional gamut compression method is obtained in the maximum luminance scene. Therefore, if the screen brightness of the device is a medium-low brightness, the final compressed color value is outside the actual color gamut, and the color is distorted.
In order to avoid the problem, the color gamut range coefficient of different device screens is set for different gray scales according to different brightness. Therefore, when the pixel point to be corrected or the selected point is judged, the color gamut range coefficient corresponding to the maximum gray scale (maximum brightness) can be selected, and the corresponding color gamut range coefficient can be selected according to the actual gray scale of the pixel point to be corrected or the selected point, so that the position of the pixel point to be corrected or the selected point is judged. The present application is not limited.
In one example, the step of obtaining the gamut range coefficient of the device screen specifically includes: calculating a color gamut range coefficient of the equipment screen according to the maximum color value of the gray-scale image displayed in the equipment screen in the color space irrelevant to the equipment and the primary color component value of each primary color of the maximum color value; the gray value of the pixel point in the gray image is equal to the gray value of the pixel point to be corrected or the maximum gray value which can be displayed by the display equipment.
If the XYZ color space is taken as an example, the process of determining the gamut range coefficient a _ screen of the device screen specifically includes:
1) the color value of the full-gray image corresponding to the maximum gray scale displayed on the device screen is measured by using a CA310 (color analyzer) or other colorimetric measuring instruments, and then the maximum color values of the red primary color, the green primary color and the blue primary color are obtained, that is, the maximum values of the red primary color, the green primary color and the blue primary color on the x axis and the y axis of the color coordinate axis are obtained, and based on the values, the maximum color gamut range of the display color gamut of the device screen can be determined.
For example, since the corresponding full-gray images of the same gray scale are different under different RGB data bit widths, for example, the full-gray image corresponding to the maximum gray scale may be at least one of the following: r (255,0,0) G (0,255,0) B (0, 255) (8bit), R (1023,0,0) G (0,1023,0) B (0, 1023) (10bit), R (4095,0,0) G (0,4095,0) B (0, 4095) (12 bit).
2) According to the maximum value of the red primary color, the green primary color and the blue primary color on the x axis and the y axis of the color coordinate axis and the corresponding Lr、Lg、LbAnd solving a matrix A _ screen according to the conversion relation between the Lxy color space and the XYZ color space. The process of obtaining the matrix a can be referred to the process of obtaining the matrix a, and is not described herein again.
In an example, if the color space unrelated to the device is XYZ color space, the application may use the following formula 12 to determine whether the color coordinate of the pixel point to be corrected or the selected point is within the display color gamut, that is, the following formula 12 may be used to calculate at least one primary color component value corresponding to the color coordinate of the pixel point to be corrected and calculate at least one primary color component value corresponding to the color coordinate of the selected point.
Wherein, the above
A range coefficient matrix for the display gamut of a device screen, as described above
For the original color value of the pixel point to be corrected, Lr、Lg、LbR, G, B corresponding to the pixel point to be corrected respectively, and the primary color component values are used for representing the color gamut range of the corresponding primary colorInner position.
For example, taking the R primary color as an example, when 0 ≦ LgWhen the color gamut is less than or equal to 1, the red primary color of the pixel point to be corrected is the color in the color gamut range of the display color gamut, and L isgSmaller (i.e., more toward 0) indicates higher saturation of the corresponding red primary, closer to the white point in the display gamut, and conversely, LgThe larger (i.e., the more toward 1) indicates that the saturation of its corresponding red primary is lower, closer to the gamut boundary of the display gamut; when L isg>And 1, indicating that the red primary color of the pixel point to be corrected is supersaturated and exceeds the color gamut range of the display color gamut.
It should be noted that, if it is to be ensured that the color value corresponding to the pixel point to be corrected is the color within the color gamut, it is necessary to satisfy L being greater than or equal to 0r≤1,0≤Lg≤1,0≤LbAnd (4) less than or equal to 1, wherein one of the three values does not meet the condition, namely the color coordinate of the pixel point is out of the color gamut range.
According to the scheme provided by the embodiment of the application, if the color coordinates of the pixel points to be corrected are out of the color gamut range of the screen of the equipment, any point in the target line segment is selected; the end points of the target line segment are respectively the pixel point to be corrected and the white point in the color gamut range, then the selected point is taken as the starting point, if the selected point is in the color gamut range, the point is continuously selected from the target line segment towards the direction of the pixel point to be corrected according to the preset step length until the selected point is out of the color gamut range; and if the selected point is out of the color gamut range, continuously selecting the point from the target line segment in the direction of the white point according to the preset step length until the selected point is in the color gamut range, and finally correcting the color coordinates of the pixel point to be corrected into the color coordinates of the last or last previously selected point. Because any point in the color gamut and the point on the connecting line between the white points all belong to the same hue, the original color value of the pixel point to be corrected is compressed along the same hue, so that the point with the minimum color difference is found as the corrected point, and the color value of the pixel point can be compressed into the display color gamut of the screen of the equipment under the condition of minimum color distortion.
It should be noted that the recursive convergence method described above is merely an example, and in a specific implementation, the final gamut boundary point may also be found by fast convergence using a halving method. The manner of finding the boundary point of the color gamut is not limited here.
Fig. 5 shows a schematic diagram of a possible structure of the color gamut compression apparatus in the above embodiment. The device includes: a processor 31, a memory 32, a system bus 33, and a communication interface 34. The memory 31 is used for storing computer executable codes, the processor 31 is connected to the memory 32 through the system bus 33, and when the apparatus is running, the processor 31 is used for executing the computer executable codes stored in the memory 32 to perform any one of the color gamut compression methods provided by the embodiments of the present invention, for example, the processor 31 is used for supporting the color gamut compression apparatus to perform all the steps in fig. 2 and/or other processes for the technology described herein, and the specific color gamut compression method may refer to the following description and the related processes in the drawings, which are not described herein again.
Embodiments of the present invention also provide a storage medium, which may include a memory 32.
An embodiment of the present invention further provides a display device, which includes the color gamut compression apparatus shown in fig. 5.
The processor 31 may be a single processor or may be a collective term for a plurality of processing elements. For example, the processor 31 may be a CPU. The processor 31 may also be other general-purpose processors, Digital Signal Processors (DSPs), Application Specific Integrated Circuits (ASICs), field-programmable gate arrays (FPGAs) or other programmable logic devices, discrete gate or transistor logic, discrete hardware components, etc., which may implement or execute the various illustrative logical blocks, modules, and circuits described in connection with the present disclosure. A general purpose processor may be a microprocessor or the processor may be any conventional processor or the like. The processor 31 may also be a dedicated processor that may include at least one of a baseband processing chip, a radio frequency processing chip, and the like. The processor may also be a combination of computing functions, e.g., comprising one or more microprocessors, DSPs, and microprocessors, among others. Further, the dedicated processor may also include chips having other dedicated processing functions of the apparatus.
The steps of the method described in connection with the present disclosure may be embodied in hardware or may be embodied in software instructions executed by a processor. The software instructions may be comprised of corresponding software modules that may be stored in Random Access Memory (RAM), flash memory, Read Only Memory (ROM), Erasable Programmable ROM (EPROM), Electrically Erasable Programmable ROM (EEPROM), registers, a hard disk, a removable disk, a compact disc read only memory (CD-ROM), or any other form of storage medium known in the art. An exemplary storage medium is coupled to the processor such the processor can read information from, and write information to, the storage medium. Of course, the storage medium may also be integral to the processor. The processor and the storage medium may reside in an ASIC. In addition, the ASIC may reside in a terminal device. Of course, the processor and the storage medium may reside as discrete components in a terminal device.
The system bus 33 may include a data bus, a power bus, a control bus, a signal status bus, and the like. For clarity of illustration in this embodiment, the various buses are illustrated in FIG. 5 as system bus 33.
The communication interface 34 may specifically be a transceiver on the device. The transceiver may be a wireless transceiver. For example, the wireless transceiver may be an antenna of the device, or the like. The processor 31 is configured to perform data interaction with other devices through the communication interface 33, for example, if the apparatus is a module or a component in the display device, the apparatus is configured to perform data interaction with other modules in the display device, e.g., the apparatus performs data interaction with a display module of the display device, and controls the display module to display images before and after color gamut compression.
Those skilled in the art will recognize that, in one or more of the examples described above, the functions described in this invention may be implemented in hardware, software, firmware, or any combination thereof. When implemented in software, the functions may be stored on or transmitted over as one or more instructions or code on a computer-readable medium. Computer-readable media includes both computer storage media and communication media including any medium that facilitates transfer of a computer program from one place to another. A storage media may be any available media that can be accessed by a general purpose or special purpose computer.
Finally, it should be noted that: the above-mentioned embodiments, objects, technical solutions and advantages of the present invention are further described in detail, it should be understood that the above-mentioned embodiments are only exemplary embodiments of the present invention, and are not intended to limit the scope of the present invention, and any modifications, equivalent substitutions, improvements and the like made on the basis of the technical solutions of the present invention should be included in the scope of the present invention.
Claims (9)
1. A method of color gamut compression, comprising:
if the color coordinates of the pixel points to be corrected are outside the color gamut range of the equipment screen, selecting any point in the target line segment; the end points of the target line segment are the pixel point to be corrected and the white point in the color gamut range respectively;
taking the point selected this time as the starting point,
if the selected point is within the color gamut range, continuing to select the point from the target line segment towards the direction of the pixel point to be corrected according to the preset step length until the selected point is outside the color gamut range;
if the selected point is out of the color gamut range, continuing to select the point from the target line segment in the direction of the white point according to a preset step length until the selected point is in the color gamut range;
and correcting the color coordinates of the pixel points to be corrected into the color coordinates of the last or last point selected last time.
2. The method of claim 1, wherein the starting point is an intersection of the target line segment and a target color gamut boundary, and wherein the target color gamut boundary is a line connecting two vertices within the color gamut of the device screen.
3. The method of claim 1, wherein the starting point is the white point or the pixel point to be corrected.
4. The method according to claim 1, wherein the step of determining whether the color coordinates of the selected point are outside the gamut of the device screen specifically comprises:
calculating at least one primary color component value corresponding to the color coordinates of the selected point by using the color gamut range coefficient of the device screen; wherein the gamut range coefficient is used to characterize a gamut range of a display gamut of the device screen; the primary color component values are used to characterize the position of the corresponding primary color within the color gamut range;
if at least one primary color component value in the color coordinates of the selected point is judged to be larger than 1, the selected point is judged to be out of the color gamut range;
and if all the primary color component values in the color coordinates of the selected point are judged to be less than or equal to 1, judging that the selected point is in the color gamut range.
5. The method according to claim 1, wherein the step of determining that the color coordinates of the pixel to be corrected are outside the color gamut of the device screen specifically comprises:
calculating at least one primary color component value corresponding to the color coordinates of the pixel point to be corrected by utilizing the color gamut range coefficient of the device screen; wherein the gamut range coefficient is used to characterize a gamut range of a display gamut of the device screen; the primary color component values are used to characterize the position of the corresponding primary color within the color gamut range;
and if at least one primary color component value in the color coordinates of the pixel point to be corrected is judged to be larger than 1, judging that the pixel point to be corrected is out of the color gamut range.
6. The method according to claim 4 or 5, wherein the step of obtaining the gamut range coefficient of the device screen specifically comprises:
calculating a color gamut range coefficient of the equipment screen according to the maximum color value of each primary color of the gray-scale image displayed in the equipment screen and the primary color component value of the maximum color value; and the gray value of the pixel point in the gray image is equal to the gray value of the pixel point to be corrected or the maximum gray value which can be displayed by the equipment screen.
7. A color gamut compression device, comprising: a processor and a memory; wherein the memory is for storing computer executable code for controlling the processor to perform the method of any one of claims 1 to 6.
8. A display device, comprising: the gamut compression device of claim 7.
9. A computer storage medium storing computer software instructions for a color gamut compression device, comprising program code configured to perform the method of any one of claims 1 to 6.
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| CN111341283B (en) * | 2020-04-20 | 2022-04-22 | 深圳Tcl数字技术有限公司 | Color gamut mapping method, color gamut mapping assembly and display device |
| CN111653232B (en) * | 2020-06-05 | 2021-11-16 | 广州视源电子科技股份有限公司 | LED screen color gamut calibration method and device |
| CN112365858B (en) * | 2020-12-10 | 2022-03-08 | 深圳市华星光电半导体显示技术有限公司 | Target color point capturing method in gamma correction and gamma correction system |
| CN113178165B (en) * | 2021-03-26 | 2022-03-18 | 卡莱特云科技股份有限公司 | LED display screen correction method and device in HDR mode |
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