Summary of the invention
For overcoming the deficiencies in the prior art, be different from traditional in the past brain controller for electric consumption, provide that a kind of to be familiar with system control more or less freely, reduce the computer mouse control device of compound motion mode of wrong occurrence probability, to realize the no limb action remote control process of computer mouse control.This invention can allow the general severe paralyse but the normally functioning disabled person of brains realizes the straighforward operation to the computer screen mouse cursor movement voluntarily, thereby realizes controlling and using computing machine.The present invention can obtain considerable social benefit and economic benefit.The technical solution used in the present invention is that a kind of computer mouse control device of compound motion mode comprises:
The silver-silver chloride electrode of dynamic EEG signals characteristic spectra power spectrum ratio decline ERD when being used to detect the people limb action being imagined;
Be used to detect open brain α wave resistance when closing one's eyes disconnected with the silver-silver chloride electrode that reappears;
Be used for to aforementioned silver-silver chloride electrode output signal amplify, the eeg amplifier of filtering;
Be used to receive, handle the computing machine of eeg amplifier output signal, this computing machine comprises importing power spectrumanalysis module, comparison and the discrimination module that EEG signals is carried out the denoising module, is used to analyze dynamic EEG signals characteristic spectra power spectrum ratio decline ERD;
Described comparison and discrimination module further are subdivided into and are used to differentiate the discrimination module whether the mouse mode identification module that whether needs mobile computer screen mouse cursor and α wave energy are higher than threshold value, the mouse mode identification module adopts the mahalanobis distance method as sorting technique mouse beacon displacement according to the dynamically power spectrumanalysis module of EEG signals characteristic spectra power spectrum ratio decline ERD and the output of data memory module;
Described computing machine also includes the computer screen display control module, the computer screen display control module is formed with the target selection district on computer screen top, be formed with the mouse direction in the bottom and select the district, selecting has four arrows to represent the direction that four mouse beacons in upper and lower, left and right move respectively in the district, and the control of computer screen display control module realizes that four arrow circulations show;
Described computer mouse control device of compound motion mode, also comprise: the control computer screen mouse cursor module that is used to produce gating pulse and call function SetCrusorPos, control computer screen mouse cursor module makes the computer screen mouse cursor move the proper number pixel to respective direction on the basis of current location according to the output of mouse mode identification module and to finish mouse is moved, and whether control computer screen mouse cursor module is higher than the output of discrimination module of threshold value as the control signal of determining to select according to the α wave energy.
Described computing machine also includes training and parameter extraction module, and this module further is subdivided into training power spectrumanalysis module, the data memory module that is used to analyze dynamic EEG signals characteristic spectra power spectrum ratio decline ERD.
The identification of mouse mode identification module is according to the dynamically power spectrumanalysis module of EEG signals characteristic spectra power spectrum ratio decline ERD and the output of data memory module, adopt the mahalanobis distance method as sorting technique mouse beacon displacement, the mahalanobis distance method is to define the mahalanobis distance of x to G1 and G2:
The structure discrimination formula is:
The structure decision rule is:
In the formula, G1 is the overall of task attitude, and G2 is the overall of Idle state, u
(1), u
(2), ∑
1, ∑
2Be respectively G
1And G
2Average and covariance matrix, ∑
1Represent a matrix, add-1 expression above this matrix inversion.
EEG signals is after eeg amplifier is input to computing machine, through 8~13Hz and keep wherein that the bandpass filter of α wave component outputs to 10ms root mean square RMS smoothing algorithm module, RMS smoothing algorithm module output two paths of signals, become the main control channel signal after one tunnel the average treatment through 400~500ms, another road becomes the auxiliary control channel signal through after the average treatment of 50ms, main channel signal and threshold voltage compare, if surmount threshold voltage, compare to judge whether being true α ripple amplification signal with the auxiliary control channel signal again.
The present invention can bring following technique effect:
1, the present invention extracts the variation characteristic of experimenter's power spectral value when imagining limb motion as control signal, realization is to the control of computer screen mouse motion, and determine the selection of mouse, thereby " move on the plane " and " click and determine " two kinds of basic functions of computer mouse have effectively been realized by the variation of opening α intensity of wave when closing one's eyes.
2, adopt mouse mode identification module and main and auxiliary control channel signal, it is more accurate to make the control of computer mouse.
3, adopt training and parameter extraction module, the user is easier to control.
Embodiment
The present invention selects for use in the brain electricity ERD feature and alpha (α) ripple as the feature control signal.Dynamic EEG signals characteristic spectra power spectrum density will change when the people imagines limb action, wherein the decline of power spectrum ratio is called ERD, usually the most obvious at 10~11Hz, can utilize thus ERD phenomenon that brain caused when imagining action thinking as thinking activities to stimulating the sign of incident effective response.And the α ripple is one of principal ingredient of spontaneous brain electricity, and corresponding with the unused rhythm and pace of moving things of visual cortex, frequency is 8~13Hz, is the composition of tool obvious characteristic in the rhythmicity brain wave.The normal person clear-headed when closing order the α ripple strengthen, open eyes, ponder a problem, or when being subjected to other and stimulating, the α ripple weakens or the electrophysiological phenomena that disappears is called the blocking-up of α ripple; After this if order is closed in experimenter's peace and quiet once again, then the α ripple occurs again.Be different from traditional in the past brain controller for electric consumption, the present invention will imagine that action ERD and the opening α wave resistance two kinds of different cognitive principles of breaking of closing one's eyes organically blend, designed the control mode of NEW TYPE OF COMPOSITE action, by at operator's back of head C3, C4, O1, the variation that the Ag-AgCl electrode detects brain electricity ERD feature and α wave amplitude is placed at the T5 place of leading, the variation characteristic of power spectral value was as control signal when the extraction experimenter imagined limb motion, realization is to the control of computer screen mouse motion, and determine the selection of mouse, thereby " move on the plane " and " click and determine " two kinds of basic functions of computer mouse have effectively been realized by the variation of opening α intensity of wave when closing one's eyes.Because system operation is simple, the general simple exercise that only needs just can control computer screen mouse cursor movement.
Further describe the present invention below in conjunction with drawings and Examples.
Fig. 2 is a system architecture synoptic diagram of the present invention.This system is based on the VC++ platform, utilizes the switch control action of normal brain electricity ERD feature and the disconnected phenomenon of α wave resistance to design corresponding BCI control panel, signal acquiring system, signal processing platform and realizes the control to the computer screen mouse cursor movement.The operator selects to produce the EEG signals that contains the phase related control information by cursor on computer screen cycle control indication; This signal through eeg amplifier amplification, filtering, is imported computing machine earlier then; In computing machine, finish denoising, power spectrumanalysis then on the Vc++ platform, deal with the work with a series of signal such as threshold voltage comparison, generation gating pulse; Making the computer screen mouse cursor move the proper number pixel to respective direction on the basis of current location by call function SetCrusorPos at last moves mouse to finish, then extract α ripple variation characteristic as the control signal of determining to select when mouse moves to the target location, represent that this is our targets option.
Main points of the present invention are the design of screen cursor cycle control indication panel, utilize brain electric control mouse and signal processing flow; Switching threshold voltage, actuation time technical parameter such as constant and noise background level sport technique segment such as determine.
1 operation interface designs, utilizes brain electric control mouse and signal processing flow
Operation interface is divided into two parts, and top is divided into the target selection district, selects the district for the mouse direction below, and as Fig. 3, the mouse direction selects the district to have four arrows to represent four control in upper and lower, left and right moving direction respectively, by corresponding programmed control circulation reality.The equipment by computer control can be simulated by the target selection district, when moving to this position to mouse, we represent to select these article, in our experimentation, can come select target by bottom-right menu, after the selection, select regional variable color to be expressed as target, click begins to experimentize then.
Fig. 4 demonstrated cursor to the right, last, left, following four direction locomotive function state of a control (corresponding light is designated as green)
The present invention utilizes brain electric control cursor of mouse flow process as follows:
(1) calculate C3 and the C4 power spectrum of EEG signals that leads, and the mean value that extracts 8-13Hz wherein is as eigenwert, earlier through after a while training, with the characteristic that obtains as training data.
Because individual difference, the eigenwert of everyone ERD is all different, must process train and parameter extraction so different people uses.If reuse, then do not need to train and directly to use through the people of training with feature extraction.Training process is to calculate the power spectrum signal value by fast fourier transform, value with 8-13Hz averages the eigenwert of training as once then, the imagination is then carried out power spectrum calculating once more and is got eigenwert next time, and Xun Lian imagination number of times is decided to be 10 times each time.The lead eigenwert imagined for ten times of two of C3, C4 is formed the matrix of a 2*10 as the sorting parameter that uses mouse.Then train after ten times the imagination is finished and finish to enter the mouse use.
After hitting " training " button, enter the training interface, the training interface as shown in Figure 5.Represent when cross occurring that tranquillization do not imagine action, then imagine hand exercise when arrow occurring, get behind enough training datas, and click " beginning " mouse beacon and move that (target area becomes blueness, as shown in Figure 6) with regard to select target.
(2) four the arrows circulations in interface below show that each direction stops certain hour, and the data that record in this time are carried out power spectrumanalysis, extracts tagsort then, imagine then mouse moves certain distance to the arrow direction indication if be judged as.
(3) repeat (1) (2) and move to the target area up to mouse.
(4) after mouse moves to the target area, calculate O1, T5 lead in the alpha wave band energy spectrum of EEG signals, and read its intermediate frequency 10Hz place energy value, determine its parameter threshold by signal Processing, represent then that when the alpha wave energy is higher than threshold value this target is exactly the target that the experimenter selects, determine to select (target area becomes white again).When being lower than threshold value, then do not operate the alpha wave energy.
The present invention finishes on the Vc++ platform, mouse moves treatment scheme as shown in Figure 7, under training mode, read earlier C3, the C4 data of leading, carry out power spectrumanalysis then, will the imagination and the result that imagines deposit two arrays respectively in, begin to enter control model after waiting training data to read enough ten groups, data are carried out classifying behind the power spectrumanalysis, be judged as and imagine then rolling mouse, do not imagine that then mouse is static.
Treatment scheme is determined as shown in Figure 8 in the target area, is picked up after original EEG signals eeg amplifier is input to computing machine by scalp electrode, and the bandpass filtering through 8~13Hz keeps wherein α wave component again; This signal is through being divided into two paths of signals behind root mean square (RMS) smoothing algorithm of 10ms: become the main control channel signal after one tunnel the average treatment through 400~500ms, be used for output control; Another road becomes the auxiliary control channel signal through after average treatment of 50ms, is used for judging that main channel signal is by the close one's eyes true α ripple amplification signal that produces or other disturbs caused noise signal of experimenter.Its determination methods is that main channel signal and threshold voltage are compared, if surmount threshold voltage, compares to judge whether true α ripple amplification signal with the auxiliary control channel signal again.Signal processing flow is exported to interface circuit with actual α ripple amplification signal as control signal at last.
2 pattern-recognitions and definite systematic parameter
2.1 rolling mouse pattern-recognition
The cursor movable part does not need to determine parameter for the present invention, only need obtain The classification basis by training mode, judges whether rolling mouse by pattern-recognition again.The sorting technique of the pattern-recognition that we adopt is the mahalanobis distance method, and the basic thought of mahalanobis distance diagnostic method is [16]: suppose to have two overall G1 and G2, x is a new sample point.Define the mahalanobis distance of x to G1 and G2:
Wherein: u (1), u (2), ∑ 1, ∑ 2 are respectively average and the covariance matrix of G1 and G2.In this problem, G1 is the overall of task attitude, and G2 is the overall of Idle state.The advantage of mahalanobis distance is the correlativity influence of having got rid of between the pattern sample.
The structure discrimination formula is:
The structure decision rule is:
2.2 determine target component
Need determine three critical technical parameters for the target determining section: first switching threshold voltage, it two is constants actuation time, continue the time of flicker before switching corresponding to pilot lamp on the control panel, it three is the caused maximum ground unrest voltages of various interference.First parameter mirror operation person open, the difference of α wave amplitude between the closed-eye state; Second parameter mirror operation person closes one's eyes back α wave amplitude above the threshold voltage required time; The 3rd parameter is to judging that the main control channel signal is a true α wave control signal or interference noise has important value.
(1) switching threshold voltage
α wave amplitude mean value was designated as V when the operator was opened eyes
Open, α wave amplitude mean value is designated as V when closing one's eyes
Close, its difference is designated as V
d, operator's switching threshold voltage reference value V then
RefCan calculate by following experimental formula:
V
ref=V
open+0.8V
d (2)
0.8 be that the operator opens in the formula, the gain coefficient of α wave amplitude difference under the closed-eye state.The present invention adopts identical threshold voltage to the different operating person, can choose corresponding switching threshold voltage setting scheme according to different controlled target and task.
(2) actuation time constant
As described above, the α wave amplitude surpassed the threshold voltage required time after actuation time, constant reflected the operator, the present invention adopts the identical gain coefficient value, determines each operator's switch control threshold voltage as stated above, and with being worth this system testing operator's actuation time.In order to obtain more reliable and more stable data, require each operator's repetitive operation test 25 times, consider system hardware collection, signal Processing required time and individual difference, the present invention chooses maximal value in data recording actuation time as constant actuation time of BCI system.
(3) maximum ground unrest voltage
A lot of disturbing factors (comprising that eye electricity, electromyographic signal and ambient noise disturb) can appear in the operating process.The action mean values can be followed the variation of the generation of action or environment and corresponding change occur when above-mentioned interference occurs, and it is a lot of to exceed normal range.For the situation that occurs is disturbed in caution significantly, the present invention is setting an interference warning value in addition (above threshold voltage on subaisle outside the main channel, within the interference range significantly that may occur), if surpass this warning value just think the control signal of main channel may be by interference cause but not the control increase of α wave amplitude down consciously, thereby suppress the output of main channel control signal.
The beneficial effect that the present invention can bring:
16 experimenters use computer screen mouse cursor movement control system of the present invention to carry out the basic controlling characteristic test.This experiment purpose is by experimenter's data analysis being investigated controlling schemes feasibility and the ease for operation and the control rate of system.The experimenter is young student (men and women half and half, and the mean age is 25.2 years old).Experiment comprises four-stage, and each stage requires the experimenter to carry out 20 Continuous Selection control.The experimenter all not through training in advance, selects the order of control task to provide at random in experiment.Pick up counting from sending the control task order,, target area color restoration selected to the controlled target direction is white (control task is finished in expression), and then timing stops, and carries out successively 20 times; If cursor does not move to target direction, then be designated as a mistake.The experimental period record is strict to be responsible for carrying out by same experimenter under same experimental conditions.
Each experimenter correct select time (containing maximal value, minimum value, intermediate value and mean value) and wrong choice number of times in continuous 20 target selection process of four-stage have been write down.From experimental data as can be seen each experimenter continuous experimentation, correct select time shortens, selects errors number obviously to gradually reduce gradually, and generally be near or below mean value from the correct select time of subordinate phase experiment beginning, after showing that the experimenter is through the phase one experiment, all can be familiar with the also control operation of adaptive system soon.It only is 10% that two experimenters error rate in experiment is first wherein arranged, three experimenters are from subordinate phase, error rate is dropped to 15%, 10% and 5% respectively, show that most experimenters have been familiar with system's control when subordinate phase is tested, thereby reduced error level rapidly.Above-mentioned basic controlling experimental result has shown that this BCI system has the characteristics of easy to understand and operation.
5 subject data statistics of table 1
Table 1 is that two classes that are easier to occur in wherein 5 experimenters experiment are selected error statistics, and first what is called " loop error " refers to that the experimenter misses this circulation because of failing in time to make a choice, and can only wait until next circulation time select target direction again.It two is " it is wrong to face choosing ", refer to the experimenter because of control has too much of a good thing the wrong adjacent direction target of having selected.Summation is analyzed as can be seen from table, and loop error occurs fewer, and its main cause is an accidentalia.And in selecting wrong number, face and select mistake to occupy larger proportion, be easier to take place.In essence, face and select mistake mainly to result from psychological factor, but can overcome through training.Can see in the table and face the choosing mistake, reduce 64.7%, reduce 70.6%, further prove the ease for operation and the unfailing performance of this BCI system to the 4th part in the second portion error rate progressively obviously reducing in the experimentation.
16 experimenter's experimental results illustrate that this BCI system has does not need complicated study or biofeedback training process, the accuracy height, easy characteristics such as grasps may be for having a normal thinking but the patient of motor function incompleteness provides a kind of new information interchange control mode and help the disabled rehabilitation and life aid.