Color resolution measuring system

Abstract

The invention discloses a system for measuring color resolution. The system comprises a parameter acquisition module, a visual stimulation generation module, a man-machine interaction module, a process control module and a data recording and analyzing module. The parameter acquisition module acquires measurement parameters; the visual stimulation generation module is used for generating color visual stimulation for measurement; the man-machine interaction module presents stimulation to the measured individual and obtains the identification condition of the measured individual on the visual stimulation; the flow control module controls the measurement process; and the data recording and analyzing module is used for recording the measurement data and analyzing and determining a color resolution threshold value. The color resolution measuring system provided by the invention can quantify the resolution capability of a measured individual to various colors through a targeted visual stimulation design, measurement process control and data analysis method, can adjust the measurement precision through parameter setting, has a simple task design and operation mode, and is suitable for large-scale popularization and application. The method is suitable for evaluating animal functions and has a wider application prospect.

Description

Technical Field

[0001] The invention belongs to the technical field of color resolution detection, and in particular relates to a color resolution measurement system. Background Art

[0002] For individual organisms, color discrimination is an important visual function that helps them find objects based solely on color differences when the brightness of the object and the background are the same.

[0003] However, there are very few measurement devices or systems for measuring the color discrimination ability of individual organisms. Color blindness and color weakness detection charts are relatively familiar tools used to examine color discrimination function. However, color blindness and color weakness detection charts can only qualitatively detect color blindness or color weakness and it is difficult to quantify the strength of color discrimination. For example, even normal people can have significant differences in their ability to distinguish the difference between red and green. Some people have strong discrimination ability, while others have weaker discrimination ability. However, as long as these differences in discrimination ability do not reach the level of color blindness or color weakness, color blindness and color weakness detection charts cannot distinguish them. Furthermore, color blindness and color weakness detection charts can only detect a limited number of colors, such as red, green, blue, and purple, and cannot be expanded to other colors commonly seen in real life. Finally, due to limitations in operation and application understanding, color blindness and color weakness detection charts are rarely used to measure animal functions. Summary of the Invention

[0004] The purpose of the present invention is to provide a technical solution for a color resolution measurement system to address the shortcomings of the existing technology. The system can quantify the ability of the measured individual to distinguish multiple colors through targeted visual stimulation design, measurement process control and data analysis methods, and can adjust the measurement accuracy through parameter setting. It also has a simple task design and operation method, is suitable for the evaluation of animal functions, and has a broader application prospect.

[0005] In order to solve the above technical problems, the present invention adopts the following technical solutions: A color resolution measurement system comprising: A parameter acquisition module acquires measurement parameters, including the first color and the second color used to distinguish, the minimum change unit of the color contrast between the two colors, and the maximum test amount; The visual stimulus generation module generates color visual stimuli for measurement based on the parameters obtained by the parameter acquisition module, the system built-in parameters and the color contrast transmitted by the process control module; The human-computer interaction module presents the generated background and color visual stimulation to the measured individual and obtains the correct / incorrect recognition of the color visual stimulation by the measured individual; The process control module continuously adjusts the color contrast of the color visual stimulus based on the measured individual's response to the color visual stimulus until the measured individual's recognition of the color visual stimulus meets the specified requirements; The data recording and analysis module records the color contrast of all color visual stimuli during the measurement process, as well as the response data of the measured individual, and analyzes and determines the color discrimination threshold of the first color and the second color under the specified discrimination accuracy based on the data.

[0006] Furthermore, the minimum unit change of color contrast ranges from 0.5 to 6.0 dB, and gradually decreases as the measurement progresses.

[0007] Furthermore, the initial value of the minimum change unit of color contrast is 2.0 dB, and after completing the first 6 test trials, it is adjusted to 1 / 2 of the initial value, that is, 1.0 dB.

[0008] Furthermore, the parameter acquisition module also needs to obtain parameters related to the visual stimulus attributes, including the size of the visual stimulus, the presentation time, and auxiliary features related to the identification of the visual stimulus, and there are two or more visual stimulus attribute options in the test for the measured individual to identify, and the two attribute options are directions that differ by π / 2 radians, such as π / 4 and 3π / 4.

[0009] Furthermore, the size of the visual stimulus is indicated by a diameter, the diameter size ranges from 2.5 to 6.0 degrees of visual angle, and the presentation time of the visual stimulus ranges from 1.0 to 5.0 seconds. Preferably, the presentation time is 3.0 seconds.

[0010] Furthermore, the auxiliary feature related to visual stimulus recognition is shape, orientation or location, and the auxiliary feature is preferably a location feature.

[0011] Furthermore, the first color and the second color used for discrimination are the three primary colors of the display device, or other colors mixed by the three primary colors in a certain proportion.

[0012] Furthermore, the color visual stimulus is composed of a mixture of the first color and the second color, and is presented on a uniform background composed of the first color. The brightness of the color visual stimulus is exactly the same as that of the background, and is distinguished only by color. The difficulty of identifying the color visual stimulus is indicated by the color contrast C of the color visual stimulus.

[0013] Furthermore, color visual stimuli are graphics with specific shape characteristics or simple meanings, and should meet the following requirements: ; ; Where C is the color contrast of color visual stimulation: Lmean，color1 Indicates the background brightness composed of the first color, l pattern，color1 Indicates the brightness corresponding to the first color in the color visual stimulus, l pattern，color2 Represents the brightness corresponding to the second color in the color visual stimulus.

[0014] Furthermore, in the process control module, the specific steps of adjusting the color contrast of the color visual stimulus are as follows: S1-1. If the current trial is the first trial, the color contrast of the color visual stimulus uses a first value, preferably 0.50; S1-2. If the result of the measured individual identifying the color visual stimulus is correct in the previous trial, then in the next trial, the color contrast of the color visual stimulus is reduced by 1 minimum change unit; if the identification result in the previous trial is incorrect, then in the next trial, the color contrast of the color visual stimulus is increased by a first specified number of minimum change units; wherein the first specified number is a positive integer greater than 1, preferably, the first specified number is 3; S1-3. If the number of trials presented to the measured individual has reached the set maximum test amount, or the color contrast of the color visual stimulus presented to the measured individual repeatedly fluctuates within the first specified range, or the color contrast of the color visual stimulus has reached the upper and lower limits of the color contrast measurement range for three consecutive times or five times cumulatively, the test is terminated; preferably, the first specified range is five minimum units of color contrast change.

[0015] Furthermore, in the data recording and analysis module, the specific steps of analyzing and determining the color resolution threshold include: S2-1. Based on the recorded response data, list the color contrast used in each trial completed normally, as well as the correct / incorrect identification of the color visual stimulus by the measured individual; S2-2. Based on the list compiled in S2-1, select the color contrasts where the color contrast trend changes during the measurement process, and record them all as C cri ; S2-3, if C cri If the number is less than the second specified number, the analysis ends and a prompt "unable to determine the threshold, should be re-measured" is given; otherwise, the process goes to step S2-4, where the preferred second specified number is 8; S2-4, if all C cri If the difference between the maximum and minimum values does not exceed the third specified number of contrast minimum change units, then all C cri The reciprocal of the arithmetic mean of is the color discrimination threshold of the measured individual for the first color and the second color; otherwise, proceed to S2-5, where the preferred third specified number is 5; S2-5, in all Ccri In the order of appearance, remove the first 3 or 4 C cri , so that the remaining C cri The number of is even, then take all the remaining C cri The reciprocal of the arithmetic mean of the values of , is the color discrimination threshold of the measured individual for the first color and the second color.

[0016] Furthermore, the human-computer interaction module includes a color brightness evaluation and conversion unit, which regularly evaluates the brightness of the screen when the display device displays any of the three primary colors, and accordingly converts the theoretical brightness of the first color and the second color required to be presented at each pixel of the color visual stimulus into the actual hardware brightness level that is closest to the theoretical requirement and is actually applied; The specific working steps of the color brightness evaluation and conversion unit are as follows: S3-1. Use any one of the three primary colors in monochrome display mode, and measure and record the actual screen brightness at each hardware brightness level as indicated by the display device bit depth. S3-2. Use the following formula to fit the test data, obtain the fitting parameters, and determine the functional relationship between the actual screen brightness and the hardware brightness level: ; ; ; Among them, lum c1 、lum c2 、lum c3 The measured brightness of the screen when using only one of the three primary colors; level c1 、level c2 、level c3 is the hardware brightness level; lum c1，max 、lum c2，max 、lum c3，max The maximum value of the screen brightness when using one of the three primary colors to display the screen; a1 c1 、a1 c2 、a1 c3 、a2 c1 、a2 c2 、a2 c3 、b1 c1 、b1 c2 、b1 c3 , BP c1 , BP c2 , BP c3are all fitting parameters; min(·) is the minimum function; max(·) is the maximum function; S3-3. When presenting a color visual stimulus, the brightness required for each of the three primary colors is determined based on the proportional relationship between the first color and the second color and the three primary colors, as well as the brightness of the first color and the second color required to be presented at each pixel of the color visual stimulus transmitted by the visual stimulus generation module. The specific formula is as follows: ; ; ; Among them, lum(x,y) c1 ,lum(x,y) c2 and lum(x,y) c3 l(x,y) represents the brightness of the point with coordinates (x,y) on the color visual stimulus image, which corresponds to the brightness of the three primary colors c1, c2 and c3; color1 and l(x,y) color2 The ratio represents the brightness of the point with coordinates (x, y) on the color visual stimulus image, which corresponds to the brightness of the first color color1 and the second color color2 required to be distinguished; color1，c1 、Ratio color1，c2 Ratio color1，c3 Ratio represents the brightness ratio of C1, C2 and C3 in the mixed light of the first color when the three primary colors C1, C2 and C3 are mixed to form the first color color1; color2，c1 、Ratio color2，c2 Ratio color2，c3 Indicates the brightness ratio of C1, C2 and C3 in the mixed light of the second color when the three primary colors C1, C2 and C3 are mixed to form the second color color2; S3-4, based on the functional relationship between the actual screen brightness obtained in S3-2 and the hardware brightness level, convert the lum(x,y) obtained in S3-3 c1 ,lum(x,y) c2 ,lum(x,y) c3 Convert to the hardware brightness level corresponding to the three primary colors of the display that should be used for actual presentation c1 、level c2 and level c3 , and then according to the principle of rounding, level c1 、level c2 and level c3Convert to the level closest to the theoretical value used by the display device , c1 、level , c2 and level , c3 ,Right now ; ; ; Among them, level c1 、level c2 and level c3 It is the theoretical level of hardware brightness that should be used when presenting color visual stimuli, calculated according to the formula in S3-2. , c1 、level , c2 and level , c3 It is the actual hardware brightness level actually applied after conversion; S3-5. Calculate the difference between the theoretical hardware brightness level that should be used when presenting color visual stimuli and the actual hardware brightness level actually applied after conversion. If the absolute value of the difference between the theoretical hardware brightness level and the actual hardware brightness level for any of the three primary colors exceeds 0.10, the data recording and analysis module is prompted that the color visual stimulus presentation is inaccurate, and the trial presenting the color visual stimulus is marked as "abnormal."

[0017] Furthermore, in the data recording and analysis module, the step of analyzing and determining the color resolution threshold value further includes: Before executing S2-1, determine the number of trials marked as "abnormal". If this number is less than 10% of all trials, execute S2-1; If this number is greater than or equal to 10% of all trials, list all color contrasts that appeared in the trials that were completed normally, and based on the correct / incorrect identification of the measured individual in these trials, calculate the accuracy of the measured individual in distinguishing color visual stimuli under the above color contrast conditions. Then find the color contrast with a discrimination accuracy greater than the specified accuracy and closest to the specified accuracy, and the color contrast with a discrimination accuracy less than the specified accuracy and closest to the specified accuracy. Use linear interpolation to calculate the color contrast under the specified accuracy condition. This is the color discrimination threshold of the measured individual for distinguishing the first color and the second color.

[0018] Furthermore, in step S1-3, the color contrast presented to the measured individual fluctuates repeatedly within the first specified range, specifically: the color contrast of the last obtained C cri Based on the first specified range, the fourth specified number of C cri The value range of the fourth specified number is 6 to 20, and the preferred fourth specified number is 8.

[0019] The present invention has the following beneficial effects due to the adoption of the above technical solution: The present invention can quantify the ability of the measured individual to distinguish multiple colors through targeted visual stimulation design, measurement process control and data analysis methods, and can adjust the measurement accuracy through parameter setting. It also has simple task design and operation methods, is suitable for the evaluation of animal functions, and has broader application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The present invention will be further described below in conjunction with the accompanying drawings: Figure 1 This is an example diagram of a color resolution measurement system according to the present invention; Figure 2 This is a schematic diagram of the color visual stimulation of the present invention; Figure 3 Schematic diagram of the test process of the present invention. DETAILED DESCRIPTION

[0021] like Figure 1 FIG. 1 is a color resolution measurement system of the present invention, comprising: (1) Parameter acquisition module, which acquires measurement parameters, including the first color and the second color used to distinguish, the minimum change unit of the color contrast between the two colors, and the maximum test amount; (2) The visual stimulus generation module generates color visual stimuli for measurement based on the parameters obtained by the parameter acquisition module, the system built-in parameters, and the color contrast transmitted by the process control module; (3) Human-computer interaction module, presenting the generated background and color visual stimuli to the measured individual, and obtaining the correct / incorrect recognition of the color visual stimuli by the measured individual; (4) The process control module continuously adjusts the color contrast of the color visual stimulus based on the measured individual's response to the color visual stimulus until the measured individual's recognition of the color visual stimulus meets the specified requirements; (5) Data recording and analysis module, which records the color contrast of all color visual stimuli during the measurement process, as well as the response data of the measured individual, and analyzes and determines the color discrimination threshold of the first color and the second color under the specified discrimination accuracy.

[0022] The maximum test volume obtained by the parameter acquisition module is related to the test completion time and also has a certain impact on the measurement results. If the maximum test volume is small, the time to complete the test will be shorter, but accurate and valid test results may not be obtained (for specific content, please refer to the introduction related to the process control module and the data recording and analysis module later). If the maximum test volume is large, accurate and valid test results can definitely be obtained, but the time to complete the test will be relatively long. Therefore, under normal circumstances, a moderate value will be selected for the maximum test volume, such as 60 to 120 trials. Preferably, the maximum test volume can be set to 80 trials. Among them, one trial means "presenting a stimulus once and receiving the recognition of the stimulus presented by the measured individual."

[0023] The minimum change unit of color contrast obtained by the parameter acquisition module is directly related to the measurement accuracy. The minimum change unit of color contrast is equivalent to the minimum scale of the measuring tool (for example, a ruler or a vernier caliper) in length measurement. Therefore, the smaller the minimum change unit, the higher the measurement accuracy. Of course, the smaller the minimum change unit is, the better. According to the process control rules applied by this system (see the introduction of the process control module later), the smaller the minimum change unit, the more difficult it is to present the stimulus during measurement from the initial level to the level corresponding to the actual functional level of the measured individual (see Figure 3 The longer the "Phase 1" (in the "Phase 1"), the more trials and time are consumed. Given a fixed test volume, the more trials consumed in Phase 1, the fewer trials are needed in the subsequent Phase 2, which has a decisive influence on the measurement results. This results in less data available in Phase 2 and lowers the accuracy of the measurement results. (Details on the analysis methods for Phase 2 data and its relationship to the measurement results are provided later.) Therefore, there's no need to overly pursue a small minimum unit of change.

[0024] Generally, the minimum change unit should be determined before measurement and remain stable during the measurement process. A stable minimum change unit means that the difference between two adjacent difficulty levels, defined by the minimum change unit, is fixed. This helps control errors during the measurement process and ensures the accuracy of the measurement results. In practical applications, the minimum change unit of contrast can be defined using the dB representation commonly used in engineering, specifically: ; Therefore, a 1.0 dB difference is approximately 1.122 times the contrast difference. In practice, the range of 0.5 to 6.0 dB is generally selected as appropriate.

[0025] In addition, to quickly get through "Phase 1" of the testing process (see Figure 3), a larger minimum unit of contrast change can be selected for the first few measurement trials. Preferably, the initial value of the minimum unit of color contrast change is 2.0 dB. After the first six measurement trials, it is adjusted to half of the initial value, i.e., 1.0 dB.

[0026] In principle, the first and second colors acquired by the parameter acquisition module are not limited. They can be the display device's three primary colors, or other colors mixed and blended in a certain proportion from the three primary colors. However, considering the operational limitations of actual measurements (see the subsequent description of the process control module and the data recording and analysis module), selecting the first and second colors from the display device's three primary colors can achieve better results and more accurate results. Generally, the display device's three primary colors are red, green, and blue. Preferably, the first color is red and the second color is green.

[0027] The parameter acquisition module can also acquire parameters related to the properties of visual stimuli, and the parameters related to the properties of visual stimuli include the size of the visual stimulus. The size of the visual stimulus is mostly indicated by diameter, and the unit is visual angle. The macular area of the human eye generally does not exceed 6 degrees of visual angle, so the value range of the stimulus size is generally 2.5 to 6.0 degrees of visual angle. The parameters related to the properties of visual stimuli also include the presentation time of the visual stimulus, and the value range of the presentation time is 1.0 to 5.0 seconds. Preferably, the presentation time is 3.0 seconds. The parameters related to the properties of visual stimuli also include auxiliary features related to stimulus identification. When the measured individual identifies the stimulus, it is mainly based on color contrast information, but it cannot directly feedback the perception of color contrast. Therefore, the stimulus should include auxiliary features, and the auxiliary features include shape, orientation or direction, such as Figure 2 shape characteristics. Figure 2 In each column, the top shape has the same color contrast as the bottom shape, but has a different shape. During measurement, the individual is asked to identify whether the visual stimulus presented is the top shape or the bottom shape in the same column.

[0028] After acquiring the necessary parameters, the visual stimulus generation module generates color visual stimuli for measurement based on the parameters acquired by the parameter acquisition module, the system's built-in parameters, and the color contrast transmitted by the process control module. It should be noted that simpler graphic stimuli are more intuitive and easier to identify, making them more conducive to animal testing.

[0029] The color visual stimulus is presented on a uniform background, with the same brightness as the background but a different color. The background consists only of the first color, while the color of the color visual stimulus is a mixture of the first and second colors. The difficulty of identifying the color visual stimulus is indicated by the color contrast C of the color visual stimulus.

[0030] Color visual stimuli are graphics drawn using lines of uniform thickness. When drawing, the following requirements should be met: ; ; Where C is the color contrast of color visual stimulation: L mean，color1 Indicates the background brightness composed of the first color, l pattern，color1 Indicates the brightness corresponding to the first color in the color visual stimulus, l pattern，color2 Represents the brightness corresponding to the second color in the color visual stimulus.

[0031] Some color graphic stimuli such as Figure 3 As shown in the figure, the first color in the three left columns is red, and the second color is green; the first color in the rightmost column is blue, and the second color is green. The two left columns in Figure 3 use the letters O and Q, while the two right columns use simple graphic stimuli. The color contrast in the first left column and the two right columns is the maximum value of 1.0, making it very easy to identify. However, the color contrast in the second left column is lower, making it relatively difficult to identify.

[0032] In order to ensure that the brightness values of the first color and the second color of the visual stimulation actually presented to the measured individual accurately reach the theoretical calculated values, the human-computer interaction module also includes a color brightness evaluation and conversion unit, which can regularly evaluate the brightness of the screen when the display device displays any one of the three primary colors, and accordingly convert the theoretical brightness of the first color and the second color required to be presented at each pixel of the color visual stimulation into the actual hardware brightness level that is closest to the theoretical requirements and can be actually applied.

[0033] It should be noted that due to the variability of display device hardware settings (for example, the "brightness," "contrast," and "gamma" parameters adjusted via buttons on the monitor) and the effects of display device hardware aging during use, the brightness distribution of the display device at different hardware brightness levels will inevitably change during use. Therefore, regular evaluation of display devices is a necessary prerequisite for ensuring the accuracy of visual stimulation.

[0034] The hardware brightness level of a display device is usually determined by the display bit depth. When the display bit depth is 8 bits, the hardware brightness level of the display device is divided into 2^8 = 256 levels; when the display bit depth is 10 bits, the hardware brightness level of the display device is divided into 2^10 = 1024 levels. To put it more intuitively, when the display bit depth is 8 bits, the 256 hardware brightness levels correspond to the brightness of the 256 cases in the palette "r = 0, g = 0, b = 0", "r = 1, g = 1, b = 1" up to "r = 255, g = 255, b = 255"; when the display bit depth is 10 bits, the 1024 hardware brightness levels correspond to the brightness of the 1024 cases in the palette "r = 0, g = 0, b = 0", "r = 1, g = 1, b = 1" up to "r = 1023, g = 1023, b = 1023".

[0035] It's worth mentioning that, without any special processing, the default setting used by display devices when displaying images is "a linear relationship between RGB values and brightness." In other words, the actual brightness corresponding to the display device's default setting of "r=200, g=200, b=200" is twice the actual brightness corresponding to "r=100, g=100, b=100." However, this is not the case. For the vast majority of display devices, the actual brightness corresponding to "r=200, g=200, b=200" is more than twice the actual brightness corresponding to "r=100, g=100, b=100." The relationship between the actual display brightness values corresponding to the 256 hardware brightness levels and the RGB values often follows a power function relationship. In a few cases, it is a more complex curve relationship, such as an S-shaped curve. Such a setting is conducive to highlighting more brightness levels when presenting images, but it is not conducive to precisely controlling the brightness of visual stimuli.

[0036] Therefore, the system cannot use the default settings of the display device to present visual stimuli. To improve the scope of application and accuracy, the system uses a piecewise power function to evaluate the correspondence between the hardware brightness level and the actual brightness.

[0037] After regular measurement and evaluation, the functional relationship between the theoretical brightness value required for visual stimulation when only one of the three primary colors is displayed and the required hardware brightness level can be obtained or updated. Based on this, the theoretical brightness value required for each pixel of the visual stimulation generated by the visual stimulation generation module can be converted into a hardware brightness level that meets the requirements and accurately presented.

[0038] The specific working steps of the color brightness evaluation and conversion unit are as follows: S3-1. Use any one of the three primary colors in monochrome display mode, and measure and record the actual screen brightness at each hardware brightness level as indicated by the display device bit depth. S3-2. Use the following formula to fit the test data, obtain the fitting parameters, and determine the functional relationship between the actual screen brightness and the hardware brightness level: ; ; ; Among them, lum c1 、lum c2 、lum c3 The measured brightness of the screen when using only one of the three primary colors; level c1 、level c2 、level c3 is the hardware brightness level; lum c1，max 、lum c2，max 、lum c3，max The maximum value of the screen brightness when using one of the three primary colors to display the screen; a1 c1 、a1 c2 、a1 c3 、a2 c1 、a2 c2 、a2 c3 、b1 c1 、b1 c2 、b1 c3 , BP c1 , BP c2 , BP c3 are all fitting parameters; min(·) is the minimum function; max(·) is the maximum function; S3-3. When presenting a color visual stimulus, the brightness required for each of the three primary colors is determined based on the proportional relationship between the first color and the second color and the three primary colors, as well as the brightness of the first color and the second color required to be presented at each pixel of the color visual stimulus transmitted by the visual stimulus generation module. The specific formula is as follows: ; ; ; Among them, lum(x,y) c1 ,lum(x,y) c2 and lum(x,y) c3l(x,y) represents the brightness of the point with coordinates (x,y) on the color visual stimulus image, which corresponds to the brightness of the three primary colors c1, c2 and c3; color1 and l(x,y) color2 The ratio represents the brightness of the point with coordinates (x, y) on the color visual stimulus image, which corresponds to the brightness of the first color color1 and the second color color2 required to be distinguished; color1，c1 、Ratio color1，c2 Ratio color1，c3 Ratio represents the brightness ratio of C1, C2 and C3 in the mixed light of the first color when the three primary colors C1, C2 and C3 are mixed to form the first color color1; color2，c1 、Ratio color2，c2 Ratio color2，c3 Indicates the brightness ratio of C1, C2 and C3 in the mixed light of the second color when the three primary colors C1, C2 and C3 are mixed to form the second color color2; S3-4, based on the functional relationship between the actual screen brightness obtained in S3-2 and the hardware brightness level, convert the lum(x,y) obtained in S3-3 c1 ,lum(x,y) c2 ,lum(x,y) c3 Convert to the hardware brightness level corresponding to the three primary colors of the display that should be used for actual presentation c1 、level c2 and level c3 , and then according to the principle of rounding, level c1 、level c2 and level c3 Convert to the level closest to the theoretical value used by the display device , c1 、level , c2 and level , c3 ,Right now ; ; ; Among them, level c1 、level c2 and level c3 It is the theoretical level of hardware brightness that should be used when presenting color visual stimuli, calculated according to the formula in S3-2. , c1、level , c2 and level , c3 It is the actual hardware brightness level that is actually applied after conversion and is close to the theoretical requirement; S3-5. Calculate the difference between the theoretical hardware brightness level that should be used when presenting color visual stimuli and the actual hardware brightness level actually applied after conversion. If the absolute value of the difference between the theoretical hardware brightness level and the actual hardware brightness level for any of the three primary colors exceeds 0.10, the data recording and analysis module is prompted that the color visual stimulus presentation is inaccurate, and the trial presenting the color visual stimulus is marked as "abnormal."

[0039] It should be noted that the hardware brightness level that should be used for actual presentation is calculated according to the formula in S3-2. c1 、level c2 and level c3 , is often a non-integer, but the actual hardware brightness level used by the display device must be a positive integer. Therefore, in actual operation, the rounding method is usually used to obtain the level , c1 、level , c2 and level , c3 . From this perspective, there is often a certain deviation between the actual presented brightness and the theoretical calculated value. In order to effectively reduce the deviation, the display bit depth of the display device should be above 10 bits, the higher the better. However, it should be noted that if the first color and the second color are not the three primary colors displayed by the display device, but other colors mixed and deployed by the three primary colors in a certain proportion, then in the above rounding process, the probability and degree of deviation will be greatly increased. Therefore, a check is performed in S3-5. If the deviation of any of the three primary colors displayed exceeds 0.10, the stimulus presentation is judged to be inaccurate, and the trial presenting the visual stimulus is marked as "abnormal" to facilitate subsequent data analysis and processing.

[0040] After the visual stimulus is generated, it can be presented to the individual being measured. After obtaining the individual's recognition of the stimulus, the next stimulus is presented. This cycle continues until all trials are completed. During the measurement process, the process control module will continuously adjust the color contrast of the visual stimulus (i.e., the difficulty level of the stimulus). The specific steps are as follows: S1-1. If the current trial is the first trial, the color contrast of the color visual stimulus uses a first value, preferably 0.50; S1-2. If the result of the measured individual identifying the color visual stimulus is correct in the previous trial, then in the next trial, the color contrast of the color visual stimulus is reduced by 1 minimum change unit; if the identification result in the previous trial is incorrect, then in the next trial, the color contrast of the color visual stimulus is increased by a first specified number of minimum change units; wherein the first specified number is a positive integer greater than 1, preferably, the first specified number is 3; S1-3. If the number of trials presented to the measured individual has reached the set maximum test amount, or the color contrast of the color visual stimulus presented to the measured individual repeatedly fluctuates within the first specified range, or the color contrast of the color visual stimulus has reached the upper and lower limits of the color contrast measurement range for three consecutive times or five times cumulatively, the test is terminated; preferably, the first specified range is five minimum contrast change units.

[0041] It should be noted that due to the hardware limitations of display devices, the actual measurable color contrast has upper and lower limits. If the function of the individual being measured is too good or too poor, exceeding the system's measurable range, the color contrast adjusted by the process control module will fluctuate around the upper and lower limits of the actual color contrast measurement range. This can lead to situations such as the "color contrast of the color visual stimulus has reached the upper and lower limits of the actual color contrast measurement range three consecutive times or five cumulative times" mentioned in S1-3. Therefore, continuing the measurement at this point is meaningless and should be terminated promptly.

[0042] Figure 3 This figure shows a portion of the testing process. The black or red circles in the figure represent each trial. The horizontal axis indicates the trial's ordinal position among all trials, and the vertical axis indicates the color contrast level of the stimulus presented in that trial. The difference between adjacent color contrast levels on the vertical axis is 2dB. The "√" above the circle and the "×" below the circle in the figure indicate the individual's recognition of the color visual stimulus in that trial. As can be seen from the figure, when the measured individual identifies correctly (i.e., "√"), the difficulty level in the next trial increases by 1 level, that is, the color contrast level decreases by 1 level (for example, it decreases by 2 dB based on 0.200, becoming 0.200 / 10^(2 / 20) = 0.158); when the measured individual identifies incorrectly (i.e., "×"), the difficulty level in the next trial decreases by 3 levels, that is, the color contrast level increases by 3 levels (for example, it increases by 2×3 = 6 dB based on 0.200, becoming 0.200×10^(2*3 / 20) = 0.0400).

[0043] The above process control rules will inevitably lead to a phenomenon. That is, if the performance of the measured individual is stable and not affected by any non-sensory factors (such as fatigue, proficiency, rewards and punishments, etc.), and the test volume is large enough, the color contrast presented to the measured individual in the middle and late stages of the test will inevitably fluctuate around a certain level (see Figure 3 Even if there are occasional deviations from this level (see Figure 3 The situation of the 30th trial) will also be pulled back by the above process rules (see Figure 3 This specific level is actually the actual functional level of the individual being measured. For example, Figure 3 The true level of the measured individual should be between color contrast levels 3 and 6.

[0044] therefore, Figure 3 The entire testing process can be divided into two phases. Phase I covers the period from the start of the test (trial 1) to the first change in the subject's stimulus recognition (trial 17), while all subsequent phases fall into Phase II. During Phase I, the stimulus difficulty level is gradually adjusted from the initial level to a level close to the subject's true functional level. This is the preparation stage for obtaining valid measurement data. During Phase II, the stimulus difficulty level fluctuates around the subject's true functional level, which is the stage for actually obtaining valid measurement data.

[0045] Theoretically, it can be predicted that in Phase 2, when the color contrast level presented reaches the true level of the individual being measured, there should be the following relationship: ; in, It is the probability that the measured individual can correctly perceive the stimulus when the color contrast level reaches the measured individual's true level. It is the degree to which the color contrast level decreases in the next trial after the measured individual correctly perceives and gives feedback. It is the probability that the measured individual fails to perceive the stimulus correctly when the color contrast level reaches the measured individual's true level. It is the degree to which the color contrast level increases in the next trial when the measured individual does not perceive and give feedback correctly.

[0046] Combined with the above rule, "In one trial, if the measured individual correctly identifies the color visual stimulus, then in the next trial, the color contrast is reduced by 1 minimum change unit; if the identification result is wrong, then in the next trial, the color contrast is increased by the first specified number (n) minimum change units", the above formula can be deduced p correct= n x p incorrect ,in accordance with p correct + p incorrect = 100% established fact, can be deduced in one step p correct = n / ( n + 1). Specifically, when n is 2, p correct = 66.7%; when n is 3, p correct = 75.0%; when n is 4, p correct = 80.0%; when n is 5, p correct = 83.3%. Therefore, theoretically, when n takes different values and is combined with sufficient testing volume, the above process control method can be used to specify the color resolution threshold for measuring a specific resolution accuracy.

[0047] Of course, due to the limitations of measurement accuracy (the minimum unit of change in color contrast) and the existence of various errors, the color contrast level of the stimulus presented in actual measurement is unlikely to exactly reach the true level of the measured individual, and generally fluctuates around the true level. Therefore, in actual measurement, statistical methods can be used to calculate all data points that "change from correct identification to incorrect identification" during the fluctuation process ( Figure 3 The data points that “changed from misidentification to correct identification” ( Figure 3 The arithmetic mean of the contrast ratios corresponding to the three data points (indicated by a red "√" in the figure) is used to infer the true level of the individual being measured. Statistically, the more data points there are, the closer the arithmetic mean of the contrast ratios corresponding to these data points will be to the true level of the individual being measured. In other words, the larger the test volume, the more accurate the analysis results.

[0048] In summary, the aforementioned process control methods, data analysis rules, and sufficient testing volume ensure the accuracy of measurement results. The process control methods theoretically ensure that the test results are positioned on the S-shaped measurement curve, while the data analysis rules and sufficient testing volume ensure that the actual operation / analysis results are statistically close to the theoretical values, meeting the operational requirements of practical applications.

[0049] It's worth noting that measurement accuracy in this system is controlled by adjusting the minimum unit of change in color contrast (i.e., the difference between adjacent levels of stimulus intensity). This has no direct connection to process control methods, data analysis rules, or test volume. Therefore, controlling measurement accuracy and the accuracy of measurement results in this system are independent and separate.

[0050] In the data recording and analysis module, the specific steps for analyzing and determining the color resolution threshold include: S2-1. Based on the recorded response data, list the color contrast used in each trial completed normally, as well as the correct / incorrect identification of the color visual stimulus by the measured individual; S2-2. Based on the list compiled in S2-1, select the color contrasts where the color contrast trend changes during the measurement process, and record them all as C cri ; S2-3, if C cri If the number is less than the second specified number, the analysis ends and a prompt "unable to determine the threshold, should be re-measured" is given; otherwise, the process goes to step S2-4, where the preferred second specified number is 8; S2-4, if all C cri If the difference between the maximum and minimum values does not exceed the third specified number of contrast minimum change units, then all C cri The reciprocal of the arithmetic mean of is the color discrimination threshold of the measured individual for the first color and the second color; otherwise, proceed to S2-5, where the preferred third specified number is 5; S2-5, in all C cri In the order of appearance, remove the first 3 or 4 C cri , so that the remaining C cri The number of is even, then take all the remaining C cri The reciprocal of the arithmetic mean of the values of , is the color discrimination threshold of the measured individual for the first color and the second color.

[0051] C mentioned in S2-2 cri ,Right now Figure 3 In addition, the color contrast of the red circle in S2-4 is cri The basic principle of the analysis method of taking the arithmetic mean has been explained in the previous article. However, in actual operation, due to the lack of familiarity of the measured individuals with the measurement method and process and possible operational errors, the first few C values obtained in the measurement process may be cri , which are less reliable than the subsequent C cri Therefore, in order to ensure that there are sufficient numbers of C cri And C criIf the difference between them is large, the first few C can be eliminated in S2-5. cri , in order to improve the accuracy of the analysis results. In addition, “eliminating the first 3 or 4 C cri , so that the remaining C cri The purpose of "having an even number" is also to ensure that the remaining C cri The number of data points of "transition from correct identification to incorrect identification" and "transition from incorrect identification to correct identification" in the two different categories is the same to provide the accuracy of the analysis results.

[0052] Based on the description of steps S2-1 to S2-5, it can be understood that if C cri If the number of tests is always within the first specified range and has reached the fourth specified number, then even if the current number of tests has not reached the maximum test amount, the test can be terminated in advance and the existing C cri Calculate the color discrimination threshold of the measured individual at a specified discrimination accuracy. Generally, the fourth specified number ranges from 6 to 20. Preferably, the fourth specified number is 8.

[0053] It's important to note that terminating the test early under these conditions effectively shortens the measurement time while ensuring the reliability of the results. Therefore, when the measured individuals are animals that can't effectively communicate, this setting helps complete the test as quickly as possible while ensuring measurement validity.

[0054] In addition, as mentioned above, if the first color and the second color are not the three primary colors of the display device, but other colors mixed and blended according to a certain proportion of the three primary colors, then in the process of generating and presenting color visual stimuli, the probability and degree of large deviations in the stimulus colors found through S3-5 verification will be greatly increased. At this time, it is very likely that a situation will occur: although the maximum test volume has been completed, due to the excessive number of trials marked as "abnormal" (for example, the number is not less than 10% of all trials), the results cannot be obtained normally according to the operations of S2-1 to S2-5. Therefore, in the above situation, the data recording and analysis module will adopt another method to calculate the color resolution threshold at the specified resolution accuracy based on the existing data. The details are as follows: List all color contrasts that appeared in the trials that were completed normally, and based on the correct / incorrect identification of the measured individual in these trials, calculate the accuracy of the measured individual in distinguishing color visual stimuli under the above color contrast conditions. Then find the color contrast with a discrimination accuracy greater than the specified accuracy and closest to the specified accuracy, and the color contrast with a discrimination accuracy less than the specified accuracy and closest to the specified accuracy. Use linear interpolation to calculate the color contrast under the specified accuracy condition. This is the color discrimination threshold of the measured individual for distinguishing the first color and the second color.

[0055] For example, if the individual's recognition accuracy is 100% at color contrast level 5, 80% at color contrast level 6, 70% at color contrast level 7, 60% at color contrast level 8, and 40% at color contrast level 9, then the color contrast level corresponding to the discrimination threshold of 75% recognition accuracy should be between levels 6 and 7. Using linear interpolation, we can calculate that the color contrast level corresponding to 75% recognition accuracy is 6.5.

[0056] Finally, optionally, the concept of color discrimination, considering the first and second colors, can be used to express the relative discrimination between the two colors, encompassing both "distinguishing the second color from the first" and "distinguishing the first color from the second." Therefore, the first and second colors can be alternately designated as background colors, and the measurement repeated twice. That is, in the first measurement, the first color is designated as the background, and the ability to distinguish the second color from the first is measured; in the second measurement, the second color is designated as the background, and the ability to distinguish the first color from the second is measured. The arithmetic mean of these two measurement results is then taken to determine the color discrimination threshold for the individual being measured to distinguish between the first and second colors.

[0057] The above are only specific embodiments of the present invention, but the technical features of the present invention are not limited thereto. Any simple changes, equivalent replacements, or modifications based on the present invention to achieve substantially the same technical effects are all within the scope of protection of the present invention.

Claims

1. A color resolution measurement system, characterized in that: include: A parameter acquisition module acquires measurement parameters, including the first color and the second color used to distinguish, the minimum change unit of the color contrast between the two colors, and the maximum test amount; The visual stimulus generation module generates color visual stimuli for measurement based on the parameters obtained by the parameter acquisition module, the system built-in parameters and the color contrast transmitted by the process control module; The human-computer interaction module presents the generated background and color visual stimulation to the measured individual and obtains the correct / incorrect recognition of the color visual stimulation by the measured individual; The process control module continuously adjusts the color contrast of the color visual stimulus based on the measured individual's response to the color visual stimulus until the measured individual's recognition of the color visual stimulus meets the specified requirements; The data recording and analysis module records the color contrast of all color visual stimuli during the measurement process, as well as the response data of the measured individual, and analyzes and determines the color discrimination threshold of the first color and the second color under the specified discrimination accuracy based on the data.

2. A color resolution measurement system according to claim 1, characterized in that: The minimum change unit of the color contrast ratio ranges from 0.5 to 6.0 dB and gradually decreases as the measurement progresses.

3. The color resolution measurement system according to claim 1, characterized in that: The parameter acquisition module also needs to obtain parameters related to the visual stimulus attributes, including the size of the visual stimulus, the presentation time, and auxiliary features related to the identification of the visual stimulus. In the test, there are two or more visual stimulus attribute options for the measured individual to identify. The size of the visual stimulus is indicated by diameter, and the diameter size ranges from 2.5 to 6.0 degrees of visual angle. The presentation time of the visual stimulus ranges from 1.0 to 5.0 seconds. The auxiliary features related to the identification of the visual stimulus are shape, orientation or direction.

4. The color resolution measurement system according to claim 1, wherein: The first color and the second color used for discrimination are the three primary colors of the display device, or other colors mixed and blended by the three primary colors in proportion.

5. The color resolution measurement system according to claim 1, characterized in that: The color visual stimulus is composed of a mixture of a first color and a second color, and is presented on a uniform background composed of the first color. The color visual stimulus and the background have exactly the same brightness and are distinguished only by color. The difficulty of identifying the color visual stimulus is indicated by the color contrast C of the color visual stimulus. Color visual stimuli are graphics with specific shape characteristics or simple meanings and should meet the following requirements: ； ； Where C is the color contrast of color visual stimulation; L mean，color1 Indicates the background brightness composed of the first color; l pattern，color1 Indicates the brightness corresponding to the first color in the color visual stimulus; l pattern，color2 Represents the brightness corresponding to the second color in the color visual stimulus.

6. The color resolution measurement system according to claim 1, characterized in that: In the process control module, the specific steps of adjusting the color contrast of the color visual stimulus are as follows: S1-1, if the current trial is the first trial, the color contrast of the color visual stimulus uses the first value; S1-2. If the result of the measured individual identifying the color visual stimulus is correct in the previous trial, then in the next trial, the color contrast of the color visual stimulus is reduced by 1 minimum change unit; if the identification result in the previous trial is incorrect, then in the next trial, the color contrast of the color visual stimulus is increased by a first specified number of minimum change units; wherein the first specified number is a positive integer greater than 1; S1-3. If the number of trials presented to the measured individual has reached the set maximum test amount, or the color contrast of the color visual stimulus presented to the measured individual repeatedly fluctuates within the first specified range, or the color contrast of the color visual stimulus has reached the upper and lower limits of the color contrast measurement range for three consecutive times or five times cumulatively, the test is terminated.

7. The color resolution measurement system according to claim 6, characterized in that: In the data recording and analysis module, the specific steps of analyzing and determining the color resolution threshold include: S2-1. Based on the recorded response data, list the color contrast used in each trial completed normally, as well as the correct / incorrect identification of the color visual stimulus by the measured individual; S2-2. Based on the list compiled in S2-1, select the color contrasts where the color contrast trend changes during the measurement process, and record them all as C cri ; S2-3, if C cri If the number is less than the second specified number, the analysis ends and a prompt "unable to determine the threshold, should be re-measured" is given; otherwise, the process goes to step S2-4; S2-4, if all C cri If the difference between the maximum and minimum values does not exceed the third specified number of color contrast minimum change units, then all C cri The reciprocal of the arithmetic mean of is the color discrimination threshold of the measured individual for the first color and the second color; otherwise, go to S2-5; S2-5, in all C cri In the order of appearance, remove the first 3 or 4 C cri , so that the remaining C cri The number of is even, then take all the remaining C cri The reciprocal of the arithmetic mean of the values of , is the color discrimination threshold of the measured individual for the first color and the second color.

8. The color resolution measurement system according to claim 7, characterized in that: The human-computer interaction module includes a color brightness evaluation and conversion unit, which regularly evaluates the brightness of the screen when the display device displays any of the three primary colors. Based on this, the theoretical brightness of the first and second colors required to be presented at each pixel of the color visual stimulus is converted into the actual hardware brightness level that is closest to the theoretical requirement and is used in real applications. The specific working steps of the color brightness evaluation and conversion unit are as follows: S3-1. Use any one of the three primary colors in monochrome display mode, and measure and record the actual screen brightness at each hardware brightness level as indicated by the display device bit depth. S3-2. Use the following formula to fit the test data, obtain the fitting parameters, and determine the functional relationship between the actual screen brightness and the hardware brightness level: ； ； ； Among them, lum c1 、lum c2 、lum c3 The measured brightness of the screen when using only one of the three primary colors; level c1 、level c2 、level c3 is the hardware brightness level; lum c1，max 、lum c2，max 、lum c3，max The maximum value of the screen brightness when using one of the three primary colors to display the screen; a1 c1 、a1 c2 、a1 c3 、a2 c1 、a2 c2 、a2 c3 、b1 c1 、b1 c2 、b1 c3 , BP c1 , BP c2 , BP c3 are all fitting parameters; min(·) is the minimum function; max(·) is the maximum function; S3-3. When presenting a color visual stimulus, the brightness required for each of the three primary colors is determined based on the proportional relationship between the first color and the second color and the three primary colors, as well as the brightness of the first color and the second color required to be presented at each pixel of the color visual stimulus transmitted by the visual stimulus generation module. The specific formula is as follows: ； ； ； Among them, lum(x,y) c1 ,lum(x,y) c2 and lum(x,y) c3 l(x,y) represents the brightness of the point with coordinates (x,y) on the color visual stimulus image, which corresponds to the brightness of the three primary colors c1, c2 and c3; color1 and l(x,y) color2 The ratio represents the brightness of the point with coordinates (x, y) on the color visual stimulus image, which corresponds to the brightness of the first color color1 and the second color color2 required to be distinguished; color1，c1 、Ratio color1，c2 Ratio color1，c3 Ratio represents the brightness ratio of C1, C2 and C3 in the mixed light of the first color when the three primary colors C1, C2 and C3 are mixed to form the first color color1; color2，c1 、Ratio color2，c2 Ratio color2，c3 Indicates the brightness ratio of C1, C2 and C3 in the mixed light of the second color when the three primary colors C1, C2 and C3 are mixed to form the second color color2; S3-4, based on the functional relationship between the actual screen brightness obtained in S3-2 and the hardware brightness level, convert the lum(x,y) obtained in S3-3 c1 ,lum(x,y) c2 ,lum(x,y) c3 Convert to the hardware brightness level corresponding to the three primary colors of the display that should be used for actual presentation c1 、level c2 and level c3 , and then according to the rounding principle, level c1 、level c2 and level c3 Convert to the level closest to the theoretical value used by the display device , c1 、level , c2 and level , c3 ,Right now ； ； ； Among them, level c1 、level c2 and level c3 It is the theoretical level of hardware brightness that should be used when presenting color visual stimuli, calculated according to the formula in S3-2. , c1 、level , c2 and level , c3 It is the actual hardware brightness level actually applied after conversion; S3-5. Calculate the difference between the theoretical hardware brightness level that should be used when presenting color visual stimuli and the actual hardware brightness level actually applied after conversion. If the absolute value of the difference between the theoretical hardware brightness level and the actual hardware brightness level for any of the three primary colors exceeds 0.10, the data recording and analysis module is prompted that the color visual stimulus presentation is inaccurate, and the trial presenting the color visual stimulus is marked as "abnormal." 9. The color resolution measurement system according to claim 8, characterized in that: In the data recording and analysis module, the step of analyzing and determining the color resolution threshold value further includes: Before executing S2-1, determine the number of trials marked as "abnormal". If this number is less than 10% of all trials, execute S2-1; If this number is greater than or equal to 10% of all trials, list all color contrasts that appeared in the trials that were completed normally, and based on the correct / incorrect identification of the measured individual in these trials, calculate the accuracy of the measured individual in distinguishing color visual stimuli under the above color contrast conditions. Then find the color contrast with a discrimination accuracy greater than the specified accuracy and closest to the specified accuracy, and the color contrast with a discrimination accuracy less than the specified accuracy and closest to the specified accuracy. Use linear interpolation to calculate the color contrast under the specified accuracy condition. This is the color discrimination threshold of the measured individual for distinguishing the first color and the second color.

10. The color resolution measurement system according to claim 7, characterized in that: In step S1-3, the color contrast presented to the measured individual fluctuates repeatedly within the first specified range, specifically: the color contrast of the last obtained C cri Based on the first specified range, the fourth specified number of C cri , the value range of the fourth specified number is 6 to 20.

Images