RU87343U1 - DEVICE FOR STUDYING INERTIALITY OF HUMAN VISUAL SYSTEM - Google Patents

Abstract

A device for studying the time of inertia of the visual system, comprising a first light source, a second light source, characterized in that a microcontroller, a liquid crystal display module, a test subject’s control panel containing controls and an additional nine pairs of light sources are additionally introduced into the device.

Description

The device relates to medical equipment and is intended to study the time of inertia of the human visual system.

A device for experimental research of the time of inertia of the visual system, containing a pendulum that sets the exposure time of the brand and a set of contrast filters [1]. On this device, the threshold contrast e is measured for an object during stationary observation, then, at different contrasts K _n created by a given set of filters, the effective contrast K _{e is} brought to the visibility threshold by selecting the exposure time t defined by the swing amplitude of the pendulum. For the time of inertia of the visual system, the effective time for maintaining the visual impression is taken and at an exposure time of t <0.01, it is determined by the formula:

q = K _n t / e.

The disadvantage of this device is its complexity, the use of the mechanical principle of setting the exposure time, which reduces the accuracy of determining the inertia time.

A device for studying the bandwidth of a human visual analyzer based on a small PROMIN-M digital computer, including a digital display, its control units, a delay device (PP9-2 m), analysis units for the accuracy of receiving a digital signal and a memory unit [2]. As test signals use the numbers shown on digital lamps IN-1 on the electronic computer display every 7 seconds. The display shows the first number from the digital array with the exposure time set before the experiment, after which an erasing image appears on the display. The test subject recognizes each number and types it on the keyboard. The dispatcher program compares this number with the subject typed on the keyboard. The error and exposure time at which it was made is recorded.

Recognition time, that is, the time required for image recognition, depends on the inertia parameters of the visual system and is determined by the time of perception of visual information [3, 4].

The disadvantage of this device is its complexity and the long duration of the experiment, which leads to fatigue of the visual system and a decrease in the accuracy of measurements.

The closest in technical essence to the proposed device is a device for studying the inertia of the visual system, containing a second pulse generator, a millisecond pulse generator, a first one-shot, a second one-shot, a third one-shot, a light source, an indication unit and a counter, the output of a second pulses generator is connected to the input of the first one-shot, the output of the counter is connected to the input of the display unit, (optionally introduced) an exclusive OR element, a second light source, the first key To reduce the adjustable delay of presenting one pulse relative to another by 1 ms, the second key to increase the adjustable delay of presenting one pulse relative to another by 5 ms, a generator of a series of five pulses and a shaper of the time interval, the output of the first one-shot being connected to the input of the second one-shot and to the first the input of the time interval shaper, the second input of which is connected to the counter output, the third input - with the output of the millisecond pulse generator, and the output - with the first input of the element that exclusive OR, whose output is connected to the input of the first light source, and the second input to the output of the second one-shot, the output of which is connected to the input of the second light source, the output of the first key is connected to the input of the third one-vibrator, the output of which is connected to the first input of the counter, the output of the second key connected to the input of a generator of a series of five pulses, the output of which is connected to the second input of the counter [5].

The time of inertia of the human visual system with the simultaneous presentation of two light pulses is equal to the value of the threshold delay time of a pulse that is adjustable in duration relative to the beginning of a reference pulse of constant duration or the threshold time of an early end of a pulse that is adjustable in duration relative to the end time of a reference pulse at the moment of subjective feeling that the light pulses start or end at the same time [5, 6].

The disadvantage of this device is the impossibility of studying inertia by early termination of a pulse that is adjustable in duration relative to the reference one, the duration of the inertia determination procedure, the lack of statistical processing of measurement results, and the inability to save measurement results.

The technical result consists in expanding the functionality of the device by using a microcontroller by adding a second mode of operation, which allows to study the inertia, changing the early end time of a pulse that is adjustable in duration relative to the reference one, reducing the duration of the procedure for determining the inertia time of the human visual system, calculating the arithmetic mean value and standard deviation of the results measurements and their confidence intervals, saving measurement results.

The technical result is achieved by the fact that in the device for studying the time of inertia of the visual system, containing the first light source, the second light source, a microcontroller, a liquid crystal display module, a test subject’s panel containing controls and an additional nine pairs of light sources are additionally introduced.

Figure 1 presents the structural diagram of the inventive device.

Figure 2 presents the sequence of pairs of presented light pulses repeated over a time interval T equal to 1 s, where Fig. 2a is a timing diagram of a reference light pulse with a duration of t _imp = 80 ms; figb is a timing diagram of an adjustable in duration light pulse delayed relative to the reference at time t _back , causing a feeling that the impulses presented do not start simultaneously; FIG. 2 c is a timing chart of a pulse of duration controlled by a pulse delayed relative to the time of presentation of the reference for a threshold time t _{ass. pore} , causing a sensation that the presented pulses start simultaneously; FIG. 2d is a timing chart of a light pulse that is adjustable in duration and ends earlier than the reference one at time t _ok , causing a feeling that the impulses presented do not end simultaneously; 2b is a timing chart of a pulse-width-adjustable pulse that ends earlier than the time of presentation of the reference for a threshold time t _{approx. pores} , causing a feeling that the pulses presented are ending at the same time.

The inventive device contains a microcontroller 1, a liquid crystal display module 2, the remote control 3.

Microcontroller 1 is a standard microcontroller having one free 8-bit port for connecting a liquid crystal display module, four free 8-bit ports for connecting a test panel and non-volatile memory for storing measurement results.

The liquid crystal display module 2 is designed to display the operating mode, delay time or early end of the adjustable pulse of the first pair relative to the reference, the results of statistical processing. As the liquid crystal display module, for example, an MT-16S2H liquid crystal module can be used.

Subject 3 remote control contains:

- ten pairs of light sources that are intended for the presentation of light pulses are connected to any ports of the microcontroller 1 and can be performed, for example, on the ALS307EM LEDs. The reference pulse is presented by the first light source of each pair, and the adjustable impulse is presented by the second light source of each pair;

- ten keys made in the form of control buttons, with each pair of light sources corresponding to one of the buttons. Each button is designed to signal the controller about the choice of the subjects pair of light sources;

- keys "Start", "Increase the interval of repetition", "Reduce the interval of repetition", "Statistical processing" and the switch "Operation mode", with the provisions: "Delay of the adjustable pulse" and "Early end of the adjustable pulse". The keys are made in the form of control buttons. The “Start” button is designed to send a signal to the controller to exit the standby mode and to start presenting a sequence of pulses. The buttons "Increase the repetition interval" and "Decrease the repetition interval" are intended to send signals to the controller to change the duration of the repetition interval T pairs of pulses (figa) with individual selection of the repetition interval in the range from 0.5 s to 1.5 s in increments of 0 , 1 p. The button “Statistical processing” is designed to send a signal to the controller to perform statistical processing of the measurement results: calculation of the arithmetic mean value, standard deviation of the series of measurements and their confidence intervals, the subsequent transfer of the microcontroller to standby mode. The “Operating mode” switch is used to set the operating mode of the device. When the switch is set to the "Adjustable pulse delay" position, pairs of pulses are presented to the test subject, and the beginnings of pulses regulated in duration are delayed relative to the reference ones. When the switch is set to the "Early end of the adjustable pulse" position, the test subject is presented with a pair of pulses, moreover, the pulses regulated in duration end earlier than the reference ones.

The device operates as follows. When you turn on the power on the liquid crystal display module 2 displays the operating mode of the device, the microcontroller goes into standby mode. The "Operating mode" switch of the test 3 remote control is set to the "Adjustable pulse delay" position. The test subject presses the “Start” button of the test subject’s remote control 3.

At the first stage, the microcontroller 1 generates a reference pulse supplied to the first LED of each pair, and an adjustable pulse supplied to the second LED of the first pair, delayed by 5 ms relative to the start of the reference.

In each subsequent pair, the duration of the reference pulse is constant, and the delay time of the beginning of the adjustable pulse relative to the beginning of the reference is increased by 5 ms compared to the delay of the adjustable pulse relative to the beginning of the reference previous pair. The delay values of the adjustable pulses are shown in table 1.

Table 1 No. of LED pairs one 2 3 four 5 6 7 8 9 10 Time delay for the presentation of an adjustable pulse (ms) 5 10 fifteen twenty 25 thirty 35 40 45 fifty

The pulse sequence is repeated with an interval of T = 1c. The test subject, if necessary, changes the duration of the interval of repetition T in the range from 0.5 s to 1.5 s in increments of 0.1 s (figa, b), by the required number of clicks of the buttons “Increase the interval of repetition” or “Decrease the interval repetition of the test subject’s remote control 3.

The subject determines the pair of LEDs with the highest number for which he subjectively senses that the reference and duration-adjustable pulses start at the same time, and presses the corresponding button on the test subject's remote control 3. The delay time for presenting the adjustable pulse of this pair relative to the reference t _task1 is fixed.

At the second stage, the microcontroller 1 generates a reference pulse supplied to the first LED of the first pair and an adjustable pulse supplied to the second LED of the first pair, delayed relative to the start of the reference by time t _ass1 .

In each subsequent pair, the duration of the reference pulse is constant, and the duration of the delay of the adjustable pulse relative to the beginning of the reference is increased by 0.5 ms compared to the delay of the adjustable pulse relative to the beginning of the reference previous pair. The delay values of the adjustable pulses are shown in table 2.

table 2 No. of LED pairs one 2 3 four 5 Time delay for the presentation of an adjustable pulse (ms) t _{ass 1} t _{ass 1} +0.5 t _ass1 +1 t _ass1 +1.5 t _{ass 1} +2 No. of LED pairs 6 7 8 9 10 Time delay for the presentation of an adjustable pulse (ms) t _ass1 +2.5 t _back1 ⁺ 3 t _{ass 1} ⁺ 3,5 t _{ass 1} +4 t _ass1 +4.5

The subject determines the pair of LEDs with the highest number, for which he subjectively senses that the reference and duration-adjustable pulses start at the same time, and presses the corresponding button on the test subject's remote control 3. The value of the delay time for the presentation of the adjustable pulse of this pair relative to the reference t reference _time is fixed and received for assessing the time of inertia of the human visual system.

The microcontroller 1 enters the value of the inertia time of the human visual system t _backspace into the non-volatile memory of the microcontroller 1, generates an adjustable pulse supplied to the second LED of the first pair, which is delayed relative to the beginning of the reference pulse supplied to the first LED of the first pair by a random value lying in the interval of (t _zad.por - 2) ms to (t _zad.por - 5) msec when (t _zad.por - 5) <0 or (t _zad.por - 2) <0 in the interval from 0 to t _{ass .perms} ms. In each subsequent pair, the duration of the reference pulse is constant, and the delay time of the beginning of the adjustable pulse relative to the beginning of the reference is increased by 5 ms compared to the delay of the adjustable pulse relative to the beginning of the reference previous pair.

The test subject performs the specified number of measurements and presses the button “Statistical processing” of the control panel of test 3. Microcontroller 1 calculates the arithmetic mean and standard deviation of the series of measurements and their confidence intervals, enters the results of the calculations into the non-volatile memory of microcontroller 1, displays them on the liquid crystal display module 2, and switches to Standby mode.

The switch "Operation mode" of the remote control of the test 3 is set to "Early termination of the adjustable pulse". The test subject presses the “Start” button of the test subject’s remote control 3.

At the first stage, the microcontroller 1 generates a reference pulse supplied to the first LED of the first pair and an adjustable pulse supplied to the second LED of the first pair, ending earlier than the reference by 5 ms.

In each subsequent pair, the duration of the reference pulse is constant, and the value of the early end of the adjustable pulse relative to the reference is increased by 5 ms compared to the early end of the adjustable pulse relative to the reference previous pair. The values of the early termination of the adjustable pulses are shown in table 3.

Table 3 No. of LED pairs one 2 3 four 5 6 7 8 9 10 Time for the early end of the adjustable pulse (ms) 5 10 fifteen twenty 25 thirty 35 40 45 fifty

The pulse sequence is repeated with an interval of T = 1c. The test subject, if necessary, changes the duration of the interval of repetition of T in the range from 0.5 s to 1.5 s in increments of 0.1 s (figa, b), by the required number of clicks of the buttons “Increase the interval of repetition” or “Decrease the interval repetition of the test subject’s remote control 3.

The subject determines the pair of LEDs with the highest number, for which he subjectively feels that the reference and duration-adjustable pulses end simultaneously, and presses the corresponding button on the test subject's remote control 3. The value of the time for the end of presentation of the controlled pulse of this pair relative to the reference t _t1 is fixed.

At the second stage, the microcontroller 1 generates a reference pulse supplied to the first LED of the first pair and an adjustable pulse supplied to the second LED of the first pair, ending earlier _{than the} reference one at a time t _ok1 .

In each subsequent pair, the duration of the reference pulse is constant, and the value of the early end of the regulated pulse relative to the beginning of the reference pulse is increased by 0.5 ms compared to the early end of the controlled pulse relative to the reference previous pair. The values of the early termination of the adjustable pulses are shown in table 4.

Table 4 No. of LED pairs one 2 3 four 5 Time for the early end of the presentation of the adjustable pulse (ms) t _ok1 t _ok1 +0.5 t _ok1 +1 t _ok1 +1.5 t _ok1 +2 No. of LED pairs 6 7 8 9 10 Time for the early end of the presentation of the adjustable pulse (ms) t _ok1 +2.5 t _ok1 +3 t _ok1 +3.5 t _ok1 +4 t _ok1 +4.5

The subject determines the pair of LEDs with the highest number, for which he subjectively senses that the reference and duration-adjustable pulses end simultaneously, and presses the corresponding button on the test subject’s remote control 3. The value of the time for the end of presentation of the regulated pulse of this pair relative to the reference t is _approx. taken as an estimate of the time of inertia of the human visual system.

The microcontroller 1 enters the value of the inertia time of the human visual system t _ok.pore into the non-volatile memory of the microcontroller 1, generates a reference pulse supplied to the first LED of the first pair and an adjustable pulse supplied to the second LED of the first pair, which ends earlier than the reference by a random value lying in interval from (t _{approx. pore} - 2) ms to (t _{approx. pore} - 5) ms, at (t _{approx. pore} - 5) <0 or (t _{approx. pore} - 2) <0 in the range from 0 to t _approx . ms In each subsequent pair, the duration of the reference pulse is constant, and the value of the early end of the adjustable pulse relative to the reference is increased by 5 ms compared to the early end of the adjustable pulse relative to the previous reference pair.

The test subject performs the specified number of measurements and presses the button “Statistical processing” of the control panel of test 3. Microcontroller 1 calculates the arithmetic mean and standard deviation of the series of measurements and their confidence intervals, enters the results of the calculations into the non-volatile memory of microcontroller 1, displays them on the liquid crystal display module 2, and switches to Standby mode.

To study the inertia of the visual system, the subject is presented with a sequence of pairs of pulses repeating over a specified time interval T. During responses to light pulses, the receptive field of a small neuron appears first. Then the receptive field expands, after which it weakens, fragmentes and disappears. After the disappearance of the receptive field, the neural structures return to their original state and become ready for the perception of a new stimulus. Since the formation of the receptive field occurs 20–80 ms after the inclusion of the light stimulus [7], the duration of the reference pulse is taken to be 80 ms.

The time interval T is selected from the condition of eliminating the influence of the masking effect, which consists in the deterioration of the perception of the first time light pulse due to the presentation of the second pulse in the immediate spatial and temporal proximity to the first. It was shown that there is not only a reverse effect, but also direct masking, in which the first light pulse affects the quality of perception of the second [8]. At an interpulse interval of 500 ms, masking effects are absent or weakly expressed [9]. To eliminate the masking effect, a sequence of pairs of light pulses is presented at an individually set time interval in the range from 500 to 1500 ms.

It was experimentally established that the inertia time of the human visual system is in the range from 15 to 25 ms [5]. In order for the subject to feel at first that the duration-controlled and reference pulses do not start or end at the same time, the delay or early termination value is taken to be 40 ms.

In order to expand the functionality of the device by adding a second mode of operation, which allows to study the inertia, changing the early end time of a pulse that is adjustable in duration relative to the reference one, calculate the arithmetic mean value and standard deviation of the measurement results and their confidence intervals, save the measurement results, a microcontroller and a liquid crystal are introduced into the device indication module, test subject's control panel containing controls and will complement Effective nine pairs of LEDs.

Information sources

1. Luizov A.V. Eye and Light.- L.: Energy, 1983.- 140 p.

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3. Ivanitsky A.M. Brain potentials in mental operations of varying degrees of complexity // Human Physiology. - 1989.- T.15. - Number 3. - S.11-18.

4. Sagittarius VB Violation of the physiological mechanisms of perception, emotions and thinking in certain types of mental pathology // Human Physiology. - 1989.- T.15. - Number 3. - S.135 -144.

5. Patent 2262293 of the Russian Federation, IPC А61В 3/02. A method for determining the time of inertia of the human visual system. / Petukhov I.V., Lezhnin A.V., Rozhentsov V.V. - Publ. 10/20/2005, Bull. No. 29.

6. The FIPS decision of 10.20.2008 on the grant of a patent for an invention on the application No. 2008102402/14 (002618). A method for determining the inertia of the human visual system / Rozhentsov V.V., Lezhnin A.V. (RF).

7. Shevelev I.A. Temporary signal processing in the visual cortex // Human Physiology. - 1997. - T.23. - No. 2. - S.68-79.

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Claims (1)

A device for studying the time of inertia of the visual system, comprising a first light source, a second light source, characterized in that a microcontroller, a liquid crystal display module, a test subject’s remote control, containing controls and an additional nine pairs of light sources are additionally introduced into the device.