Spatial Information Acquisition Of EEG Electrode

Electroencephalography(EEG)is of great significance in the diagnosis of brain diseases and brain cognitive functions,especially for the diagnosis of diseases such as epilepsy.An important goal for the EEG-based functional brain studies is to estimate the location of brain sources,and one of the necessary links is to estimate the spatial coordinates of the EEG electrodes.In recent years,many scholars have proposed various solutions to the problem of EEG electrode positioning,and have achieved good results.Among them,photogrammetry has the characteristics of low cost and high speed compared with other methods,so it has become the most popular research method.This paper analyzes the advantages and disadvantages of various photogrammetry methods,and proposes an EEG electrode positioning method based on the CCD + TOF camera group and the characteristics of the depth camera.The main research contents of the article are as follows:1.This paper builds a set of EEG electrode spatial information acquisition system based on CCD + TOF camera group.The CCD camera is responsible for obtaining the color information of the scene,and the TOF camera is responsible for obtaining the scene point cloud information.In order to obtain all the electrode points,the system collects data from 5 perspectives,and then all electrode points are unified into a coordinate system.2.For the joint calibration of the camera group,this paper proposes a joint calibration method of the CCD + TOF camera group based on the point cloud data captured by TOF camera.Because the depth map obtained by TOF camera has the characteristics of low resolution and high noise,this paper uses the more accurate point cloud data obtained by TOF camera to calibrate the camera group.In this paper,a 2.5D calibration board is designed based on the depth-sensing characteristics of the TOF camera,and the calibration of the relative position of the CCD camera coordinate system and the TOF camera coordinate system is completed using the calibration board as the target coordinate system.The experimental results show that the joint calibration scheme of this camera group has achieved a small re-projection error and can effectively support the subsequent experiments.3.For the positioning and fusion of EEG electrodes,this paper proposes a set of EEG electrode positioning and registration schemes.Through the morphological processing of the electrode color image,the pixel coordinates of the electrode can be extracted,and the optimal spatial position of the electrode can be obtained by combining the results of joint calibration of the camera group and related optimization strategies.Then use singular value decomposition(SVD)algorithm to unify all electrode points into a coordinate system.Experimental results show that the solution proposed in this paper can effectively extract the spatial position of the electrode points and register them to a unified coordinate system.