CN115918066A

CN115918066A - Display method and device and electronic equipment

Info

Publication number: CN115918066A
Application number: CN202080103365.0A
Authority: CN
Inventors: 刘洋; 刘海啸; 李睿哲
Original assignee: Huawei Technologies Co Ltd
Current assignee: Huawei Technologies Co Ltd
Priority date: 2020-08-24
Filing date: 2020-08-24
Publication date: 2023-04-04
Also published as: WO2022040889A1

Abstract

The embodiment of the application provides a display method and device and electronic equipment. The method comprises the following steps: acquiring a first RGB of a first pixel to be displayed; acquiring a third display look-up table LUT corresponding to the first application mode, wherein the third LUT is generated by fusing the first LUT and a second LUT corresponding to the first application mode, and comprises a one-to-one correspondence relationship between a plurality of first initial RGB and first display RGB; the first LUT comprises a one-to-one mapping relation between a plurality of first initial RGB and target RGB, and the second LUT comprises a one-to-one mapping relation between a plurality of second initial RGB and display RGB; and determining second RGB corresponding to the first RGB in the first application mode according to the third LUT, and sending the second RGB to the first display for displaying. This application embodiment can effectively promote the efficiency and the rate of accuracy that the display screen carries out color space conversion.

Description

Display method and device and electronic equipment

Technical Field

The present application relates to the field of display technologies, and in particular, to a display method and apparatus, and an electronic device.

Background

Color gamut is a method of encoding a color and refers to the collection of colors that a technical system is capable of producing. In computer graphics processing, a color gamut is some complete subset of colors. The most common application of color subsets is to accurately represent a given situation. Such as a given color space or a color gamut of an output device. The displayed color gamut is different for different displays, resulting in the same graphic being displayed differently on different displays. The objective measurement index can be quantified according to CIE1931 color space.

The CIE1931 color space (also known as CIE1931 XYZ color space) is one of the first mathematically defined color spaces. The CIE1931 color space associates each color to tristimulus values X, Y and Z, where the Y parameter is a measure of the lightness or brightness of the color. The chromaticity of a color is specified by two derived parameters x and Y of X, Y and Z, the derived color space being specified in x, Y, which is called the CIE xyY color space and is widely used in practice to specify colors. The CIE1931 color space is special in that it is a direct measure based on human color vision and serves as the basis for the definition of many other color spaces.

sRGB color space, DCI-P3 or Adobe RGB, etc., are standard color spaces for displays, printers, and the Internet. Taking sRGB as an example, when RGB color values are output from a display, the RGB color values are displayed in the corresponding CIE1931 color space in addition to the corresponding RGB color values. Thus, when a display needs to be converted from one CIE1931 color space to another CIE1931 color space for display, the conversion may be accomplished by inputting different RGB color values.

In the process, the corresponding relation between the sRGB color space and the CIE1931 color space needs to be determined, and if the corresponding relation is calculated through matrix transformation, the problem of low accuracy exists; and the corresponding relation is searched through the corresponding relation table generated by the measuring result, and a large amount of labor cost and time cost are consumed for measuring.

Disclosure of Invention

The application provides a display method, a display device and an electronic device, which can improve the accuracy and efficiency of display of a display by converting from one color gamut to another color gamut.

In a first aspect, an embodiment of the present application provides a display method, where the method includes: acquiring a first RGB of a first pixel to be displayed; acquiring a third display look-up table LUT corresponding to the first application mode, wherein the third LUT corresponding to the first application mode is generated by fusion according to the first LUT and a second LUT corresponding to the first application mode, the third LUT comprises a one-to-one correspondence relationship between a plurality of first initial RGB and first display RGB, the first initial RGB corresponds to initial chromaticity and brightness parameters, and the first display RGB corresponds to chromaticity and brightness parameters of the first application mode; the first LUT comprises a one-to-one mapping relation between a plurality of first initial RGB and target RGB, and the target RGB correspondingly specifies chroma and brightness parameters; the second LUT comprises a one-to-one mapping relation between a plurality of second initial RGB and display RGB, the second initial RGB correspondingly specifies brightness and chromaticity parameters, the display RGB is related to application modes, the corresponding display RGB of the same second initial RGB in different application modes is different, and one application mode corresponds to one second LUT; and determining second RGB corresponding to the first RGB in the first application mode according to the third LUT, and sending the second RGB to the first display for displaying.

Alternatively, the display method provided by the first aspect includes: acquiring a first RGB of a first pixel to be displayed; acquiring a corresponding third look-up table (LUT) according to the first application mode, wherein the third LUT is generated by fusing the first LUT and the second LUT; wherein, different application modes correspond to different second LUTs; the third LUT comprises a one-to-one mapping relation between a plurality of first initial RGB and first display RGB, and the first display RGB corresponds to the first application mode; the first LUT comprises a one-to-one mapping relation between a plurality of first initial RGB and target RGB, wherein the first initial RGB corresponds to initial chromaticity and brightness parameters, and the target RGB corresponds to specified chromaticity and brightness parameters; the second LUT comprises a one-to-one mapping relation between a plurality of second initial RGB and display RGB, the second initial RGB correspondingly designates chromaticity and brightness parameters, the display RGB is related to the application mode, and the corresponding display RGB of the same initial RGB in different application modes is different; determining a second RGB corresponding to the first RGB in the first application mode according to the third LUT; and sending the second RGB to a display for displaying.

In the embodiment of the application, the first LUT for converting each display screen from the first initial RGB to the target RGB corresponding to the designated chromaticity and luminance parameter is obtained, and the first LUT is used for describing the color space corresponding to each display screen in consideration of the actual characteristics of each display screen panel, so that the display accuracy is improved; in addition, a second LUT for converting a second initial RGB corresponding to a designated chromaticity and a brightness parameter into a second LUT for displaying RGB in each application mode is obtained, a third LUT is generated by fusing the second LUT with the first LUT, only the corresponding relation between the designated chromaticity and the brightness parameter and the displaying RGB in different application modes can be measured, and the corresponding relation between the RGB when each display screen is converted into different application modes can be obtained by combining the first LUT of each display screen, instead of measuring the corresponding relation between the RGB when each display screen is converted into different application modes, so that lookup tables required in different scenes can be generated under the condition of one group of test parameters, the measurement time is reduced, the color space conversion efficiency is improved, and the conversion accuracy can be ensured.

In one optional example, the method further comprises: and acquiring a third LUT corresponding to the second application mode, wherein the third LUT corresponding to the second application mode is generated by fusing the first LUT and the second LUT corresponding to the second application mode.

In one optional example, the method further comprises: retrieving a first LUT from a memory; or receiving a first LUT from a server; or receiving the corresponding target RGB from the server according to the preset first initial RGB or acquiring the corresponding target RGB from the memory, and further determining the first LUT.

In the embodiment of the application, only the target RGB is stored in the memory, and the target RGB corresponding to different first LUTs is obtained through the preset first initial RGB, so that the first RGB in each first LUT does not need to be repeatedly stored, and the storage pressure is reduced.

In one optional example, the method further comprises: acquiring a second LUT corresponding to the first application mode from a plurality of second LUTs stored in a memory; or receiving a second LUT corresponding to the first application mode from the server.

In one optional example, the method further comprises: an updated second LUT is received from the server.

In an optional example, receiving the updated second LUT from the server comprises: receiving an updated second LUT from the server at a preset time or in case of receiving a preset instruction.

In this embodiment, the second LUT is a lookup table for converting the designated chromaticity and luminance parameters to different application modes, and when the application mode is changed, the updated second LUT needs to be obtained, and the updated second LUT is obtained at a preset time, so that the real-time performance of obtaining the second LUT can be ensured; and when the preset instruction is received, the updated second LUT is acquired, so that the practicability of acquiring the second LUT can be ensured.

In one optional example, obtaining the third LUT comprises: acquiring a first initial RGB in a first LUT and a target RGB corresponding to the first initial RGB; determining real-time first display RGB obtained by mapping the target RGB according to the second LUT; a third LUT comprising a mapping of the first initial RGB and the first display RGB is generated.

In this embodiment, the first initial RGB in the first LUT is mapped to the target RGB, the target RGB corresponds to the designated chromaticity and luminance parameter, and the second initial RGB in the second LUT also corresponds to the designated chromaticity and luminance parameter, so that the second LUT may be directly traversed according to the target RGB and matched with the second initial RGB, if the matching is successful, the corresponding relationship between the first display RGB corresponding to the second initial RGB and the first initial RGB may be directly determined, and the third LUT may be determined according to the corresponding relationship.

In one optional example, obtaining the first LUT comprises: converting the first initial RGB to obtain intermediate RGB; performing iterative transformation on the intermediate RGB according to a preset step length to obtain target RGB; and determining a first LUT according to the one-to-one mapping relation of the first initial RGB and the target RGB.

In this embodiment, the intermediate RGB obtained by the matrix calculation is not directly used as the target RGB, but the RGB for which the display screen is specified to display the chromaticity and luminance parameters is repeatedly determined by iteration as the target RGB, so that the accuracy of the generated first LUT is improved.

In an optional example, the iteratively transforming the intermediate RGB according to a preset step size to obtain the target RGB includes: s1: for RGB according to preset step length _i Carrying out transformation and obtaining the corresponding chroma and brightness parameter change values; s2: obtaining RGB according to preset step length _i+1 According to RGB _i Obtaining RGB by corresponding intermediate chroma and brightness parameter and chroma and brightness parameter variation value _i+1 Corresponding intermediate chrominance and luminance parameters; s3: determine RGB _i+1 Whether the difference value between the corresponding intermediate chroma and brightness parameter and the designated chroma and brightness parameter is less than a preset threshold value; if RGB _i+1 If the difference between the corresponding intermediate chroma and brightness parameters and the designated chroma and brightness parameters is not less than the preset threshold, making i = i +1, and repeating S1-S3 until RGB is reached _i+1 The difference value between the corresponding intermediate chroma and brightness parameters and the designated chroma and brightness parameters is less than a preset threshold, and when i =1, RGB _i Intermediate RGB.

In an alternative example, according to RGB _i Obtaining RGB by corresponding intermediate chroma and brightness parameter and chroma and brightness parameter variation value _i+1 Corresponding intermediate chroma and brightness parameters include RGB calculated according to the following formula _i+1 Corresponding intermediate chrominance and luminance parameters:

wherein xyY _i+1 Is RGB _i+1 Corresponding intermediate chrominance and luminance parameter, xyY _i Is RGB _i Corresponding intermediate chroma and brightness parameters, wherein RGB comprises R parameter, G parameter and B parameter, and delta R, delta G and delta B are respectively the preset step length of R parameter, G parameter and B parameter, and delta x _R ，Δy _R For the change value of the chromaticity parameter caused by the iteration of the R parameter according to the preset step length，ΔY _R For the value of variation of the brightness parameter, Δ x, caused by iteration of the R parameter according to a preset step length _G ，Δy _G Is the chromaticity parameter variation value, delta Y, caused by the iteration of the G parameter according to the preset step length _G The change value of the brightness parameter, delta x, caused by the iteration of the G parameter according to the preset step length _B ，Δy _B Is the chroma parameter change value delta Y caused by B parameter iteration according to the preset step length _B And the brightness parameter change value is the brightness parameter change value caused by iteration of the B parameter according to the preset step length.

In an alternative example, converting the first initial RGB to obtain an intermediate RGB includes: performing Gamma transformation on the first initial RGB based on the first Gamma value to obtain a first linear RGB; converting the first linear rgb according to the first transformation matrix to obtain the designated chromaticity and brightness parameters; converting the designated brightness and chromaticity parameters according to a second transformation matrix to obtain a second linear rgb, wherein the second transformation matrix is generated according to the measured brightness parameters of the first display; and performing inverse Gamma transformation on the second linear RGB based on a second Gamma value to obtain an intermediate RGB, wherein the second Gamma value is determined according to the measured brightness parameter of the first display.

In a second aspect, an embodiment of the present application provides a display method, which is applied to a server, and the method includes: generating a second LUT, wherein the second LUT comprises a one-to-one mapping relation between a plurality of second initial RGB and display RGB, the display RGB is related to application modes, the display RGB corresponding to the same second initial RGB in different application modes is different, and one application mode corresponds to one second LUT; the second LUT is sent to the terminal.

In this embodiment, the server generates the second LUT, and then sends the second LUT to the terminal, so that the terminal generates the third LUT by combining the first LUT and the second LUT, because the second LUT is only related to the application mode and the specified chromaticity and luminance parameters, and in the case that the first two are determined, the server can issue the second LUT uniformly, thereby reducing the computing resource overhead of the terminal.

In one optional example, generating the second LUT comprises: converting the second initial RGB to obtain display RGB, so that display chromaticity and brightness parameters under a first application mode corresponding to the display RGB are obtained; and generating a second LUT corresponding to the first application mode according to the one-to-one mapping relation between the second initial RGB and the display RGB.

In one optional example, the method further comprises: generating a first LUT, wherein the first LUT comprises a one-to-one mapping relation between a plurality of first initial RGB and target RGB, and the target RGB correspondingly specifies chromaticity and brightness parameters; the first LUT is sent to the terminal.

In the embodiment of the application, the server generates the first LUT and sends the first LUT to the terminal, and the server can acquire the chromaticity and brightness parameters of each display screen and generate the first LUT corresponding to each display screen, so that the calculation resource overhead of the terminal can be effectively reduced.

In one optional example, generating the first LUT comprises: converting the first initial RGB to obtain intermediate RGB; performing iterative transformation on the intermediate RGB according to a preset step length to obtain target RGB; and determining a first LUT according to the one-to-one mapping relation of the first initial RGB and the target RGB.

In one optional example, the method further comprises: generating an updated second LUT, wherein the updated second LUT is a second LUT corresponding to the updated first application mode; or the updated second LUT is the second LUT corresponding to the newly added application mode; the updated second LUT is sent to the terminal.

In a third aspect, an embodiment of the present application provides an apparatus for display processing, where the apparatus includes a processing module, an obtaining module, and a processing module, where the obtaining module is configured to obtain a first RGB of a first pixel to be displayed; the processing module is used for acquiring a third display look-up table (LUT) corresponding to the first application mode, the third LUT corresponding to the first application mode is generated by fusion according to the first LUT and a second LUT corresponding to the first application mode, the third LUT comprises a one-to-one correspondence relationship between a plurality of first initial RGB and first display RGB, the first initial RGB corresponds to initial chromaticity and brightness parameters, and the first display RGB corresponds to chromaticity and brightness parameters of the first application mode; the first LUT comprises a one-to-one mapping relation between a plurality of first initial RGB and target RGB, and the target RGB correspondingly specifies chroma and brightness parameters; the second LUT comprises a one-to-one mapping relation between a plurality of second initial RGB and display RGB, the second initial RGB corresponds to initial chromaticity and brightness parameters, the display RGB is related to application modes, the corresponding display RGB of the same second initial RGB in different application modes are different, and one application mode corresponds to one second LUT; and the processing module is used for determining second RGB corresponding to the first RGB in the first application mode according to the third LUT and sending the second RGB to the first display for displaying.

In an optional example, the obtaining module is further configured to: and acquiring a third LUT corresponding to the second application mode, and generating the third LUT corresponding to the second application mode by fusing the first LUT and the second LUT corresponding to the second application mode.

In an optional example, the obtaining module is further configured to: retrieving a first LUT from a memory; or

Receiving a first LUT from a server; or receiving the corresponding target RGB from the server or obtaining the corresponding target RGB from the memory according to the preset first initial RGB, and further determining the first LUT.

In an optional example, the obtaining module is further configured to: acquiring a second LUT corresponding to the first application mode from a plurality of second LUTs stored in a memory; or receiving a second LUT corresponding to the first application mode from the server.

In an optional example, the obtaining module is further configured to: an updated second LUT is received from the server.

In an optional example, the obtaining module is specifically configured to: receiving an updated second LUT from the server at a preset time or in case of receiving a preset instruction.

In an optional example, the processing module is specifically configured to: acquiring a first initial RGB in a first LUT and a target RGB corresponding to the first initial RGB; determining real-time first display RGB obtained by mapping the target RGB according to the second LUT; a third LUT comprising a mapping of the first initial RGB and the first display RGB is generated.

In an optional example, the processing module is specifically configured to: converting the first initial RGB to obtain intermediate RGB; performing iterative transformation on the intermediate RGB according to a preset step length to obtain target RGB; and determining a first LUT according to the one-to-one mapping relation of the first initial RGB and the target RGB.

In an optional example, the processing module is specifically configured to: s1: converting the RGBI according to a preset step length, and obtaining a corresponding chrominance and luminance parameter change value; s2: obtaining RGBi +1 according to a preset step length, and obtaining intermediate chromaticity and brightness parameters corresponding to RGBi +1 according to the intermediate chromaticity and brightness parameters and the chromaticity and brightness parameter variation values corresponding to RGBi; s3: judging whether the difference value between the intermediate chromaticity and brightness parameters corresponding to the RGBi +1 and the designated chromaticity and brightness parameters is smaller than a preset threshold value or not; if the difference between the intermediate chromaticity and luminance parameter corresponding to the RGBi +1 and the designated chromaticity and luminance parameter is not less than the preset threshold, making i = i +1, and repeatedly executing S1-S3 until the difference between the intermediate chromaticity and luminance parameter corresponding to the RGBi +1 and the designated chromaticity and luminance parameter is less than the preset threshold, and when i =1, the RGBi is intermediate RGB.

In an optional example, the processing module is specifically configured to: RGB is obtained by calculation according to the following formula _i+1 Corresponding intermediate chrominance and luminance parameters:

wherein xyY _i+1 Is RGB _i+1 Corresponding intermediate chrominance and luminance parameter, xyY _i Is RGB _i Corresponding intermediate chroma and brightness parameters, wherein RGB comprises R parameter, G parameter and B parameter, and delta R, delta G and delta B are respectively the preset step length of R parameter, G parameter and B parameter, and delta x _R ，Δy _R Is the chromaticity parameter variation value delta Y caused by the iteration of the R parameter according to the preset step length _R For the value of variation of the brightness parameter, Δ x, caused by iteration of the R parameter according to a preset step length _G ，Δy _G Is the chromaticity parameter variation value, delta Y, caused by the iteration of the G parameter according to the preset step length _G The change value of the brightness parameter, delta x, caused by the iteration of the G parameter according to the preset step length _B ，Δy _B Is the chroma parameter change value delta Y caused by B parameter iteration according to the preset step length _B For B parameter asAnd (4) iterating the brightness parameter change value caused by the preset step length.

In an optional example, the processing module is specifically configured to: performing Gamma transformation on the first initial RGB based on the first Gamma value to obtain a first linear RGB; converting the first linear rgb according to the first transformation matrix to obtain the designated chromaticity and brightness parameters; converting the designated brightness and chrominance parameters according to a second transformation matrix to obtain a second linear rgb, wherein the second transformation matrix is generated according to the measured brightness parameters of the first display; and performing inverse Gamma transformation on the second linear RGB based on a second Gamma value to obtain intermediate RGB, wherein the second Gamma value is determined according to the measured brightness parameter of the first display.

In a fourth aspect, an embodiment of the present application provides an apparatus for display processing, the apparatus including a processor and an interface circuit, the interface circuit being configured to receive code instructions and transmit the code instructions to the processor, and the processor being configured to execute the code instructions to perform the method according to any one of the first aspect or the second aspect.

In a fifth aspect, embodiments of the present application provide an apparatus for display processing, the apparatus comprising a processor, a transceiver, a memory, and computer executable instructions stored on the memory and executable on the processor, which when executed by the computer cause the communication apparatus to perform the method according to any one of the first aspect or perform the method according to any one of the second aspect.

In a sixth aspect, there is provided a computer readable storage medium having stored therein program instructions which, when run on a computer or processor, cause the computer or processor to perform the method of any of the above aspects.

In a seventh aspect, there is provided a computer program product comprising instructions which, when run on a computer or processor, cause the computer or processor to perform the method of any of the above aspects.

In an eighth aspect, an electronic device is provided, which includes the above display processing apparatus.

For technical effects brought by any one of the design manners in the second aspect to the eighth aspect, reference may be made to the technical effects brought by different design manners in the first aspect, and details are not described herein.

Drawings

Fig.1 is a schematic diagram of an exemplary apparatus according to an embodiment of the present application;

FIG. 2 is a schematic view of a color value transformation scene of a display screen according to an embodiment of the present disclosure;

FIG. 3 is a schematic diagram illustrating a color value transformation process of a display panel according to an embodiment of the present disclosure;

fig. 4A is a schematic diagram of a color gamut correction system according to an embodiment of the present application;

FIG. 4B is a flowchart of a display method according to an embodiment of the present disclosure;

fig. 4C is a schematic diagram of a process of applying a third LUT according to an embodiment of the present application;

fig. 4D is a schematic diagram of a third LUT generated by fusing a first LUT and a second LUT provided in the embodiment of the present application;

fig. 4E is a flowchart of determining a target RGB according to an embodiment of the present disclosure;

fig. 4F is a schematic diagram of a fusion process of a first LUT and a second LUT provided in the embodiment of the present application;

fig. 5 is a block diagram of an apparatus for display processing according to an embodiment of the present disclosure;

fig. 6 is a schematic hardware structure diagram of an apparatus for display processing according to an embodiment of the present disclosure.

Detailed Description

The technical solutions in the embodiments of the present application will be described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are only some embodiments of the present application, and not all embodiments.

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 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 relevant concepts in a concrete fashion. In the description of the embodiments of the present application, the meaning of "a plurality" means two or more unless otherwise specified. For example, a plurality of processing units refers to two or more processing units; the plurality of systems refers to two or more systems. In the following, the terms "first", "second", etc. are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first," "second," etc. may explicitly or implicitly include one or more of that feature. In the description of the present application, "a plurality" means two or more unless otherwise specified.

Fig.1 is a schematic structural diagram of an exemplary apparatus according to an embodiment of the present disclosure. As shown in fig.1, the apparatus 01 includes: a processor 11, a Radio Frequency (RF) circuit 12, a power supply 13, a memory 14, an input unit 15, a display unit 16, an audio circuit 17, and the like. Those skilled in the art will appreciate that the configuration of the apparatus shown in fig.1 is not intended to be limiting, and that the apparatus may include more or less components than those shown in fig.1, or some of the components shown in fig.1 may be combined, or the arrangement of components may be different than those shown in fig. 1.

The processor 11 is a control center of the apparatus, connects various parts of the entire apparatus using various interfaces and lines, performs various functions of the apparatus and processes data by running or executing software programs and/or modules stored in the memory 14 and calling data stored in the memory 14, thereby monitoring the entire apparatus. Alternatively, processor 11 may include one or more processing units; preferably, the processor 11 may integrate an application processor, which mainly handles operating systems, user interfaces, application programs, etc., and a modem processor, which mainly handles wireless communications. It will be appreciated that the modem processor described above may not be integrated into the processor 11.

The RF circuit 12 may be used for receiving and transmitting signals during information transmission and reception or during a call, and in particular, receives downlink information of a base station and then processes the received downlink information to the processor 11; in addition, the uplink data is transmitted to the base station. Typically, the RF circuitry includes, but is not limited to, an antenna, at least one amplifier, a transceiver, a coupler, a Low Noise Amplifier (LNA), a duplexer, and the like. In addition, the RF circuitry 12 may also communicate with networks and other devices via wireless communications. The wireless communication may use any communication standard or protocol, including but not limited to global system for mobile communications (GSM), general Packet Radio Service (GPRS), code Division Multiple Access (CDMA), wideband Code Division Multiple Access (WCDMA), long Term Evolution (LTE), email, short Message Service (SMS), etc.

The device includes a power supply 13 (e.g., a battery) for supplying power to various components, and optionally, the power supply may be logically connected to the processor 11 through a power management system, so as to implement functions of managing charging, discharging, and power consumption through the power management system.

The memory 14 may be used to store software programs and modules, and the processor 11 executes various functional applications and data processing of the apparatus by operating the software programs and modules stored in the memory 14. The memory 14 may mainly include a program storage area and a data storage area, wherein the program storage area may store an operating system, an application program required by at least one function (such as a sound playing function, an image playing function, etc.), and the like; the storage data area may store data (such as audio data, image data, a phonebook, etc.) created according to the use of the cellular phone, and the like. Further, the memory 14 may include high speed random access memory, and may also include non-volatile memory, such as at least one magnetic disk storage device, flash memory device, or other volatile solid state storage device.

The input unit 15 may be used to receive input numeric or character information and generate key signal inputs related to user settings and function control of the device. Specifically, the input unit 15 may include a touch screen 151 and other input devices 152. The touch screen 151, also referred to as a touch panel, may collect a touch operation of a user on or near the touch screen (for example, an operation of the user on or near the touch screen 151 by using any suitable object or accessory such as a finger or a stylus pen), and drive a corresponding connection device according to a preset program. Alternatively, the touch screen 151 may include two parts, a touch detection device and a touch controller. The touch detection device detects the touch direction of a user, detects a signal brought by touch operation and transmits the signal to the touch controller; the touch controller receives touch information from the touch sensing device, converts the touch information into touch point coordinates, sends the touch point coordinates to the processor 11, and can receive and execute commands sent by the processor 11. In addition, the touch screen 151 may be implemented in various types, such as resistive, capacitive, infrared, and surface acoustic wave. Other input devices 152 may include, but are not limited to, one or more of a physical keyboard, function keys (such as volume control keys, power switch keys, etc.), a trackball, a mouse, a joystick, and the like.

The display unit 16 may be used to display information input by a user or information provided to the user and various menus of the apparatus. The display unit 16 may include a display panel 161, and in the present application, the display panel 161 may be configured using an AMOLED display screen. Further, the touch screen 151 may cover the display panel 161, and when the touch screen 151 detects a touch operation on or near the touch screen 151, the touch operation is transmitted to the processor 11 to determine the type of the touch event, and then the processor 11 provides a corresponding visual output on the display panel 161 according to the type of the touch event. Although in fig.1 the touch screen 151 and the display panel 161 are shown as two separate components to implement the input and output functions of the device, in some embodiments the touch screen 151 and the display panel 161 may be integrated to implement the input and output functions of the device.

Audio circuitry 17, a speaker 171 and a microphone 172 for providing an audio interface between the user and the device. The audio circuit 17 may transmit the electrical signal converted from the received audio data to the speaker 171, and convert the electrical signal into a sound signal by the speaker 171 for output; on the other hand, the microphone 172 converts the collected sound signals into electrical signals, converts the electrical signals into audio data after being received by the audio circuit 17, and then outputs the audio data to the RF circuit 12 to be transmitted to, for example, another device, or outputs the audio data to the memory 14 for further processing.

Optionally, the device shown in FIG.1 may also include various sensors. Such as gyroscope sensors, hygrometer sensors, infrared sensors, magnetometer sensors, etc., and will not be described in detail herein. Optionally, the apparatus shown in fig.1 may further include a wireless fidelity (WiFi) module, a bluetooth module, and the like, which are not described herein again.

It is understood that, in the embodiment of the present application, an electronic device (for example, the apparatus shown in fig.1 described above) may perform some or all of the steps in the embodiment of the present application, and these steps or operations are merely examples, and the embodiment of the present application may also perform other operations or various modifications of the operations. Further, the various steps may be performed in a different order presented in the embodiments of the application, and not all operations in the embodiments of the application may be performed. The embodiments of the present application may be implemented individually or in any combination, and the present application is not limited to these.

To facilitate understanding of the embodiments of the present application, some concepts or terms referred to by the embodiments of the present application are explained.

(1) Gamma correction

Gamma correction is a method for performing nonlinear tone editing on an image, and can detect a dark color part and a light color part in an image signal, and increase the proportion of the dark color part and the light color part, thereby improving the image contrast effect. The photoelectric conversion characteristics of current display screens, photographic film, and many electronic cameras can all be non-linear. This is achieved byThe relationship between the output and the input of the non-linear components can be expressed by a power function, namely: output = (input) ^γ 。

The non-linear conversion of the color values output by the device is due to the fact that the human visual system is not linear, and human senses visual stimuli through comparison. The outside strengthens the stimulus in a certain proportion, and the stimulus is uniformly increased for people. Therefore, the physical quantity increasing in an equal ratio series is uniform to human perception. In order to display the input color according to the human visual law, the linear color value needs to be converted into the nonlinear color value through the nonlinear conversion in the form of the above power function. The value γ of gamma can be determined according to the photoelectric conversion curve of the color space.

(2) Color space

The color may be a different perception of the eye by different frequencies of light, or may represent the presence of different frequencies of light objectively. A color space is a range of colors defined by a coordinate system that one establishes to represent colors. Together with the color model, the color gamut defines a color space. Wherein the color model is an abstract mathematical model representing colors with a set of color components. The color model may include, for example, a Red Green Blue (RGB) mode, a print four Color (CMYK) mode. Color gamut refers to the aggregate of colors that a system is capable of producing. Illustratively, adobe RGB and sRGB are two different color spaces based on the RGB model.

Each device, such as a display or printer, has its own color space and can only generate colors within its gamut. When moving an image from one device to another, the colors of the image may change on different devices as each device converts and displays RGB or CMYK according to its own color space.

Several commonly used color spaces are described below.

(1) CIE1931 color space

The CIE1931 color space (also known as CIE1931 XYZ color space) is one of the first mathematically defined color spaces. The CIE XYZ color space is directly measured based on human color vision and can serve as a basis for the definition of other color spaces. The Y parameter used by the CIE XYZ color space is the lightness or brightness of a color. The chromaticity of a color is determined using parameters x and y, the relationship between chromaticity x, y and tristimulus values X, Y and Z is:

the parameters x, Y can be used to determine a color, and for a display screen, the chromaticity coordinates x, Y and the luminance value Y can be measured using a color analyzer. Wherein, X and Z in the tri-stimulus value can be calculated from chromaticity coordinates X and Y and luminance Y:

(2) sRGB color space

The sRGB (standard Red Green Blue) color space is a standard RGB color space developed by Hewlett packard in 1996 along with Microsoft for displays, printers, and the Internet. It provides a standard method to define colors, allowing various computer peripherals and applications, such as display, print and scan, to have a common language for colors. The color space of the sRGB is based on independent color coordinates, so that colors can correspond to the same color coordinate system in different equipment use transmission without being influenced by different color coordinates of the equipment. However, the gamut space of sRGB is relatively small. sRGB defines the colors of the three primary colors of red, green, and blue, in which the color value of one of the three primary colors takes the maximum value, and the corresponding color when the color values of the other two colors are both zero represents the one color. Illustratively, in the three primary colors of red, green and blue, the color values R, G and B are both 0-255, and when the value of R, G is zero, the corresponding color represents blue when the value of B is 255.

If the two monochromatic lights are combined into a test color light, the three primary color value perceived by the observer is the sum of the three primary color values respectively and independently observed by the two monochromatic lights.

In other words, if the first and second beams are monochromatic, and { R1, G1, B1}, { R2, B2, G2} are the viewer's perceived three-primary values for the first and second beams, respectively, when the two beams are combined, the viewer's perceived three-primary values are { R, G, B }, wherein:

R＝R1+R2

G＝G1+G2

B＝B1+B2

the first light beam { R1, G1, B1} and the second light beam { R2, G2, B2} are expressed by CIE1931 color space and respectively correspond to tristimulus values { X1, Y1, Z1} and { X2, Y2, Z2}, and then an observer feels that the tristimulus values { X, Y, Z } corresponding to the three primary colors { R, G, B } are

X＝X1+X2

Y＝Y1+Y2

Z＝Z1+Z2

(3) Color space conversion

Conversion between different color spaces is possible, and conversion of the color spaces is described below by taking the CIE1931 color space and the sRGB color space as examples.

The calculation of the three primary colors in sRGB from the CIE XYZ coordinate system first requires its transformation to the CIE XYZ ternary mode. That is, using equation (3) and equation (4) to determine X, Z results in three values X, Y and Z in the CIE1931 color space. Then, linear R, G and B values are obtained by utilizing conversion matrix calculation:

sRGB is a color value that reflects a typical display with a real world gamma of 2.2, so the linear value is converted to sRGB using the following transformation formula:

(3) Color value conversion for display screen

When the display screen displays, because the color gamut corresponding to different display screens is different, when the same RGB color value is input, human eyes feel that the same X, Y, Y tristimulus values are also different. If human eyes feel the same three-color stimulus value X, Y, Y, the color gamut of the display screen needs to be converted, and the corresponding color value of the input sRGB color space also needs to be corrected.

Referring to fig. 2, fig. 2 is a schematic diagram of a color value transformation scenario of a display screen according to an embodiment of the present application, as shown in fig. 2, an input image fig.1 is input to a display screen 201, when the display screen 201 is in an initial color gamut, taking an example of a target pixel in the fig.1, a corresponding color value of the target pixel when the initial color gamut is displayed is a first RGB, and a corresponding XYZ stimulus value is an initial XYZ stimulus value. The color gamut of the display screen 201 is corrected such that the color value corresponding to the target pixel is the second RGB, and the corresponding XYZ stimulus value is the target XYZ stimulus value.

The process of converting the first RGB to the second RGB for displaying on the display screen in fig.1 specifically includes the following steps:

step one, carrying out linear transformation on the color value of the received standard color gamut image.

The display screen displays a standard color gamut image in the initial color gamut, and also takes an example of a target pixel, where the color value of the target pixel is the first RGB. Since in the first RGB: the red component value R0, the green component value G0, and the blue component value B0 are all non-linear, and the non-linear color values need to be converted into linear color values before color value transformation is performed. Referring to fig. 3, fig. 3 is a schematic diagram illustrating a color value transformation process of a display panel according to an embodiment of the present disclosure, which can convert a first RGB from a non-linear value to a linear value through gamma transformation. For example, a first gamma (gamma) lookup table is stored, the first gamma lookup table includes a mapping relationship between nonlinear RGB and its corresponding linear rbg, and the conversion of the nonlinear color value into the linear color value is realized by the first gamma lookup table. Specifically, the gamma may be 2.2, and the mapping relationship of the first gamma lookup table may be that the input red component value R0, the input green component value G0, and the input blue component value B0 are sequentially mapped into a red component value R1, a green component value G1, and a blue component value B1, where the red component value R1, the green component value G1, and the blue component value B1 are referred to as a first linear rgb. Wherein, the conversion of the input nonlinear RGB into the first linear RGB is realized by the following formula:

in the first gamma lookup table, a non-linear range of color values may correspond to a linear range of color values. For example, non-linear color values in the range of (R0- Δ R, R0+ Δ R) all correspond to R1 in the first gamma lookup table. For example, please refer to table 1, where table 1 is an example of a first gamma lookup table provided in an embodiment of the present application.

TABLE 1 first gamma lookup Table

As shown in Table 1, the color values R0, G0 and B0 can all take the values of 0-2 ¹⁰ And R0 in a certain range corresponds to the same R1 in the first gamma lookup table. Normalization can be performed according to a value selected from a range corresponding to R0, so that the obtained values are all between 0 and 1, then gamma calculation is performed, and a 10-bit value is output, namely R1. For example, when R0 is 0-31, the corresponding R1 is (15/1023) 2.2 x1023. For R0 values sequentially falling within the ranges of 32-63, 64-95 … … 992-1023, the corresponding R1 values in the first gamma lookup table are sequentially (47/1023) ^2.2 *1023，(79/1023) ^2.2 *1023……(1007/1023) ^2.2 *1023, etc.

In addition, in the first gamma lookup table, a non-linear color value may correspond to a linear color value. The linear color values corresponding to the non-linear color values not stored in the first gamma lookup table may be determined by interpolation of the linear color values corresponding to the non-linear color values stored in the lookup table. For example, please refer to table 2, where table 2 is an example of another first gamma lookup table provided in the embodiments of the present application.

TABLE 2 first gamma lookup table

R0/G0/B0	0	32	64	……	1023
R1/G1/B1	0	(32/1023) ^2.2 *1023	(64/1023) ^2.2 *1023	……	(1023/1023) ^2.2 *1023

As shown in Table 2, the color values R0, G0 and B0 can all take the values of 0-2 ¹⁰ Taking R0 as an example, R0 takes the values of 0,32, 64 … … 1023, and the values of R1 in the first gamma lookup table are 0, (32/1023) ^2.2 *1023. (64/1023) 2.2 x 1023 … … (1023/1023) 2.2 x 1023. In addition, in order to avoid precision loss, a 12-bit R1 value can be output. For example, when R0 is 32, the corresponding R1 may be (32/1023) ^2.2 * 4095. When the value of R0 is a value other than 0,32, 64 … … 1023, the corresponding value of R1 is determined by interpolating the known values of R1 in the first gamma lookup table, for example, when the value of R0 is 25, the value of R1 corresponding to the value of R0 being 25 can be determined by interpolating according to the corresponding values of R1 when the value of R0 is sequentially 0 and 32. In the embodiment of the present application, a specific algorithm used in the interpolation method is not limited, and may be a linear interpolation method, a lagrange interpolation method, or the like, or may use other interpolation methods.

It should be understood that the above-mentioned example of the first gamma lookup table is only used for explaining the embodiment of the present application, and should not be construed as limiting. In the embodiment of the present application, conversion between a nonlinear color value and a linear color value is described by taking the example that gamma is 2.2, which should not be limited in examples, and a specific gamma value may also be determined according to a photoelectric conversion curve of a color space.

And step two, performing color gamut conversion to obtain the color value of the display screen.

(1) Gamut conversion by a conversion matrix

After the first linear RGB corresponding to the first RGB is obtained through the first gamma lookup table, color gamut conversion may be performed, that is, the initial XYZ stimulus values of the display screen are converted to the target XYZ stimulus values, and at the same time, the first linear RGB is converted to the second linear RGB, and the second linear RGB is the linear color values corresponding to the second RGB. The target XYZ stimulus values can be expressed as: xt, yt and Zt.

Because the color gamut of different display screens is different, human eyes want to feel the same target XYZ stimulus value, and the corresponding input RGB color value needs to be corrected. The process requires color space conversion and color gamut correction of the display screen at the same time, and the specific principle is as follows:

in the formula (8)

The target color value to which the display screen needs to be converted, i.e. the second linear RGB corresponding to the second RGB.

The conversion matrix from the sRGB color space to the 1931 color space may be, specifically, the inverse matrix of the conversion matrix of 3 × 3 in the formula (5).

In, X _R 、Y _R And Z _R Taking the maximum value of the red color value R of the display screen and the corresponding tristimulus value X _G 、Y _G And Z _G Taking the maximum value of the green color value G of the display screen and the corresponding tristimulus value X _B 、Y _B And Z _B And taking the corresponding tristimulus value when the display screen blue color value B takes the maximum value. Illustratively, the color values R, G and B of the display screen both take values of 0-255, then X _R 、Y _R And Z _R Taking the corresponding tristimulus value X of 255 as the red color value R of the display screen _G 、Y _G And Z _G Corresponding to the green color value G of the display screen when taking 255Tristimulus value of (A), X _B 、Y _B And Z _B And taking the corresponding tristimulus value of 255 for the display screen blue color value B.

Transforming equation (8) yields:

in the formula (9), let

Thus obtaining:

can store

The conversion of the linear color values R1, G1 and B1 output by the first gamma lookup table into the linear color values R on the display gamut of the display screen is realized by using the 3 × 3 conversion matrix _pannel 、G _pannel And B _pannel 。

(2) Gamut conversion by look-up tables

Alternatively, the gamut conversion on the display screen may be performed directly by storing a look-up table of color values. Namely, under the condition of determining the first RGB, the corresponding second RGB is searched through the color value lookup table, so that the display screen displays under the target XYZ stimulus value, and the color gamut conversion is completed. The mapping relationship of the color value lookup table may be obtained by measurement, and a three-dimensional color value lookup table is established through a known target color gamut and a color value on the corresponding color gamut of the display screen measured by the color analyzer. The three dimensions are R, G and B, respectively, and the initial color value R is in the color value lookup table _in 、G _in And B _in The same set of values can uniquely correspond to a set of display screen target color values R according to three dimensions _out 、G _out 、B _out The value of (c). When the color value lookup table is used for looking up the values of R1, G1 and B1 which are not stored, the positions of the input linear color values in three dimensions in the color value lookup table are looked up, the color value of the display screen is determined through an interpolation method, the description of the interpolation method can refer to the specific description in the step one, and details are not repeated here.

Alternatively, the color value RGB stored in the color value lookup table may be a linear value or a non-linear value.

And step three, carrying out nonlinear conversion on the linear color value.

R obtained from the above formula (10) _pannel 、G _pannel 、B _pannel Is a linear color value over the display gamut of the display screen. In order to ensure that the colors are displayed according to the human visual law, the colors need to be subjected to nonlinear conversion. The non-linear transformation may be implemented by a look-up table similar to the linear transformation in step one. Specifically, a second gamma lookup table may be stored, where the second gamma lookup table includes a correspondence between a linear RGB and a corresponding nonlinear RGB thereof, and the conversion of a linear color value on the display color gamut of the display screen into a nonlinear color value is realized through the second gamma lookup table. Specifically, the gamma may be 2.2, and the mapping relationship of the second gamma lookup table may be the red component value R to be input _pannel Green component value G _pannel And blue component value B _pannel Mapped in sequence as a red component value R2, a green component value G2 and a blue component value B2. Wherein:

in the second gamma lookup table, a linear range of color values corresponds to a non-linear range of color values. For example (R) _pannel -ΔR1，R _pannel Linear color values within + Δ R1) correspond to R2 in the first gamma lookup table. In addition, in the second gamma lookup table, a linear color value may correspond to a non-linear color value. The non-linear color value corresponding to the linear color value not stored in the second gamma lookup table can be determined by an interpolation method. The description of the interpolation method may refer to the specific description in step one, and is not repeated here.

And step four, the display screen displays the nonlinear color value obtained by conversion.

And obtaining the corresponding second RGB when the display screen is converted to the target XYZ stimulus value, specifically the nonlinear red component value R2, green component value G2 and blue component value B2, and displaying the display screen according to the corresponding color values.

The display screen related in the embodiment of the present application may be an LED display screen, and may specifically include various organic light-emitting diode (OLED) display screens, such as an AMOLED display screen, a passive matrix organic light-emitting diode (PM-OLED) display screen, and may also include other types of LEDs, and may also include a display of a type that newly appears in the future, which is not limited in the embodiment of the present application.

In the above-mentioned color domain conversion process of the display screen, when the color value conversion is performed by the conversion matrix, the white brightness of the display is generally required to be corrected to gamma 2.2, so as to satisfy the perception characteristic of human eyes to brightness. However, crosstalk exists between RGB pixels of the display, so that when the gamma curve of white luminance is corrected to 2.2, the luminance corresponding to the R, G, B three-component does not necessarily conform to gamma 2.2, and the gamma is different for displays of different process levels, so that the linear domain and the nonlinear domain cannot be accurately converted, and the color accuracy is affected. Meanwhile, since the LED light-emitting wavelength is affected by the driving voltage, no matter the OLED which actively emits light or the LCD which uses the LED as a backlight, the chromaticity coordinates x and y of RGB change with the luminance, especially when the luminance is low, the variation is large, and a fixed 3x3 matrix cannot well correct the color gamut of the display screen to the standard color gamut, thereby affecting the color accuracy.

The color value conversion through the color value lookup table is to directly map the standard color gamut image RGB color values as input RGB components to the RGB components output by the display, theoretically, if the color value lookup table is large enough, the input RGB components can be mapped to the RGB components output by the display one by one, and therefore the display screen can display accurate colors.

In practical application, each RGB component cannot be mapped one by one, so that a color value lookup table of 5 × 5,9 × 9, even 17 × 17x17 is adopted, the position of the corresponding color value lookup table is searched according to the input RGB, and then interpolation calculation is performed to obtain the corresponding output value.

Before generating the color value look-up table, each node in the table needs to be corrected to display the exact color. The calibration process is as follows: when a color analyzer is used for testing the corresponding chromaticity and brightness parameters (namely, the XYZ parameters which are used for describing the colors of pixels and have a functional relation with the tristimulus values XYZ sensed by human eyes) when a certain RGB color value is input into the display screen, the chromaticity and brightness parameters are calculated by a computer and then written into the mobile phone for storage, and the more the tested information is, the more accurate the corrected color is. However, excessive sampling tests affect the actual display shipment throughput, for example, each color measurement on the display requires 200-500 ms, and usually more than 17 × 17 colors are required to achieve accurate color gamut correction, which is about an hour.

Meanwhile, the display needs to be corrected to different color gamuts for different display scenes, and different color value lookup tables are also generally used. In order to ensure the display consistency in different scenes, color correction needs to be performed for different scenes, so that the correction time is longer as the use scenes are increased.

Based on the above description, embodiments of the present application provide a display method to solve the above-mentioned problems of low accuracy of display colors and low efficiency of color gamut conversion. First, a system architecture to which the method is applied will be described. Referring to fig. 4A, fig. 4A is a schematic diagram of a color gamut correction system architecture corresponding to an embodiment of the present application, as shown in fig. 4A, the system architecture 40 includes various functional modules 401, such as a user interface, an image module, a video module, and a shooting module; then includes a Graphics Processing Unit (GPU) 402 capable of image processing, a display subsystem 403 for deciding display colors, a display screen 404 for displaying colors, and the like. The display subsystem 403 further includes various sub-modules for determining display colors, such as a scaling module, a color space conversion module, a high-dynamic range (HDR) image module, and a color module. The color module 4036 is used to generate a color value lookup table, so that the initial RGB displayed in the current color gamut of the display screen can find the corresponding display RGB according to the color value lookup table, so that when the display screen displays RGB, the corresponding XYZ tristimulus values are the same as the standard color gamut, i.e., the display screen is corrected to the standard color gamut. Fig. 4A may be fully disposed in the electronic device shown in fig.1, or partially disposed in the electronic device shown in fig.1, so as to implement the display method described in this embodiment of the present application.

Referring to fig. 4B, fig. 4B is a flowchart of a display method according to an embodiment of the present disclosure, as shown in fig. 4B, the method includes the following steps:

501. a first RGB of a first pixel to be displayed is acquired.

In some cases, for a terminal device, it may be referred to as a terminal (terminal), also referred to as a User Equipment (UE), or a Subscriber Unit (SU), and may be specifically a mobile phone (mobile phone), a tablet computer (tablet computer), a laptop computer (laptop computer), a wearable device (such as a smart watch, a smart bracelet, a smart helmet, and smart glasses), and other devices with wireless access capability, such as a smart car, various internet of things (IOT) devices, including various smart home devices (such as a smart meter and a smart home appliance), and smart city devices (such as a security or monitoring device, and a smart road transportation facility), and the like. In the case where the terminal device includes a display screen, the image may be displayed in accordance with its color gamut, screen material, or other parameters. For a specific image, the corresponding color of the specific image can be described by the RGB color value of each pixel, and therefore, after an input image that needs to be displayed on the first display screen is acquired, the first RGB corresponding to each pixel of the input image is acquired first to describe the input image.

502. Acquiring a third display look-up table LUT corresponding to a first application mode, wherein the third LUT corresponding to the first application mode is generated by fusing the first LUT and a second LUT corresponding to the first application mode, the third LUT comprises a one-to-one correspondence relationship between a plurality of initial RGB and first display RGB, the initial RGB corresponds to initial chromaticity and brightness parameters, and the first display RGB corresponds to chromaticity and brightness parameters of the first application mode; the first LUT comprises a one-to-one mapping relation between a plurality of initial RGB and target RGB, and the target RGB correspondingly specifies chroma and brightness parameters; the second LUT comprises a one-to-one mapping relationship between a plurality of initial RGB and display RGB, the display RGB is related to an application mode, the display RGB corresponding to the same initial RGB in different application modes is different, and one application mode corresponds to one second LUT.

503. And determining a second RGB corresponding to the first RGB in the first application mode according to the third LUT, and sending the second RGB to a first display for displaying.

Generally, the application modes include a plurality of modes divided by products, such as a mobile phone mode, a tablet computer mode, a television mode, and the like; or a plurality of modes divided in different application scenarios, for example, divided according to the energy consumption mode, which may include a normal mode and a power saving mode; according to the application content division, a web page mode, a video mode, an image mode and the like can be included. Different application modes have different corresponding color gamuts, that is, for the same input image, the RGB color values and the XYZ tristimulus values in each application mode are also different.

In the embodiment of the present application, after a pixel to be displayed (which may be an image or a video) is acquired, to convert the pixel to be displayed into a color gamut in different application modes for displaying, a Look Up Table (LUT) corresponding to each application mode may be generated, and then after a first application mode corresponding to a display screen is determined, a first RGB of an input image is input into the LUT corresponding to the first application mode, and a second RGB corresponding to the application mode is acquired, so that when the display screen displays through the second RGB, the color gamut corresponding to the first application mode is displayed.

Before the mapping relation of the third LUT is applied to determine that each input image displays the corresponding second RGB, the third LUT needs to be generated. Wherein the third LUT comprises a one-to-one correspondence of a plurality of first initial RGB and first display RGB. The first initial RGB is a color value corresponding to the display screen when displaying in the current color gamut. Typically, each display screen is capable of displaying in the interval of R, G, B values of 0-255 (10 bins). Then the first initial RGB may be some typical sample RGB, such as the values obtained after 17 equal divisions from 0-255, then the initial RGB may be (0,0,16), (0,32,16), (16,16,48), (16,64,16), (240,0,0) … … (255 ), etc. When the first display RGB is the color gamut when the display screen is converted into the first application mode, the initial RGB is correspondingly converted into the color value. The contents of the third LUT may be as shown in the following table:

TABLE 3 third LUT

First initial RGB	First display RGB
(0,,0,16)	(0,0,10)
(0,32,32)	(0,25,25)
…	…
(255,255,255)	(250,250,250)

For example, the first initial RGB of the input image is (255,255,255), i.e., the red, green and blue component values are all 255, as a white image. In the first application mode, for all white images, display at a lower luminance, that is, display mapped to display RGB (250,250,250) is required.

For each display screen on the production line, it is necessary to determine the corresponding third LUT in each application mode. So as to determine the corresponding display RGB of the input image on each display screen in each application mode. Specifically, referring to fig. 4C, fig. 4C is a schematic diagram of a process of applying the third LUT according to an embodiment of the present disclosure, as shown in fig. 4C, a same input image may be input into different display screens, and due to differences of displayable luminance and color, transmittance of the LCD, material of the OLED, and the like, each display screen may make human eyes feel the same chromaticity and luminance, and RGB displayed correspondingly may be different. On the other hand, the same display screen can be applied to a plurality of application modes, namely, the same display screen can display under different chromaticities and brightness, and the corresponding display RGB is different. Therefore, after the input image is inputted into the display screen, the display RGB of the corresponding output image is related to the display screen on one hand and the application mode of the display screen on the other hand, and a third LUT may be generated and applied according to each application mode of each display screen.

As can be seen from the foregoing description, for each display screen, the corresponding display RGB of the display screen in each application mode can be measured multiple times to directly generate the third LUT in the application mode, but this will cause a problem of generating inefficiency. Or the corresponding display RGB of each display screen in different application modes is obtained according to the matrix transformation calculation, and then a third LUT is generated, which may cause inaccuracy of the obtained display RGB, and further cause inaccuracy of the chromaticity and luminance parameters displayed on the display screen. In the embodiment of the present application, the third LUT is generated by fusing the first LUT and the second LUT. As shown in fig. 4D, when, for any first display screen, the first display screen is converted from the initial color gamut to the specified color gamut of the specified display screen, the corresponding color value is converted from the first initial RGB to the target RGB, and the first LUT corresponding to the display screen is generated according to a one-to-one mapping relationship between the first initial RGB and the target RGB; when the designated display screen is converted into the display color gamut corresponding to each application mode from the designated color gamut, the corresponding output RGB is converted into the display RGB from the second initial RGB, the display RGB is related to the application modes, the corresponding display RGB of the same second initial RGB under different application modes is different, and one application mode corresponds to one second LUT. Each second LUT comprises a one-to-one mapping of a plurality of second initial RGB to display RGB, where the second initial RGB in the second LUT is also some typical RGB values, e.g., a value obtained after 17 equal divisions of 0-255, then the second initial RGB can be (0,0,16), (0,32,16), (16,16,48), (16,64,16), (240,0,0) … … (255 ), etc. In different application modes, the same second initial RGB value may be mapped to different display RGB, for example, in a second LUT corresponding to the night eye protection mode, when the second initial RGB is (255 ), the mapped display RGB may be (150,150,150); and in the second LUT corresponding to the outdoor mode, when the second initial RGB is (255,255,255), the mapped display RGB may be (250,250,250). And finally, fusing the first LUT and the second LUT to generate a third LUT, wherein the application mode corresponding to the third LUT is the application mode corresponding to the second LUT.

Specifically, for each display screen, inputting an RGB, there will be XYZ tristimulus values sensed by human eyes corresponding to the RGB, and parameters x, Y derived from the XYZ tristimulus values are used to represent the luminance and color corresponding to the tristimulus values. The initial color gamut (which may be a factory color gamut, a default color gamut, etc.) of each display screen may be characterized by initial RGB and initial chromaticity and luminance parameters corresponding to the initial RGB, the conversion relationship between RGB and XYZ stimulus values may be obtained by calculation according to the foregoing formulas (5) and (6), and the functional relationship between XYZ stimulus values and chromaticity and luminance parameters may be determined according to the foregoing formulas (1) to (4), so that the conversion relationship between RGB and chromaticity and luminance parameters may be derived.

For the first display screen and the designated display screen, the corresponding relationship among the RGB color values, luminance and chromaticity parameters, and color gamut is shown in the following table:

table 4 color gamut relationship table for first display screen and specified display screen

The first initial RGB and the second RGB may be the same color value, for example, both the initial RGB1, the initial RGB2 or the initial RGB3, but the first initial RGB corresponds to the initial luminance and chrominance parameters, the second initial RGB corresponds to the designated chrominance and luminance parameters, i.e., the actual characteristics of different display screens are different, and the color and luminance (or color gamut) perceived by the human eye are different. In order to convert the first display screen to the color gamut of the designated display screen, that is, to display the first display screen at the designated luminance and chrominance parameters, the output RGB of the first display screen needs to be converted to the target RGB, and then a first LUT is generated according to the one-to-one mapping relationship between the first initial RGB and the target RGB.

Assuming that in gamut correction system 40, color module 4036 includes a storage module storing first initial RGB of the first display screen and corresponding initial luminance and chrominance parameters, a second initial RGB of the designated display screen and corresponding designated luminance and chrominance parameters may be obtained. Or, the program defaults to initial RGB (corresponding to the first initial RGB and the second initial RGB), stores corresponding initial luminance and chrominance parameters in the memory, and specifies the luminance and chrominance parameters. Alternatively, the specified luminance and chrominance parameters may be read from the temporary storage space in real time. And then generating a first LUT by a first LUT generating module, wherein the first LUT is a one-to-one correspondence table for converting the first initial RGB to the target RGB when the display screen is converted from the initial color gamut to the specified color gamut of the specified display screen. The specific process is as follows:

1. assuming that the first initial RGB is (R0, G0, B0), the first initial RGB is first converted into a linear domain by gamma conversion to obtain a first linear RGB, which is expressed as (R, G, B), and the specific conversion formula is:

2. converting the linear rgb into XYZ tristimulus values using a conversion matrix specifying a color gamut, see in particular the following equations:

where Xt, yt, and Zt correspond to the initial chromaticity and luminance parameters.

3. After obtaining the initial chrominance and luminance parameters corresponding to the first initial RGB, the initial chrominance and luminance parameters may be converted into linear spatial domain values of the target RGB according to the aforementioned formula (8), resulting in the second linear RGB. The method specifically comprises the following steps:

wherein (r, g, b) _panel I.e. the second linear rgb, according to glasmann's third law:

after the second linear RGB is obtained, the nonlinear RGB values can be obtained by passing them through an inverse gamma transformation.

Since the fixed gamma value does not necessarily enable the RGB values to be accurately converted between the linear domain and the nonlinear domain, in the embodiment of the present application, when the second linear RGB is subjected to the inverse gamma conversion, the corresponding second gamma value is obtained by calculating the measurement value. Specifically, the second gamma value obtaining formula is:

gamma2＝log(Y _gray1 /Y _gray2 )/log(Gray1/Gray2) (17)

where gray1 and gray2 represent gray values corresponding to any two sets of RGB values, Y _gray1 And Y _gray2 The luminance values corresponding to the gray scale value of gray1 and the luminance values corresponding to the gray scale value of gray2 are respectively indicated. Wherein the gray values corresponding to any two groups of RGB can be obtained by measurement. The second gamma value is calculated from the measured value.

And finally, performing inverse gamma conversion on the second linear RGB according to gamma2 to obtain intermediate RGB correspondingly output by the first display screen, wherein the formula is as follows:

matrix in the above process

The values in (1) are all selected according to the designated brightness and chrominance parameters, so that when the intermediate RGB obtained by the matrix calculation is converted into the designated brightness and chrominance parameters for the first display screen, the corresponding output RGB (nonlinear RGB) is theoretically obtained. However, due to the limitation of the matrix selection, the intermediate RGB obtained from the matrix is not necessarily the output RGB corresponding to the first display screen when the luminance and chrominance parameters are specified for displaying. Therefore, in the embodiment of the present application, it is further required to further obtain a target RGB, where the target RGB is displayed on the first display screen at the specified brightness and chromaticity parametersThe actual corresponding output RGB.

In the embodiment of the application, the intermediate RGB is subjected to iterative transformation according to a preset step length, corresponding chromaticity and brightness parameters of the intermediate RGB obtained by each iteration are calculated until the measured chromaticity and brightness parameters are the same as or similar to the specified chromaticity and brightness parameters, and the intermediate RGB is determined to be the target RGB. Referring to fig. 4E, fig. 4E is a flowchart for determining a target RGB according to an embodiment of the present application, and as shown in fig. 4E, the process includes the following steps:

601. according to the preset step length to RGB _i Carrying out transformation and obtaining the corresponding chroma and brightness parameter change values;

602. obtaining RGB according to the preset step length _i+1 According to said RGB _i Obtaining the RGB according to the corresponding intermediate chroma and brightness parameters and the chroma and brightness parameter variation values _i+1 Corresponding intermediate chrominance and luminance parameters;

603. judging the RGB _i+1 Whether the difference value between the corresponding intermediate chroma and brightness parameter and the designated chroma and brightness parameter is smaller than a preset threshold value or not;

604. if the RGB _i+1 If the difference value between the corresponding intermediate chroma and brightness parameter and the designated chroma and brightness parameter is not less than a preset threshold value, i = i +1, and S1-S3 are repeatedly executed until the RGB is obtained _i+1 The difference value between the corresponding intermediate chroma and brightness parameter and the designated chroma and brightness parameter is less than a preset threshold value, and the RGB is obtained _i+1 As the target RGB. When i =1, the RGB _i Is the intermediate RGB.

The preset step size may be a fixed value of Δ R, Δ G, and/or Δ B, for example, the preset step size may be (0,0, Δ R), (0, Δ G, 0), or (Δ R, Δ G, Δ B), etc. The intermediate RGB obtained by the matrix calculation is used as an initial value of the iterative transformation, and is set to, for example, RGB ₁ . When the output RGB of the first display screen is RGB ₁ Then, the corresponding intermediate chroma and luma parameters 1 can be measured, if this value is associated with the specified lumaThe degree is equal to the chromaticity parameter (or the difference between the degree and the chromaticity parameter is smaller than the preset threshold), which means that the intermediate RGB obtained by the matrix calculation is the target RGB displayed by the first display screen in the designated color gamut, and the intermediate RGB does not need to be iteratively transformed.

If the difference value between the intermediate chromaticity and brightness parameter 1 and the designated chromaticity and brightness parameter is larger than the preset threshold value, the difference between the current display color gamut of the first display screen and the designated color gamut is larger, and the RGB is processed ₁ Conversion according to a predetermined step, e.g. RGB ₁ Adding or subtracting delta R, delta G and delta B to the corresponding R, G and B values to obtain RGB2, changing the corresponding chromaticity and brightness parameters when the RGB output by the first display screen changes, recording the chromaticity and brightness parameter change values, and adding or subtracting the chromaticity and brightness parameter change values with the intermediate chromaticity and brightness parameter 1 to obtain the RGB2 ₂ Corresponding intermediate chrominance to luminance parameter 2. The corresponding formula can be expressed as:

wherein xyY _i+1 Is RGB _i+1 Corresponding intermediate chrominance and luminance parameter, xyY _i Is RGB _i The corresponding intermediate chromaticity and luminance parameter, and the intermediate chromaticity and luminance parameter 2 correspond to the case of i =1 in the above equation. RGB comprises R parameter, G parameter and B parameter, wherein delta R, delta G and delta B are respectively the preset step length of R parameter, G parameter and B parameter, and delta x _R ，Δy _R Is the chromaticity parameter variation value delta Y caused by the iteration of the R parameter according to the preset step length _R For the value of variation of the brightness parameter, Δ x, caused by iteration of the R parameter according to a preset step length _G ，Δy _G Is the chromaticity parameter variation value, delta Y, caused by the iteration of the G parameter according to the preset step length _G The change value of the brightness parameter, delta x, caused by the iteration of the G parameter according to the preset step length _B ，Δy _B The variation value of chromaticity parameter, delta Y, caused by B parameter iteration according to a preset step length _B Is caused by iteration of the B parameter according to a preset step lengthThe luminance parameter variation value of (1).

Or the first display screen output RGB can be directly measured and obtained ₂ The corresponding intermediate chrominance and luminance parameter 2. After obtaining the intermediate chroma and brightness parameter 2, similarly comparing the intermediate chroma and brightness parameter with the specified chroma and brightness parameter, if the difference value between the two is less than the preset threshold value, stopping iteration, and combining RGB ₂ And taking the target RGB, and otherwise, continuing the iteration. Until RGB is obtained iteratively _i And enabling the brightness and the chromaticity parameters corresponding to the first display screen to be designated brightness and chromaticity parameters, which indicates that the color gamut of the first display screen is converted into a designated color gamut, and the corresponding RGB is the target RGB.

On the first display screen, after the output RGB is converted from the first initial RGB to the target RGB, the displayed brightness and chromaticity parameters are converted from the initial chromaticity and brightness parameters to the designated chromaticity and brightness parameters, namely the first display screen is converted to the designated color gamut for display.

It can be seen that, in the embodiment of the present application, an intermediate RGB to which an initial color gamut of a first display screen needs to be converted is calculated through a matrix corresponding to a designated color gamut, then the intermediate RGB is used as an output RGB of the first display screen, measurement of corresponding chromaticity and luminance parameters is performed, whether the first display screen is converted to the designated color gamut is determined, if not, iterative transformation is performed on the output RGB according to a preset step length until it is determined that the first display screen is converted to the designated color gamut, and a corresponding target RGB is obtained. In the process, the gamma value is determined according to the measured gray value on each display screen, so that the accuracy of matrix conversion is improved, in addition, the intermediate RGB obtained according to matrix calculation is not directly used as the target RGB of the first display screen for displaying in the specified color gamut, the target RGB is determined by repeated iteration, and the accuracy of the generated first LUT is further improved.

Optionally, the process of obtaining the first LUT may also be performed in other devices or processors, and in the color gamut correction system 40, the color module 4036 does not include the first LUT generation module, and when a third LUT needs to be generated, the communication module in the system directly requests to obtain the first LUT from the other devices or processors, so that the system data processing consumption can be reduced; or the communication module acquires the first LUT in advance and stores the first LUT in the storage module, and when the third LUT needs to be generated, the first LUT is read from the storage module. Since the first initial RGB may be a value set by default by the program, the system acquires or stores the target RGB corresponding to the first initial RGB, and the storage pressure is reduced. The system may also determine the first LUT according to the default set first initial RGB and the obtained target RGB.

After the first LUT is acquired, the first LUT needs to be fused with the second LUT to generate a third LUT. And the second LUT is a one-to-one corresponding relation table for converting the second initial RGB into the display RGB when the specified display screen is converted from the specified color gamut into the corresponding color gamut under different application scenes. If the assigned display screens used by the plurality of first display screens are the same, the second LUT used by the plurality of first display screens is the same.

As is known from the foregoing description, the current color gamut (designated color gamut) of the designated display screen can be indicated by the second initial RGB, for example, the second initial RGB is (0,0,16), (0,32,16), … …, (255 ) and the corresponding chromaticity and luminance parameters are: the corresponding relationship is shown in table 5 after the chromaticity and luminance parameter 1 is designated, the chromaticity and luminance parameter 2, … … is designated, the chromaticity and luminance parameter N is designated, and the display gamut is converted into the display gamut in different application modes:

TABLE 5 color gamut relationship Table specifying display Screen and different application modes

Namely, on the designated display screen, the designated color gamut is converted into a first display color gamut corresponding to the first application mode, the designated brightness and chromaticity parameters are converted into the display chromaticity and brightness parameters, and correspondingly, the output RGB of the designated display screen is converted into the display RGB from the second initial RGB. The second LUT may include only the correspondence between the second initial RGB and the display RGB, and one second LUT may be provided for each application mode.

The second LUT is generated in other devices or processors, and then the communication interface of the color gamut correction system 40 acquires the second LUT from the server when a third LUT needs to be generated; or the color gamut correction system 40 has already obtained and stored the second LUT in advance, and when the third LUT needs to be generated, the second LUT may be read from the memory.

The first LUT and the second LUT are fused to generate a third LUT, comprising: acquiring a first initial RGB in a first LUT and a target RGB corresponding to the first initial RGB; determining real-time first display RGB obtained by mapping the target RGB according to the second LUT; a third LUT comprising a mapping of the first initial RGB and the first display RGB is generated.

Specifically, referring to fig. 4F, fig. 4F is a schematic diagram of a fusion process of a first LUT and a second LUT provided in the present embodiment, as shown in fig. 4F, after obtaining a target RGB corresponding to a first initial RGB according to the first LUT, the target RGB is used as an input value of the second LUT to search for a corresponding display RGB. Since the target RGB corresponds to the designated chromaticity and luminance parameters, and the second initial RGB also corresponds to the designated chromaticity and luminance parameters, when the target RGB = the second initial RGB, the corresponding relationship between the second initial RGB and the display RGB can be regarded as the corresponding relationship between the target RGB and the display RGB. For example, in fig. 4F, when the first initial RGB1 in the first LUT is (0,0,16), the corresponding target RGB1 is (0,0,32), and the second initial RGB2 in the second LUT is (0,0,32), and its corresponding display RGB2 is (0,0,48), then the display RGB1 corresponding to the first initial RGB1 (0,0,16) in the generated third LUT is (0,0,48). If the target RGB in the first LUT does not correspond to the second initial RGB already existing in the second LUT, interpolation or the like may be used to obtain the correspondence between the first initial RGB and the display RGB. For example, in fig. 4F, the target RGB2 corresponding to the first initial RGB2 (0,0,32) is (0,0,40), the target RGB2 is an intermediate value between the second initial RGB2 and the second initial RGB3 in the second LUT, and may be interpolated from the display RGB2 and the display RGB3 in the LUT2, and if the second initial RGB2 is (0,0,40), the corresponding color value B of the display RGB2 is: (48 + 72)/2 =60, i.e. the display RGB2 corresponding to the first initial RGB2 (0,0,32) is (0,0,60).

After a third LUT is generated according to the first LUT and a corresponding second LUT in the first application mode, for an initial image (described by first RGB) originally displayed on the first display screen, the first RGB is input into the third LUT, and is matched or interpolated with the first initial RGB in the third LUT, so as to obtain a corresponding output second RGB as a display RGB corresponding to the first RGB. And the first display displays the chromaticity and the brightness parameters corresponding to the second RGB, namely, the initial image is converted into the first application mode for displaying.

As can be seen, in the embodiment of the present application, a third LUT corresponding to each application mode is generated, and then, when the first display screen is converted from the current color gamut to the target color gamut corresponding to each application mode for display, the corresponding relationship of converting the first RGB of the first pixel to the second RGB is determined according to the third LUT. The efficiency of the first display screen from the initial color gamut to the target color gamut of the different application modes is improved. In addition, the first LUT for converting the first initial RGB into the target RGB corresponding to the designated chromaticity and brightness parameters of each display screen is obtained, and the first LUT is used for describing the color space corresponding to each display screen by considering the actual characteristics of each display screen panel, so that the display accuracy is improved; in addition, a second LUT for converting a second initial RGB corresponding to a designated chromaticity and a brightness parameter into a second LUT for displaying RGB in each application mode is obtained, a third LUT is generated by fusing the second LUT with the first LUT, only the corresponding relation between the designated chromaticity and the brightness parameter and the displaying RGB in different application modes can be measured, and the corresponding relation between the RGB when each display screen is converted into different application modes can be obtained by combining the first LUT of each display screen, instead of measuring the corresponding relation between the RGB when each display screen is converted into different application modes, so that lookup tables required in different scenes can be generated under the condition of one group of test parameters, the measurement time is reduced, the color space conversion efficiency is improved, and the conversion accuracy can be ensured.

In some possible cases, the second LUT may be updated. For example, if the mobile phone has new application modes, including a sleep mode, a teenager eye protection mode, etc., the possibility of switching the designated display screen to a different application mode increases, i.e., the number of the second LUTs increases. Or, if the previous application mode is updated, for example, the contrast and brightness of the video mode are optimized, the second LUT corresponding to the video mode is updated. In this case, the gamut correction system 40 may obtain the updated second LUT from the other device through the communication interface, the gamut correction system 40 stores the updated second LUT in the ROM after receiving the updated second LUT sent by the other device, and the fusion module in the color module 4036 reads the ROM as needed to obtain the updated second LUT, and then fuses the generated first LUT to generate the third LUT. The method can update the third LUT in real time, and improve the display efficiency of the display screen in different application modes.

Fig. 5 is a device for display processing according to an embodiment of the present application, so as to perform the display method in the foregoing embodiment. As shown in fig. 5, the control device 70 for screen brightness provided by the present embodiment may include:

an obtaining module 701, configured to obtain a first RGB of a first pixel to be displayed;

a processing module 702, configured to obtain a third display look-up table LUT corresponding to a first application mode, where the third LUT corresponding to the first application mode is generated by fusing the first LUT and a second LUT corresponding to the first application mode, and the third LUT includes a one-to-one correspondence relationship between a plurality of first initial RGB and first display RGB, where the first initial RGB corresponds to an initial chromaticity and luminance parameter, and the first display RGB corresponds to a chromaticity and luminance parameter of the first application mode; the first LUT comprises a one-to-one mapping relation between a plurality of first initial RGB and target RGB, and the target RGB correspondingly specifies chroma and brightness parameters; the second LUT comprises a one-to-one mapping relation between a plurality of second initial RGB and display RGB, the second initial RGB corresponds to the designated luminance and chrominance parameters, the display RGB is related to an application mode, the display RGB corresponding to the same initial RGB in different application modes is different, and one application mode corresponds to one second LUT;

the processing module 702 is further configured to determine, according to the third LUT, a second RGB corresponding to the first RGB in the first application mode, and send the second RGB to the first display for display.

Optionally, the obtaining module 701 is further configured to: and acquiring a third LUT corresponding to a second application mode, wherein the third LUT corresponding to the second application mode is generated by fusion according to the first LUT and a second LUT corresponding to the second application mode.

Optionally, the obtaining module 701 is further configured to: retrieving the first LUT from a memory; or receiving the first LUT from a server; or receiving the corresponding target RGB from the server or acquiring the corresponding target RGB from the memory according to the preset first initial RGB, and further determining the first LUT.

Optionally, the obtaining module 701 is further configured to: obtaining a second LUT corresponding to the first application mode from a plurality of second LUTs stored by the memory; or receiving a second LUT corresponding to the first application mode from the server.

Optionally, the obtaining module 701 is further configured to: receiving an updated second LUT from the server.

Optionally, the obtaining module 701 is specifically configured to: receiving the updated second LUT from the server at a preset time or upon receiving a preset instruction.

Optionally, the processing module 702 is specifically configured to: acquiring a first initial RGB in the first LUT and the corresponding target RGB; determining real-time first display RGB obtained by mapping the target RGB according to the second LUT; generating the third LUT including a mapping of the first initial RGB and the first display RGB.

Optionally, the processing module 702 is specifically configured to: converting the first initial RGB to obtain intermediate RGB; performing iterative transformation on the intermediate RGB according to a preset step length to obtain the target RGB; and determining the first LUT according to the one-to-one mapping relation of the first initial RGB and the target RGB.

Optionally, the processing module 702 is specifically configured to:

s1: converting the RGBI according to the preset step length, and obtaining a corresponding chromaticity and brightness parameter change value;

s2: obtaining RGBI +1 according to the preset step length, and obtaining intermediate chromaticity and brightness parameters corresponding to the RGBI +1 according to the intermediate chromaticity and brightness parameters corresponding to the RGBI and the chromaticity and brightness parameter variation values;

s3: judging whether the difference value between the intermediate chromaticity and brightness parameters corresponding to the RGBI +1 and the designated chromaticity and brightness parameters is smaller than a preset threshold value or not; if the difference value between the intermediate chromaticity and brightness parameter corresponding to the RGBi +1 and the designated chromaticity and brightness parameter is not less than a preset threshold, making i = i +1, and repeatedly executing S1-S3 until the difference value between the intermediate chromaticity and brightness parameter corresponding to the RGBi +1 and the designated chromaticity and brightness parameter is less than the preset threshold, and when i =1, the RGBi is the intermediate RGB.

Optionally, the processing module 702 is specifically configured to: the RGB is obtained by calculation according to the following formula _i+1 Corresponding intermediate chrominance and luminance parameters:

wherein said xyY _i+1 As the RGB _i+1 Corresponding intermediate chrominance and luminance parameters, said xyY _i As the RGB _i Corresponding intermediate chroma and brightness parameters, wherein the RGB comprises R parameters, G parameters and B parameters, and the delta R, the delta G and the delta B are respectively the preset step length of the R parameters, the G parameters and the B parameters, and the delta x _R ，Δy _R The variation value of the chromaticity parameter, delta Y, caused by the iteration of the R parameter according to the preset step length _R For the change value of the brightness parameter, deltax, caused by the iteration of the R parameter according to the preset step length _G ，Δy _G The change value of the chromaticity parameter, delta Y, caused by the G parameter according to the preset step length iteration _G The change value of the brightness parameter, delta x, caused by the iteration of the G parameter according to the preset step length _B ，Δy _B The variation value of the chromaticity parameter, delta Y, caused by the B parameter according to the preset step length iteration _B And the brightness parameter change value is the brightness parameter change value caused by the B parameter iteration according to the preset step length.

Optionally, the processing module 702 is specifically configured to: performing Gamma transformation on the first initial RGB based on a first Gamma value to obtain a first linear RGB; converting the first linear rgb according to a first transformation matrix to obtain the specified chrominance and luminance parameters;

converting the specified luminance and chrominance parameters according to a second transformation matrix to obtain a second linear rgb, wherein the second transformation matrix is generated according to the measured luminance parameters of the first display;

inverse Gamma transforming the second linear RGB based on a second Gamma value determined from measured brightness parameters of the first display to obtain the intermediate RGB.

It should be noted that the division of each module of the apparatus shown in fig. 5 is only a logical division, and all or part of the actual implementation may be integrated into one physical entity or may be physically separated. And these modules can be realized in the form of software called by processing element; or may be implemented entirely in hardware; and part of the modules can be realized in the form of calling by the processing element through software, and part of the modules can be realized in the form of hardware. For example, the processing module 702 may be a separate processing element, or may be integrated into a chip of the apparatus, or may be stored in a memory of the apparatus in the form of a program, and a processing element of the apparatus calls and executes the function of the processing module 702. The other modules are implemented similarly. In addition, all or part of the modules can be integrated together or can be independently realized. The processing element described herein may be an integrated circuit having signal processing capabilities. In implementation, the steps of the method or the units above may be implemented by hardware integrated logic circuits in a processor element or instructions in software.

These above modules may be one or more integrated circuits configured to implement the above methods, such as: one or more application-specific integrated circuits (ASICs), or one or more Digital Signal Processors (DSPs), or one or more field-programmable gate arrays (FPGAs), among others. For another example, when some of the above modules are implemented in the form of a processing element scheduler, the processing element may be a general-purpose processor, such as a Central Processing Unit (CPU) or other processor capable of calling programs. As another example, these modules may be integrated together and implemented in the form of a system-on-a-chip (SOC).

Fig. 6 is a schematic hardware structure diagram of an apparatus for display processing according to an embodiment of the present disclosure. As shown in fig. 6, the display processing apparatus 80 includes: a processor 801, a transceiver 802, a controller 803, and a screen 804.

The transceiver 801 is configured to acquire a first RGB of a first pixel to be displayed;

the processor 802 is configured to obtain a third display look-up table LUT corresponding to a first application mode, where the third LUT corresponding to the first application mode is generated by fusing the first LUT and a second LUT corresponding to the first application mode, and the third LUT includes a one-to-one correspondence relationship between a plurality of first initial RGB and first display RGB, where the first initial RGB corresponds to an initial chromaticity and luminance parameter, and the first display RGB corresponds to a chromaticity and luminance parameter of the first application mode; the first LUT comprises a one-to-one mapping relation between a plurality of first initial RGB and target RGB, and the target RGB correspondingly specifies chroma and brightness parameters; the second LUT comprises a one-to-one mapping relationship between a plurality of second initial RGB and display RGB, the second initial RGB corresponds to the designated luminance and chrominance parameters, the display RGB is related to an application mode, the corresponding display RGB of the same second initial RGB in different application modes are different, and one application mode corresponds to one second LUT;

the controller 803 is configured to determine, according to the third LUT, second RGB corresponding to the first RGB in the first application mode, and send the second RGB to the screen 804 for display.

Thus, the display processing apparatus in this embodiment may execute the display method in the foregoing embodiment, and the specific process and step of obtaining the third LUT have been described in detail in the foregoing embodiment, and are not described again here.

Thus, after the processor 802 determines the first LUT, the transceiver 801 may be used to obtain the first RGB corresponding to the target image to be displayed when displaying on the initial color gamut of the first display screen, and after obtaining the second RGB corresponding to the first RGB in the first application mode according to the first LUT, the controller 803 may output the second RGB to the screen 804 and control the screen 804 to display on the second RGB, that is, the process of displaying the target image on the color gamut corresponding to the first application mode is completed, which is not described herein again.

In addition, optionally, the display processing apparatus 80 may further include a memory 805, and the memory 804 is configured to store the first LUT, the second LUT, and/or the third LUT acquired from another server.

The screen 804 is usually formed by an Organic Light Emitting Display (OLED) or an Active-matrix Organic Light Emitting diode (AMOLED). For example, the screen 804 is taken as an OLED screen for explanation, in order to enable each pixel point of the OLED screen to perform desired luminance and color display output, the controller 803 in the display processing apparatus generates corresponding voltages according to the gray scale values of the second RGB for driving, and when different voltages are applied to the screen, different luminances can be displayed, so as to display the display luminance values corresponding to the input gray scale values.

Specifically, the controller 803 may include a voltage generator 8031 and a brightness controller 8032. Wherein the voltage generator is operable to generate a corresponding reference voltage from the input gray scale value; and the brightness controller may be configured to control the screen to display a display brightness value corresponding to the input gray scale value based on the reference voltage.

Since the input gray scale value is usually a digital signal, in order to convert the input gray scale value into an analog voltage value, the voltage generator 8031 may be a digital to analog converter (DAC). The dac is configured to convert the input gray scale value into an analog reference voltage value, so that the brightness controller 8032 can control the display brightness value of the screen according to the reference voltage value, so that the screen displays a corresponding display brightness value when powered on. Specifically, the digital-to-analog converter can change an input gray-scale value into an actual reference voltage value after receiving the input gray-scale value as a digital signal. When the input gray-scale values are different, the corresponding reference voltage values are changed, so that the screen can emit light rays with different brightness under the excitation of different reference voltage values and current values to display an actual image.

Among other things, the processor 802, the transceiver 801, the controller 803, and the memory 805 may utilize a communication bus or other data path to enable the transfer of data and signals between them. Since the memory 805 is electrically connected to the processor 802 and the controller 803, the first LUT and/or the second LUT stored in the memory 805 can be transmitted to the processor 802 to generate a third LUT, and then the transceiver 801 determines the second RGB according to the obtained first RGB and the third LUT, transmits the second RGB to the controller 803 to determine the input gray scale value that the pixel should have according to the second RGB, and allows the controller 803 to control the display brightness value of each pixel on the screen 804 according to the input gray scale value.

The processor 802 is typically a control center of a display processing device, and may be connected to different hardware components such as the memory 805 by a communication bus, and execute various functions of the terminal device and process data by running or executing software programs and/or modules and calling data stored in the memory, thereby performing a brightness control operation of the screen. The processor 71 may be a Micro Controller Unit (MCU), or a Central Processing Unit (CPU), or a stand-alone system-on-a-chip (SOC), or one or more integrated circuits configured to implement the above method, such as: one or more Application Specific Integrated Circuits (ASICs), or one or more microprocessors (DSPs), or one or more Field Programmable Gate Arrays (FPGAs), among others.

Optionally, the processor 802 may include one or more processing units; and different processing units are utilized to respectively execute the different instructions and programs so as to respectively execute different functions.

While memory 805 may be, but is not limited to, a read-only memory (ROM) or other type of static storage device that may store static information and instructions, a Random Access Memory (RAM) or other type of dynamic storage device that may store information and instructions, an electrically erasable programmable read-only memory (EEPROM), a compact disk read-only memory (CD-ROM) or other optical disk storage, optical disk storage (including compact disk, laser disk, optical disk, digital versatile disk, blu-ray disk, etc.), magnetic disk storage or other magnetic storage devices, or any other medium that can be used to carry or store desired program code in the form of instructions or data structures and that can be accessed by a computer. The memory 805 may be separate and coupled to the processor 802 and the transceiver 801 via a bus. The memory 805 may also be integrated with the processor 802.

In addition to storing the preset gamma correction look-up table, the memory 805 may also be used to store application program codes for implementing the present invention, and the processor 802 controls the execution of the application program codes. The processor 802 is configured to execute the application program code stored in the memory 805, so as to implement the screen brightness control method provided by the above-mentioned embodiment of the present application.

In addition, the display processing apparatus further includes a Pulse Width Modulation (PWM) dimmer 806, where the PWM dimmer 806 can modulate on/off of a switching device such as a transistor gate or a MOS transistor base inside, so as to generate a series of pulses with equal Pulse widths, and implement different equivalent analog outputs by changing the widths or duty ratios of the pulses, so as to adjust the output brightness of the screen 804. Illustratively, the PWM dimmer 806 is electrically connected to the screen 804, and the PWM dimmer 806 may receive a digital signal from the control chip, and convert the digital signal into pulses with different pulse widths or duty ratios, at this time, voltage signals with different amplitudes may be equivalently output, and along with the difference in the magnitudes of the voltage signals, each pixel point on the screen 804 may also display different luminances, thereby implementing normal display and luminance adjustment of an image. For example, the PWM dimmer 806 may be electrically connected to the processor 802 or be included as part of the controller 803 to adjust the display brightness of the screen 804 according to the input gray-scale values and the like.

In the above embodiments, the implementation may be wholly or partially realized by software, hardware, firmware, or any combination thereof. When implemented using a software program, may be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions. The procedures or functions described in accordance with the embodiments of the present application are all or partially generated upon loading and execution of computer program instructions on a computer. The computer may be a general purpose computer, a special purpose computer, a network of computers, or other programmable device. The computer instructions may be stored on a computer readable storage medium or transmitted from one computer readable storage medium to another, for example, from one website, computer, server, or data center to another website, computer, server, or data center via wire (e.g., coaxial cable, fiber optic, digital Subscriber Line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.). The computer-readable storage medium can be any available medium that can be accessed by a computer or can comprise one or more data storage devices, such as a server, a data center, etc., that can be integrated with the medium. The usable medium may be a magnetic medium (e.g., floppy disk, hard disk, magnetic tape), an optical medium (e.g., DVD), or a semiconductor medium (e.g., solid State Disk (SSD)), among others.

Claims

A method of display processing, the method comprising:

acquiring a first RGB of a first pixel to be displayed;

acquiring a third display look-up table LUT corresponding to a first application mode, wherein the third LUT corresponding to the first application mode is generated by fusing the first LUT and a second LUT corresponding to the first application mode, the third LUT comprises a one-to-one correspondence relationship between a plurality of first initial RGB and first display RGB, the first initial RGB corresponds to initial chromaticity and brightness parameters, and the first display RGB corresponds to chromaticity and brightness parameters of the first application mode; the first LUT comprises a one-to-one mapping relation between a plurality of first initial RGB and target RGB, and the target RGB correspondingly specifies chroma and brightness parameters; the second LUT comprises a one-to-one mapping relationship between a plurality of second initial RGB and display RGB, the second initial RGB corresponds to the designated luminance and chrominance parameters, the display RGB is related to an application mode, the corresponding display RGB of the same second initial RGB in different application modes are different, and one application mode corresponds to one second LUT;

and determining a second RGB corresponding to the first RGB in the first application mode according to the third LUT, and sending the second RGB to a first display for displaying.
The method of claim 1, further comprising:

and acquiring a third LUT corresponding to a second application mode, wherein the third LUT corresponding to the second application mode is generated by fusion according to the first LUT and a second LUT corresponding to the second application mode.
The method according to claim 1 or 2, characterized in that the method further comprises:

retrieving the first LUT from a memory; or

Receiving the first LUT from a server; or

And receiving the corresponding target RGB from the server or acquiring the corresponding target RGB from the memory according to the preset first initial RGB, and further determining the first LUT.
The method according to any one of claims 1-3, further comprising:

acquiring a second LUT corresponding to the first application mode from a plurality of second LUTs stored in the memory; or receiving a second LUT corresponding to the first application mode from the server.
The method according to any one of claims 1-4, further comprising: receiving an updated second LUT from the server.
The method of claim 5, wherein the receiving an updated second LUT from the server comprises: receiving the updated second LUT from the server at a preset time or upon receiving a preset instruction.
The method of any of claims 1-6, wherein obtaining the third LUT comprises:

acquiring a first initial RGB in the first LUT and the corresponding target RGB;

determining real-time first display RGB obtained by mapping the target RGB according to the second LUT;

generating the third LUT comprising a mapping of the first initial RGB and the first display RGB.
The method of any of claims 1-7, wherein obtaining the first LUT comprises:

converting the first initial RGB to obtain intermediate RGB;

performing iterative transformation on the intermediate RGB according to a preset step length to obtain the target RGB;

and determining the first LUT according to the one-to-one mapping relation of the first initial RGB and the target RGB.
The method of claim 8, wherein the iteratively transforming the intermediate RGB by a preset step size to obtain the target RGB comprises:

s1: according to the preset step length to RGB _i Carrying out transformation and obtaining the corresponding chroma and brightness parameter change values;

s2: obtaining RGB according to the preset step length _i+1 According to said RGB _i Obtaining the RGB according to the corresponding intermediate chroma and brightness parameters and the chroma and brightness parameter variation values _i+1 Corresponding intermediate chrominance and luminance parameters;

s3: judging the RGB _i+1 Whether the difference value between the corresponding intermediate chroma and brightness parameter and the designated chroma and brightness parameter is smaller than a preset threshold value or not; if the RGB _i+1 If the difference between the corresponding intermediate chroma and brightness parameter and the designated chroma and brightness parameter is not less than a preset threshold value, making i = i +1, and repeatedly executing S1-S3 until the RGB is reached _i+1 The difference value between the corresponding intermediate chroma and brightness parameter and the designated chroma and brightness parameter is less than a preset threshold value, and when i =1, the RGB _i Is the intermediate RGB.
The method of claim 9, wherein the RGB is based on the RGB _i Obtaining the RGB according to the corresponding intermediate chroma and brightness parameters and the chroma and brightness parameter variation values _i+1 Corresponding intermediate chroma and brightness parameters, including RGB calculated according to the following formula _i+1 Corresponding intermediate chrominance and luminance parameters:

wherein said xyY _i+1 Is the RGB _i+1 Corresponding intermediate chrominance and luminance parameters, said xyY _i Is the RGB _i Corresponding intermediate chroma and brightness parameters, wherein RGB comprises R parameter, G parameter and B parameter, and Δ R, Δ G, and Δ B are the preset step length, Δ x, of the R parameter, the G parameter and the B parameter, respectively _R Δy _R For the R parameter is as followsAccording to the change value of the chromaticity parameter, delta Y, caused by the preset step length iteration _R For the value of the change of the brightness parameter caused by the iteration of the R parameter according to the preset step length, the delta x _G ，Δy _G A chrominance parameter variation value delta Y is generated for the G parameter according to the preset step length iteration _G The change value of the brightness parameter caused by the G parameter according to the preset step length iteration is delta x _B ，Δy _B A chrominance parameter variation value delta Y is generated for the B parameter according to the preset step length iteration _B And the brightness parameter change value is the brightness parameter change value caused by the B parameter iteration according to the preset step length.
The method according to any of claims 8-10, wherein said converting said initial RGB to obtain intermediate RGB comprises:

performing Gamma transformation on the first initial RGB based on a first Gamma value to obtain a first linear RGB;

converting the first linear rgb according to a first transformation matrix to obtain the specified chrominance and luminance parameters;

converting the specified luminance and chrominance parameters according to a second transformation matrix to obtain a second linear rgb, wherein the second transformation matrix is generated according to the measured luminance parameters of the first display;

inverse Gamma transforming the second linear RGB based on a second Gamma value determined from measured brightness parameters of the first display to obtain the intermediate RGB.
An apparatus for display processing, the apparatus comprising:

the display device comprises an acquisition module, a display module and a display module, wherein the acquisition module is used for acquiring a first RGB of a first pixel to be displayed;

the processing module is used for acquiring a third display look-up table LUT corresponding to a first application mode, the third LUT corresponding to the first application mode is generated by fusion according to the first LUT and a second LUT corresponding to the first application mode, the third LUT comprises a one-to-one correspondence relationship between a plurality of first initial RGB and first display RGB, the first initial RGB corresponds to an initial chromaticity and brightness parameter, and the first display RGB corresponds to a chromaticity and brightness parameter of the first application mode; the first LUT comprises a one-to-one mapping relationship between a first plurality of initial RGB and target RGB, wherein the target RGB correspondingly specifies chromaticity and brightness parameters; the second LUT comprises a one-to-one mapping relationship between a plurality of second initial RGB and display RGB, the second initial RGB corresponds to the designated luminance and chrominance parameters, the display RGB is related to an application mode, the display RGB corresponding to the same second initial RGB in different application modes is different, and one application mode corresponds to one second LUT;

the processing module is further configured to determine, according to the third LUT, a second RGB corresponding to the first RGB in the first application mode, and send the second RGB to the first display for display.
The apparatus of claim 12, wherein the processing module is further configured to: and acquiring a third LUT corresponding to a second application mode, wherein the third LUT corresponding to the second application mode is generated by fusing the first LUT and the second LUT corresponding to the second application mode.
The apparatus of claim 12 or 13, wherein the obtaining module is further configured to:

retrieving the first LUT from a memory; or

Receiving the first LUT from a server; or

And receiving the corresponding target RGB from the server or acquiring the corresponding target RGB from the memory according to the preset first initial RGB, and further determining the first LUT.
The apparatus according to any of claims 12-14, wherein the obtaining module is further configured to:

obtaining a second LUT corresponding to the first application mode from a plurality of second LUTs stored by the memory; or receiving a second LUT corresponding to the first application mode from the server.
The apparatus of any one of claims 12-15, wherein the obtaining module is further configured to: receiving an updated second LUT from the server.
The apparatus of claim 16, wherein the obtaining module is specifically configured to: receiving the updated second LUT from the server at a preset time or upon receiving a preset instruction.
The apparatus according to any one of claims 12 to 17, wherein the processing module is specifically configured to:

acquiring a first initial RGB in the first LUT and the corresponding target RGB;

determining real-time first display RGB obtained by mapping the target RGB according to the second LUT;

generating the third LUT comprising a mapping of the first initial RGB and the first display RGB.
The apparatus according to any one of claims 12 to 18, wherein the processing module is specifically configured to:

converting the first initial RGB to obtain intermediate RGB;

performing iterative transformation on the intermediate RGB according to a preset step length to obtain the target RGB;

and determining the first LUT according to the one-to-one mapping relation of the first initial RGB and the target RGB.
The apparatus according to claim 19, wherein the processing module is specifically configured to:

s1: converting the RGBI according to the preset step length, and obtaining a corresponding chromaticity and brightness parameter change value;

s2: obtaining RGBI +1 according to the preset step length, and obtaining intermediate chromaticity and brightness parameters corresponding to the RGBI +1 according to the intermediate chromaticity and brightness parameters corresponding to the RGBI and the chromaticity and brightness parameter variation values;

s3: judging whether the difference value between the intermediate chromaticity and brightness parameters corresponding to the RGBI +1 and the designated chromaticity and brightness parameters is smaller than a preset threshold value or not; if the difference value between the intermediate chromaticity and luminance parameter corresponding to the RGBi +1 and the designated chromaticity and luminance parameter is not less than a preset threshold, i = i +1, and S1-S3 are repeatedly executed until the difference value between the intermediate chromaticity and luminance parameter corresponding to the RGBi +1 and the designated chromaticity and luminance parameter is less than the preset threshold, and when i =1, the RGBi is the intermediate RGB.
The apparatus of claim 20, wherein the processing module is specifically configured to: the RGB is obtained by calculation according to the following formula _i+1 Corresponding intermediate chrominance and luminance parameters:

wherein said xyY _i+1 Is the RGB _i+1 Corresponding intermediate chrominance and luminance parameters, said xyY _i As the RGB _i Corresponding intermediate chroma and brightness parameters, wherein the RGB comprises R parameters, G parameters and B parameters, the delta R, the delta G and the delta B are the R parameters, the preset step length of the G parameters and the preset step length of the B parameters, and the delta x _R ，Δy _R The variation value of the chromaticity parameter, delta Y, caused by the iteration of the R parameter according to the preset step length _R The delta x is a brightness parameter variation value caused by the iteration of the R parameter according to the preset step length _G ，Δy _G A chrominance parameter variation value delta Y is generated for the G parameter according to the preset step length iteration _G The change value of the brightness parameter, delta x, caused by the iteration of the G parameter according to the preset step length _B ，Δy _B Caused by iteration of said B parameter according to said preset step lengthValue of variation of a colorimetric parameter, Δ Y _B And the brightness parameter change value is the brightness parameter change value caused by the B parameter iteration according to the preset step length.
The apparatus according to any one of claims 19 to 21, wherein the processing module is specifically configured to:

performing Gamma transformation on the first initial RGB based on a first Gamma value to obtain a first linear RGB;

converting the first linear rgb according to a first transformation matrix to obtain the specified chrominance and luminance parameters;

converting the specified luminance and chrominance parameters according to a second transformation matrix to obtain a second linear rgb, wherein the second transformation matrix is generated according to the measured luminance parameters of the first display;

performing an inverse Gamma transformation on the second linear RGB based on a second Gamma value determined from a measured brightness parameter of the first display to obtain the intermediate RGB.
An apparatus for display processing, the apparatus comprising a processor and an interface circuit coupled to the processor, the processor being configured to execute code instructions stored in a memory to perform the method of any of claims 1 to 11.
A computer-readable storage medium, in which program instructions are stored, which, when run on a computer or a processor, cause the computer or the processor to carry out the method according to any one of claims 1-11.