CN103989474B - Human visual electrophysiological simulation device and method - Google Patents

Abstract

The invention provides a human eye visual electrophysiological simulation device, which includes a photoelectric conversion module, an integral measurement module, a pulse shaping module, a timing module, a timing module, a signal generation module, an operation control module, an input interface module and a display interface module. The external optical signal is input to the photoelectric conversion module, the photoelectric conversion module, the pulse shaping module, the timing module, the timing module, and the signal generation module are connected in sequence. The module, the signal generating module, the display interface module and the input interface module are respectively connected. The invention also provides a method for simulating human visual electrophysiology. The advantages of the human eye visual electrophysiological simulation device and method of the present invention are: it can quantitatively simulate the visual electrophysiological activities of the human eye when receiving flash stimulation and graphic stimulation in visual electrophysiological examination, the accuracy is high, it is easy to adjust, and it is widely applicable to measurement and quality control areas.

Description

Human visual electrophysiological simulation device and method

technical field

The invention relates to a detection device and method, in particular to a human eye visual electrophysiological simulation device and method.

Background technique

When the human eye is stimulated by a light signal, the human visual system will generate a corresponding electrical signal after a certain delay, which is called a visual electrophysiological signal. The signal can be detected by electrodes in the cornea, nasotemporal or occipital lobe of the human eye. The duration of the visual electrophysiological signal is generally tens to hundreds of milliseconds, and the amplitude is generally several microvolts to hundreds of microvolts.

The process of detecting visual electrophysiological signals is divided into two steps: applying light stimulation signals to human eyes and measuring visual electrophysiological signals. In visual electrophysiological examination items such as electroretinogram and visual evoked potential, flashing or graphic stimulation signals are usually used. The former is a light stimulation signal with short duration and high instantaneous brightness emitted by a xenon lamp or LED, which can be a single flash or multiple flashes periodically; the latter is the alternating light and dark grids of the bright and dark checkerboard graphics displayed on the monitor. The changing light stimulation signal is generally alternately changing periodically and multiple times. The human eye's response to the flash stimulus starts at the end of each flash pulse, while the response to the graphic stimulus starts at the moment when the bright grid changes to dark grid and the dark grid changes to bright grid. The human eye is stimulated by a standardized light stimulation signal, and the abnormal changes in the measured visual electrophysiological signal amplitude and delay imply pathological information in different links of the visual system. For example, the measurement indicators of a single flash ERG include the latency, the peak times and amplitudes of waves a and b, etc., while the measurement indicators of the graphic ERG include the peak times and amplitudes of P50 and N95, etc. The prolongation of the peak time or the decrease of the amplitude usually means a local lesion of the visual system, and in the clinical visual electrophysiological examination, the measurement result is usually compared with the reference value corresponding to the examination item for diagnosis.

Instruments that diagnose visual diseases by measuring visual electrophysiological signals are collectively referred to as visual electrophysiological instruments. The parameters of the flash stimulus sent by the visual electrophysiological instrument include flash intensity, flash duration, flash frequency, background brightness, etc., and the parameters of the graphic stimulus include the brightness of the bright grid and the dark grid of the graphic, and the flipping frequency of the graphic. Physiological signal parameters include amplitude and time. The former is the peak value and valley value of the signal, and the latter is the time elapsed from the application of the optical stimulation signal to the appearance of the characteristic electrical signal, which represents the synchronous delay relationship between the electrical signal and the optical stimulation signal. . The change of light stimulation parameters directly affects the visual response of the human eye, thereby affecting the diagnosis of visual diseases by doctors. For this reason, in the standard documents issued by the International Society for Clinical Visual Electrophysiology, there are clear regulations on the values of the light stimulation parameters used in the visual electrophysiological examination, and the instrument needs to be checked and calibrated regularly. For example, the document stipulates that the flash intensity of the standard flash electroretinogram examination is 3.0cd·s/m2, the error is not more than ±10%, and the flash duration is not more than 5ms. Under the action of standardized light stimulation signals, the visual electrophysiological instrument also needs to accurately measure the amplitude and time parameters of the visual electrophysiological signals of the human eye in order to ensure the reliability of clinical diagnosis. Visual electrophysiology instrument is widely used in the clinical diagnosis of various fundus diseases, such as retinopathy, macular degeneration, optic nerve disease, cataract and glaucoma, etc. It can be used as an effective objective test for infants, the elderly, uncooperative or pseudoblind people. Visual function detection. Visual electrophysiology is a quantitative detection instrument. The accuracy of its light stimulation parameters and electrical signal measurement results directly affects the doctor's diagnosis and is related to the health and interests of patients, so it is necessary to use special detection tools for regular detection.

In order to realize the detection and calibration of the visual electrophysiological instrument, a device that can quantitatively simulate the visual electrophysiological activity of the human eye is required, and the following requirements must be met at the same time:

Automatically identify flash stimulation and graphic stimulation, and send corresponding standard electrical signals according to the type and parameters of light stimulation, thereby simulating the visual electrophysiological activities of the human eye;

It can measure the flash intensity, flash duration, flash frequency and background brightness of flash stimulation;

It can measure the brightness of the bright grid, the brightness of the dark grid and the flipping frequency of graphics stimulation;

After detecting the light stimulation signal, a standard electrical signal can be sent after a certain time delay;

The delay time between receiving the light stimulation signal and sending out the standard electrical signal is adjustable;

It is easy to adjust to ensure its own accuracy.

However, in the prior art, no human eye visual electrophysiological simulation device or visual electrophysiological instrument detection device has appeared, and the demand for a device capable of quantitatively simulating human visual electrophysiological activity cannot be met by the prior art.

Contents of the invention

The purpose of the present invention is to overcome the existing problems and defects of the prior art, to provide a human visual electrophysiological system that can automatically identify the type of light stimulus, quantitatively simulate the visual electrophysiological activity of the human eye, and detect and calibrate the visual electrophysiological instrument. Simulation device and method.

In order to achieve the above object, the human eye visual electrophysiological simulation device provided by the present invention includes a photoelectric conversion module, an integral measurement module, a pulse shaping module, a timing module, a timing module, a signal generation module, an operation control module, an input interface module and a display interface module, wherein: the external optical signal is input to the photoelectric conversion module, the photoelectric conversion module, pulse shaping module, timing module, timing module, and signal generation module are connected in sequence, and the photoelectric conversion module is connected to the photoelectric conversion module through the integral measurement module The operation control module is connected to the operation control module, and the operation control module is connected to the timing module, timing module, signal generation module, display interface module and input interface module respectively; the photoelectric conversion module converts the light stimulation signal into an electrical signal and outputs it to the The pulse shaping module and the integral measurement module, the pulse shaping module outputs a square wave signal corresponding to the light stimulation signal, the square wave signal triggers the timing module and the timing module, and the timing module judges the type of light stimulation and controls The timing module starts timing from the corresponding time point, the integral measurement module measures the integral value of the brightness and time of the light stimulation signal under the synchronous control of the pulse measurement module, and the operation control module receives the input interface module The input parameters are set, the integral measurement results are calculated, and electrical signals are output through the signal generation module, and at the same time, the state parameters and measurement results are output to the display interface module.

The human eye visual electrophysiological simulation device of the present invention, wherein said operation control module adopts the single-chip microcomputer chip that the model is STC89C51 and the programmable crystal oscillator chip that the model is SG-8002 to form; The 12-bit analog-to-digital conversion chip of ADS804, the reference voltage chip of model TL431 and the single-chip microcomputer chip of model STC89C51; The timing module adopts the counter chip of model 74LS90, the counter chip of model 82C54, the monostable flip-flop chip of model 74LS121, the OR chip of model 74V1T32, the NAND chip of model 74LS132, the model It is composed of an AND gate chip of LN74SZ08; the timing module is composed of a counter chip of the type 82C54; wherein: the data bit pin and the control bit pin of the single-chip microcomputer chip in the operation control module are respectively connected with the single-chip microcomputer chip of the integral measurement module, The timing module is connected with the counter chip, signal generation module, input interface module and display interface module in the timing module; the output pin of the photoelectric detection module is respectively measured by the non-inverting input terminal and integral measurement of the operational amplifier chip in the pulse shaping module through the resistance The non-inverting input terminal of the operational amplifier chip in the module is connected; the TXD and RXD pins of the single-chip microcomputer in the integral measurement module are connected with the RXD and TXD pins of the single-chip microcomputer in the operation control module; the NAND gate chip in the pulse shaping module The 2Y pin of the integrated measurement module is connected to the P2.1 pin of the single-chip microcomputer chip in the integral measurement module, and the B pin of one monostable flip-flop chip in the timing module and the A1 and A2 pins of the other monostable flip-flop chip Pins, counter 0 and GATE0 pins of the counter chip, and 4A and 4B pins of the NAND gate chip are connected correspondingly; the 1Y pin of the OR gate chip in the timing module is connected to the GATE0 pin of the counter chip in the timing module. The A1 and A2 pins of the steady-state trigger chip are connected with the P2.0 pin of the single-chip microcomputer chip; the OUT0 pin of the chip in the timing module is connected with the signal generation module.

In order to achieve the above object, the simulation method of the human eye visual electrophysiological simulation device provided by the present invention comprises the following steps:

Step 1, converting the photostimulation signal into an electrical signal whose amplitude is proportional to the brightness of the photostimulation signal, and performing integral measurement on the electrical signal;

Step 2. Identify the type of light stimulus signal, convert the integral measurement signal into a square wave signal, measure the width of the square wave by timing, and identify the flash stimulus signal and the graphic stimulus signal by the difference in time characteristics. If it is a flash stimulus signal, execute Next step; if it is a graphic stimulus signal, perform step 4;

Step 3, if the luminescence corresponds to the high level of the square wave, and the interval between two luminescences corresponds to the low level of the square wave, then the integrated measurement result during the high level period is used as the intensity of the flash pulse, while the integral measurement during the low level period The result is taken as the integral value of the background brightness versus time, the high-level time of the timing measurement results is taken as the time course of the flash stimulus, the sum of the high-level time and the low-level time is taken as the period of the flash stimulus, and the reciprocal is taken as the frequency of the flash stimulus, The integral value of the background brightness to time is divided by the time interval as the background brightness value, and step 5 is performed;

Step 4. Use the edge of the square wave signal to perform segmented integral measurement. The square wave is in the bright grid state corresponding to the graphic stimulus at a high level, and the square wave is in the dark grid state corresponding to the graphic stimulus at a low level. The square wave is obtained by integral measurement respectively. Integral value of graphics brightness to time at high level and low level, timing measurement to obtain high level duration time value and low level duration time value, and divide the two integral values by the corresponding time respectively, and respectively As the brightness of the bright grid and the dark grid of the graphics, add the duration value of the high level and the duration of the low level as the graphics flip cycle, take its reciprocal as the graphics flip frequency, and execute the next step;

Step 5, input setting parameters on the input interface, and output integral measurement, timing measurement and their calculation results to the display interface.

The advantages of the human eye visual electrophysiological simulation device and method of the present invention are: due to the integration measurement module, timing module, timing module, signal generation module, and operation control module, the human eye can be quantitatively simulated when the visual electrophysiological examination is stimulated by flashing light. Visual electrophysiological activity during graphic stimulation, including automatically judging the type of optical stimulation signal, and sending out a corresponding standard visual electrophysiological analog signal according to the type of optical stimulation and the measured optical stimulation parameters. The timing module and the timing module are independent from the operation control module and the signal generation module, which has high precision and is easy to adjust, and is widely used in the fields of measurement and quality inspection.

Description of drawings

Fig. 1 is the block diagram of human eye visual electrophysiological simulation device of the present invention;

Figure 2 is a schematic diagram of the waveform of flash stimulation;

Fig. 3 is a schematic diagram of the waveform of graphic stimulation;

Fig. 4 is a schematic circuit diagram of the human eye visual electrophysiological simulation device of the present invention.

Detailed ways

Embodiments of the human eye visual electrophysiological simulation device and method of the present invention will be described in detail below with reference to the accompanying drawings.

Referring to Fig. 1, the human eye visual electrophysiological simulation device provided by the present invention includes a photoelectric conversion module, an integral measurement module, a pulse shaping module, a timing module, a timing module, a signal generation module, an operation control module, an input interface module and a display interface module . The external optical signal is input to the photoelectric conversion module, and the photoelectric conversion module, pulse shaping module, timing module, timing module, and signal generation module are connected in sequence. The photoelectric conversion module is connected to the operation control module through the integral measurement module. The module, the signal generating module, the display interface module and the input interface module are respectively connected.

The photoelectric conversion module converts the light stimulation signal into an electrical signal and outputs it to the pulse shaping module and the integral measurement module. The pulse shaping module outputs a square wave signal corresponding to the light stimulation signal. The square wave signal triggers the timing module and the timing module, and the timing module judges the light Stimulus type and control the timing module to start timing from the corresponding time point, the integral measurement module measures the brightness and time integral value of the light stimulation signal under the synchronous control of the pulse measurement module, the operation control module receives the parameter setting input by the input interface module, Calculate and integrate the measurement results, and output electrical signals through the signal generation module, and at the same time, output state parameters and measurement results to the display interface module.

In the simulated visual electrophysiological examination, it includes the electroretinogram and visual evoked potential activities when the human eye is stimulated by flashes and graphics. When receiving a flash stimulus or a graphic stimulus, measure the flash intensity, flash duration, flash frequency and background brightness of the flash stimulus, the bright grid brightness, dark grid brightness and graphic flipping frequency of the graphic stimulus, and at the same time, after a preset delay A standard electrical signal is sent out at time, and parameters such as the amplitude, waveform and delay of the electrical signal can be preset, and the parameter correspondence between the standard electrical signal and the light stimulation signal can also be preset. in:

Flash intensity: the integral of flash brightness versus time, in cd s/m2;

Flash duration: the duration of the flash, in ms;

Flash frequency: the number of flashes per unit time, in Hz;

Background brightness: the brightness of the flash stimulator before emitting flash stimulation, the unit is cd/m2;

Graphics flip frequency: the number of times that the bright grid changes to dark grid and back to bright grid in unit time, the unit is Hz.

Below the embodiment that the human eye visual electrophysiological simulation device of the present invention provides is described as follows:

1. Identification of the type of photostimulation signal

The human eye visual electrophysiological simulation device identifies the type of light stimulus based on the difference in time characteristics between the flash stimulus and the graphic stimulus. Regardless of whether the light source used for the flash stimulation of the visual electrophysiological apparatus is a xenon lamp or an LED, the duration of light emission does not exceed 5ms. The frequency of flash stimulation is not more than 30Hz, and the pattern flip frequency is not more than 10Hz, which means that the interval between two consecutive flashes and the interval between pattern flips are both much greater than 5ms. Referring to Fig. 2 and Fig. 3, shown is the waveform schematic diagram of the square wave outputted by the flash stimulus and the pattern stimulus after passing through the photoelectric conversion module and the pulse shaping module, and the light stimulus type can be judged by measuring the width of the square wave by the timing module, thereby further Control the working mode of the timing module and the output of the signal generation module.

2. Measurement of Flash Parameters

After the flash stimulation signal is converted into an electric pulse signal by the photoelectric conversion module, it is respectively received by the pulse shaping module and the integral measurement module. The pulse shaping module detects the start and end times of the pulse signal, and sends out a corresponding square wave signal, which is used to control the integral measurement module. If the light emission corresponds to the high level of the square wave, the interval between two light emission corresponds to the low level of the square wave. Then, the result measured by the integral measurement module during the high level period is the intensity of the flash pulse, and the result measured during the low level period is the integral value of the background brightness versus time. The pulse shaping module outputs the square wave signal to the timing module, and the timing module measures the high level time and low level time of the square wave signal, and outputs the measurement result to the calculation control module. The high-level time is the duration of flash stimulation; the sum of high-level time and low-level time is the period of flash stimulation, and the reciprocal is the frequency of flash stimulation. The operation control module divides the integrated value of the background brightness versus time measured by the integral measurement module by the time interval, and the result is the background brightness value. If the light corresponds to the low level of the square wave, and the intermittent corresponds to the high level of the square wave, the working principle is similar.

3. Measurement of graphic parameters

After the pattern inversion signal passes through the photoelectric conversion module and the pulse shaping module, the inversion changes of the bright grid and the dark grid of the graphic are converted into corresponding square wave signals. The edge-controlled integral measurement module of the square wave signal performs subsection integral measurement. When the square wave is in the state of high level and low level, it corresponds to the state of bright grid and dark grid of graphic stimulation respectively. The integral measurement module respectively measures the integrated value of the graphic brightness versus time when the square wave is at high level and low level, and the timing module measures the duration value of the high level and low level. The control calculation module divides the integral value by the corresponding time to obtain the brightness of the bright grid and the dark grid of the graphic; the duration of the high level and the low level is added to obtain the graphic flip cycle, and the inverse of it is the graphic flip frequency.

4. Electric signal delay occurs

The flash stimulation signal or graphic stimulation signal is converted into a square wave signal after passing through the photoelectric conversion module and the pulse shaping module. The timing module judges the type of the light stimulation signal according to the width of the square wave and controls the work of the timing module according to the judgment result. If it is a flash stimulation signal, the timing module starts timing from the moment when each flash ends; if it is a pattern stimulation signal, the timing module starts timing from the moment of each pattern flip. The operation control module can control the signal generation module to output corresponding standard visual electrophysiological analog signals according to the type of light stimulation and the measured parameters, and can also control the signal generation module to output standard electrical signals such as square waves and sine waves according to the input parameters of the input interface module. Signal. After the signal generation module is ready, the timing module reaches the timing time to trigger the signal generation module to start outputting standard electrical signals. The delay introduced by the photoelectric conversion module and the pulse shaping module can be controlled at the microsecond level, which is negligible compared with the millisecond time of the timing module and the timing module; the operation of the operation control module and the signal generation module is the same as that of the timing module and the timing module It is carried out at the same time. After the signal generation module is ready, the timing module triggers the output of standard electrical signals, which avoids the delay error caused by the uncertainty of its own running time; the timing module and the timing module operate independently to ensure the accuracy of time. , and easier to adjust.

With reference to Fig. 4, in the embodiment of human eye visual electrophysiological simulation device of the present invention, operation control module adopts the single-chip microcomputer chip U1 of model STC89C51 and the programmable crystal oscillator chip of model SG-8002 to form, wherein SG-8002 generation frequency is 10MHz clock signal.

The integral measurement module is composed of an operational amplifier chip model OPA642, a 12-bit analog-to-digital conversion chip model ADS804, a reference voltage chip model TL431 and a single-chip microcomputer chip U3 model STC89C51, in which TL431 provides ADS804 for analog-to-digital conversion The reference voltage of the single-chip microcomputer chip U3 reads the analog-to-digital conversion data for calculation and outputs the result.

The pulse shaping module is composed of a proportional amplifier circuit composed of two operational amplifier chips of model OP07AJ and a NAND gate chip U12 of model 74LS312, in which 74LS312 inverts the signal output by the second stage operational amplifier circuit and then outputs it.

The timing module adopts the counter chip of model 74LS90, the counter chip U7 of model 82C54, the monostable flip-flop chips U15 and U17 of model 74LS121, the OR chip of model 74V1T32, the NAND chip U10 of model 74LS132, The AND gate chip model is LN74SZ08, in which 74LS90 converts the system 10MHz clock signal into a 2MHz clock signal and provides it to the counter chip U7 and the counter chip U14 in the timing module. The two monostable trigger chips detect the rise of the input signal respectively. Output positive pulse along edge and falling edge, counter 0 and counter 1 of counter chip U7 measure the high level time and high level time of the input signal respectively, counter 2 measures the width of square wave to judge the type of light stimulation signal, 74V1T32 will The pulse signals output by two 74LS121 are synthesized, 74LS312 inverts the output signal OUT2 of counter 2 in 74LS90 and outputs it, and LN74SZ08 outputs the signal to the operation control module.

The timing module is composed of a counter chip U14 with a model number of 82C54, and the counter 0 of the counter chip U14 is used to control the time delay between the light stimulation signal and the electrical signal.

The connection relationship of each module is: the data bit pin and the control bit pin of the single-chip microcomputer chip U1 in the operation control module are respectively connected with the single-chip microcomputer chip U3 of the integral measurement module, the timing module and the counter chip and signal generation in the timing module in the form of a bus. The module, the input interface module and the display interface module are connected; the output pins of the photoelectric detection module are respectively connected to the non-inverting input terminal of the operational amplifier chip in the pulse shaping module and the non-inverting input terminal of the operational amplifier chip in the integral measurement module through a resistor ; The TXD and RXD pins of the single-chip microcomputer U3 in the integral measurement module are correspondingly connected with the RXD and TXD pins of the single-chip microcomputer U1 in the operation control module; the 2Y pins of the NAND gate chip in the pulse shaping module are connected with the The P2.1 pin of the single-chip microcomputer chip U3 is connected to the B pin of one monostable flip-flop chip U15 in the timing module, the A1 and A2 pins of another monostable flip-flop chip U17, and the counter of the counter chip U7 0 and GATE0 pins, 4A and 4B pins of the NAND gate chip U10 are connected correspondingly; the 1Y pin of the OR gate chip in the timing module is connected with the GATE0 pin of the counter chip U14 in the timing module, and the monostable trigger The A1 and A2 pins of the chip U15 are connected to the P2.0 pin of the single-chip microcomputer chip U1; the OUT0 pin of the chip U14 in the timing module is connected to the signal generation module.

In the embodiment of the human eye visual electrophysiological simulation device of the present invention, the working mode is as follows:

After the human visual electrophysiological simulation device is turned on, the control module in it outputs the status information of the device to the display interface module, receives the parameters input by the user through the input interface module, sets the timing module and the timing time of the timing module and the signal generation module. Output waveform parameters, or keep the default parameter state.

1) When the photoelectric conversion module receives a flash stimulation signal, the output terminal of the photoelectric conversion module outputs an electrical pulse signal consistent with the flash stimulation pulse waveform, which is output to the pulse shaping module, and the pulse shaping module converts the amplified voltage pulse signal into a square wave signal, the width of the square wave signal is the same as the width of the flash pulse, its rising edge and falling edge or falling edge and rising edge correspond to the start and end of the flash signal respectively, the high voltage and low voltage of the square wave signal or Low and high voltages correspond to digital high and low levels, respectively.

The square wave signal is output to the integral measurement module, the timing module and the timing module at the same time; the square wave signal controls the time when the integral measurement module starts integration and ends the integration, and the integral measurement module measures the integrated value of the brightness to time within the duration of the flash, that is, the flash intensity value, and output the result to the operation control module; the timing module and the timing module start timing under the trigger of the front edge of the square wave signal, and the timing module measures the width of the square wave, that is, the flash duration; the square wave width measured by the timing module is less than 5ms, the internal logic of the timing module judges that the light stimulation signal is a flash stimulation, and sends a signal to the timing module to reset the timing module to reset and re-time; The measurement results are calculated and output to the display interface module; the operation control module sends a corresponding status signal to the signal generation module according to the flash parameter measurement results, and the signal generation module is ready; the timing module sends a signal to the signal generation module after a preset time delay Send a signal to make the signal generation module output a standard electrical signal through the electrical signal output interface, and at the same time the timing module resets itself to zero; the signal generation module outputs a visual electrophysiological analog signal corresponding to the flash parameters or other types of electrical signals such as sine waves , square wave, sawtooth wave, etc.

Triggered by the rear edge of the square wave signal, the timing module restarts timing, and the integral measurement module restarts measuring the integration of background brightness against time until the next flash stimulus signal appears; the timing module and integral measurement module output the measurement results to the calculation control module, the operation control module divides the result of the integral measurement module by the result of the timing module to obtain the background brightness; the two adjacent measurement results of the timing module are summed to obtain the period of the flash stimulation, and the reciprocal of it is the flash frequency; If the stimulus is a single flash, the timing module and integral measurement module can perform timing and measurement according to the preset maximum timing time (greater than the period of multiple flashes, such as 100ms), without waiting for the next flash stimulation signal.

When the photoelectric conversion module receives the next flash stimulation signal, each module of the device repeats the above process to start working.

2) When the photoelectric conversion module receives a signal that the graphic stimulus is flipped from bright grid to dark grid or from dark grid to bright grid, the output voltage of the output terminal of the photoelectric conversion module drops or rises synchronously with the graphic flip, and the amplitude of the output electrical signal After the value is amplified by the signal amplification module, it is output to the pulse shaping module. The pulse shaping module converts the change of the electrical signal into a step signal. The falling edge or rising edge of the step signal is synchronized with the graph flip. The high voltage and The low voltage or the low voltage and the high voltage correspond to the digital high level and low level of the timing module and the input terminal of the timing module respectively.

The step signal is output to the integral measurement module, the timing module and the timing module at the same time; the integral measurement module starts integral measurement under the trigger of the step signal, and the timing module and the timing module start timing under the trigger of the step signal; after a period of delay Finally, the pattern inversion signal received by the photoelectric conversion module is opposite to the previous pattern inversion signal. After passing through the signal amplification module and the pulse shaping module, the pulse shaping module outputs a step signal in the opposite direction, forming a complete pattern with the previous step signal. Triggered by the step signal, the integral measurement module outputs the integral measurement result to the operation control module, the timing module outputs the time measurement result to the operation control module, and the integral measurement module resets to zero and restarts the measurement.

The width of the square wave measured by the timing module is greater than 5ms. The internal logic of the timing module judges that the light stimulation signal is a graphic stimulus, and sends a signal indicating the type of light stimulation to the control module. The timing module resets itself and restarts timing; , time measurement results are output to the operation control module; the operation control module calculates the brightness of the measured graphic bright grid or dark grid according to the measurement results of the integral measurement module and the timing module, and outputs the calculation results to the display interface module; the operation control module according to The graphic parameter measurement results send a corresponding status signal to the signal generation module, and the signal generation module is ready; the timing module sends a signal to the signal generation module after a preset time delay, so that the signal generation module outputs an electrical signal through the electrical signal output interface At the same time, the timing module resets and clears itself; the signal generation module outputs visual electrophysiological analog signals corresponding to the graphic parameters or other types of electrical signals such as sine waves, square waves, and sawtooth waves.

When the photoelectric conversion module receives the next graphic flip signal, the integral measurement module measures the integral value of the brightness of the dark or bright grid of the graphic to the time, and the timing module measures its duration; the integral measurement module and the timing module will measure the result Output to the calculation control module; the calculation control module divides the measurement result of the integral measurement module by the measurement result of the timing module to obtain the brightness value of the dark or bright grid of the graph, and sums the measurement results of two adjacent timing modules to obtain a graph flip signal The period of , taking its reciprocal is the graphic flipping frequency; the calculation control module outputs the calculation result to the display interface module.

When the photoelectric conversion module receives the next graphic inversion signal, each module of the device repeats the above process to start working. The specific working process is as follows:

After the human visual electrophysiological simulation device is turned on, the single-chip microcomputer of the operation control module initializes each module through the bus, outputs the status information of the device to the display interface module, and receives the parameters input by the user through the input interface module. The working method is as follows:

After starting up, the single-chip microcomputer chip of the operation control module initializes each chip, wherein the counter 0 and the initial count value of the counter 1 of the counter chip U7 in the timing module are set to 0 (corresponding to the maximum count value), and the timing module is set according to the input parameters. The counter 2 in is set as the time parameter for distinguishing the light stimulation type as flash stimulation, such as 5ms, and the counter 0 of the counter chip U14 in the timing module is set as the delay time from receiving the light stimulation to sending out the electrical signal, such as 10ms, the counter 0 and counter 1 in the timing module work in mode 4, the counter 2 of U7 in the timing module and the counter 0 of U14 in the timing module work in mode 5; the A1 and A2 pins of the monostable flip-flop chip U15 Set it to 0, so that it is in the normal working state of detecting the rising edge; when the photoelectric conversion module receives the light stimulation signal, the output terminal of the photoelectric conversion module outputs an electric pulse signal consistent with the light stimulation signal waveform, and the pulse signal is measured by integration After the two-stage amplifying circuit of the module is amplified, a square wave signal is output at the 2Y pin of the NAND gate chip U12; the square wave signal is output to the integral measurement module, the timing module and the timing module at the same time; the pulse signal is output to the amplifying circuit of the integral measurement module At the input end, the square wave signal is output to the P2.2 pin of the single-chip microcomputer chip U3 of the integral measurement module. After the pulse signal is amplified, it is converted into a digital signal by the analog-to-digital conversion chip ADS804, and then input to the single-chip microcomputer chip U3. The single-chip microcomputer chip U3 is based on P2. The level state of the 2 pins respectively calculates the integral value of the brightness to time in the high level and low level states; the square wave is converted into two short pulses after passing through two monostable triggers and an AND gate, corresponding to The rising edge and falling edge of the square wave are output to the GATE0 pin of the counter chip 82C54 (U14) of the timing module, and the counter 0 starts to count down from the preset value, and outputs a negative pulse on the OUT0 pin to the signal generation module at the end of the counting , the output signal of the control signal generating module; the square wave is output to the GATE0 pin and the GATE2 pin of the counter chip 82C54 (U7) of the timing module, and output to the GATE1 pin after inversion, and the counter 0 counts when the square wave is at a high level. Counter 1 counts at the low level of the square wave, and the counting status signals OUT0 and OUT1 are output to the single-chip microcomputer chip U1 of the operation control module. The rising edge triggers to start counting, the OUT2 output is 0 before the counting ends, and the OUT2 output is 1 after the counting ends.

(1) If the optical stimulation signal is a flash signal, before the counter 2 of the counter chip U7 of the timing module counts, the monostable flip-flop chip U17 detects the falling edge of the square wave corresponding to the end state of the flash and outputs a positive pulse, After the NAND gate chip U10 outputs a positive pulse to the single-chip microcomputer chip U1 of the operation control module, after the single-chip microcomputer chip U1 receives the positive pulse, it sets the A1 and A2 pins of the monostable trigger chip U15 to 1, and the monostable trigger The timer chip U15 no longer detects the rising edge of the square wave, and the counter 0 of the counter chip U14 of the timing module is only triggered by the falling edge of the square wave, so as to realize the function of delaying the output of the electrical signal only after the flash stimulation ends. The single-chip microcomputer calculates according to the measurement results obtained by the timing module and the integral measurement module, respectively obtains the flash intensity value, flash duration, background brightness value, flash frequency and other parameters, and outputs them to the display interface module, and sends corresponding instructions to the signal generation according to the results The module outputs an electrical signal corresponding thereto. If the light stimulus is a single flash, the counter 1 of the timing module will automatically end after counting down from the maximum value to 0, and the integral measurement module will stop integrating accordingly without waiting for the next flash stimulation signal. When the photoelectric conversion module receives the next flash stimulation signal, each module of the device repeats the above process to start working.

(2) If the optical stimulation signal is a graphic signal, after the counter 2 of the counter chip U7 of the timing module counts, the monostable flip-flop chip U17 detects the square wave falling edge output pulse, and at this time the counter chip U7 The counter 2 output OUT2 pin is 1, the output of the non-gate chip U10 is kept as 0, the single-chip microcomputer chip U1 has no action, the A1 and A2 pins of the monostable flip-flop chip U15 are kept as 0, and the monostable flip-flop chip U15 can be The rising edge of the square wave is normally detected, and the counter 0 of the counter chip U14 of the timing module is triggered by the rising and falling edges of the square wave at the same time, so as to realize the trigger signal when the bright grid becomes dark or the dark grid becomes bright in the graphic stimulus The generation module delays outputting electrical signals. The single-chip microcomputer calculates according to the measurement results obtained by the timing module and the integral measurement module, respectively obtains parameters such as bright grid brightness value, dark grid brightness value and graphic flip frequency, and outputs them to the display interface module, and sends corresponding instructions to the signal generation module according to the results , and output the corresponding electrical signal. When the photoelectric conversion module receives the next graphic inversion signal, each module of the device repeats the above process to start working.

The simulation method of the human eye visual electrophysiological simulation device provided by the invention comprises the following steps:

Step 1, converting the photostimulation signal into an electrical signal whose amplitude is proportional to the brightness of the photostimulation signal, and performing integral measurement on the electrical signal;

Step 2. Identify the type of light stimulus signal, convert the integral measurement signal into a square wave signal, measure the width of the square wave by timing, and identify the flash stimulus signal and the graphic stimulus signal by the difference in time characteristics. If it is a flash stimulus signal, execute Next step; if it is a graphic stimulus signal, perform step 4;

Step 3, if the luminescence corresponds to the high level of the square wave, and the interval between two luminescences corresponds to the low level of the square wave, then the integrated measurement result during the high level period is used as the intensity of the flash pulse, while the integral measurement during the low level period The result is taken as the integral value of the background brightness versus time, the high-level time of the timing measurement results is taken as the time course of the flash stimulus, the sum of the high-level time and the low-level time is taken as the period of the flash stimulus, and the reciprocal is taken as the frequency of the flash stimulus, The integral value of the background brightness to time is divided by the time interval as the background brightness value, and step 5 is performed;

Step 4. Use the edge of the square wave signal to perform segmented integral measurement. The square wave is in the bright grid state corresponding to the graphic stimulus at a high level, and the square wave is in the dark grid state corresponding to the graphic stimulus at a low level. The square wave is obtained by integral measurement respectively. Integral value of graphics brightness to time at high level and low level, timing measurement to obtain high level duration time value and low level duration time value, and divide the two integral values by the corresponding time respectively, and respectively As the brightness of the bright grid and the dark grid of the graphics, add the duration value of the high level and the duration of the low level as the graphics flip cycle, take its reciprocal as the graphics flip frequency, and execute the next step;

Step 5, input setting parameters on the input interface, and output integral measurement, timing measurement and their calculation results to the display interface. The human eye visual electrophysiological simulation device and method of the present invention use the same set of integral measurement module, pulse shaping module and timing module to realize the flash intensity, flash time course, flash frequency, background brightness and bright frame brightness of graphic stimulation, Measure the brightness of the dark grid and the frequency of graphic flipping, and at the same time automatically output the corresponding standard electrical signal according to the type of the optical stimulation signal, and automatically output the corresponding standard electrical signal according to the parameters of the optical stimulation signal. And an external timing module is used to realize the adjustable time delay from light stimulation to electrical signal output.

The above-mentioned embodiments are only descriptions of preferred implementations of the present invention, and are not intended to limit the concept and scope of the present invention. Under the premise of not departing from the design concept of the present invention, various modifications and improvements made by ordinary persons in the art to the technical solution of the present invention shall fall within the scope of protection of the present invention, and the technical content claimed in the present invention has been fully described in the claims.

Claims (3)

1. A human visual electrophysiological simulation device, characterized in that: comprising a photoelectric conversion module, an integral measurement module, a pulse shaping module, a timing module, a timing module, a signal generation module, an operation control module, an input interface module and a display interface module , wherein: the external optical signal is input to the photoelectric conversion module, the photoelectric conversion module, pulse shaping module, timing module, timing module, and signal generation module are connected in sequence, and the photoelectric conversion module is connected to the photoelectric conversion module through the integral measurement module The operation control module is connected, and the operation control module is respectively connected with the timing module, timing module, signal generation module, display interface module and input interface module; the photoelectric conversion module converts the light stimulation signal into an electrical signal, and outputs it to the The pulse shaping module and the integral measurement module, the pulse shaping module outputs a square wave signal corresponding to the light stimulation signal, the square wave signal triggers the timing module and the timing module, and the timing module judges the type of light stimulation and controls the The timing module starts timing from the corresponding time point, the integral measurement module measures the integral value of the brightness and time of the light stimulation signal under the synchronous control of the pulse shaping module, and the operation control module receives the input from the input interface module The parameters are set, the integral measurement results are calculated, and electrical signals are output through the signal generation module, and at the same time, the state parameters and measurement results are output to the display interface module. 2. The human eye visual electrophysiological simulation device according to claim 1, characterized in that: wherein said operation control module adopts the single-chip microcomputer chip U1 of STC89C51 and the programmable crystal oscillator chip of SG-8002 to form; integral measurement The module is composed of an operational amplifier chip model OPA642, a 12-bit analog-to-digital conversion chip model ADS804, a reference voltage chip model TL431 and a single-chip microcomputer chip U3 model STC89C51; the pulse shaping module consists of two operational amplifiers model OP07AJ The proportional amplification circuit composed of the chip and the NAND gate chip U12 of the model 74LS312 are composed; the timing module adopts the counter chip of the model 74LS90, the counter chip U7 of the model 82C54, the monostable trigger chip U15 of the model 74LS121 and the monostable State flip-flop chip U17, OR chip of model 74V1T32, NAND chip U10 of model 74LS132 and AND chip of model LN74SZ08; the timing module is composed of counter chip U14 of model 82C54; among them: operation control module The data bit pin and the control bit pin of the single-chip microcomputer chip U1 in the bus are respectively connected with the single-chip microcomputer chip U3 of the integral measurement module, the counter chip U7 in the timing module, and the counter chip U14 in the timing module, the signal generation module, and the input interface. The module is connected to the display interface module; the output pins of the photoelectric detection module are respectively connected to the non-inverting input terminal of the operational amplifier chip in the pulse shaping module and the non-inverting input terminal of the operational amplifier chip in the integral measurement module through resistance; the integral measurement module The TXD and RXD pins of the single-chip microcomputer chip U3 in the operation control module are correspondingly connected with the RXD and TXD pins of the single-chip microcomputer chip U1 in the operation control module; the 2Y pins of the NAND gate chip in the pulse shaping module are respectively connected with the single-chip microcomputer in the integral measurement module The P2.1 pin of the chip U3, the B pin of the monostable flip-flop chip U15 in the timing module, the counter 0 and GATE0 pins of the counter chip U7, and the 4A and 4B pins of the NAND gate chip U10 are connected correspondingly ; The 1Y pin of the OR gate chip in the timing module is connected to the GATE0 pin of the counter chip U14 in the timing module, and the A1 and A2 pins of the monostable flip-flop chip U15 are connected to the P2.0 pin of the single-chip microcomputer chip U1 ; The OUT0 pin of the chip U14 in the timing module is connected with the signal generation module. 3. A simulation method that adopts the human eye visual electrophysiology simulation device described in claim 1 or 2, is characterized in that: the method comprises the steps: Step 1, converting the photostimulation signal into an electrical signal whose amplitude is proportional to the brightness of the photostimulation signal, and performing integral measurement on the electrical signal; Step 2. Identify the type of light stimulus signal, convert the integral measurement signal into a square wave signal, measure the width of the square wave by timing, and identify the flash stimulus signal and the graphic stimulus signal by the difference in time characteristics. If it is a flash stimulus signal, execute Next step; if it is a graphic stimulus signal, perform step 4; Step 3, if the luminescence corresponds to the high level of the square wave, and the interval between two luminescences corresponds to the low level of the square wave, then the integrated measurement result during the high level period is used as the intensity of the flash pulse, while the integral measurement during the low level period The result is taken as the integral value of the background brightness versus time, the high-level time of the timing measurement results is taken as the time course of the flash stimulus, the sum of the high-level time and the low-level time is taken as the period of the flash stimulus, and the reciprocal is taken as the frequency of the flash stimulus, The integral value of the background brightness to time is divided by the time interval as the background brightness value, and step 5 is performed; Step 4. Use the edge of the square wave signal to perform segmented integral measurement. The square wave is in the bright grid state corresponding to the graphic stimulus at a high level, and the square wave is in the dark grid state corresponding to the graphic stimulus at a low level. The square wave is obtained by integral measurement respectively. Integral value of graphics brightness to time at high level and low level, timing measurement to obtain high level duration time value and low level duration time value, and divide the two integral values by the corresponding time respectively, and respectively As the brightness of the bright grid and the dark grid of the graphics, add the duration value of the high level and the duration of the low level as the graphics flip cycle, take its reciprocal as the graphics flip frequency, and execute the next step; Step 5, input setting parameters on the input interface, and output integral measurement, timing measurement and their calculation results to the display interface.