Measurement system for consistent motion perception capability

Abstract

The invention provides a measurement system for consistent motion perception capability. The measurement system comprises a parameter setting module; the visual stimulation generation module is used for generating random point movement stimulation for identification based on the parameters set by the parameter setting module and the consistent movement proportion transmitted by the process control module; a man-machine interaction module; the flow control module is used for adjusting the consistent motion proportion until the identification condition of the measured individual on the motion stimulation reaches a preset requirement; and a data recording and analyzing module. Through the targeted visual stimulation design, the measurement process control and the data analysis method, the consistency motion perception ability of the measured individual is quantified, the measurement precision can be adjusted through parameter setting, and the method has wide application prospects.

Description

Technical Field

[0001] The present invention relates to the technical field of motion perception ability detection, and in particular to a measurement system for consistent motion perception ability. Background Art

[0002] In real life, there are often examples where "there are many individuals moving in different directions in the field of vision, but only the movement directions of some individuals need to be identified and paid attention to."

[0003] Some scenarios require processing motion elements. For example, when people are shopping with friends, they need to keep track of each other's locations to avoid getting separated. Another example is when wolves hunt bison, they first disperse the herd, then select and seize the weak, old, or young ones. In these situations, individual animals need to identify all moving elements within their field of view, while also analyzing and integrating information about certain moving elements with specific characteristics.

[0004] For example, when determining the groups of motion elements, it is necessary to determine which motion elements possess specific characteristics that warrant inclusion in the same group, and which motion elements cannot be combined with other elements because their characteristics do not meet the established criteria. For elements already grouped together, further consideration is needed to determine whether their characteristics need to be integrated.

[0005] This ability, which requires classifying and integrating information from different motion elements, is collectively referred to as "holistic motion perception." Holistic motion perception can also be categorized into multiple subcategories based on the specific characteristics of the motion elements of interest. When the motion elements of interest have consistent or relatively consistent directions of motion, the ability to perceive this type of motion is called "consistent motion perception."

[0006] However, there are currently few devices or systems for measuring consistent motion perception ability. Summary of the Invention

[0007] The purpose of the present invention is to propose a measurement system for consistent motion perception ability based on the technical problems existing in the background technology. The system can quantify the consistent motion perception ability of the measured individual through targeted visual stimulation design, measurement process control and data analysis methods, and can adjust the measurement accuracy through parameter setting, and has broad application prospects.

[0008] To achieve the above object, the present invention provides the following technical solutions:

[0009] A system for measuring consistent motion perception ability, comprising:

[0010] Parameter setting module, used to set parameters related to measurement;

[0011] The visual stimulus generation module generates random point motion stimuli for identification based on the parameters set by the parameter setting module and the consistency motion ratio transmitted by the process control module;

[0012] The human-computer interaction module presents random point motion stimuli to the measured individual and obtains the measured individual's recognition of the consistent motion direction in the motion stimulus;

[0013] The process control module adjusts the consistency movement ratio until the measured individual's recognition of the movement stimulus meets the preset requirements;

[0014] The data recording and analysis module records the consistent motion ratio of all motion stimuli during the measurement process, as well as the response data of the measured individuals, and analyzes and determines the threshold of consistent motion perception ability.

[0015] Preferably, the minimum unit of change in the consistency motion ratio is 5%. After completing the initial three trial measurements, it is adjusted to 2 / 5 of the initial value. After the adjustment, after completing another three trial measurements, it is further adjusted to 1 / 5 of the initial value.

[0016] Preferably, the random dot motion stimulus generated by the visual stimulus generation module includes non-color random dot motion stimulus and color random dot motion stimulus.

[0017] Preferably, when determining the movement directions of the consistent movement elements and the inconsistent movement elements according to the consistent movement direction and the random movement direction range set in the parameter setting module, the specific steps are:

[0018] S1-1. Preliminarily determine the direction of motion of the moving element and record it as D S1 ;

[0019] S1-2, build D S1 As the center, is a normal distribution with a variance, and then random sampling is performed to determine the final movement direction.

[0020] Preferably, the random point motion stimulation periodically refreshes the positions and consistent motion attributes of all motion elements, but does not refresh other features such as motion speed and consistent motion direction.

[0021] Preferably, the motion element in the random dot motion stimulus may also be a motion grating, specifically:

[0022] The moving element in the non-color random dot motion stimulus is a moving grating with brightness change characteristics;

[0023] When the moving element in the non-color random dot motion stimulus is a moving grating, the background is gray and the brightness is the average brightness of the moving grating;

[0024] The motion element in the color random dot motion stimulus is a motion grating with color change characteristics.

[0025] Preferably, in the process control module, the method for adjusting the consistency motion ratio is as follows:

[0026] S2-1. If the current trial is the first trial, the first value of the consistency movement ratio is used;

[0027] S2-2. If the subject correctly identified the consistent motion direction of the random dot motion stimulus in the previous trial, then in the next trial, the consistent motion ratio of the random dot motion stimulus is reduced by 1 minimum change unit; if the identification result in the previous trial was incorrect, then in the next trial, the consistent motion ratio is increased by the first specified number of minimum change units;

[0028] S2-3. If the number of trials presented to the measured individual has reached the set maximum test amount, the test is terminated.

[0029] Preferably, the data recording and analysis module analyzes and determines the threshold of the motion direction discrimination ability of the measured individual in the following specific steps:

[0030] S3-1. Based on the recorded data, list the proportion of consistent movements used in each completed trial and the stimulus recognition of the measured individual;

[0031] S3-2. Based on the list compiled in S3-1, select the consistent motion ratios where the trend of the consistent motion ratio changes during the measurement process, and record them all as C cri ;

[0032] S3-3, if C cri If the number of is less than the second specified number, the analysis ends; otherwise, the process goes to S3-4;

[0033] S3-4, if all C cri If the difference between the maximum and minimum values ​​does not exceed the minimum change unit of the third specified number of consistent motion ratios, then all C cri The arithmetic mean of is the threshold of the measured individual's consistent motion perception ability to random point motion stimulation; otherwise, proceed to S3-5;

[0034] S3-5, in all C cri In the order of appearance, remove the preset number of C cri , so that the remaining C cri The number of is even, then take all the remaining C cri The arithmetic mean of the values ​​is taken as the threshold of the consistent motion perception ability of the measured individual to random dot motion stimuli.

[0035] Preferably, the step S2-3 further includes terminating the test when the consistency motion ratio has reached the upper and lower limits of the measured range for a preset number of consecutive times:

[0036] The proportion of consistent movements presented to the measured individual fluctuates repeatedly within the first specified range, specifically: the last obtained C cri Based on the first specified range, the fourth specified number of C cri .

[0037] Preferably, the relationship between the refresh rate of the display device used to present the random dot motion stimulus in the human-computer interaction module and the motion speed of the motion element in the random dot motion stimulus is:

[0038]

[0039] where ω is the temporal frequency of the motion elements in the random dot motion stimulus.

[0040] The present invention has the following beneficial effects due to the adoption of the above technical solution:

[0041] The present invention quantifies the motion direction discrimination ability of the measured individual through targeted visual stimulation design, measurement process control and data analysis methods, and can adjust the measurement accuracy through parameter setting, which has broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] The present invention will be further described below with reference to the accompanying drawings.

[0043] Figure 1 This is a schematic diagram of the system proposed in the present invention.

[0044] Figure 2 Schematic diagram of random dot motion stimulation.

[0045] Figure 3 A schematic diagram of a test process. DETAILED DESCRIPTION

[0046] like Figure 1 FIG. 1 is a measurement system for motion direction discrimination capability according to the present invention, comprising:

[0047] The parameter setting module is used to set parameters related to the measurement, including the size, speed, range and total number of motion elements, the direction of consistent motion of motion elements, the direction range of random motion, the minimum change unit of consistent motion ratio, and the maximum test amount;

[0048] The visual stimulus generation module generates random point motion stimuli for identification based on the parameters set by the parameter setting module and the consistency motion ratio transmitted by the process control module;

[0049] The human-computer interaction module presents random point motion stimuli to the measured individual and obtains the correct / incorrect identification of the consistent motion direction in the motion stimulus by the measured individual;

[0050] The process control module continuously adjusts the consistency motion ratio based on the recognition of the measured individual on the consistency motion until the measured individual's recognition of the motion stimulus meets the specified requirements;

[0051] The data recording and analysis module records the consistency motion ratio of all motion stimuli during the measurement process, as well as the response data of the measured individuals, and analyzes and determines the consistency motion perception ability threshold under the specified resolution accuracy.

[0052] The relevant parameters set by the parameter setting module are mainly used for the generation of visual stimuli and measurement process control, and are also related to the accuracy of the measurement itself.

[0053] The size and total number of motion elements set in the parameter settings module have a certain impact on the accuracy of the measurement results. If the area occupied by a single motion element is too large, multiple elements moving simultaneously may cause significant overlap, interfering with the identification of consistent motion directions. Therefore, individual motion elements should not be too large, and their number should not be too large. Generally, the ratio of the area occupied by all motion elements (i.e., the size of a single element multiplied by the total number) to the area of ​​the motion range (for example, a circular area with a diameter of 20 degrees of viewing angle) should not exceed 25%.

[0054] On the other hand, individual motion elements should not be too small. If they are too small, the subject's vision may be poor, and difficulty identifying the individual motion elements themselves may further interfere with their ability to discern the direction of consistent motion. Therefore, the size of individual motion elements is generally 0.25 to 1.00 square degrees, where degrees are the unit of visual angle.

[0055] Generally speaking, the movement speed of the moving element is 1.00 to 10.00 degrees per second.

[0056] Among the moving elements, some elements have a uniform moving direction, which is called "consistent moving direction", and the remaining elements have completely random moving directions.

[0057] The consistent motion direction of a moving element is typically set to 2-4 directions, which serve as options for the subject to determine the consistent motion direction. For example, "left" or "right," "up" or "down," "upper left 45 degrees," "upper right 45 degrees," "lower left 45 degrees," or "lower right 45 degrees." When determining the consistent motion direction of a moving element, the subject should select the most likely option from among several options. It is important to note that the direction options should differ significantly from each other. For example, the difference between "left" and "right" is 180 degrees, and the difference between "lower left 45 degrees" and "lower right 45 degrees" is 90 degrees. If the differences are small or minimal, the measurement results will tend to reflect "consistent motion direction discrimination ability" rather than "consistent motion direction perception ability."

[0058] The random motion direction of a moving element should not include the consistent motion direction and should maintain a certain distance from the consistent motion direction. For example, when the consistent motion direction option is "left" (i.e., 0 degrees) or "right" (i.e., 180 degrees), the random motion direction range can be set to 15-165 degrees and 195-345 degrees.

[0059] The maximum test volume set in the parameter setting module is related to the test completion time. If the maximum test volume is large, the test completion time will be relatively long. Generally, the maximum test volume is 50-100 trials; preferably, the maximum test volume can be set to 80 trials.

[0060] Among them, a trial means "presenting a stimulus once and receiving the recognition of the stimulus presented by the measured individual."

[0061] The ratio of all moving elements with consistent motion directions to the total number of moving elements is called the "consistent motion ratio." This ratio changes continuously during measurement to help the measurement system determine the minimum consistent motion ratio required to achieve a specified recognition accuracy, known as the "consistent motion perception threshold."

[0062] The minimum change unit of the consistency movement ratio set by the parameter setting module is directly related to the measurement accuracy. The minimum change unit 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 below for details), the smaller the minimum change unit, the more difficult the stimulus presented during measurement (i.e., the consistency movement ratio) will be (see the process of changing from the initial level to the level corresponding to the actual functional level of the individual being measured). Figure 3The longer the "Phase 1" (in the "Phase 1"), the more trials and time are consumed. Given a fixed test volume in a single reference motion direction, the more trials consumed in Phase 1, the fewer trials there are 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.

[0063] Generally, the minimum unit of change should be determined before measurement and remain stable during the measurement process. A stable minimum unit of change means that the difference between two adjacent difficulty levels, defined by the minimum unit of change, remains constant. This helps control measurement errors and ensures the accuracy of the results.

[0064] In addition, to quickly get through "Phase 1" of the testing process (see Figure 3 To improve measurement efficiency, a larger minimum unit of change in the coherent motion ratio can be selected in the first few measurement trials, and then gradually reduced. Preferably, the minimum unit of change in the coherent motion ratio is initially set to 5%. After the first three measurement trials, it is adjusted to 2 / 5 of the initial value, i.e., 2%. After the adjustment, it is further adjusted to 1 / 5 of the initial value, i.e., 1%, after another three measurement trials.

[0065] Optionally, the parameter setting module can also set several options for the motion range of the motion element. Generally, the motion range is a circular area with a diameter ranging from 10 to 25 degrees of viewing angle. Preferably, the diameter is 20 degrees of viewing angle.

[0066] Optionally, the parameters set by the parameter setting module also include the presentation time of the motion element. Generally, the presentation time of the motion element is 0.5 to 5.0 seconds. Preferably, the presentation time is 2.5 seconds.

[0067] The visual stimulus generation module can generate random dot motion stimuli for identification based on the parameters set by the parameter setting module and the consistency motion ratio transmitted by the process control module. Random dot motion stimuli include non-color random dot motion stimuli and color random dot motion stimuli, such as Figure 2 shown.

[0068] The non-color random dot motion stimulus consists of a black background and white motion elements, or a white background and black motion elements, and the motion elements are evenly distributed in a designated area of ​​the background; preferably, the shape of the motion elements is circular.

[0069] The colored random dot motion stimulus consists of a colored background and colored motion elements, and the motion elements are evenly distributed in a specified area on the background; the motion elements and the background have exactly the same brightness, but present different colors, the motion elements are the first color, and the background is the second color; preferably, the first color is red and the second color is green.

[0070] In the non-color and color random dot motion stimuli, some elements randomly selected from the motion elements are set as consistent motion elements, the number of which is round (total number of motion elements × consistent motion ratio), and the motion direction is one of several options for consistent motion directions set in the parameter setting module; all other remaining motion elements are random motion elements (or, inconsistent motion elements), and the motion direction is randomly selected from the random motion direction range set in the parameter setting module; where round(·) is the rounding function.

[0071] In the non-color and color random dot motion stimuli, the movement speed of all motion elements is consistent, which is the movement speed set in the parameter setting module.

[0072] If the moving element leaves the designated area on the background during the movement, the moving primary color is deleted and a new moving element is regenerated in the designated area; the newly generated moving element is completely consistent with the deleted moving element in terms of consistent motion properties (i.e., whether it is a consistent motion element or a random motion element), motion direction, motion speed, etc.

[0073] The direction of motion of the moving element can be directly obtained from the parameters set in the parameter setting module, or random directional noise can be added during the acquisition process to increase the difficulty of identification. The specific steps are as follows:

[0074] S1-1. Based on the parameters set in the parameter setting module, preliminarily determine the movement direction of the motion element, specifically:

[0075]

[0076] Where f(D) is the probability distribution function of the consistent motion direction set in the parameter setting module, or the probability density function of the random motion direction, RandomSampling(·) is the random sampling function, and D S1 It is the movement direction of the motion element that is preliminarily determined;

[0077] S1-2, build D S1 As the center, is the normal distribution of variance, and then random sampling is performed to determine the final movement direction, specifically

[0078]

[0079] in, So D S1 As the center, is the normal distribution of variance, RandomSampling(·) is the random sampling function, D S2 is the final direction of motion of the moving element. D 5 degrees.

[0080] The "probability distribution function of consistent motion direction, or the probability density function of random motion direction" mentioned in S1-1 is a function that describes the specific values ​​and probabilities of consistent motion directions or random motion directions. For example, if the consistent motion direction is equally likely to be "left" or "right," then the probability distribution function F(x) is:

[0081]

[0082] Wherein, x represents the direction of movement. A value of 0 represents the direction of movement to the left, and a value of 180 represents the direction of movement to the right.

[0083] If the direction of random motion ranges from 15 to 165 degrees and is selected with equal probability, then the probability density function F is:

[0084]

[0085] Where x represents the direction of motion and U(·) represents the uniform distribution function.

[0086] It should be noted that some unconventional methods may be used when identifying consistent motion direction. For example, focusing on a portion of moving elements, regardless of whether these elements have consistent motion directions, and inferring the consistent motion direction based solely on the direction of these moving elements. This method does not always produce correct results, but when the focused moving elements persist for a long time, this method may still yield a correct answer with a certain probability, significantly improving the measurement results for individuals with poor consistent motion perception.

[0087] To avoid these issues, a regular refresh mechanism can be implemented for random dot motion stimuli. For example, a random dot motion stimulus that originally appeared for 2.5 seconds can now be refreshed every 0.5 seconds, resulting in a total of four refreshes within the 2.5-second presentation period. This regular refresh method effectively shortens the lifespan of motion elements. Specifically, without a regular refresh mechanism, motion elements generally have a longer lifespan, refreshing only when they leave the designated motion range on the background during motion. However, with a regular refresh mechanism, upon the expiration of the refresh time, all motion elements are deleted and new ones are generated. The total number of newly generated motion elements remains the same as before the refresh, and the positions of all new motion elements are randomly generated according to the rules used to generate the motion stimulus. The consistent motion attributes of the new motion elements (i.e., whether they are consistent or random) are all randomly assigned. Characteristics such as the speed, direction, and range of motion of all motion elements remain unchanged before and after the refresh. It can be seen that this periodic refresh setting can regulate the life cycle of all motion elements, effectively reducing the possibility of the aforementioned abnormal identification method obtaining correct identification results, and improving the accuracy of the measurement.

[0088] When evaluating the differences in consistent motion direction perception between different measured individuals, it's also necessary to consider the impact of differences in the measured individuals' ability to perceive motion elements on the final consistent motion direction perception. That is, it's possible that measured individuals A and B have no difference in their ability to integrate motion element information, but because A is nearsighted and didn't wear glasses during the measurement, A's ability to discern motion elements is reduced, ultimately resulting in B's measurement result for consistent motion direction perception being significantly better than A's. To avoid false positives like these, it's sometimes necessary to adjust the discernibility of motion elements based on the individual's situation during measurement.

[0089] To ensure that the identifiability of motion elements is consistent across different individuals being measured, the motion elements can be set as gratings with a specific brightness or color contrast. The specific method is:

[0090] (1) The motion element in the non-color random dot motion stimulus is set as a motion grating with brightness change characteristics. The specific formula is:

[0091]

[0092] Among them, l(x,y,t) represents the brightness of the point with coordinates (x,y) on the moving grating at time t; L meanis the average brightness of the moving grating; C is the brightness contrast of the moving grating; f is the spatial frequency of the moving grating (in cycles / degree); DPD is the visual angle occupied by each pixel on the moving grating image (in degrees / pixel); θ is the orientation of the moving grating, perpendicular to the direction of motion; ω is the temporal frequency of the moving grating (in cycles / second); φ is the grating phase.

[0093] When the moving element in the non-color random dot motion stimulus is a moving grating, the background is no longer black or white, but should be gray, and the brightness is the average brightness of the moving grating (that is, L in the above formula). mean ).

[0094] (2) The motion element in the color random dot motion stimulus is set as a motion grating with color change characteristics. The specific formula is:

[0095]

[0096]

[0097]

[0098] Among them, l(x,y,t) represents the brightness of the point with coordinates (x,y) on the moving grating at time t; l(x,y,t) colorl Indicates the brightness of the point corresponding to the first color at time t; l(x,y) color2 Indicates the brightness of the point corresponding to the second color at time t; L mean，color1 represents the brightness of the background with the first color; C is the color contrast of the moving grating, f is the spatial frequency of the moving grating (unit: "cycles / degree"); DPD is the visual angle occupied by each pixel on the moving grating image (unit: "degrees / pixel"); θ is the orientation of the moving grating, perpendicular to the direction of motion; ω is the temporal frequency of the moving grating (unit: "cycles / second"); φ is the grating phase.

[0099] By configuring the moving elements as gratings, the brightness or color contrast can be adjusted to ensure that different individuals can identify the moving elements at the same level. For example, if individual A has good vision and is highly able to identify moving elements, a lower brightness or color contrast can be used in the moving elements presented to A. For individual B, who has poorer vision, a higher brightness or color contrast can be used, ensuring that both individuals A and B can identify the moving elements at the same level.

[0100] When generating visual stimuli, the initial value of the consistent motion ratio also needs to be considered. The necessity of shortening "Phase 1" during the test process has been explained above. From this perspective, it seems that the closer the initial difficulty is to the actual functional level of the individual being measured, the shorter Phase 1 will be, and the more conducive it will be to improving the accuracy of the measurement results. However, a lower initial difficulty that is far from the actual functional level of the individual being measured is beneficial for the individual being measured to identify the stimulus at the beginning of the measurement and quickly become familiar with the measurement process, avoiding errors caused by unfamiliar operations that reduce the accuracy of the measurement results. Therefore, the most appropriate choice is to appropriately adjust the initial difficulty so that it is relatively close to, rather than absolutely close to, the actual functional level of the individual being measured. In general, the initial value is set in the range of 30% to 50%. Preferably, the initial value is set to 35%.

[0101] After the visual stimulus is generated, it is presented to the individual being measured by the human-computer interaction module under the control of the process control module. After the stimulus is presented, the individual being measured must determine which of several predetermined options the motion direction of the portion of motion elements with consistent motion directions is moving in. Once this determination is complete, the individual can provide feedback to the system using a device such as a mouse, keyboard, or controller in the human-computer interaction module regarding their identification of the consistent motion direction. After obtaining the individual's identification, the system generates and presents the next motion stimulus. This cycle continues until all trials are completed.

[0102] Furthermore, the display device in the human-computer interaction module should be able to accurately display motion stimuli. This was previously a problem when using traditional cathode-ray tube (CRT) displays to display motion stimuli. This is because in traditional CRT displays, the brightness changes of the pixels on the display are caused by an electron beam striking the phosphor screen. As soon as the electron beam strikes the screen, the phosphor immediately begins to glow, and when the electron beam disappears, the glow ceases immediately, leaving a very short residual glow. Consequently, traditional CRT displays have a response time of only 1 to 3 milliseconds, allowing them to accurately display most motion stimuli. However, today's displays are mostly liquid crystal displays (LCDs), and pixel brightness changes on LCDs are primarily achieved by applying voltage to the liquid crystal molecules, causing them to twist. This twisting and recovery process takes time, resulting in a relatively long response time for LCDs, which often results in a trailing effect in dynamic images (especially those requiring accurate motion display). Therefore, when using LCDs to present motion stimuli, at least three frames of each identical image should be maintained to avoid smearing and ensure accurate display of the motion stimuli. Furthermore, to avoid the illusion of motion, the phase difference between adjacent frames of the grating should not exceed 90 degrees. This means that at least four frames are required to complete one cycle (360 degrees) of grating movement. Furthermore, for a moving grating with a temporal frequency of ω (unit: cycles / second), at least 4ω frames are required per second. Converted to the refresh rate of the display device (i.e., the number of frames that can be displayed in 1 second), 4ω frames correspond to 12ω frames.

[0103] Therefore, the display device used to present motion stimuli in the human-computer interaction module should ensure that the relationship between its refresh rate and the motion speed of the motion elements in the random point motion stimulus meets the following conditions:

[0104]

[0105] where ω is the temporal frequency of the motion element (i.e., the motion grating) in the random-dot motion stimulus.

[0106] During the measurement process, the process control unit will continuously adjust the consistency movement ratio of the random motion stimulus in the next trial based on the recognition status of the measured person, specifically:

[0107] S2-1. If the current trial is the first trial, the first value of the consistency movement ratio is used;

[0108] S2-2. If the measured individual correctly identified the consistent motion direction of the random dot motion stimulus in the previous trial, then in the next trial, the consistent motion ratio of the random dot motion stimulus is reduced by 1 minimum change unit; if the identification result in the previous trial is incorrect, then in the next trial, the consistent motion ratio 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;

[0109] S2-3. If the number of trials presented to the measured individual has reached the set maximum test amount, or the consistent movement ratio fluctuates repeatedly within the first specified range, or the consistent movement ratio has reached the upper and lower limits of the measured range for three consecutive times or five times in total, the test is terminated.

[0110] Figure 3 This diagram illustrates the progress of a test. Each circle represents a trial. The horizontal axis indicates its position within the total number of trials, and the vertical axis indicates the difficulty level of the coherent motion of the stimulus presented in that trial. The difference between adjacent levels on the vertical axis is 1 degree. The "√" mark above the circle and the "×" mark below the circle indicate the individual's identification of the stimulus in that trial. As can be seen from the diagram, except for the first six trials at the beginning of the test, for all trials in which the individual correctly identified the stimulus (i.e., "√"), the difficulty level of the next trial increased by one level, meaning the proportion of coherent motion decreased by 1%. For incorrect identification (i.e., "×"), the difficulty level of the next trial decreased by three levels, meaning the proportion of coherent motion increased by 3%.

[0111] 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 additional movement direction 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 24th and 28th trials) 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 individuals should be between 9% and 14% of the consistent movement ratio.

[0112] therefore, Figure 3The 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 10), 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.

[0113] Theoretically, it can be predicted that in Phase 2, when the difficulty level of the consistent motion ratio of the presented stimulus reaches the true level of the individual being measured, there should be the following relationship:

[0114]

[0115] in, It is the probability that the measured individual can correctly perceive the stimulus after it appears when the proportion of consistent movement reaches the true level of the measured individual. It is the degree to which the proportion of consistent movement in the next trial decreases after the measured individual correctly perceives and gives feedback. It is the probability that the individual being measured fails to perceive the stimulus correctly when the proportion of consistent movement reaches the true level of the individual being measured. It is the degree to which the proportion of consistent movements in the next trial increases when the measured individual does not correctly perceive and give feedback.

[0116] Combined with the above rule, "In one trial, if the result of the measured individual identifying the stimulus is correct, then in the next trial, the proportion of consistent movement decreases by 1 minimum change unit; if the identification result is wrong, then in the next trial, the proportion of consistent movement increases by the first specified number (n) minimum change units", we can deduce the above formula ,in accordance with The established facts can be deduced in one step Specifically, when n is 2, ; When n is 3, ; When n is 4, ; When n is 5, Therefore, theoretically, when n takes different values ​​and is combined with sufficient testing volume, the above process control method can specify the threshold value of the consistent motion ratio under a specific resolution accuracy.

[0117] Of course, due to the limitations of measurement accuracy (the minimum unit of change in the coherent motion ratio) and the existence of various errors, the coherent motion ratio of the stimulus presented in actual measurement is unlikely to exactly reach the true level of the measured individual, and generally fluctuates repeatedly 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 circles marked with “×” in the figure) and the data points that “changed from misidentification to correct identification” ( Figure 3 The arithmetic mean of the corresponding coherent movement ratios (circles marked with a "√" in the figure) is used to infer the true level of the measured individual. Statistically, the more data points there are, the closer the arithmetic mean of the corresponding coherent movement ratios will be to the measured individual's true level. In other words, the larger the test volume, the more accurate the analysis results.

[0118] 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.

[0119] It's worth noting that measurement accuracy in this system is controlled by adjusting the minimum unit of change in the coherent motion ratio (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.

[0120] The system will record data during the measurement process and analyze the data after the measurement is completed. The specific contents include:

[0121] S3-1. Based on the recorded data, list the proportion of consistent movements used in each trial completed normally, as well as the correct / incorrect status of the stimulus identification by the measured individual;

[0122] S3-2. Based on the list compiled in S3-1, select the consistent motion ratios where the trend of the consistent motion ratio changes during the measurement process, and record them all as C cri ;

[0123] S3-3, 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, enter S3-4;

[0124] S3-4, if all C criIf the difference between the maximum and minimum values ​​does not exceed the minimum change unit of the third specified number of consistent motion ratios, then all C cri The arithmetic mean of is the threshold of the measured individual's consistent motion perception ability to random point motion stimulation; otherwise, proceed to S3-5;

[0125] S3-5, 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 arithmetic mean of the values ​​is the threshold of the measured individual's consistent motion perception ability to random point motion stimuli.

[0126] Among them, the C mentioned in S3-4 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 cri If the difference between them is large, the first few C can be eliminated in S3-5. 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.

[0127] Based on the description of S3-1 to S3-5, it can be understood that if the C cri If the frequency always fluctuates within the first specified range and has accumulated to the fourth specified number, then even if the number of tests at this spatial frequency has not reached the maximum test amount, the test at this spatial frequency can be terminated in advance and the existing C cri Calculate the sensitivity of the measured individual at the spatial frequency. Generally, the fourth specified number has a value range of 6 to 20. Preferably, the fourth specified number is 8.

[0128] It should be noted that terminating the test early under the above conditions effectively shortens the measurement time while ensuring the reliability of the measurement results. Therefore, when the individual being measured is a young child who has difficulty concentrating for a long time, the above settings can help complete the test as quickly as possible while ensuring measurement validity.

[0129] 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 system for measuring consistent motion perception, characterized in that: include: Parameter setting module, used to set parameters related to measurement; The visual stimulus generation module generates random point motion stimuli for identification based on the parameters set by the parameter setting module and the consistency motion ratio transmitted by the process control module; The human-computer interaction module presents random point motion stimuli to the measured individual and obtains the measured individual's recognition of the consistent motion direction in the motion stimulus; The process control module adjusts the consistency movement ratio until the measured individual's recognition of the movement stimulus meets the preset requirements; The data recording and analysis module records the consistent motion ratio of all motion stimuli during the measurement process, as well as the response data of the measured individuals, and analyzes and determines the threshold of consistent motion perception ability.

2. The consistent motion perception ability measurement system according to claim 1, characterized in that: The minimum unit of change in the consistency movement ratio is 5%. After completing the initial three trial measurements, it is adjusted to 2 / 5 of the initial value. After completing the measurement of another three trials after adjustment, it is further adjusted to 1 / 5 of the initial value.

3. The consistent motion perception ability measurement system according to claim 1, characterized in that: The random dot motion stimuli generated by the visual stimulus generation module include non-color random dot motion stimuli and color random dot motion stimuli.

4. The consistent motion perception ability measurement system according to claim 3, characterized in that: When determining the movement directions of the consistent movement elements and the inconsistent movement elements according to the consistent movement direction and the random movement direction range set in the parameter setting module, the specific steps are as follows: S1-1. Preliminarily determine the direction of motion of the moving element and record it as D S1 ; S1-2, build D S1 As the center, is a normal distribution with a variance, and then random sampling is performed to determine the final movement direction.

5. The consistent motion perception ability measurement system according to claim 3, characterized in that: Random dot motion stimulation periodically refreshes the position and consistent motion properties of all motion elements, but does not refresh other features such as motion speed and consistent motion direction.

6. The consistent motion perception ability measurement system according to claim 3, characterized in that: The motion element in the random dot motion stimulus can also be a motion grating, specifically: The moving element in the non-color random dot motion stimulus is a moving grating with brightness change characteristics; When the moving element in the non-color random dot motion stimulus is a moving grating, the background is gray and the brightness is the average brightness of the moving grating; The motion element in the color random dot motion stimulus is a motion grating with color change characteristics.

7. The consistent motion perception ability measurement system according to claim 1, characterized in that: In the process control module, the method for adjusting the consistency motion ratio is as follows: S2-1. If the current trial is the first trial, the first value of the consistency movement ratio is used; S2-2. If the subject correctly identified the consistent motion direction of the random dot motion stimulus in the previous trial, then in the next trial, the consistent motion ratio of the random dot motion stimulus is reduced by 1 minimum change unit; if the identification result in the previous trial was incorrect, then in the next trial, the consistent motion ratio is increased by the first specified number of minimum change units; S2-3. If the number of trials presented to the measured individual has reached the set maximum test amount, the test is terminated.

8. The consistent motion perception ability measurement system according to claim 7, characterized in that: The data recording and analysis module analyzes and determines the threshold of the motion direction discrimination ability of the measured individual in the following specific steps: S3-1. Based on the recorded data, list the proportion of consistent movements used in each completed trial and the stimulus recognition of the measured individual; S3-2. Based on the list compiled in S3-1, select the consistent motion ratios where the trend of the consistent motion ratio changes during the measurement process, and record them all as C cri ; S3-3, if C cri If the number of is less than the second specified number, the analysis ends; otherwise, the process goes to S3-4; S3-4, if all C cri If the difference between the maximum and minimum values ​​does not exceed the minimum change unit of the third specified number of consistent motion ratios, then all C cri The arithmetic mean of is the threshold of the measured individual's consistent motion perception ability to random point motion stimulation; otherwise, proceed to S3-5; S3-5, in all C cri In the order of appearance, remove the preset number of C cri , so that the remaining C cri The number of is even, then take all the remaining C cri The arithmetic mean of the values ​​is taken as the threshold of the consistent motion perception ability of the measured individual to random dot motion stimuli.

9. The consistent motion perception ability measurement system according to claim 8, characterized in that: Step S2-3 further includes terminating the test when the consistency motion ratio repeatedly fluctuates within the first specified range; The proportion of consistent movements presented to the measured individual fluctuates repeatedly within the first specified range, specifically: the last obtained C cri Based on the first specified range, the fourth specified number of C cri .

10. The consistent motion perception ability measurement system according to claim 6, characterized in that: The relationship between the refresh rate of the display device used to present random dot motion stimulation in the human-computer interaction module and the motion speed of the motion elements in the random dot motion stimulation is: , where ω is the temporal frequency of the motion elements in the random dot motion stimulus.

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