| EEG singal is a kind of voltage value which is produced when neuronal cells are interchanging material each oher, transmiting various sensory response, and sending the brain command. When human body is stimulated by outside world or subjective thinking, EEG will be changed and brain wave will appear difference, and this differences will only be expressed by wave variation in traditional EEG diasplay interface.In this paper, the display-control software adds the head model into the display terminal, and adds virtual lead in the model to simulate the electrodes of electrical test. In the simulation, through the reading of the EEG signals,the characteristics of EEG singal can be displayed by different states of virtual lead characterization. The software also divides modal into some parts by the brain function, and each function part has established a particular relationship with virtual leads which it contains.When the virtual leads has been changed, the function part will be marked as the current activity area of brain and showed by color variation.First of all, in this paper, we create the head model through 3DMAX, divide the head model into five parts according to the division standard of brain function and add electrodes into the head model according to the 10-20 lead method. We use OpenGL graphics interface finishing the reading of the model and designing the function of the rotation, translation, picking up and color rendering for model. In the study of EEG signal scientists have summarized some regularity of EEG variation,and the P300 potential variation is a kind of regularity which the brain responses to stimulation. Blind source separation algorithm is commonly used in P300 potential analysis,and it can complete the characteristic signal extraction by the condition of blended unknown source signal and unknown channel parameters. Based on a priori theory for the characteristics of P300 potentials, we make the leads which contain P300 potentials signal frequency domain filtering, remove redundant data and retain the characteristics of P300 signal.Then we use the FastICA algorithm separating mixed blind source signal and getting some independent component. And we analyse the characteristic peak and energy of P300 in the independent component and get several independent components which are the most closed to P300 potentials. Finally,we choose several electrodes which have larger weight value as the current activity in these independent components. Then we design the realization of the human-computer interaction and the function modules of EEG machine software, including the main interface design module, the lead setting module, the serial port configuration module and the waveform drawing module. There are the function modules of the electrodes status displayed,activity electrodes marked,function area marked and the electrodes picked up. Finally, through the four specific stimuli, we verify the correctness of the algorithm for active electrode acquired and checkout the function of the human-computer interaction and function modules.In the designing of the software we broke the traditional EEG machine's single waveform output function, make the EEG signal variation displaying on the head model directly and realize the visualization of the semaphore. In this paper, the EEG display-control software can display the dynamic variation of the EEG signals, realize the analog control of the electrodes and the electrode slice' distinction disply of different work condition,and avoid the electrodes'none access in measurement,or the problem of missing data. At the same time,the software can also realize the picking up of virtual leads, check up each electrode slice's working condition,reconnect the abnormal working condition's lead and disconnect the useless electrode to reduce test data and save resources. |
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