A system for measuring consistent motion awareness

Abstract

The application provides a measurement system of consistent motion perception ability, comprising a parameter setting module, a visual stimulation generation module, a man-machine interaction module, a process control module and a data recording and analysis module; the visual stimulation generation module generates random point motion stimulation for recognition based on parameters set by the parameter setting module and a consistent motion ratio transmitted by the process control module; the process control module adjusts the consistent motion ratio until the recognition of the motion stimulation by the measured individual reaches a preset requirement; the data recording and analysis module quantifies the consistent motion perception ability of the measured individual, and the measurement precision can be adjusted through parameter setting, so that the application has a wide application prospect.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of motion perception ability detection, and particularly relates to a consistent motion perception ability measurement system. BACKGROUND

[0002] In real life, there are often examples of "there are many individuals moving in different directions in the field of vision, but only the motion directions of some individuals need to be recognized and focused on".

[0003] In some scenarios, there are cases of processing motion elements. For example, when people go shopping together with friends, they need to pay attention to each other's positions to prevent getting lost; for example, when a wolf pack hunts a wild ox, it will first disperse the wild ox herd, and then select and capture the old and weak or young wild ox. In such cases, biological individuals need to recognize all motion elements in the field of vision, and analyze and integrate information of some motion elements with specific characteristics.

[0004] For example, when determining the grouping of motion elements, it is necessary to determine which motion elements have specific characteristics and can be grouped together, and which motion elements cannot be combined with other elements because their characteristics do not meet the specified conditions. For elements that have been grouped together, it is further necessary to consider whether their characteristics need to be integrated.

[0005] This kind of ability to classify and integrate information of different motion elements is collectively referred to as "overall motion perception ability". Overall motion perception ability can be further divided into multiple subcategories according to different specific characteristics of the motion elements that need to be focused on. When the motion elements that need to be focused on have consistent or relatively consistent motion directions, the ability to perceive such motion is referred to as "consistent motion perception ability".

[0006] However, there are currently few devices or systems for measuring consistent motion perception ability. SUMMARY

[0007] The present application aims to solve the technical problems existing in the background art by providing a consistent motion perception ability measurement system. 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, which has broad application prospects.

[0008] To achieve the above-mentioned purpose, the present application provides the following technical solutions:

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

[0010] A parameter setting module for setting parameters related to measurement;

[0011] a visual stimulus generation module, generating the random dot motion stimulus for recognition based on the parameters set by the parameter setting module and the consistency motion proportion delivered by the flow control module;

[0012] a human-computer interaction module, presenting the random dot motion stimulus to the measured individual and obtaining the recognition of the consistency motion direction in the motion stimulus by the measured individual;

[0013] a flow control module, adjusting the consistency motion proportion until the recognition of the motion stimulus by the measured individual meets the preset requirement;

[0014] a data recording and analysis module, recording the consistency motion proportion of all motion stimuli in the measurement process and the reaction data of the measured individual, and analyzing and determining the consistency motion perception ability threshold.

[0015] Preferably, the minimum change unit of the change of the consistency motion proportion is 5%, after completing the initial 3 trial measurements, adjusting to 2 / 5 of the initial value, after completing 3 trial measurements after the adjustment, further adjusting 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 motion direction of the consistency motion element and the non-consistency motion element according to the direction of the consistency motion and the direction range of the random motion set in the parameter setting module, the specific steps are:

[0018] S1-1, initially determining the motion direction of the motion element, and recording it as D S1 ;

[0019] S1-2, constructing a normal distribution with D S1 as the center and as the variance, then performing random sampling to determine the final motion direction.

[0020] Preferably, the random dot motion stimulus periodically refreshes the positions and consistency motion attributes of all motion elements, but does not refresh other characteristics such as motion speed and consistency motion direction.

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

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

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

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

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

[0026] S2-1, if the current test is the first test, the consistent motion ratio uses the first value;

[0027] S2-2, if the consistent motion direction recognition result of the measured individual to the random dot motion stimulation in the previous test is correct, the consistent motion ratio of the random dot motion stimulation is reduced by one minimum change unit in the next test; if the recognition result in the previous test is incorrect, the consistent motion ratio is increased by the first specified number of minimum change units in the next test;

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

[0029] Preferably, the data recording and analysis module, the specific steps for analyzing and determining the motion direction discrimination ability threshold of the measured individual include:

[0030] S3-1, based on the recorded data, list the consistent motion ratio used in each test completed and the recognition of the measured individual to the stimulation;

[0031] S3-2, based on the list sorted out in S3-1, select the consistent motion ratio where the change trend of the consistent motion ratio in the measurement process changes, and all are recorded as C cri ;

[0032] S3-3, if the number of C cri is less than the second specified number, the analysis is ended; otherwise, enter S3-4;

[0033] S3-4, if the difference between the maximum value and the minimum value of all C cri does not exceed the third specified number of minimum change units of the consistent motion ratio, the arithmetic mean value of all C cri is determined as the consistent motion perception ability threshold of the measured individual to the random dot motion stimulation; otherwise, enter S3-5;

[0034] S3-5, among all C cri , according to the time order of appearance, a preset number of C cri is removed, so that the number of remaining C cri is even, and then the arithmetic mean value of all remaining C cri is taken as the consistent motion perception ability threshold of the measured individual to the random dot motion stimulation.

[0035] Preferably, the step S2-3 further comprises that if the consistency motion ratio has reached the upper and lower limits of the measured range for a continuous preset number of times, the test is terminated.

[0036] The consistency motion ratio presented to the measured individual repeatedly fluctuates within the first specified range, specifically referring to: taking the last obtained C cri as the reference, the fourth specified number of C cri has been accumulated within the first specified range.

[0037] Preferably, the refresh rate of the display device for presenting the random point motion stimulus in the human-computer interaction module is related to the motion speed of the motion element in the random point motion stimulus as follows:

[0038]

[0039] wherein ω is the time frequency of the motion element in the random point motion stimulus.

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

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

[0042] The present application will be further described below in combination with the drawings.

[0043] Figure 1 The system principle diagram of the present application.

[0044] Figure 2 The schematic diagram of the random point motion stimulus.

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

[0046] As shown in Figure 1 , a motion direction discrimination ability measurement system of the present application, comprising:

[0047] A parameter setting module for setting parameters related to measurement, including the size, motion speed, motion range and total number of the motion element, the direction of the motion element consistency motion, and the direction range of the random motion, the minimum change unit of the consistency motion ratio, and the maximum test amount;

[0048] a visual stimulus generation module, which generates the random dot motion stimulus for recognition based on the parameters set by the parameter setting module and the coherence motion proportion passed by the flow control module;

[0049] a human-computer interaction module, which presents the random dot motion stimulus to the measured individual and acquires the recognition correct / incorrect situation of the measured individual on the coherence motion direction in the motion stimulus;

[0050] a flow control module, which continuously adjusts the coherence motion proportion based on the recognition situation of the measured individual on the coherence motion until the recognition situation of the measured individual on the motion stimulus reaches the specified requirement;

[0051] a data recording and analysis module, which records the coherence motion proportion of all motion stimuli in the measurement process and the reaction data of the measured individual, and analyzes and determines the coherence motion perception ability threshold under the specified correct recognition rate based on the data.

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

[0053] The size and total number of the motion elements set in the parameter setting module have a certain relationship with the accuracy of the measurement result. If the area occupied by a single motion element is too large, when multiple elements move simultaneously, it may cause serious mutual overlap and interfere with the recognition of the coherence motion direction. Therefore, the single motion element should not be too large and the number should not be too many. Generally, the proportion of the area occupied by all motion elements (i.e., the size of a single element x the total number) to the area of the motion range (for example, a circular area with a diameter of 20 degrees of visual angle) should not exceed 25%.

[0054] On the other hand, the single motion element should not be too small. If the single motion element is too small, when the measured person has poor eyesight, the difficulty of the measured person in recognizing the single motion element itself may further interfere with his recognition of the coherence motion direction. Therefore, the size of the single motion element is generally 0.25-1.00 square degrees, and the degree is the unit of visual angle.

[0055] Generally, the motion speed of the motion element is 1.00-10.00 degrees per second.

[0056] In the motion element, part of the elements have a unified motion direction, which is called "coherence motion direction", and the remaining elements have completely random motion direction.

[0057] The consistent motion direction of the motion elements, usually set as 2-4 directions, is used as the option for the subject to judge the consistent motion direction. For example, "left" or "right", "up" or "down", "left up 45 degrees", "right up 45 degrees", "left down 45 degrees" or "right down 45 degrees". When the subject judges the consistent motion direction of the motion elements, he / she should choose the most possible option from several options. It should be noted that the difference between the set direction options should be relatively large. For example, the difference between "left" and "right" is 180 degrees, and the difference between "left down 45 degrees" and "right down 45 degrees" is 90 degrees. If the difference is small or very small, the measurement result reflects more on the "consistent motion direction discrimination ability" rather than the "consistent motion direction perception ability".

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

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

[0060] Wherein, one trial represents "presenting a stimulus once and receiving the subject's recognition of the presented stimulus".

[0061] The proportion of the number of motion elements with consistent motion direction to the total number of motion elements is called "consistent motion proportion". The consistent motion proportion changes constantly during the measurement process to help the measurement system determine the minimum value of the consistent motion proportion under the condition of meeting the specified recognition accuracy, i.e., the "consistent motion perception ability threshold".

[0062] The minimum change unit of the consistent motion proportion set in the parameter setting module is directly related to the measurement accuracy. The minimum change unit is equivalent to the smallest scale of the measurement tool (e.g., meter ruler or vernier caliper) in length measurement. Therefore, the smaller the minimum change unit, the higher the measurement accuracy. Of course, the minimum change unit is not the smaller the better. According to the flow control rules of the system (see later), the smaller the minimum change unit, the more difficult it is to present the stimulus during the measurement process (i.e., the consistent motion proportion) from the initial level to the level corresponding to the true functional level of the subject (see Figure 3The longer the "Phase One" in the process, the more test times and time are consumed. In the case of fixed test amount in a single reference movement direction, the more test times consumed in Phase One, the less test times in Phase Two which has a decisive influence on the measurement result, the less data obtained in Phase Two, and the lower accuracy of the measurement result (the analysis method of data in Phase Two and its relationship with the measurement result will be described later). Therefore, it is unnecessary to pursue a small minimum change unit too much.

[0063] Generally, the minimum change unit should be determined before measurement and kept stable during measurement. The stable minimum change unit means that the gap between two adjacent difficulty levels defined by the minimum change unit is fixed. This helps to control the error in the measurement process and ensure the accuracy of the measurement result.

[0064] In addition, in order to quickly pass the "Phase One" in the test process (see Figure 3 ), improve the measurement efficiency, a larger consistent movement ratio minimum change unit can be selected in the first few test times of measurement, and then gradually reduced. Preferably, the initial value of the consistent movement ratio minimum change unit is set to 5%, and after completing the initial 3 test times of measurement, it is adjusted to 2 / 5 of the initial value, i.e. 2%, and after completing 3 test times of measurement after adjustment, it is further adjusted to 1 / 5 of the initial value, i.e. 1%.

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

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

[0067] The visual stimulus generation module can generate random point movement stimuli for recognition based on the parameters set by the parameter setting module and the consistent movement ratio passed by the flow control module. The random point movement stimuli include non-color random point movement stimuli and color random point movement stimuli, as shown in Figure 2 .

[0068] The non-color random point movement stimulus is composed of a black background and white movement elements, or a white background and black movement elements, and the movement elements are uniformly distributed in the specified area of the background; preferably, the shape of the movement element is circular.

[0069] The color random dot motion stimulus is composed of a color background and color motion elements, the motion elements are uniformly distributed in a specified area on the background; the motion elements and the background have 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 stimulus, part of the elements randomly selected from the motion elements are set as consistent motion elements, the number is round (total number of motion elements x consistent motion proportion), and the motion direction is one of the several options set in the parameter setting module; all other motion elements are random motion elements (or, non-consistent motion elements), and the motion direction is randomly selected from the direction range of the random motion set in the parameter setting module; wherein, round(·) is a rounding function.

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

[0072] If the motion element leaves the specified area on the background during the motion process, the motion element is deleted and a new motion element is generated in the specified area; the newly generated motion element is completely consistent with the deleted motion element in terms of consistent motion attributes (i.e., whether it belongs to consistent motion elements or random motion elements), motion direction, motion speed, etc.

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

[0074] S1-1, based on the parameters set in the parameter setting module, the motion direction of the motion element is preliminarily determined, specifically:

[0075]

[0076] Wherein, 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, D S1 is the preliminarily determined motion direction of the motion element;

[0077] S1-2, a normal distribution with D S1 as the center and as the variance is constructed, and then random sampling is performed to determine the final motion direction, specifically

[0078]

[0079] wherein, is a normal distribution with D S1 as the center, as the variance, and RandomSampling(·) is a random sampling function, D S2 is the final determined motion direction of the motion element. Preferably, σ D is 5 degrees.

[0080] The "probability distribution function of the consistent motion direction, or the probability density function of the random motion direction" mentioned in S1-1 is a function describing the specific numerical value of the consistent motion direction or the random motion direction and the probability of the value. For example, if the consistent motion direction is selected with equal probability in "left" or "right", the probability distribution function F(x) is:

[0081]

[0082] wherein, x represents the motion direction, and the value of 0 represents the motion direction to the left, and the value of 180 represents the motion direction to the right.

[0083] If the range of the random motion direction is 15-165 degrees, and the selection is with equal probability, the probability density function F is:

[0084]

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

[0086] It should be noted that when identifying the consistent motion direction, there may be some non-normal identification methods. For example, focusing on part of the motion elements, regardless of whether this part of the elements has a consistent motion direction, only according to the direction of this part of the motion elements to infer the consistent motion direction. This method does not always obtain the correct result, but when the survival time of the part of the motion elements focused on is longer, this method still has a certain probability of obtaining the correct answer, which will significantly improve the measurement results of some measurement individuals with poor consistent motion perception ability.

[0087] To avoid the above problems, a mechanism for periodic refreshing of random dot motion stimuli can be set. For example, the original 2.5-second random dot motion stimulus is now set to refresh every 0.5 seconds; within the 2.5-second presentation time, a total of 4 refreshes are performed. This periodic refreshing method can effectively shorten the survival period of the motion elements. That is, without setting periodic refreshing, the survival period of the motion elements is generally longer, and only when the motion elements leave the specified motion range on the background during the motion process will they be refreshed; but after setting periodic refreshing, as soon as the refresh time comes, all motion elements are deleted and new motion elements are generated; the total number of newly generated motion elements remains consistent with the total number of motion elements before refreshing, and the positions of all new motion elements are randomly generated according to the rules for generating motion stimuli before; the consistency of motion attributes in new motion elements (i.e., whether they belong to consistent motion elements or random motion elements) is randomly set again; the motion speed of all motion elements, the motion direction of consistent motion elements, and the motion direction range of random motion elements remain unchanged before and after refreshing. As can be seen, this periodic refreshing setting can control the life cycle of all motion elements, effectively reduce the possibility of obtaining correct recognition results by the aforementioned abnormal recognition method, and improve the accuracy of measurement.

[0088] When assessing the differences in the ability to perceive consistent motion direction among different measured individuals, the differences in the ability of the measured individuals to perceive motion elements also need to be considered, which affects the final consistent motion direction perception ability. That is, measured individuals A and B may have no difference in the ability to integrate motion element information, but A has decreased recognition ability for motion elements because A is nearsighted and did not wear glasses during measurement, resulting in a measurement result of B's consistent motion direction perception ability that is significantly better than A. To avoid the above false positive results, the recognizability of motion elements needs to be adjusted according to the situation of different measured individuals during measurement.

[0089] To ensure the recognizability of motion elements by different measured individuals, motion elements can be set as gratings with specific brightness contrast or color contrast. The specific way is:

[0090] (1) In non-color random dot motion stimuli, motion elements are set as motion gratings with brightness variation characteristics, and the specific formula is:

[0091]

[0092] where l(x, y, t) represents the brightness of the point with coordinates (x, y) on the motion grating at time t; L meanL is the average luminance of the moving grating; C is the luminance contrast of the moving grating; f is the spatial frequency of the moving grating (unit: "cycle / degree"); DPD is the visual angle occupied by each pixel point on the image of the moving grating (unit: "degree / pixel"); θ is the orientation of the moving grating, which is perpendicular to the moving direction; ω is the time frequency of the moving grating (unit: "cycle / second"); and φ is the grating phase.

[0093] When the moving element in the non-color random point motion stimulation is a moving grating, the background is no longer black or white, but gray, and the luminance is the average luminance of the moving grating (i.e., L in the above formula). mean ).

[0094] (2) The moving element in the color random point motion stimulation is set to a moving grating with color change characteristics, and the specific formula is:

[0095]

[0096]

[0097]

[0098] wherein l(x, y, t) represents the luminance of a point with coordinates (x, y) on the moving grating at time t; l(x, y, t) colorl represents the luminance corresponding to the first color in the luminance of the point at time t; l(x, y) color2 represents the luminance corresponding to the second color in the luminance of the point at time t; L mean，color1 represents the luminance 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: "cycle / degree"); DPD is the visual angle occupied by each pixel point on the image of the moving grating (unit: "degree / pixel"); θ is the orientation of the moving grating, which is perpendicular to the moving direction; ω is the time frequency of the moving grating (unit: "cycle / second"); and φ is the grating phase.

[0099] On the basis of the above moving element being set to a grating, the recognition condition of the moving element by different individuals can be ensured to reach the same level by adjusting the luminance contrast or the color contrast. For example, when the visual acuity of a measured individual A is better and the recognition ability of the moving element is higher, a lower luminance contrast or color contrast can be used in the moving element presented to A, while a higher luminance contrast or color contrast is used for a measured individual B with poor visual acuity, so that the recognition conditions of the moving element by the measured individuals A and B reach the same level.

[0100] The initial value of the consistent motion proportion should also be considered when generating the visual stimulus. As mentioned above, it is necessary to shorten the "Phase One" in the test process. In this regard, it seems that the closer the initial difficulty is to the actual functional level of the measured individual, the shorter the "Phase One" and the more conducive to improving the accuracy of the measurement results. However, a lower initial difficulty, which is far from the actual functional level of the measured individual, is conducive to the measured individual identifying the stimulus at the beginning of the measurement and quickly familiarizing with the measurement process, avoiding errors caused by unfamiliar operation and reducing the accuracy of the measurement results. Therefore, it is the most appropriate choice to appropriately adjust the initial difficulty to be relatively close to but not absolutely close to the actual functional level of the measured individual. Generally, 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 can be presented to the measured individual under the control of the process control module by the human-computer interaction module. After the stimulus is presented, the measured individual should distinguish the motion direction of the part of the motion elements with consistent motion direction from all the motion elements, and determine which one of the several options is the motion direction. After the judgment is completed, the measured individual can feed back the recognition of the consistent motion direction to the system through the mouse, keyboard or handle in the human-computer interaction module. The system generates and presents the next motion stimulus after obtaining the recognition of the measured individual. The cycle continues until all the trials are completed.

[0102] In addition, the display device in the human-computer interaction module should be able to accurately display the motion stimulus. This was basically not a problem when using a traditional cathode ray tube display (i.e., CRT display) to display the motion stimulus. Because in the traditional CRT display, the brightness change of the pixel points on the display is caused by the electron beam hitting the fluorescent screen. As long as the electron beam hits the fluorescent screen, the fluorescent powder can immediately emit light, and when the electron beam disappears, it can immediately stop emitting light, and the afterglow time is very short. Therefore, the response time of the traditional CRT display is only 1-3 ms, and most motion stimuli can be accurately displayed. But now the display used is basically a liquid crystal display, and the brightness change of the pixel points on the liquid crystal display is mainly realized by applying voltage to the liquid crystal molecules and making the liquid crystal molecules twist. The process of liquid crystal molecule twisting and recovery needs time, so the response time of the liquid crystal display is relatively long, which often leads to the feeling of tail shadow dragging in dynamic pictures (especially motion stimuli that need to be accurately displayed). Therefore, when using a liquid crystal display to present a motion stimulus, each identical picture should be maintained for at least 3 frames to avoid the phenomenon of trailing and ensure the accurate display of the motion stimulus. In addition, in order to avoid the generation of motion illusion, the phase change of the gratings in adjacent two pictures of the display grating motion should not exceed 90 degrees. This means that the grating needs at least 4 pictures to move one cycle (360 degrees). Further, for a motion grating with a time frequency of ω (unit: cycle / s), at least 4ω pictures are needed per second. When converted into the refresh rate of the display device (i.e., the number of frames that can be displayed in 1 second), 4ω pictures correspond to 12ω frames.

[0103] Therefore, the display device for presenting the motion stimulus 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 dot motion stimulus satisfies the following conditions:

[0104]

[0105] Where ω is the time frequency of the motion elements (i.e., motion gratings) in the random dot motion stimulus.

[0106] During the measurement process, the flow control unit will continuously adjust the consistent motion proportion of the random motion stimulus in the next trial based on the recognition of the measured person, which is:

[0107] S2-1, if the current trial is the first trial, the consistent motion proportion uses the first value;

[0108] S2-2, if the consistency motion direction recognition result of the measured individual to the random point motion stimulus in the previous test is correct, then in the next test, the consistency motion proportion of the random point motion stimulus is reduced by 1 minimum change unit; if the recognition result in the previous test is incorrect, then in the next test, the consistency motion proportion is increased by the 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 tests presented to the measured individual has reached the set maximum test amount, or the consistency motion proportion repeatedly fluctuates within the first specified range, or the consistency motion proportion has reached the upper and lower limits of the measured range for 3 consecutive times or a total of 5 times, then the test is terminated.

[0110] Figure 3 A schematic diagram of the progress of a certain test is shown in the figure. The circles in the figure represent each test, and the horizontal coordinate represents the sequential position of the test among all tests, and the vertical coordinate represents the difficulty level of the consistency motion direction of the stimulus presented in the test. The difference between adjacent levels on the vertical coordinate is 1 degree. The "√" above and "×" below the circle in the figure represent the recognition of the measured individual to the stimulus in the test. From the figure, it can be seen that, except for the first 6 tests at the beginning of the test, when the measured individual recognizes correctly (i.e. "√"), the difficulty level in the next test is increased by 1 level, i.e. the consistency motion proportion is reduced by 1%; when the measured individual recognizes incorrectly (i.e. "×"), the difficulty level in the next test is reduced by 3 levels, i.e. the consistency motion proportion is increased by 3%.

[0111] The above flow 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, and rewards and punishments, etc.), and the test amount is large enough, the additional motion direction presented to the measured individual in the middle and later stages of the test will inevitably fluctuate around a certain specific level (see the situation after the 7th test in Figure 3 ). Even if there are occasional deviations from this level (see the 24th and 28th tests in Figure 3 ), they will be pulled back by the above flow rules (see the situation of the 29th to 34th tests in Figure 3 ). This specific level is actually the true functional level of the measured individual. For example, Figure 3 the true level of the measured individual in should be between 9% and 14% consistency motion proportion.

[0112] Therefore, Figure 3The whole testing procedure in the method can be divided into two stages. From the beginning of the test (the first trial) to the first time the recognition of the stimulus by the measured individual changes (the tenth trial), it belongs to stage one, and after that it belongs to stage two. In stage one, the difficulty level of the stimulus is gradually adjusted from the initial level to the level near the real functional level of the measured individual, which is the preparation stage for obtaining effective measurement data. In stage two, the difficulty level of the stimulus fluctuates near the real functional level of the measured individual, which is the stage of truly obtaining effective measurement data.

[0113] It can be theoretically predicted that in stage two, when the consistent motion proportion difficulty level of the presented stimulus reaches the real level of the measured individual, there should be the following relationship:

[0114]

[0115] wherein, is the probability that the measured individual can correctly perceive after the stimulus appears when the consistent motion proportion reaches the real level of the measured individual, is the degree of reduction of the consistent motion proportion in the next trial after the measured individual correctly perceives and feeds back, is the probability that the measured individual cannot correctly perceive after the stimulus appears when the consistent motion proportion reaches the real level of the measured individual, is the degree of increase of the consistent motion proportion in the next trial when the measured individual does not correctly perceive and feed back.

[0116] Combining the aforementioned rules, "in one trial, if the measured individual correctly recognizes the stimulus, the consistent motion proportion is reduced by one minimum change unit in the next trial; if the recognition result is incorrect, the consistent motion proportion is increased by the first specified number (n) of minimum change units", it can be deduced that , according to the established fact of , it can be deduced that . Specifically, when n takes 2, ; when n takes 3, ; when n takes 4, ; when n takes 5, . Therefore, theoretically, when n takes different values and is combined with sufficient test quantity, the above flow control method can specify the consistent motion proportion threshold at a specific resolution correct rate.

[0117] Of course, due to the limitation of measurement accuracy (the minimum change unit of consistent movement ratio) and the existence of various errors, it is difficult to exactly reach the true level of the measured individual in the actual measurement of the consistent movement ratio of the presented stimulus, and generally there is repeated fluctuation around the true level. Therefore, in the actual measurement, statistical methods can be used to take the arithmetic mean of the consistent movement ratio corresponding to the data points (circles marked with "X" in Figure 3 ) where "recognition correct is changed to recognition error" and the data points (circles marked with "√" in Figure 3 ) where "recognition error is changed to recognition correct" in the fluctuation process, so as to infer the true level of the measured individual. From the statistical law, the more the above data points, the closer the arithmetic mean of the consistent movement ratio corresponding to these data points to the true level of the measured individual. That is, the larger the test amount, the higher the accuracy of the analysis result.

[0118] In summary, the above process control method, data analysis rule and sufficient test amount can ensure the accuracy of the measurement result. Among them, the process control method can theoretically ensure the positioning of the test result on the S-shaped measurement curve, while the data analysis rule and sufficient test amount can ensure that the actual operation / analysis result approaches the theoretical value in statistics, meeting the operational demand of practical application.

[0119] It is worth mentioning that the control of measurement accuracy in the system can be realized by adjusting the minimum change unit of consistent movement ratio (i.e. the size of the difference between adjacent levels of stimulus intensity), which is not directly related to the process control method, data analysis rule and test amount. Therefore, the control of measurement accuracy and measurement result accuracy in the system is independent of each other and separated from each other.

[0120] During the measurement process, the system will record data, and after the measurement is completed, the system will analyze the data, the specific content including:

[0121] S3-1, based on the recorded data, list the consistent movement ratio used in each trial completed normally, and the correct / incorrect recognition of the stimulus by the measured individual;

[0122] S3-2, based on the list sorted out in S3-1, select the consistent movement ratio where the change trend of the consistent movement ratio changes during the measurement process, and all mark as C cri ;

[0123] S3-3, if the number of C cri is less than the second specified number, end the analysis and prompt "threshold cannot be determined, should be re-measured"; otherwise, go to S3-4;

[0124] S3-4, if all C crithe difference between the maximum and minimum values of all C cri , the arithmetic mean of the remaining C cri is the threshold of the consistent motion perception ability of the measured individual to the random point motion stimulus; otherwise, go to S3-5.

[0125] S3-5, among all C cri , the first 3 or 4 C cri are removed in the order of time, so that the number of the remaining C cri is even, and then the arithmetic mean of all the remaining C cri is taken as the threshold of the consistent motion perception ability of the measured individual to the random point motion stimulus.

[0126] The analysis method of taking the arithmetic mean of C cri mentioned in S3-4 has been described above. However, in actual operation, the first several C cri obtained in the measurement process are less reliable than the subsequent C cri due to the unfamiliarity of the measured individual with the measurement method and process and possible operation errors. Therefore, under the premise of ensuring a sufficient number of C cri and a large difference between C cri , the first several C cri can be removed in S3-5 to improve the accuracy of the analysis result. In addition, the purpose of “removing the first 3 or 4 C cri so that the number of the remaining C cri is even” is also to ensure that the number of data points that “change from recognizing correctly to recognizing incorrectly” and the number of data points that “change from recognizing incorrectly to recognizing correctly” in the remaining C cri are the same, so as to provide the accuracy of the analysis result.

[0127] Based on the description of S3-1 to S3-5, it can be understood that if the C cri fluctuate within the first specified range all the time during the measurement process and have accumulated to the fourth specified number, the test at this spatial frequency can be terminated in advance even if the number of tests at this spatial frequency has not reached the maximum test amount, and the sensitivity of the measured individual at this spatial frequency can be calculated using the existing C cri . Generally, the value of the fourth specified number is in the range of 6-20. Preferably, the fourth specified number is 8.

[0128] It should be noted that the test is terminated in advance under the above conditions, which effectively shortens the measurement time on the basis of ensuring the reliability of the measurement results. Therefore, when the measured individual is a child who has difficulty in concentrating for a long time, the above setting helps to complete the test as soon as possible on the basis of ensuring the effectiveness of the measurement.

[0129] The above merely describes specific embodiments of the present application, but the technical features of the present application are not limited thereto. Any simple change, equivalent replacement or modification made on the basis of the present application for realizing basically the same technical effects is included in the protection scope of the present application.

Claims

1. A measurement system for consistent motion sensing capability, characterized in that, include: The parameter setting module is used to set measurement-related parameters; The visual stimulus generation module generates random point motion stimuli for identification based on the parameters set by the parameter setting module and the consistent 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 stimuli. The process control module adjusts the proportion of consistent movement until the measured individual's recognition of the movement stimulus reaches the preset requirements. The data recording and analysis module records the proportion of consistent motion for all motion stimuli during the measurement process, as well as the response data of the measured individual, and analyzes and determines the threshold of consistent motion perception ability. The specific steps for analyzing and determining the threshold of an individual's ability to distinguish the direction of movement include: S3-1. Based on the recorded data, list the proportion of consistent movement used in each completed trial, as well as the individual's recognition of the stimulus. S3-2. Based on the list compiled in S3-1, select the points where the trend of the uniform motion ratio changes during the measurement process, and denote them all as C. cri ; S3-3, If C cri If the number is less than the second specified number, the analysis ends; otherwise, proceed 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 movement proportions, then all C values ​​are determined. cri The arithmetic mean of the values ​​is the threshold for the measured individual's consistent motion perception ability to random point motion stimuli; otherwise, proceed to S3-5. S3-5, in all C cri In the middle, according to the order of their appearance, remove a preset number of C's. cri This makes the remaining C cri If the quantity is even, then take all the remaining C. cri The arithmetic mean of the values ​​is used as the threshold for the measured individual's consistent motion perception ability to random point motion stimuli.

2. The measurement system for consistent motion sensing capability according to claim 1, characterized in that, The minimum unit of change for the uniform motion ratio is 5%. After completing the first three trials, it is adjusted to 2 / 5 of the initial value. After completing another three trials, it is further adjusted to 1 / 5 of the initial value.

3. The measurement system for consistent motion sensing capability according to claim 1, characterized in that, The random point motion stimuli generated by the visual stimulus generation module include non-colored random point motion stimuli and colored random point motion stimuli.

4. The measurement system for consistent motion sensing capability according to claim 3, characterized in that, Based on the direction range of consistent motion and random motion set in the parameter setting module, the specific steps for determining the motion direction of consistent motion elements and non-consistent motion elements are as follows: S1-1. Initially determine the direction of motion of the moving elements and denote it as D. S1 ; S1-2, Constructing D S1 Centered on, The variance follows a normal distribution, and then randomized sampling is performed to determine the final direction of motion.

5. The measurement system for consistent motion sensing capability according to claim 3, characterized in that, Random point motion stimuli periodically refresh the position and consistent motion attributes of all motion elements, but do not refresh the motion speed and consistent motion direction.

6. The measurement system for consistent motion sensing capability according to claim 3, characterized in that, The motion element in a random point motion stimulus is a motion grating, specifically: The motion element in the non-color random point motion stimulus is a motion grating with brightness variation characteristics; When the motion element in the non-color random point motion stimulus is a motion grating, the background is gray and the brightness is the average brightness of the motion grating; The motion elements in the color random dot motion stimulus are motion gratings with color change characteristics.

7. The measurement system for consistent motion sensing capability 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 is used for the consistency motion ratio. S2-2. If the measured individual correctly identifies the consistent movement direction of the random point motion stimulus in the previous trial, the proportion of consistent movement of the random point motion stimulus will decrease by 1 minimum change unit in the next trial; if the identification result is incorrect in the previous trial, the proportion of consistent movement will increase by the first specified number of minimum change units in the next trial. S2-3. If the number of tests presented to the individual being measured has reached the maximum set number of tests, then the test shall be terminated.

8. The measurement system for consistent motion sensing capability according to claim 1, characterized in that, Steps S2-3 also include terminating the test if the proportion of consistent motion fluctuates repeatedly within a first specified range. Among them, the proportion of consistent movement presented to the measured individual fluctuates repeatedly within a first specified range, specifically referring to: the proportion of the last obtained C cri Based on the first specified range, a fourth specified number of C has been accumulated. cri .

9. A measurement system for consistent motion sensing capability according to claim 6, characterized in that, The refresh rate of the display device used to present random point motion stimuli in the human-computer interaction module is related to the motion speed of the moving elements in the random point motion stimuli as follows: ； Where ω is the time frequency of the motion element in the random point motion stimulus.

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