Method for constructing color volume model and evaluation system

Abstract

The application discloses a color volume model construction method and an evaluation system. The method comprises the following steps: controlling a display device to display a test image according to a current display brightness; obtaining test results corresponding to a plurality of chrominance values on a plurality of chrominance rays; determining a plurality of target chrominance values according to the test results corresponding to the plurality of chrominance values; determining a JNCD plane corresponding to the current display brightness according to the plurality of target chrominance values; obtaining a next display brightness, taking the next display brightness as a new current display brightness, and re-executing the step of controlling the display device to display the test image according to the current display brightness until the current display brightness is greater than a brightness threshold; and constructing a JNCD color volume model according to the JNCD planes corresponding to a plurality of display brightnesses. The color volume model constructed by the application can accurately reflect the chrominance resolution range that can be perceived by a user's eyes when the display device displays at different display brightnesses, and is helpful for accurately evaluating the color performance of the display device.

Description

Technical Field

[0001] This application relates to the field of display technology, specifically to a method for constructing a color volume model and an evaluation system. Background Technology

[0002] With the rapid development of ultra-high-definition display technology, more and more users and industry manufacturers are considering the color performance of display devices, such as color reproduction accuracy, color gamut coverage, and color uniformity, as key factors in selecting and developing display equipment. Therefore, accurately quantifying the color performance of display devices has become one of the most pressing issues to be addressed. Summary of the Invention

[0003] This application provides a method for constructing a color volume model and an evaluation system. The constructed color volume model can accurately reflect the range of color resolution that the user's eye can perceive when the display device displays at different brightness levels, which helps to accurately evaluate the color performance of the display device.

[0004] The first aspect of this application discloses a method for constructing a color volume model, comprising:

[0005] Control the display device to display the test image according to the current display brightness;

[0006] Starting from a preset chromaticity reference point, the display device is controlled to adjust the chromaticity value of the test image along multiple chromaticity rays, and test results corresponding to multiple chromaticity values ​​on each chromaticity ray are obtained. The test results include a first result and / or a second result. The first result indicates that the human eye can perceive the chromaticity change produced by the test image, and the second result indicates that the human eye cannot perceive the chromaticity change produced by the test image.

[0007] Based on the test results corresponding to the multiple chromaticity values ​​on each chromaticity ray, multiple target chromaticity values ​​corresponding to each chromaticity ray are determined, and the test results corresponding to the target chromaticity values ​​are the first results;

[0008] Based on the multiple target chromaticity values ​​corresponding to the multiple chromaticity rays, the just-perceptible chromaticity difference (JNCD) plane corresponding to the current display brightness is determined;

[0009] Obtain the next display brightness and use the next display brightness as the new current display brightness. Repeat the step of controlling the display device to display the test image according to the current display brightness until the current display brightness is greater than the brightness threshold.

[0010] Based on the JNCD planes corresponding to multiple display brightness levels, a JNCD color volume model corresponding to the display device is constructed.

[0011] In the above technical solution, by acquiring the test results corresponding to multiple chromaticity values ​​on each chromaticity ray, and determining the JNCD plane corresponding to the current display brightness based on the test results as the target chromaticity value of the first result, the sensitivity of the human eye to chromaticity changes under the current display brightness can be accurately quantified. This allows for the acquisition of the range of chromaticity differences that the human eye can just perceive under the current display brightness. Based on the JNCD planes corresponding to multiple display brightnesses, a JNCD color volume model corresponding to the display device is constructed. This model can accurately reflect the range of chromaticity resolution that the human eye can perceive under full brightness and full chromaticity dimensions, making the evaluation of the color performance of the display device more in line with the human visual experience and improving the accuracy and reliability of color evaluation.

[0012] In some possible embodiments, determining the just-perceptible chromaticity difference (JNCD) plane corresponding to the current display brightness based on the multiple target chromaticity values ​​corresponding to the multiple chromaticity rays includes:

[0013] Based on the multiple target chromaticity values ​​corresponding to the multiple chromaticity rays, a first target chromaticity value and a second target chromaticity value corresponding to each of the multiple chromaticity rays are determined. The first target chromaticity value corresponding to the target chromaticity ray is the chromaticity value in the target chromaticity ray that is closest to the preset chromaticity reference point, and the second target chromaticity value corresponding to the target chromaticity ray is the chromaticity value in the target chromaticity ray that is farthest from the preset chromaticity reference point. The target chromaticity ray can be any chromaticity ray.

[0014] Based on the first target chromaticity values ​​corresponding to the multiple chromaticity rays, a first chromaticity curve is obtained by fitting.

[0015] Based on the second target chromaticity values ​​corresponding to the multiple chromaticity rays, a second chromaticity curve is obtained by fitting.

[0016] Based on the first chromaticity curve and the second chromaticity curve, construct the JNCD plane corresponding to the current display brightness.

[0017] In the above technical solution, by determining the target chromaticity values ​​closest to and farthest from the preset chromaticity reference point for each chromaticity ray, and fitting them to obtain a first chromaticity curve and a second chromaticity curve, the first chromaticity curve represents the minimum threshold boundary at which the human eye can just perceive chromaticity changes, while the second chromaticity curve reflects the limit range of chromaticity changes that the human eye can perceive. Thus, the JNCD plane constructed based on the first and second chromaticity curves not only contains information on the minimum perceptible difference, but also encompasses the dynamic range of chromaticity perception. This allows the JNCD plane to more comprehensively and accurately describe the color resolution capability of the display device under the current display brightness, and to better conform to the actual chromaticity visual perception law of the human eye, thereby improving the completeness and accuracy of the characterization of the color performance of the display device.

[0018] In some possible embodiments, the display device includes a backlight module;

[0019] Before controlling the display device to adjust the chromaticity values ​​of the test image along multiple chromaticity rays starting from a preset chromaticity reference point, the method further includes:

[0020] Based on the current display brightness, determine the theoretical backlight data of the backlight module;

[0021] Obtain the current actual backlight data of the backlight module;

[0022] Calculate the difference between the theoretical backlight data and the current actual backlight data;

[0023] If the difference is greater than a preset difference threshold, the backlight module is adjusted according to the difference, and the step of obtaining the current actual backlight data of the backlight module is repeated until the difference is less than or equal to the preset difference threshold.

[0024] In the above technical solution, by continuously adjusting the current actual backlight data of the backlight module before adjusting the chromaticity value along the chromaticity ray, the display brightness is not accurate due to the deviation between the actual backlight and the theoretical backlight of the backlight module. This avoids introducing additional brightness change interference during the chromaticity test, ensuring that the chromaticity value measurement results corresponding to each chromaticity ray are true and reliable, thereby improving the accuracy and reliability of the constructed JNCD plane.

[0025] In some possible embodiments, after controlling the display device to adjust the chromaticity values ​​of the test image along multiple chromaticity rays starting from a preset chromaticity reference point, the method further includes:

[0026] If the measurement result corresponding to the current chromaticity value is the first result, the actual chromaticity value corresponding to the display device is obtained by the colorimeter, and the current ambient brightness corresponding to the current chromaticity value is obtained.

[0027] After determining the just-perceptible chromaticity difference (JNCD) plane corresponding to the current display brightness based on the multiple target chromaticity values ​​corresponding to the multiple chromaticity rays, the method further includes:

[0028] Based on the actual chromaticity values ​​corresponding to multiple target chromaticity values ​​and the corresponding current ambient brightness, the JNCD plane corresponding to the current display brightness is chromaticity drift corrected to obtain the corrected JNCD plane.

[0029] The step of constructing the JNCD color volume model corresponding to the display device based on multiple JNCD planes corresponding to different display brightness levels includes:

[0030] Based on the corrected JNCD planes corresponding to the multiple display brightness levels, a JNCD color volume model corresponding to the display device is constructed.

[0031] In the above technical solution, by using the actual chromaticity values ​​corresponding to multiple target chromaticity values ​​and the corresponding current ambient brightness, the JNCD plane corresponding to the current display brightness is used to correct chromaticity drift. This can effectively eliminate the evaluation error caused by the chromaticity output offset of the display device, making the corrected JNCD plane more consistent with the human eye's color perception rules in real scenes. As a result, the JNCD color volume model constructed based on the multi-brightness corrected JNCD plane can more accurately and completely reflect the color resolution capability of the display device under different brightness and actual working conditions, thus improving the authenticity and reliability of the JNCD color volume model.

[0032] In some possible embodiments, after controlling the display device to adjust the chromaticity values ​​of the test image along multiple chromaticity rays starting from a preset chromaticity reference point, the method further includes:

[0033] If the measurement result corresponding to the current chromaticity value is the first result, the actual display brightness of the display device corresponding to the measurement obtained by the colorimeter is obtained;

[0034] After constructing the JNCD color volume model corresponding to the display device based on multiple JNCD planes corresponding to different display brightness levels, the method further includes:

[0035] Based on the current display brightness and the actual display brightness corresponding to the multiple target chromaticity values, the perception correction parameters corresponding to the multiple target chromaticity values ​​are determined respectively;

[0036] Based on the perception correction parameters corresponding to the multiple target chromaticity values, the perceived display brightness corresponding to the multiple target chromaticity values ​​is determined, and the current display brightness corresponding to the multiple target chromaticity values ​​in the JNCD color volume model is corrected to the corresponding perceived display brightness.

[0037] In the above technical solution, the actual display brightness of the display device is collected simultaneously when the first result of the color change that can be perceived by the human eye is obtained, and the perception correction parameters are determined based on the relationship between the actual display brightness and the current display brightness. This corrects the display brightness corresponding to each target color value in the JNCD color volume model to a more realistic perceived display brightness. This can effectively eliminate model errors caused by the brightness output deviation of the display device or the nonlinear perception characteristics of the human eye for different brightness levels. As a result, the corrected JNCD color volume model can more accurately describe the perception boundary of color differences under actual viewing conditions, further improving the accuracy and reliability of the JNCD color volume model.

[0038] In some possible embodiments, determining the perceived display brightness corresponding to each of the plurality of target chromaticity values ​​based on the perceived correction parameters corresponding to each of the plurality of target chromaticity values ​​includes:

[0039] The initial perceived brightness is obtained by performing a power operation based on the current display brightness and a preset power law exponent.

[0040] The product of the preset scaling parameters, the initial perceived brightness, and the perceived correction parameters corresponding to the multiple target chromaticity values ​​is calculated to obtain the perceived display brightness corresponding to the multiple target chromaticity values.

[0041] In the above technical solution, by introducing the power law relationship from Stevens' color appearance theory, that is, the human eye's perception of brightness follows a power function rather than a simple linear mapping, the initial perceived brightness is obtained by exponentiation of the current display brightness and the preset power law exponent. Then, by multiplying the preset scaling parameters with the perception correction parameters corresponding to each target chromaticity value, the physical display brightness is accurately converted into a perceived display brightness that conforms to the subjective perception characteristics of the human eye. This can improve the matching degree between the JNCD color volume model and the actual response characteristics of the human visual system. The corrected JNCD color volume model can not only reflect the perceptible threshold of chromaticity difference, but also accurately describe the nonlinear change law of color perception under different brightness levels, thus achieving a more accurate and realistic quantitative evaluation of the color performance of display devices.

[0042] In some possible embodiments, the step of controlling the display device to adjust the chromaticity values ​​of the test image along multiple chromaticity rays, starting from a preset chromaticity reference point, and obtaining the test results corresponding to the multiple chromaticity values ​​on each chromaticity ray, includes:

[0043] The chromaticity value corresponding to a preset chromaticity reference point is used as the current chromaticity value, and the display device is controlled to adjust the chromaticity value of the test image to the current chromaticity value.

[0044] Obtain the test result corresponding to the current chromaticity value;

[0045] Along the target chromaticity ray, the current chromaticity value is updated according to the first update step size to obtain a new current chromaticity value, and the step of controlling the display device to adjust the chromaticity value of the test image to the current chromaticity value is re-executed until the current chromaticity value is greater than the chromaticity threshold corresponding to the target chromaticity ray.

[0046] In the above technical solution, by taking a preset chromaticity reference point as the starting point, iteratively updating the current chromaticity value along the target chromaticity ray according to the first update step size, and obtaining the test results in real time after each adjustment, until the chromaticity threshold is reached, it can be ensured that the critical point from imperceptible to just perceptible to the human eye can be accurately captured on the hues corresponding to multiple chromaticity rays. This provides a reliable and accurate data foundation for subsequently determining the first target chromaticity value and the second target chromaticity value on each chromaticity ray, thereby improving the accuracy and robustness of JNCD plane construction, and enabling the final generated JNCD color volume model to more finely depict the true color resolution capability of the display device at each brightness level.

[0047] In some possible embodiments, the control display device displays the test image according to the current display brightness, including:

[0048] Under the first ambient brightness, the display device is controlled to display the test image according to the current display brightness;

[0049] The step of constructing the JNCD color volume model corresponding to the display device based on multiple JNCD planes corresponding to different display brightness levels includes:

[0050] Based on the JNCD planes corresponding to the plurality of display brightnesses, construct a JNCD color volume model of the display device and the first ambient brightness.

[0051] The method further includes:

[0052] Obtain JNCD color volume models corresponding to multiple ambient brightness levels, wherein the multiple ambient brightness levels include at least the first ambient brightness and the second ambient brightness, and the first ambient brightness is greater than the second ambient brightness.

[0053] Based on the JNCD color volume models corresponding to the multiple ambient brightness levels, the color performance parameters of the display device corresponding to the first ambient brightness are determined.

[0054] In the above technical solution, since ambient brightness affects the user's visual perception and color difference discrimination ability when viewing the display device, the higher the ambient brightness, the fewer colors the user can distinguish from the display device and the lower the sensitivity to color difference perception. Consequently, the test results that can be just perceived will also change. Therefore, by obtaining JNCD color volume models corresponding to multiple ambient brightness levels and determining the color performance parameters of the display device corresponding to the first ambient brightness based on the JNCD color volume models corresponding to multiple ambient brightness levels, the influence of ambient brightness on the human eye's color perception ability can be quantified. This allows the constructed JNCD color volume model to not only reflect the color resolution range of the display device itself under different display brightness levels, but also reveal the modulation effect of changes in ambient lighting conditions on the color difference that can be just perceived by the user. This more realistically simulates the interaction between the color performance of the display device and the human eye's visual perception in actual viewing scenarios, improving the accuracy and practicality of the evaluation of the display device's color performance and model construction.

[0055] In some possible embodiments, the color performance parameters include volume collapse rate and / or hue shift.

[0056] The step of determining the color performance parameters of the display device corresponding to the first ambient brightness based on the JNCD color volume models corresponding to the multiple ambient brightness levels includes:

[0057] Obtain the first volume data of the JNCD color volume model corresponding to the first ambient brightness, and the second volume data of the color volume model corresponding to the second ambient brightness;

[0058] Based on the first volume data and the second volume data, determine the volume collapse rate of the display device corresponding to the first ambient brightness;

[0059] And / or,

[0060] Obtain the first hue value corresponding to the test chromaticity value in the JNCD color volume model corresponding to the first ambient brightness, and the second hue value corresponding to the test chromaticity value in the color volume model corresponding to the second ambient brightness, wherein the test chromaticity value is one or more of the plurality of target chromaticity values;

[0061] Based on the first hue value and the second hue value corresponding to the test chromaticity value, determine the hue shift of the display device and the test chromaticity value under the first ambient brightness.

[0062] The color performance parameters also include JNCD density; the method further includes:

[0063] Based on the JNCD color volume model corresponding to the first ambient brightness and the current display brightness, the JNCD density of the display device corresponding to the current display brightness is determined.

[0064] In the above technical solution, by introducing color performance parameters such as volume collapse rate, hue shift, and JNCD density, the degree of shrinkage of the resolvable color range of the display device caused by changes in ambient brightness, the degree of interference of changes in ambient brightness on the hue accuracy of the display device, and the fineness of color resolution of the display device under the current display brightness and the first ambient brightness can be reflected intuitively and accurately in numerical form. This provides a standardized and objective measurement basis for evaluating the color performance of the display device. Moreover, the above color performance parameters all correspond directly to the subjective visual perception of the human eye when actually viewing the display device. This can more comprehensively reflect the degree of matching between the objective performance of the display device's color presentation under changes in ambient brightness in actual use scenarios and the user's subjective perception. This makes the evaluation of color performance based on the JNCD color volume model more comprehensive, realistic, and of greater practical reference value.

[0065] A second aspect of this application discloses an evaluation system including a memory and a processor, wherein the memory stores a computer program that, when executed by the processor, causes the processor to perform the method as described in any of the above embodiments. Attached Figure Description

[0066] To more clearly illustrate the implementation methods in some embodiments or related technologies of this application, the accompanying drawings used in the description of the embodiments or related technologies will be briefly introduced below. Obviously, the accompanying drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings.

[0067] Figure 1 An application scenario diagram illustrating a method for constructing a color volume model provided in an embodiment of this application;

[0068] Figure 2 A flowchart illustrating a method for constructing a color volume model as provided in an embodiment of this application;

[0069] Figure 3 A flowchart for adjusting the backlight of a backlight module provided in an embodiment of this application;

[0070] Figure 4 A flowchart for obtaining test results corresponding to each chromaticity value provided in this application embodiment;

[0071] Figure 5A schematic diagram illustrating the determination of multiple target chromaticity values ​​corresponding to a target chromaticity ray provided in an embodiment of this application;

[0072] Figure 6 A flowchart for constructing the JNCD plane corresponding to the current display brightness, provided in an embodiment of this application;

[0073] Figure 7 A schematic diagram of the first chromaticity curve and the second chromaticity curve provided for embodiments of this application;

[0074] Figure 8 A schematic diagram of a portion of the JNCD color volume model provided in the embodiments of this application;

[0075] Figure 9 A flowchart for correcting the JNCD color volume model based on actual chromaticity values ​​provided in this application embodiment;

[0076] Figure 10 A flowchart illustrating the correction of the JNCD color volume model based on actual display brightness, provided in this application embodiment;

[0077] Figure 11 This is a flowchart illustrating the process of obtaining color performance parameters of a display device, as provided in an embodiment of this application. Detailed Implementation

[0078] To make the objectives, implementation methods and advantages of this application clearer, the exemplary implementation methods of this application will be clearly and completely described below with reference to the accompanying drawings of the exemplary embodiments of this application. Obviously, the described exemplary embodiments are only some embodiments of this application, and not all embodiments.

[0079] It should be noted that the brief descriptions of terms in this application are only for the convenience of understanding the embodiments described below, and are not intended to limit the embodiments of this application. Unless otherwise stated, these terms should be understood in their ordinary and common meaning.

[0080] Furthermore, the terms “comprising” and “having”, and any variations thereof, are intended to cover but not exclusively include, for example, a product or device that includes a series of components is not necessarily limited to those that are explicitly listed, but may include other components that are not explicitly listed or that are inherent to such product or device.

[0081] Figure 1 This diagram illustrates an application scenario for a method of constructing a color volume model provided in an embodiment of this application. For example... Figure 1 As shown, the method for constructing a color volume model can be applied to an evaluation system 100. The evaluation system 100 may include a display device 110, a control device 120, and a data acquisition device 130. The control device 120 is connected to the display device 110 and the data acquisition device 130, respectively.

[0082] Display device 110 is used to display test images, control device 120 is used to construct a color volume model based on the user's evaluation results of the test images displayed by display device 110 and the display brightness and chromaticity values ​​of display device 110 when displaying test images, and acquisition device 130 is used to acquire the actual display brightness and chromaticity values ​​of display device 110 when displaying test images.

[0083] The color volume model refers to a three-dimensional quantitative model constructed based on the brightness and chromaticity dimensions of the display device 110. It is used to characterize the color gamut coverage or color reproduction capability of the display device 110 at different brightness levels. It can transform abstract color perception into a quantifiable and analyzable three-dimensional spatial volume model.

[0084] In some embodiments, the color volume model is a three-dimensional spatial coordinate system constructed with the chromaticity value of the display device 110 as the horizontal plane (i.e., the chromaticity plane) and the display brightness of the display device 110 as the vertical axis perpendicular to the horizontal plane.

[0085] In some embodiments, chromaticity values ​​may include u'-v' chromaticity coordinates, where u' may be the abscissa of a CIE 1976 uniform chromaticity scale diagram, and v' may be the ordinate of a CIE 1976 uniform chromaticity scale diagram. Optionally, chromaticity values ​​may also be other chromaticity coordinates, but are not limited thereto. Unless otherwise specified below, chromaticity values ​​are all u'-v' chromaticity coordinates.

[0086] In some embodiments, the user's evaluation result of the test image displayed by the display device 110 includes Just Noticeable Color Difference (JNCD), which is the minimum critical value of color change at which the human eye can just distinguish the color difference between the test image before and after the color change when the color of the test image displayed by the display device 110 changes.

[0087] In some embodiments, the control device 120 may be an electronic device such as a computer or a smart terminal, capable of receiving measured data transmitted by the acquisition device 130, retrieving the operating parameters of the display device 110, and obtaining the user's evaluation results of the test images displayed by the display device 110.

[0088] In some embodiments, the acquisition device 130 may include a colorimeter for acquiring the actual brightness and chromaticity values ​​displayed by the display device 110 when displaying a test image.

[0089] In some embodiments, the display device 110 may be of various types, such as a liquid crystal display device, an organic light-emitting diode display device, or a quantum dot display device.

[0090] In some embodiments, the display device 110 may be a display device with high dynamic range (HDR).

[0091] High Dynamic Range (HDR) is a display technology standard that aims to reproduce the complete brightness range from extremely dark shadows to extremely bright highlights in the real world, as well as the true color details within that range, by expanding the brightness range, color gamut, and color depth of display devices. Compared to traditional Standard Dynamic Range (SDR) display devices, HDR display devices have a wider brightness range, a broader color gamut, and a higher color depth.

[0092] It's important to note that while HDR displays can achieve high contrast and rich color reproduction by expanding the brightness range to better match human visual perception, significant differences exist in the hardware calibration and color gamut coverage of HDR displays across different brands and specifications. This results in varying HDR color reproduction capabilities, leading to different color gamuts perceived by the human eye from different HDR displays. Therefore, accurately quantifying the color performance of HDR displays has become a crucial issue that urgently needs to be addressed.

[0093] In this embodiment, by obtaining the test results corresponding to multiple chromaticity values ​​on each chromaticity ray, and determining the plane corresponding to the current display brightness based on the target chromaticity value of the test result as the first result, the sensitivity of the human eye to chromaticity changes under the current display brightness can be accurately quantified. This allows for the acquisition of the range of chromaticity differences that the human eye can just perceive under the current display brightness. Based on the JNCD planes corresponding to multiple display brightnesses, a JNCD color volume model corresponding to the display device is constructed. This model can accurately reflect the range of chromaticity resolution that the human eye can perceive under full brightness and full chromaticity dimensions, making the evaluation of the color performance of the display device more in line with the human visual experience and improving the accuracy and reliability of color evaluation.

[0094] Figure 2 A flowchart illustrating a method for constructing a color volume model as provided in an embodiment of this application. Figure 2 As shown, the method may include the following steps:

[0095] Step 202: Control the display device to display the test image according to the current display brightness.

[0096] Current display brightness refers to the display brightness that the display device should output according to control instructions or preset parameters, that is, the brightness value that the display device needs to achieve and present in the current frame or the current display stage.

[0097] Test images may include solid color block images, grayscale images, or color calibration images, etc., without specific limitations. For example, a test image may be an image with a gray background and a white circular area in the foreground.

[0098] In some embodiments, when the display device is a liquid crystal display device, the display device includes a backlight module. After the controller controls the display device to display the test image at the current display brightness, the controller also needs to adjust the backlight of the backlight module so that the actual display brightness of the display device is close to the current display brightness.

[0099] Figure 3 This is a flowchart illustrating the adjustment of the backlight of a backlight module, provided as an embodiment of this application. Figure 3 As shown, the method may further include the following steps:

[0100] Step 301: Determine the theoretical backlight data of the backlight module based on the current display brightness.

[0101] The controller can pre-establish and store the correspondence between display brightness and backlight data. After obtaining the current display brightness, the controller can directly obtain the theoretical backlight data of the backlight module through this correspondence.

[0102] Alternatively, the controller can deduce the theoretical backlight data of the backlight module based on the optical mapping relationship between display brightness, backlight brightness, and LCD panel transmittance.

[0103] In some embodiments, the controller can determine the theoretical backlight data of the backlight area corresponding to the chromaticity reference point in the backlight module based on the current display brightness corresponding to the chromaticity reference point, so as to calibrate the backlight of the backlight area corresponding to the chromaticity reference point.

[0104] Step 303: Obtain the current actual backlight data of the backlight module.

[0105] The controller can directly read the operating parameters of the backlight module to obtain the current actual backlight data of the backlight module.

[0106] Step 305: Calculate the difference between the theoretical backlight data and the current actual backlight data.

[0107] Step 307: Determine whether the difference is greater than the preset difference threshold. If yes, proceed to step 309; otherwise, proceed to step 311.

[0108] Understandably, if the difference is greater than the preset difference threshold, it indicates that the output intensity of the current backlight module is insufficient or excessive, failing to meet the display brightness requirements. The actual display brightness of the display device does not match the display brightness that should be output, affecting the color reproduction accuracy and overall display effect of the display device. If the difference is less than or equal to the preset difference threshold, it indicates that the output intensity of the current backlight module matches the target requirements of the current display brightness and is in a reasonable working state. The deviation between the actual display brightness of the display device and the display brightness that should be output is within the allowable range, and the display can be displayed normally.

[0109] Step 309: Adjust the backlight module according to the difference, and repeat step 301.

[0110] In some embodiments, the controller adjusts the backlight driving parameters of the backlight module according to the magnitude and direction of the difference. The backlight driving parameters include at least one of the backlight driving current, the backlight pulse current duty cycle, and the backlight driving voltage.

[0111] When the difference is positive, the actual display brightness is too low. Therefore, the controller can determine the adjustment amount of the backlight drive parameters according to the magnitude of the difference to enhance the backlight output intensity. Similarly, when the difference is negative, the actual display brightness is too high. Therefore, the controller can determine the adjustment amount of the backlight drive parameters according to the magnitude of the difference to reduce the backlight output intensity.

[0112] Step 311: Adjust the backlight of the backlight module.

[0113] In the above technical solution, by continuously adjusting the current actual backlight data of the backlight module before adjusting the chromaticity value along the chromaticity ray, the display brightness is not accurate due to the deviation between the actual backlight and the theoretical backlight of the backlight module. This avoids introducing additional brightness change interference during the chromaticity test, ensuring that the chromaticity value measurement results corresponding to each chromaticity ray are true and reliable, thereby improving the accuracy and reliability of the constructed JNCD plane.

[0114] Step 204: Starting from a preset chromaticity reference point, control the display device to adjust the chromaticity value of the test image along multiple chromaticity rays, and obtain the test results corresponding to the multiple chromaticity values ​​on each chromaticity ray.

[0115] A chromaticity reference point can refer to the starting position of each chromaticity ray, and each chromaticity ray radiates outward from the chromaticity reference point.

[0116] For example, the chromaticity reference point can be the D65 white point, and when the chromaticity value is u'-v' chromaticity coordinates, the u'-v' chromaticity coordinates corresponding to the chromaticity reference point D65 white point can be u' = 0.2009, v' = 0.4610.

[0117] The test results include a first result and / or a second result, where the first result represents chromaticity changes in the test image that are perceptible to the human eye, and the second result represents chromaticity changes in the test image that are imperceptible to the human eye.

[0118] Figure 4 This is a flowchart illustrating the process of obtaining test results corresponding to various chromaticity values, as provided in an embodiment of this application. Figure 4 As shown, step 204 includes steps 402 to 408.

[0119] Step 402: Use the chromaticity value corresponding to the preset chromaticity reference point as the current chromaticity value.

[0120] Step 404: Control the display device to adjust the chromaticity value of the test image to the current chromaticity value.

[0121] Step 406: Obtain the test result corresponding to the current chromaticity value.

[0122] If the user can perceive a chromaticity change when the chromaticity value of the test image is adjusted to the current chromaticity value, the user can press the first button to indicate that the chromaticity change is perceptible in the test image with the current chromaticity value. The controller, by obtaining feedback from the first button, determines the test result corresponding to the current chromaticity value as the first result and continues to execute steps 408 to 410. If the user cannot perceive a chromaticity change, the user can press the second button so that the controller, based on the feedback from the second button, determines the test result corresponding to the current chromaticity value as the second result and executes steps 408 to 410.

[0123] Step 408: Determine whether the current chromaticity value is greater than the chromaticity threshold corresponding to the target chromaticity ray. If not, proceed to step 410; if yes, proceed to step 412.

[0124] Step 410: Update the current chromaticity value along the target chromaticity ray according to the first update step size to obtain a new current chromaticity value, and then re-execute step 404.

[0125] In some embodiments, when the chromaticity value is u'-v' chromaticity coordinates, the first update step size can be a fixed distance moved each time along the target chromaticity ray direction. The first update step size includes a first update step size corresponding to the u' horizontal axis and a first update step size corresponding to the v' vertical axis.

[0126] For example, the first update step size corresponding to the horizontal axis u' is The first update step size corresponding to the vertical axis v' is The chromaticity coordinates corresponding to the current chromaticity value are In this case, the current chromaticity value is updated according to the first update step size, resulting in the chromaticity coordinates corresponding to the new current chromaticity value. .

[0127] Optionally, the first update step size can also be dynamically adjusted based on the color difference between the current chromaticity value and the chromaticity value corresponding to the chromaticity reference point, but is not limited to this.

[0128] Step 412: Complete the test of the target chromaticity rays.

[0129] Optionally, the controller can also update the current chromaticity value along the target chromaticity ray according to the first update step size. After obtaining the new current chromaticity value, it can determine whether the new current chromaticity value is greater than the chromaticity threshold corresponding to the target chromaticity ray. If it is not greater, the controller can adjust the chromaticity value of the test image to the current chromaticity value and obtain the test result corresponding to the current chromaticity value. If it is greater, the test of the target chromaticity ray is completed.

[0130] In the above technical solution, by taking a preset chromaticity reference point as the starting point, iteratively updating the current chromaticity value along the target chromaticity ray according to the first update step size, and obtaining the test results in real time after each adjustment, until the chromaticity threshold is reached, it can be ensured that the critical point from imperceptible to just perceptible to the human eye can be accurately captured on the hues corresponding to multiple chromaticity rays. This provides a reliable and accurate data foundation for subsequently determining the first target chromaticity value and the second target chromaticity value on each chromaticity ray, thereby improving the accuracy and robustness of JNCD plane construction, and enabling the final generated JNCD color volume model to more finely depict the true color resolution capability of the display device at each brightness level.

[0131] Step 206: Determine multiple target chromaticity values ​​corresponding to each chromaticity ray based on the test results corresponding to multiple chromaticity values ​​on each chromaticity ray.

[0132] The test result corresponding to the target chromaticity value is the first result.

[0133] The controller can use multiple chromaticity values ​​that are the first result on each chromaticity ray as the target chromaticity value corresponding to each chromaticity ray.

[0134] In some embodiments, when the chromaticity value is u'-v' chromaticity coordinates, the controller can mark the target chromaticity value corresponding to the target chromaticity ray in the u'-v' chromaticity scale diagram.

[0135] Figure 5 This is a schematic diagram illustrating the determination of multiple target chromaticity values ​​corresponding to a target chromaticity ray, provided as an embodiment of this application. For example... Figure 5As shown, in the u'-v' chromaticity scale diagram, with the D65 white point u'= 0.2009 and v'= 0.4610 as the chromaticity reference point, in the target chromaticity ray corresponding to red, the chromaticity coordinates A, B, C and D corresponding to the four target chromaticity values ​​with the test result of the first result are marked with solid black dots, while the chromaticity coordinates corresponding to the chromaticity values ​​with the test result of the second result are not marked.

[0136] Step 208: Determine the just-perceptible chromaticity difference (JNCD) plane corresponding to the current display brightness based on the multiple target chromaticity values ​​corresponding to the multiple chromaticity rays.

[0137] Figure 6 This is a flowchart illustrating the construction of the JNCD plane corresponding to the current display brightness, provided as an embodiment of this application. For example... Figure 5 As shown, step 208 may include steps 602 to 608.

[0138] Step 602: Determine the first target chromaticity value and the second target chromaticity value corresponding to the multiple chromaticity rays based on the multiple target chromaticity values ​​corresponding to the multiple chromaticity rays respectively.

[0139] The first target chromaticity value corresponding to the target chromaticity ray is the chromaticity value in the target chromaticity ray that is closest to the preset chromaticity reference point, and the second target chromaticity value corresponding to the target chromaticity ray is the chromaticity value in the target chromaticity ray that is farthest from the preset chromaticity reference point. The target chromaticity ray can be any chromaticity ray.

[0140] In some embodiments, during the test, when the current chromaticity value is updated along the target chromaticity ray according to the first update step size, the controller can sequentially store the target chromaticity values ​​for which the test result is the first result in the update order, and from the stored multiple target chromaticity values, take the target chromaticity value that is first in the order as the first target chromaticity value, and take the target chromaticity value that is last in the order as the second target chromaticity value.

[0141] Step 604: Based on the first target chromaticity values ​​corresponding to the multiple chromaticity rays, a first chromaticity curve is obtained by fitting.

[0142] Step 606: Based on the second target chromaticity values ​​corresponding to the multiple chromaticity rays, a second chromaticity curve is obtained by fitting.

[0143] The first chromaticity curve is a closed curve formed by connecting the chromaticity coordinates of the first target chromaticity value that is closest to the preset chromaticity reference point on multiple chromaticity rays. Within the area enclosed by the first chromaticity curve, the human eye cannot distinguish the chromaticity difference between the corresponding chromaticity value and the chromaticity reference point. Only when the chromaticity value exceeds the enclosed range of the first chromaticity curve can the human eye just perceive the chromaticity difference from the reference point.

[0144] The second chromaticity curve is a closed curve formed by sequentially connecting the chromaticity coordinates of the second target chromaticity value that is farthest from the preset chromaticity reference point on multiple chromaticity rays.

[0145] In some embodiments, the controller can sequentially connect multiple chromaticity rays to the chromaticity coordinates corresponding to the first target chromaticity values ​​to obtain a first initial curve. Then, spline interpolation or least squares regression algorithms are used to fit the first initial curve to optimize its smoothness and data fit, thus obtaining a first chromaticity curve. The second chromaticity curve is similar and will not be described in detail here.

[0146] Step 608: Construct the JNCD plane corresponding to the current display brightness based on the first chromaticity curve and the second chromaticity curve.

[0147] The JNCD plane is the effective color range that the human eye can stably distinguish from a display device under the current display brightness.

[0148] In one implementation, the controller can use the annular region between the first chromaticity curve and the second chromaticity curve as the JNCD plane corresponding to the current display brightness.

[0149] Figure 7 This is a schematic diagram of the first and second chromaticity curves provided for embodiments of this application. Figure 7 As shown, the first chromaticity curve is formed by sequentially connecting the chromaticity coordinates of the first target chromaticity value (u'= 0.2009, v'= 0.4610) on multiple chromaticity rays, and the second chromaticity curve is formed by sequentially connecting the chromaticity coordinates of the second target chromaticity value (u'= 0.2009, v'= 0.4610) on multiple chromaticity rays, and the third chromaticity curve is formed by sequentially connecting the chromaticity coordinates of the second target chromaticity value (u'= 0.2009, v'= 0.4610) on multiple chromaticity rays.

[0150] In the above technical solution, by determining the target chromaticity values ​​closest to and farthest from the preset chromaticity reference point for each chromaticity ray, and fitting them to obtain a first chromaticity curve and a second chromaticity curve, the first chromaticity curve represents the minimum threshold boundary at which the human eye can just perceive chromaticity changes, while the second chromaticity curve reflects the limit range of chromaticity changes that the human eye can perceive. Thus, the JNCD plane constructed based on the first and second chromaticity curves not only contains information on the minimum perceptible difference, but also encompasses the dynamic range of chromaticity perception. This allows the JNCD plane to more comprehensively and accurately describe the color resolution capability of the display device under the current display brightness, and to better conform to the actual chromaticity visual perception law of the human eye, thereby improving the completeness and accuracy of the characterization of the color performance of the display device.

[0151] Step 210: Determine whether the current display brightness is greater than the brightness threshold. If not, proceed to step 212; if yes, proceed to step 214.

[0152] Step 212: Obtain the next display brightness and use it as the new current display brightness. Then, re-execute step 202.

[0153] In some embodiments, the controller may update the current display brightness according to the second update step size to obtain the next display brightness, and use the next display brightness as the new current display brightness to re-execute step 202.

[0154] Alternatively, the controller can pre-store multiple display brightness values ​​arranged from smallest to largest, and the maximum value among the multiple display brightness values ​​is the brightness threshold. If the current display brightness is not greater than the brightness threshold, that is, if the current display brightness is not the last display brightness value in the sequence, the controller can take the display brightness value arranged next to the current display brightness value as the new current display brightness value and re-execute step 202.

[0155] Step 214: Construct a JNCD color volume model corresponding to the display device based on the JNCD planes corresponding to the multiple display brightness levels.

[0156] In some embodiments, when the chromaticity values ​​are u'-v' chromaticity coordinates, the controller can construct a three-dimensional spatial coordinate system with u' as the horizontal axis, v' as the vertical axis, and the display brightness as the Z axis. This allows the controller to sequentially stack multiple JNCD planes corresponding to the display brightness along the Z axis according to the order of the multiple display brightness values, thereby constructing a JNCD color volume model corresponding to the display device.

[0157] Optionally, for the uncovered display brightness range between the JNCD planes corresponding to two adjacent display brightness levels, the controller can calculate the first chromaticity curve and the second chromaticity curve of any display brightness in the uncovered display brightness range based on the first chromaticity curve and the second chromaticity curve corresponding to the two adjacent display brightness levels through linear interpolation or nonlinear fitting, and then obtain the corresponding JNCD plane.

[0158] Figure 8 This is a schematic diagram of a portion of the JNCD color volume model provided in an embodiment of this application. For example... Figure 8As shown, the four JNCD planes corresponding to different display brightness levels are stacked sequentially along the Z-axis, and the higher the display brightness, the smaller the JNCD planes corresponding to these four brightness levels. It should be noted that the size of the JNCD planes has a non-linear relationship with the display brightness. At low display brightness, the human eye has a high JNCD threshold for chromatic differences, and can only distinguish a few colors with extremely high saturation, resulting in a smaller perceptible color range, i.e., a smaller JNCD plane. As the display brightness gradually increases from low to medium, the red, green, and blue cone cells in the human eye are activated sequentially, rapidly increasing the sensitivity to different wavelengths of light. The JNCD threshold decreases significantly, and the human eye can distinguish more fine chromatic differences, causing the JNCD plane to expand rapidly. Conversely, as the display brightness gradually increases from medium to high, the saturation of cone cells, the pupillary constriction caused by high-brightness screens, and retinal glare effects further increase the human eye's JNCD threshold for chromatic differences, leading to a shrinking of the JNCD plane.

[0159] In this embodiment, by obtaining the test results corresponding to multiple chromaticity values ​​on each chromaticity ray, and determining the JNCD plane corresponding to the current display brightness based on the target chromaticity value of the test result as the first result, the sensitivity of the human eye to chromaticity changes under the current display brightness can be accurately quantified. This allows for the acquisition of the range of chromaticity differences that the human eye can just perceive under the current display brightness. Based on the JNCD planes corresponding to multiple display brightnesses, a JNCD color volume model corresponding to the display device is constructed. This model can accurately reflect the range of chromaticity resolution that the human eye can perceive under full brightness and full chromaticity dimensions, making the evaluation of the color performance of the display device more in line with the human visual experience and improving the accuracy and reliability of color evaluation.

[0160] In some embodiments, even if the controller can control the display device to adjust the chromaticity value of the test image to the current chromaticity value, the chromaticity drift error of the display device itself will cause the measured chromaticity value of the actual output image of the display device to be inconsistent with the preset current chromaticity value, which will lead to a deviation in the test results obtained based on the preset current chromaticity value. Therefore, the controller needs to correct the JNCD plane according to the actual chromaticity value to ensure the accuracy and reliability of the JNCD color volume model.

[0161] Figure 9 A flowchart illustrating the correction of the JNCD color volume model based on actual chromaticity values, provided for embodiments of this application. Figure 9 As shown, the method may include the following steps:

[0162] Step 901: If the measurement result corresponding to the current chromaticity value is obtained as the first result, obtain the actual chromaticity value corresponding to the display device collected by the colorimeter, and obtain the current ambient brightness corresponding to the current chromaticity value.

[0163] If the controller obtains the measurement result corresponding to the current chromaticity value as the first result, it can simultaneously control the colorimeter to collect the actual chromaticity value corresponding to the display device and the current ambient brightness.

[0164] Optionally, the colorimeter may be a spectroradiometric colorimeter or other types of colorimeter, without specific limitations.

[0165] Step 903: After obtaining the JNCD plane corresponding to the current display brightness, perform chromaticity drift correction on the JNCD plane corresponding to the current display brightness according to the actual chromaticity values ​​corresponding to multiple target chromaticity values ​​and the corresponding current ambient brightness, and obtain the corrected JNCD plane.

[0166] In some embodiments, when the chromaticity value is in u'-v' chromaticity coordinates, the controller can acquire multiple sets of actual chromaticity values ​​of samples, current chromaticity values ​​of samples, and ambient brightness of samples. Then, it uses polynomial regression to fit the chromaticity shift on the u' horizontal axis between the actual and current chromaticity values ​​of samples and the ambient brightness of samples, obtaining the model parameters corresponding to the polynomial regression. After obtaining the JNCD plane corresponding to the current display brightness, the controller can determine the chromaticity shift corresponding to the u' horizontal axis based on the current ambient brightness and the model parameters corresponding to the polynomial regression, and thus make corrections based on the chromaticity shift corresponding to the u' horizontal axis and the corresponding current chromaticity value on the JNCD plane. Similarly, the controller can make corrections based on the chromaticity shift corresponding to the v' vertical axis and the corresponding current chromaticity value on the JNCD plane.

[0167] Step 905: Construct a JNCD color volume model corresponding to the display device based on the corrected JNCD planes corresponding to multiple display brightness levels.

[0168] In the above technical solution, by using the actual chromaticity values ​​corresponding to multiple target chromaticity values ​​and the corresponding current ambient brightness, the JNCD plane corresponding to the current display brightness is used to correct chromaticity drift. This can effectively eliminate the evaluation error caused by the chromaticity output offset of the display device, making the corrected JNCD plane more consistent with the human eye's color perception rules in real scenes. As a result, the JNCD color volume model constructed based on the multi-brightness corrected JNCD plane can more accurately and completely reflect the color resolution capability of the display device under different brightness and actual working conditions, thus improving the authenticity and reliability of the JNCD color volume model.

[0169] In some embodiments, since the display brightness of the display device may not be the perceived display brightness that conforms to the subjective perception characteristics of the human eye, it is also necessary to convert the physical display brightness into a perceived display brightness that conforms to the subjective perception characteristics of the human eye, so as to ensure that the constructed JNCD color volume model can fit the actual visual experience of the human eye.

[0170] Figure 10 A flowchart illustrating the JNCD color volume model correction based on actual display brightness, provided for embodiments of this application. Figure 10 As shown, the method may include the following steps:

[0171] Step 1002: If the measurement result corresponding to the current chromaticity value is obtained as the first result, obtain the actual display brightness of the display device corresponding to the data collected by the colorimeter.

[0172] Step 1004: Determine the perception correction parameters corresponding to the multiple target chromaticity values ​​based on the current display brightness and the corresponding actual display brightness.

[0173] Step 1006: Determine the perceived display brightness corresponding to the multiple target chromaticity values ​​based on the perception correction parameters corresponding to the multiple target chromaticity values, and correct the current display brightness corresponding to the multiple target chromaticity values ​​in the JNCD color volume model to the corresponding perceived display brightness.

[0174] In some embodiments, the controller may determine the perceived display brightness corresponding to the multiple target chromaticity values ​​based on Stevens color appearance theory and perceptual correction parameters corresponding to the multiple target chromaticity values ​​and the current display brightness.

[0175] The controller can perform a power operation based on the current display brightness and the preset power law exponent to obtain the initial perceived brightness. Then, it can calculate the product of the preset scaling parameters, the initial perceived brightness, and the perception correction parameters corresponding to the multiple target chromaticity values ​​to obtain the perceived display brightness corresponding to the multiple target chromaticity values.

[0176] For example, the controller can determine the perception correction parameters corresponding to the multiple target chromaticity values ​​based on the current display brightness and the corresponding actual display brightness, respectively:

[0177] Equation (1);

[0178] in, The perceptual correction parameters corresponding to the target chromaticity value. The current display brightness corresponding to the target chromaticity value. The actual display brightness corresponding to the target chromaticity value. This represents the strength of the logarithmic correction term.

[0179] The controller can calculate the product of preset scaling parameters, initial perceived brightness, and perceived correction parameters corresponding to multiple target chromaticity values ​​to obtain the perceived display brightness corresponding to each of the multiple target chromaticity values:

[0180] Equation (2);

[0181] in, The perceived display brightness corresponding to the target chromaticity value. The preset power-law exponent. The preset scaling parameters, The current display brightness corresponding to the target chromaticity value. Initial perceived brightness, The perceptual correction parameter corresponding to the target chromaticity value.

[0182] Among them, the preset scaling parameters Determines the perceived display brightness The overall scale The value affects the perceived pixel brightness. The range of numerical values.

[0183] Preset power law index Controls the current display brightness in the power-law relationship. L With perceived display brightness The degree of nonlinearity between them. γ The shape of the power law curve varies depending on the value. When... γ When the value is 1, the power-law relationship becomes a linear relationship, i.e., the perceived display brightness... With current display brightness L Proportional; when γ When the value is greater than 1, the current display brightness will increase. L Increased perceived display brightness It increases even faster, and the power-law curve bulges upward; when 0 < γ When <1, the brightness of the display increases accordingly. L Increased perceived display brightness The increase slows down, and the power-law curve bulges downwards. Power-law exponent This reflects the difference in the human eye's sensitivity to changes in brightness at different brightness levels.

[0184] Logarithmic correction strength Controlling the logarithmic terms α log(1+ L / L 0) Perceived display brightness The degree of correction. The larger the value, the more the logarithmic term... The greater the impact on the entire function, the stronger the additional correction effect on the perceived display brightness in the high-brightness area; The smaller the value, the weaker the effect on the numerical terms, and the closer the function is to the original power-law relationship. By adjusting... This allows for better adaptation to the complexity of human eye's perception of brightness under high dynamic range, enabling the function to more accurately describe brightness perception in high brightness regions.

[0185] In some embodiments, the controller can correct the current display brightness corresponding to multiple target chromaticity values ​​in the JNCD color volume model to the corresponding perceived display brightness, thereby obtaining a corrected JNCD color volume model.

[0186] In the above technical solution, by introducing the power law relationship from Stevens' color appearance theory, that is, the human eye's perception of brightness follows a power function rather than a simple linear mapping, the initial perceived brightness is obtained by exponentiation of the current display brightness and the preset power law exponent. Then, by multiplying the preset scaling parameters with the perception correction parameters corresponding to each target chromaticity value, the physical display brightness is accurately converted into a perceived display brightness that conforms to the subjective perception characteristics of the human eye. This can improve the matching degree between the JNCD color volume model and the actual response characteristics of the human visual system. The corrected JNCD color volume model can not only reflect the perceptible threshold of chromaticity difference, but also accurately describe the nonlinear change law of color perception under different brightness levels, thus achieving a more accurate and realistic quantitative evaluation of the color performance of display devices.

[0187] In some embodiments, the controller can determine the color performance parameters of the display device by comparing the JNCD color volume model under different ambient brightness, thereby more accurately quantifying the color performance of the display device.

[0188] Figure 11 This is a flowchart illustrating the process of obtaining color performance parameters of a display device, as provided in an embodiment of this application. Figure 11 As shown, the method includes the following steps:

[0189] Step 1101: Under the first ambient brightness, control the display device to display the test image according to the current display brightness.

[0190] The first ambient brightness can be the ambient brightness when the user is using the display device normally.

[0191] Step 1103: Based on the JNCD planes corresponding to the multiple display brightness levels, construct a JNCD color volume model corresponding to the display device and the first ambient brightness.

[0192] Step 1105: Obtain JNCD color volume models corresponding to multiple ambient brightness levels.

[0193] The multiple ambient brightnesses include at least a first ambient brightness and a second ambient brightness, and the first ambient brightness is greater than the second ambient brightness.

[0194] In some embodiments, the second ambient brightness may be the ambient brightness in a dark room environment, that is, the ambient brightness is close to zero and insufficient to have a visual impact on the display effect of the display device.

[0195] Step 1107: Determine the color performance parameters of the display device corresponding to the first ambient brightness based on the JNCD color volume models corresponding to multiple ambient brightness levels.

[0196] Color performance parameters may include one or more of volume collapse rate, hue shift amount, and JNCD density.

[0197] Volume collapse rate refers to the degree of reduction in the actual color volume of the JNCD color volume model compared to the reference color volume during changes in ambient brightness.

[0198] In one implementation, the controller can acquire first volume data of the JNCD color volume model corresponding to the first ambient brightness and second volume data of the color volume model corresponding to the second ambient brightness, and determine the volume collapse rate of the display device corresponding to the first ambient brightness based on the first volume data and the second volume data.

[0199] For example, the volume collapse rate of the display device corresponding to the first ambient brightness is:

[0200] Equation (3);

[0201] in, The volume collapse rate of the display device corresponding to the brightness of the first ambient light. This represents the first volume data of the JNCD color volume model corresponding to the first ambient brightness. This is the second volume data of the color volume model corresponding to the second ambient brightness.

[0202] Hue shift refers to the quantitative offset of the hue output by the display device from the reference hue.

[0203] In one implementation, the controller can obtain the first hue value corresponding to the test chromaticity value in the JNCD color volume model corresponding to the first ambient brightness, and the second hue value corresponding to the test chromaticity value in the color volume model corresponding to the second ambient brightness. Based on the first hue value and the second hue value corresponding to the test chromaticity value, the controller determines the hue shift between the display device and the test chromaticity value under the first ambient brightness. The test chromaticity value is one or more of a plurality of target chromaticity values.

[0204] For example, under the first ambient brightness, the hue shift of the display device corresponding to the test chromaticity value is:

[0205] Equation (4);

[0206] in, This refers to the first hue value corresponding to the tested chromaticity value in the JNCD color volume model for the first ambient luminance. This refers to the second hue value corresponding to the tested chromaticity value in the color volume model corresponding to the second ambient brightness. This refers to the amount of hue shift between the display device and the tested chromaticity value under the first ambient brightness.

[0207] Optionally, the test chromaticity value can also be any chromaticity value in the JNCD plane, but is not limited to this.

[0208] JNCD density can be used to measure the density of color difference distribution within a unit JNCD color volume.

[0209] As one implementation method, the controller can determine the JNCD density of the display device at the first ambient brightness and the current display brightness based on the JNCD color volume model corresponding to the first ambient brightness and the current display brightness, the unit chromaticity volume and the number of target chromaticity values ​​within the unit chromaticity volume.

[0210] For example, the JNCD density of the display device under the first ambient brightness and the current display brightness is:

[0211] Equation (5);

[0212] in, per unit chromaticity volume, This represents the number of target chromaticity values ​​per unit chromaticity volume. The JNCD density is the ratio of the display device's current display brightness to the first ambient brightness.

[0213] In the above technical solution, by introducing color performance parameters such as volume collapse rate, hue shift, and JNCD density, the degree of shrinkage of the resolvable color range of the display device caused by changes in ambient brightness, the degree of interference of changes in ambient brightness on the hue accuracy of the display device, and the fineness of color resolution of the display device under the current display brightness and the first ambient brightness can be reflected intuitively and accurately in numerical form. This provides a standardized and objective measurement basis for evaluating the color performance of the display device. Moreover, the above color performance parameters all correspond directly to the subjective visual perception of the human eye when actually viewing the display device. This can more comprehensively reflect the degree of matching between the objective performance of the display device's color presentation under changes in ambient brightness in actual use scenarios and the user's subjective perception. This makes the evaluation of color performance based on the JNCD color volume model more comprehensive, realistic, and of greater practical reference value.

[0214] This application also provides a computer-readable storage medium storing a computer program, wherein when the computer program is executed by a controller, the controller implements any of the color volume model construction methods disclosed in this application.

[0215] This application discloses a computer program product, including a computer program that, when executed by a controller, enables the controller to implement any of the color volume model construction methods disclosed in this application.

[0216] It should be understood that the phrase "one embodiment" or "an embodiment" throughout the specification means that a specific feature, structure, or characteristic related to the embodiment is included in at least one embodiment of this application. Therefore, "in one embodiment" or "in an embodiment" appearing throughout the specification does not necessarily refer to the same embodiment. Furthermore, these specific features, structures, or characteristics can be combined in any suitable manner in one or more embodiments. Those skilled in the art should also recognize that the embodiments described in the specification are optional embodiments, and the actions and modules involved are not necessarily essential to this application.

[0217] The units described above as separate components may or may not be physically separate. The components shown as units may or may not be physical units; they can be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0218] Furthermore, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.

[0219] The foregoing has provided a detailed description of a method for constructing a color volume model and an evaluation system disclosed in the embodiments of this application. Specific examples have been used to illustrate the principles and implementation methods of this application. The descriptions of the embodiments above are merely for the purpose of helping to understand the method and core ideas of this application. Furthermore, those skilled in the art will recognize that, based on the ideas of this application, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. A method for constructing a color volume model, characterized in that, include: Control the display device to display the test image according to the current display brightness; Starting from a preset chromaticity reference point, the display device is controlled to adjust the chromaticity value of the test image along multiple chromaticity rays, and test results corresponding to multiple chromaticity values ​​on each chromaticity ray are obtained. The test results include a first result and / or a second result. The first result indicates that the human eye can perceive the chromaticity change produced by the test image, and the second result indicates that the human eye cannot perceive the chromaticity change produced by the test image. Based on the test results corresponding to the multiple chromaticity values ​​on each chromaticity ray, multiple target chromaticity values ​​corresponding to each chromaticity ray are determined, and the test results corresponding to the target chromaticity values ​​are the first results; Based on the first chromaticity curve and the second chromaticity curve, a just-perceptible chromaticity difference (JNCD) plane corresponding to the current display brightness is constructed. The first chromaticity curve is a closed curve formed by sequentially connecting the chromaticity coordinates of the first target chromaticity value closest to the preset chromaticity reference point on the multiple chromaticity rays. The second chromaticity curve is a closed curve formed by sequentially connecting the chromaticity coordinates of the second target chromaticity value farthest from the preset chromaticity reference point on the multiple chromaticity rays. Obtain the next display brightness and use the next display brightness as the new current display brightness. Repeat the step of controlling the display device to display the test image according to the current display brightness until the current display brightness is greater than the brightness threshold. Based on the JNCD planes corresponding to multiple display brightness levels, a JNCD color volume model corresponding to the display device is constructed.

2. The method according to claim 1, characterized in that, Before constructing the just-perceptible chromaticity difference (JNCD) plane corresponding to the current display brightness based on the first chromaticity curve and the second chromaticity curve, the method further includes: By sequentially connecting the chromaticity coordinates corresponding to the first target chromaticity values ​​of the multiple chromaticity rays, a first initial curve is obtained; The first initial curve is fitted using spline interpolation or least squares regression algorithm to obtain the first chromaticity curve.

3. The method according to claim 1, characterized in that, The display device includes a backlight module; Before controlling the display device to adjust the chromaticity values ​​of the test image along multiple chromaticity rays starting from a preset chromaticity reference point, the method further includes: Based on the current display brightness, determine the theoretical backlight data of the backlight module; Obtain the current actual backlight data of the backlight module; Calculate the difference between the theoretical backlight data and the current actual backlight data; If the difference is greater than a preset difference threshold, the backlight module is adjusted according to the difference, and the step of obtaining the current actual backlight data of the backlight module is repeated until the difference is less than or equal to the preset difference threshold.

4. The method according to claim 1, characterized in that, After adjusting the chromaticity values ​​of the test image by controlling the display device along multiple chromaticity rays starting from a preset chromaticity reference point, the method further includes: If the measurement result corresponding to the current chromaticity value is the first result, the actual chromaticity value corresponding to the display device is obtained by the colorimeter, and the current ambient brightness corresponding to the current chromaticity value is obtained. After determining the just-perceptible chromaticity difference (JNCD) plane corresponding to the current display brightness based on the multiple target chromaticity values ​​corresponding to the multiple chromaticity rays, the method further includes: Based on the actual chromaticity values ​​corresponding to multiple target chromaticity values ​​and the corresponding current ambient brightness, the JNCD plane corresponding to the current display brightness is chromaticity drift corrected to obtain the corrected JNCD plane. The step of constructing the JNCD color volume model corresponding to the display device based on multiple JNCD planes corresponding to different display brightness levels includes: Based on the corrected JNCD planes corresponding to the multiple display brightness levels, a JNCD color volume model corresponding to the display device is constructed.

5. The method according to any one of claims 1 to 4, characterized in that, After adjusting the chromaticity values ​​of the test image by controlling the display device along multiple chromaticity rays starting from a preset chromaticity reference point, the method further includes: If the measurement result corresponding to the current chromaticity value is the first result, the actual display brightness of the display device corresponding to the measurement obtained by the colorimeter is obtained; After constructing the JNCD color volume model corresponding to the display device based on multiple JNCD planes corresponding to different display brightness levels, the method further includes: Based on the current display brightness and the actual display brightness corresponding to the multiple target chromaticity values, the perception correction parameters corresponding to the multiple target chromaticity values ​​are determined respectively; Based on the perception correction parameters corresponding to the multiple target chromaticity values, the perceived display brightness corresponding to the multiple target chromaticity values ​​is determined, and the current display brightness corresponding to the multiple target chromaticity values ​​in the JNCD color volume model is corrected to the corresponding perceived display brightness.

6. The method according to claim 5, characterized in that, The step of determining the perceived display brightness corresponding to each of the plurality of target chromaticity values ​​based on the perceived correction parameters corresponding to each of the plurality of target chromaticity values ​​includes: The initial perceived brightness is obtained by performing a power operation based on the current display brightness and a preset power law exponent. The product of the preset scaling parameters, the initial perceived brightness, and the perceived correction parameters corresponding to the multiple target chromaticity values ​​is calculated to obtain the perceived display brightness corresponding to the multiple target chromaticity values.

7. The method according to claim 1, characterized in that, The process involves controlling the display device to adjust the chromaticity values ​​of the test image along multiple chromaticity rays, starting from a preset chromaticity reference point, and obtaining test results corresponding to multiple chromaticity values ​​on each chromaticity ray, including: The chromaticity value corresponding to a preset chromaticity reference point is used as the current chromaticity value, and the display device is controlled to adjust the chromaticity value of the test image to the current chromaticity value. Obtain the test result corresponding to the current chromaticity value; Along the target chromaticity ray, the current chromaticity value is updated according to the first update step size to obtain a new current chromaticity value, and the step of controlling the display device to adjust the chromaticity value of the test image to the current chromaticity value is re-executed until the current chromaticity value is greater than the chromaticity threshold corresponding to the target chromaticity ray, where the target chromaticity ray is any chromaticity ray.

8. The method according to claim 1, characterized in that, The control display device displays the test image according to the current display brightness, including: Under the first ambient brightness, the display device is controlled to display the test image according to the current display brightness; The step of constructing the JNCD color volume model corresponding to the display device based on multiple JNCD planes corresponding to different display brightness levels includes: Based on the JNCD planes corresponding to the plurality of display brightnesses, construct a JNCD color volume model of the display device and the first ambient brightness. The method further includes: Obtain JNCD color volume models corresponding to multiple ambient brightness levels, wherein the multiple ambient brightness levels include at least the first ambient brightness and the second ambient brightness, and the first ambient brightness is greater than the second ambient brightness. Based on the JNCD color volume models corresponding to the multiple ambient brightness levels, the color performance parameters of the display device corresponding to the first ambient brightness are determined.

9. The method according to claim 8, characterized in that, The color performance parameters include volume collapse rate and / or hue shift; The step of determining the color performance parameters of the display device corresponding to the first ambient brightness based on the JNCD color volume models corresponding to the multiple ambient brightness levels includes: Obtain the first volume data of the JNCD color volume model corresponding to the first ambient brightness, and the second volume data of the color volume model corresponding to the second ambient brightness; Based on the first volume data and the second volume data, determine the volume collapse rate of the display device corresponding to the first ambient brightness; And / or, Obtain the first hue value corresponding to the test chromaticity value in the JNCD color volume model corresponding to the first ambient brightness, and the second hue value corresponding to the test chromaticity value in the color volume model corresponding to the second ambient brightness, wherein the test chromaticity value is one or more of the plurality of target chromaticity values; Based on the first hue value and the second hue value corresponding to the test chromaticity value, determine the hue shift of the display device and the test chromaticity value under the first ambient brightness. The color performance parameters also include JNCD density; the method further includes: Based on the JNCD color volume model corresponding to the first ambient brightness and the current display brightness, the JNCD density of the display device corresponding to the current display brightness is determined.

10. An evaluation system, characterized in that, The method includes a memory and a processor, wherein the memory stores a computer program that, when executed by the processor, causes the processor to perform the method as described in any one of claims 1 to 9.

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