CN111803066B - Dual stimulation method of visual evoked brain-computer interface based on coded modulation - Google Patents
Dual stimulation method of visual evoked brain-computer interface based on coded modulation Download PDFInfo
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Abstract
The invention relates to a visual induction brain-computer interface dual-stimulation method based on coded modulation, which comprises the steps of firstly using self-made robot pictures, including a flicker stimulation picture and a sliding stimulation picture, wherein the effect of the robot pictures on inducing brain electricity is far better than that of pure-color pictures; secondly, the invention designs a dual-stimulation method of flicker stimulation and sliding stimulation, which reduces the induction period of the brain electrical signal and increases the instruction output speed of the brain electrical signal; the third invention uses the same binary code to modulate the flicker stimulus and the sliding stimulus at the same time, and the brain electrical signals induced by the two stimulus modes are different and can be distinguished, so that the length of the binary code is reduced, and the number of instructions is doubled.
Description
Technical Field
The invention belongs to the technical field of biomedical engineering brain-computer interfaces, relates to an induction mode of event-related potential, and particularly relates to a visual induction brain-computer interface dual-stimulation method based on coded modulation.
Background
Some people lose some or all of their ability to communicate information due to accidents, diseases, etc., wherein normal information transfer between the pivot nervous system and effectors is hindered, resulting in failure of the person's intent to express and effectuate movements. The patient population loses the normal way of communicating with the outside, thereby becoming a self-closing individual. The advent of brain-machine interfaces has significant practical implications for their reconstruction of the information pathway to external communication.
A brain-machine interface is a system that detects central nervous activity and converts it into manually output commands. The brain-machine interface system can replace, repair, enhance, supplement, or improve the normal output of the central nervous system, thereby altering the interaction between the central nervous system and the external environment.
The brain-computer interface technology has a plurality of defects, such as low instruction transmission speed, small instruction quantity, high mental power consumption for users and the like. Coded modulation based Visual evoked potential brain-computer interfaces like the Hongze Zhao design (Hongze Zhao, yijun Wang, individual Identification Based on Code-Modulated Visual-Evoked Potentials, IEEE transactions on Information Forensics and Security,2019, vol.14, no. 12) require very long binary codes, typically above 60 bits. Because the accuracy of recognition is guaranteed, the cyclic shift of the code is also more than 4 bits, which makes the binary code length always be increased to increase the instruction number of the brain-computer interface system, and the overlong binary code reduces the stimulation period, so that the empty window period of the brain-computer interface is longer, which obviously is difficult to meet the practical requirement of the brain-computer interface.
The dual-stimulation method based on coded modulation can increase the information transmission rate of the brain-computer interface, increase the number of instructions and improve the identification accuracy. The invention also greatly shortens the number of binary codes for modulating the stimulation target, doubles the number modulated by the binary codes with the same length and improves the practicability of the brain-computer interface.
Disclosure of Invention
The invention aims to provide a dual stimulation method of a visual evoked brain-computer interface based on coded modulation, which designs two stimulation targets of flicker stimulation and sliding stimulation, and the time of the event related potential of flicker stimulation and sliding stimulation is different for the same stimulation-evoked event related potential, so that different stimulation modes of the same coded modulation can be distinguished by data analysis of the event related potential. The present invention uses this principle to double the number of instructions in the brain-computer interface.
In order to achieve the above purpose, the invention adopts the following technical scheme:
a method of dual stimulation of a visually-evoked brain-computer interface based on coded modulation, the method comprising:
1) Determining that the number of working states of an object to be stimulated is 2n, adopting a stimulation interface with different action states, wherein the number of stimulation targets on the stimulation interface is 2n, and sending out instructions by a user through looking at pictures of different states of the stimulation interface;
2) The stimulation interface simultaneously comprises a flicker stimulation picture and a sliding stimulation picture, the number of groups of binary codes is half of the number of working states of an object to be stimulated, namely n groups, the same binary code is used for simultaneously modulating flicker stimulation and sliding stimulation, each group of binary codes controls the flicker stimulation and the sliding stimulation, the number of bits of each group of binary codes is 4n, the binary codes of the n groups are obtained by cyclic shift of one binary code with 4n bits, each cyclic shift is four bits, the shift is carried out for n-1 times, n groups of binary codes are obtained, the binary codes follow a pseudo-random sequence rule, and the balance standard, the run standard and the correlation standard are met.
When the binary code is 1, flicker stimulation appears, and sliding stimulation slides; when the binary code is 0, the flicker stimulus disappears, and the sliding stimulus is not moved.
The binary code of each group is a single stimulus, the duration of the single stimulus is 3s, 1 single stimulus is defined as a repetition, a rest time of 1 second is defined between the repetition, 2n repetitions are defined as a repetition group, the combination of the stimulus mode and the binary code is realized, the bit number of the binary code is 36 binary codes, and the value of n is 9.
The flicker stimulation pictures and the sliding stimulation pictures are randomly distributed on the stimulation interface.
The flicker stimulation and the sliding stimulation are stimulated simultaneously, the flicker stimulation picture is positioned on the left side of the stimulation interface, and the sliding stimulation picture is positioned on the right side of the stimulation interface.
The sliding stimulus comprises sliding from left to right or right to left, top to bottom, bottom to top using a sliding line of bright color, the sliding line being blue, red, yellow or a gradient color.
Binary codes use either an m-sequence, a golay complementary sequence, or a near perfect sequence.
The object to be stimulated is a robot or a mobile platform.
The invention also protects a brain-computer interface test method, which comprises the following steps:
1) Determining that the number of working states of the robot to be controlled is 2n, and numbering the stimulation targets on the stimulation interface in sequence, wherein the number of the stimulation targets on the stimulation interface is 2 n; the number of groups of binary codes is half of the number of working states of the robot to be controlled, namely n groups, and the same binary code is used for modulating flicker stimulation and sliding stimulation simultaneously; the n groups of binary codes are obtained by cyclic shift of a 4 n-bit binary code, each cyclic shift is performed for four bits, and the shift is performed for n-1 times, so that n groups of binary codes are obtained; setting 4n binary codes to perform one-time stimulation to form single stimulation, defining 1 single stimulation as one repetition, defining 2n repetitions as one repetition group, wherein 1 second rest time exists between the repetitions;
2) Training phase: the user watches the first picture, the watching time is the time spent by 10 'repetition', after watching is finished, a picture with different stimulation modes is selected to watch, the watching time is still the time spent by 10 'repetition', namely if the current picture is a flickering stimulation picture, a sliding stimulation picture is selected after watching is finished, and vice versa;
in the data processing process of the training stage, firstly, carrying out band-pass filtering, baseline correction and channel dimension reduction on the electroencephalogram data of a user, and then, carrying out breaking and connection on the electroencephalogram obtained by the flicker stimulation picture which is watched by the user in a binary code cyclic shift mode to obtain electroencephalogram templates of other flicker stimulation pictures;
dividing and connecting the electroencephalogram signals obtained by the sliding stimulation picture which is watched by the user in a binary code cyclic shift mode to obtain electroencephalogram signal templates of other sliding stimulation pictures; the binary code circularly shifts, and brain signal templates in different stimulation modes are selected according to different stimulation modes to circularly shift according to the sequence, so that all the brain signal templates corresponding to the working state of the robot are obtained; ending the training stage;
3) Testing: the user sequentially watches 2n target stimulations in a numbering sequence, the watching time of each stimulations is 1 repetition, and a short rest time is used for the user to watch the next stimulations after one repetition is finished; after one round of repeated groups is finished, the user gazes 2n stimulation pictures, the test stage is totally 5 repeated groups, the user is required to sequentially gaze five rounds of stimulation, and the test stage is finished after the gazing is finished;
4) And filtering and dimension reduction is carried out on the electroencephalogram signals of the user testing stage, then correlation degree operation is carried out on the electroencephalogram data of the testing stage and templates obtained in each training stage, the correlation value of each template is obtained, and which stimulus is watched by the user is determined according to the magnitude of the correlation value of each template.
The brain-computer interface testing method can be applied to the fields of brain-computer typing systems, brain-controlled wheelchairs or intelligent rehabilitation robots.
Compared with the prior art, the invention has the beneficial effects that:
1) The invention designs a new brain-computer interface stimulation method based on code modulation, which better utilizes the capability of the brain to process different information for different stimulation targets, so that the same binary code can control a plurality of stimulation targets, for example, a group of 36-bit binary codes are found according to the standard of a pseudo-random sequence, and then the binary codes are circularly shifted eight times and four bits each time to obtain nine groups of binary codes. One set of binary codes controls one, i.e. two, stimulation targets, one flashing one sliding each, and nine sets of binary codes control nine, i.e. 18 targets in total. Therefore, the invention can effectively increase the number of the stimulation targets, reduce the stimulation period and shorten the stimulation time.
2) The invention uses the dual stimulation method, thus the length of binary code for modulating stimulation can be reduced, and the time interval for transmitting command instructions by the brain-computer interface system can be reduced.
3) The brain-computer interface system (comprising a computer for displaying a stimulation interface, an electroencephalogram acquisition instrument, curry8 and 64-guide electroencephalogram caps and matlab for analyzing electroencephalogram data) has higher identification accuracy by adopting the stimulation method, so that the time for correcting error instructions is reduced, the fluency of a user using brain-computer interface equipment is improved, and the brain fatigue degree of the user is reduced.
4) The invention can be applied to the technical fields of brain-computer typing systems, brain-controlled wheelchairs, intelligent rehabilitation robots and the like, and has the advantages of high command output speed and high fluency when in use, and can effectively improve the practicability of brain-computer interface equipment.
5) The number of instructions of the brain-computer interface needs to cover all dimensions of the brain-computer interface system, for example, the number of instructions of the typing system must exceed the number of English letters, arabic numerals and common symbols, and the smaller number of instructions can directly influence the functions of the brain-computer interface system, so that the brain-computer interface has a simple function. The general information transmission rate of the existing brain-computer interface is 39.1 bits per minute, the lower transmission rate is difficult to meet the use requirement of the brain-computer interface system, the number of instructions is six generally, the accuracy is lower, the lower instruction transmission speed can reduce the experience feeling when a user uses the brain-computer interface device, and the brain fatigue of the user is caused. The core innovation point of the application is that two types of stimulation are regulated and controlled simultaneously by using binary codes, and the interface of the application uses robot stimulation pictures comprising sliding stimulation and flickering stimulation.
Drawings
Fig. 1 is an evoked interface for a brain-machine interface experiment.
Fig. 2 is a nine-set binary code obtained by 36-bit pseudo-random code cycling.
Fig. 3 is a diagram of nine sets of binary code lines from a 36-bit pseudorandom code loop.
Fig. 4 is a flow chart of the experimental training phase.
Fig. 5 is a flow chart of the experimental test phase.
Detailed Description
The process according to the invention is described in detail below with reference to the figures and examples.
The hardware equipment for carrying out experiments by using the method comprises a 64-conductor electrode cap, an electroencephalogram acquisition instrument and a computer, and the software equipment comprises matlab and curry8. Experiments are required to be carried out in a quiet laboratory, so that the user has good mental state and hair is clean; the user sits in a comfortable chair about 70 cm from the display and should try to avoid blinking during the experiment.
The invention relates to a dual stimulation method of a visual induction brain-computer interface based on coded modulation, which comprises the following steps:
3) The method comprises the steps that a stimulation interface with different action states of a robot is adopted, the number of stimulation targets on the stimulation interface is 2n, and a user sends out instructions by looking at pictures in different states of the stimulation interface;
4) The method comprises the steps that a flicker stimulus picture and a sliding stimulus picture are simultaneously contained on a stimulus interface, n groups of binary codes are designed, the same binary code is used for simultaneously modulating the flicker stimulus and the sliding stimulus, each group of binary codes controls the flicker stimulus and the sliding stimulus, the bit number of each group of binary codes is 4n, each group of binary codes of n groups is obtained by cyclic shift of one binary code of 4n bits, each cyclic shift is four bits, the shift is carried out n-1 times, n groups of binary codes are obtained, the binary codes follow a pseudo-random sequence rule, and balance standards, run standards and correlation standards are met;
5) When the binary code is 1, flicker stimulation appears, and sliding stimulation slides; when the binary code is 0, the flicker stimulus disappears, and the sliding stimulus is not moved.
The invention uses robot pictures with different actions and states as stimulus targets (each picture of the robot represents one action of the robot, for example, one picture is a robot lifting mechanical arm, and each picture is different; in addition, the invention designs a dual-stimulation method of flicker stimulation and sliding stimulation, which reduces the induction period of the brain electrical signal and increases the instruction output speed of the brain electrical signal; the invention uses the same binary code to modulate the flicker stimulus and the sliding stimulus simultaneously, namely, when the binary code is 1, both the stimulus acts, and when the binary code is 0, both the stimulus acts, and the brain electrical signals induced by the two stimulus modes are different and can be distinguished, so that the length of the binary code is reduced, and the number of instructions is doubled.
The invention uses the robot picture which is convenient for the user to identify to induce the brain electric signal of the user to output the command, and then uses the dual stimulation of the flicker stimulation and the sliding stimulation and the pseudo-random binary code to regulate and control, so that the number of control targets of the binary codes with the same length is increased, and the stimulation period is reduced.
The stimulation interface comprises a flicker stimulation picture and a sliding stimulation picture, the flicker stimulation and the sliding stimulation are stimulated simultaneously, the flicker stimulation picture is positioned on the left side of the stimulation interface, and the sliding stimulation picture is positioned on the right side of the stimulation interface.
The same group of stimuli is regulated by the same binary code as shown in fig. 2, nine binary codes in total, the binary code of the first group being used to control the two stimuli of the first group, one of which is a blinking stimulus and one of which is a sliding stimulus. The binary codes of the second group are the binary codes of the first group shifted four bits to the right, the last four of the codes of the first group being shifted to the forefront. The third set of binary codes is the second set of binary codes shifted four bits to the right, and so on, resulting in nine sets of binary codes. When the binary code is 1, the robot picture with flicker stimulation appears, and a blue line slides from right to left in the sliding stimulation; when the binary code is 0, the robot picture of the flickering stimulus disappears, and the sliding stimulus remains unchanged.
The scintillation stimulus and the slip stimulus remain consistent: that is, the two meanings are included, namely, two kinds of stimulation occur simultaneously, not flashing first and then sliding or first and then flashing, and two kinds of flashing stimulation and the same code of the sliding stimulation are regulated, and if the flashing stimulation is 1 flashing, the same group of sliding stimulation is also necessarily 1 sliding.
The binary code of each group is a single stimulus, the duration of the single stimulus is 3s, 1 single stimulus is defined as a repetition, a rest time of 1 second exists between the repetition, 2n repetitions are defined as a repetition group, the combination of a stimulus mode and the binary code is realized (3 seconds are required for each round of stimulus, namely one repetition, the state of a stimulus target picture is controlled by the binary code of the group within 3 seconds), the number of working states of an object to be stimulated is required to be controlled to be 2n, the number of the groups of the binary code is half of the number of the working states of the object (robot) to be stimulated, when the number of bits of the binary code is 4n, n=9, the number of bits of the binary code is 36 bits, and when n is taken to be 13, the number of bits of the binary code is 52 bits, at the moment, the number of the working states of the robot to be controlled is 26, the more refined action control of the robot can be realized, and the value of n is generally an integer of 8-15.
The sliding stimulus includes sliding from left to right or right to left, top to bottom, bottom to top, etc. using a sliding line of bright color, which is blue, red, yellow, or gradient, etc. to ensure that the line color is bright enough to attract attention.
The same stimulation interface comprises the flickering stimulation pictures and the sliding stimulation pictures at the same time, the flickering stimulation pictures and the sliding stimulation pictures are randomly distributed on the stimulation interface, namely the flickering stimulation pictures and the sliding stimulation pictures on the stimulation interface are not necessarily placed together, and the sequence can be disordered and the flickering stimulation pictures and the sliding stimulation pictures can be randomly distributed.
The same code of the flicker stimulus and the sliding stimulus is regulated, the flicker stimulus and the sliding stimulus of the same group are controlled by the same code, and the binary codes of the stimuli of different groups are obtained by cyclic shift of one binary code.
The binary code may use m-sequences, golay complementary sequences, near perfect sequences, etc.
Examples
1) The stimulation interface used in this embodiment has 18 stimulation targets, and the arrangement mode is 3 rows and 6 columns; wherein the left 3 rows and 3 columns of 9 targets are scintillation stimuli and the right 3 rows and 3 columns of 9 targets are sliding stimuli. Stimulation targets are numbered 1 to 18 in a top-to-bottom left-to-right order. All the stimuli are modulated by binary codes, when the binary code is 1, the stimulus pictures of the flickering stimulus appear, and the stimulus pictures of the sliding stimulus slide; when the binary code is 0, the stimulation picture of the flicker stimulation disappears, and the stimulation picture of the sliding stimulation is not moved. The 36-bit binary code is used for performing one stimulus as a single stimulus, the duration of the single stimulus is 3 seconds, 1 single stimulus is defined as a repetition, a rest time of 1 second exists between the repetition, and 18 repetition are defined as a repetition group.
2) The experiment is divided into a training phase and a testing phase. The training phase starts, the user looks at picture No.1, and the looking time is 10 times required by repetition; after finishing fixation, the user fixates the No. 4 picture, wherein the fixation time is 10 times required by repetition; in the data processing process of the training stage, firstly, carrying out band-pass filtering, baseline correction and channel dimension reduction on the electroencephalogram data of a user, and then, carrying out breaking and connection on the electroencephalogram obtained by the flicker stimulation when the user gazes the No.1 picture in a binary code cyclic shift mode to obtain electroencephalogram templates of other eight flicker stimulation pictures; dividing and connecting the brain electrical signals obtained by sliding stimulation when the user watches the No. 10 picture according to a binary code cyclic shift mode to obtain templates of other eight sliding stimulation pictures; the binary code is circularly shifted, different stimulation forms of electroencephalogram signals are selected according to different stimulation modes, the electroencephalogram signals are circularly shifted in sequence, all electroencephalogram signal templates corresponding to the working states of the robot are required to be controlled (namely, nine scintillation stimulation numbers on the left are respectively 1, 2, 3, 7, 8, 9, 13, 14 and 15, the number 2 picture electroencephalogram signal is that the number 1 picture electroencephalogram signal template is shifted backwards and the four last electroencephalogram signals are corresponding to the four last electroencephalogram signal, the scintillation stimulation picture electroencephalogram signal templates are obtained by connecting the last scintillation stimulation electroencephalogram signal template in a breaking mode (namely, the number 3 picture electroencephalogram signal is that the number 2 picture electroencephalogram signal template is shifted backwards and the four last electroencephalogram signal is corresponding to the four last, the number 7 picture electroencephalogram signal is that the number 3 picture electroencephalogram signal template is shifted backwards and the four last electroencephalogram signal corresponding to the front), and the sliding target electroencephalogram signal templates except the first electroencephalogram signal template, namely the number 4 picture are obtained by connecting the last sliding stimulation electroencephalogram signal templates in a breaking mode).
3) The test phase starts, the user sequentially watches 18 target stimuli in a numbered sequence, the watching time of each stimulus is 1 repetition, and a short rest time is used for the user to watch the next stimulus after one repetition is finished. After one round of repeated group is finished, the user gazes at 18 stimulation pictures, the test stage is totally 5 repeated groups, the user is required to sequentially gaze at five rounds of stimulation, and the test stage is finished after gazing is finished.
4) And filtering and dimension reduction is carried out on the electroencephalogram signals of the user in the test stage, and then correlation degree operation is carried out on the electroencephalogram data of the test stage and each template to obtain the correlation value of each template. According to the magnitude of the relevant values of each template, determining which stimulus is watched by the user, and further determining what working state control the user wants to control the robot, wherein the working state control is used for controlling the robot to execute corresponding actions by the brain-computer interface.
The method is applicable to the prior art, and the related processes of correlation calculation, filtering dimension reduction, baseline correction and the like are realized according to the prior art.
Claims (10)
1. A method of dual stimulation of a visually-evoked brain-computer interface based on coded modulation, the method comprising:
1) Determining that the number of working states of an object to be stimulated is 2n, adopting a stimulation interface with different action states, wherein the number of stimulation targets on the stimulation interface is 2n, and sending out instructions by a user through looking at pictures of different states of the stimulation interface;
2) The stimulation interface simultaneously comprises a flicker stimulation picture and a sliding stimulation picture, the number of groups of binary codes is half of the number of working states of an object to be stimulated, namely n groups, the same binary code is used for simultaneously modulating flicker stimulation and sliding stimulation, each group of binary codes controls the flicker stimulation and the sliding stimulation, the number of bits of each group of binary codes is 4n, the binary codes of the n groups are obtained by cyclic shift of one binary code with 4n bits, each cyclic shift is four bits, the shift is carried out for n-1 times, n groups of binary codes are obtained, the binary codes follow a pseudo-random sequence rule, and the balance standard, the run standard and the correlation standard are met;
the method uses dual stimulation of scintillation stimulation and sliding stimulation and uses pseudo-random binary code regulation, so that the number of control targets of binary codes with the same length is increased, the stimulation period is reduced, the same code regulation of the scintillation stimulation and the sliding stimulation is realized, the scintillation stimulation and the sliding stimulation of the same group are controlled by the same code, and the binary codes of the stimulation of different groups are obtained by cyclic shift of one binary code;
the scintillation stimulus and the slip stimulus remain consistent: that is, the two meanings are included, namely, two kinds of stimulation occur simultaneously, not flashing first and then sliding or first and then flashing, and two kinds of flashing stimulation and the same code of the sliding stimulation are regulated, and if the flashing stimulation is 1 flashing, the same group of sliding stimulation is also necessarily 1 sliding.
2. The dual stimulation method of claim 1, wherein when the binary code is 1, a blinking stimulus occurs and the sliding stimulus slides; when the binary code is 0, the flicker stimulus disappears, and the sliding stimulus is not moved.
3. The method of claim 1, wherein each group of binary codes is a single stimulus, the duration of the single stimulus is 3s, 1 single stimulus is defined as a repetition, a rest time of 1 second is defined between the repetitions, 2n repetitions are defined as a repetition group, and the combination of the stimulus mode and the binary codes is realized, the bit number of the binary codes is 36 binary codes, and the value of n is 9.
4. The dual stimulation method of claim 1, wherein the flicker stimulation pictures and the sliding stimulation pictures are randomly distributed across the stimulation interface.
5. The dual stimulation method of claim 1 wherein the flicker stimulation is simultaneous with the sliding stimulation, the flicker stimulation picture being located to the left of the stimulation interface and the sliding stimulation picture being located to the right of the stimulation interface.
6. The dual stimulation method of claim 1, wherein the sliding stimulation comprises sliding from left to right, right to left, top to bottom, or bottom to top using sliding lines of bright color, the sliding lines being blue, red, yellow, or gradient in color.
7. The dual stimulation method of claim 1, wherein the binary code uses any of an m-sequence, a golay complementary sequence, or a near perfect sequence.
8. The dual stimulation method according to claim 1, wherein the object to be stimulated is a robot or a mobile platform.
9. A brain-machine interface test method, characterized in that a dual stimulation method of a visually induced brain-machine interface based on coded modulation according to claim 1 is adopted, the brain-machine interface test method comprising the following steps:
1) Determining that the number of working states of the robot to be controlled is 2n, and numbering the stimulation targets on the stimulation interface in sequence, wherein the number of the stimulation targets on the stimulation interface is 2 n; the number of groups of binary codes is half of the number of working states of the robot to be controlled, namely n groups, and the same binary code is used for modulating flicker stimulation and sliding stimulation simultaneously; the n groups of binary codes are obtained by cyclic shift of a 4 n-bit binary code, each cyclic shift is performed for four bits, and the shift is performed for n-1 times, so that n groups of binary codes are obtained; setting 4n binary codes to perform one-time stimulation to form single stimulation, defining 1 single stimulation as one repetition, defining 2n repetitions as one repetition group, wherein 1 second rest time exists between the repetitions;
2) Training phase: the user watches the first picture, the watching time is the time spent by 10 'repetition', after watching is finished, a picture with different stimulation modes is selected to watch, the watching time is still the time spent by 10 'repetition', namely if the current picture is a flickering stimulation picture, a sliding stimulation picture is selected after watching is finished, and vice versa;
in the data processing process of the training stage, firstly, carrying out band-pass filtering, baseline correction and channel dimension reduction on the electroencephalogram data of a user, and then, carrying out breaking and connection on the electroencephalogram obtained by the flicker stimulation picture which is watched by the user in a binary code cyclic shift mode to obtain electroencephalogram templates of other flicker stimulation pictures;
dividing and connecting the electroencephalogram signals obtained by the sliding stimulation picture which is watched by the user in a binary code cyclic shift mode to obtain electroencephalogram signal templates of other sliding stimulation pictures; the binary code circularly shifts, and brain signal templates in different stimulation modes are selected according to different stimulation modes to circularly shift according to the sequence, so that all the brain signal templates corresponding to the working state of the robot are obtained; ending the training stage;
3) Testing: the user sequentially watches 2n target stimulations in a numbering sequence, the watching time of each stimulations is 1 repetition, and a short rest time is used for the user to watch the next stimulations after one repetition is finished; after one round of repeated groups is finished, the user gazes 2n stimulation pictures, the test stage is totally 5 repeated groups, the user is required to sequentially gaze five rounds of stimulation, and the test stage is finished after the gazing is finished;
4) And filtering and dimension reduction is carried out on the electroencephalogram signals of the user testing stage, then correlation degree operation is carried out on the electroencephalogram data of the testing stage and templates obtained in each training stage, the correlation value of each template is obtained, and which stimulus is watched by the user is determined according to the magnitude of the correlation value of each template.
10. The test method according to claim 9, wherein the test method is applicable in the field of brain-computer typing systems, brain-controlled wheelchairs or intelligent rehabilitation robots.
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