首页生物学
   首页医药科学
0


基于贝叶斯框架的脑-机界面单试验脑电图分类的空间-光谱滤波器优化

Spatio-Spectral Filter Optimization in a Bayesian Framework for Single-Trial EEG Classification in Brain-Computer Interface
课程网址: http://videolectures.net/bbci2012_lee_brain_computer_interface/  
主讲教师: Seong-Whan Lee
开课单位: 高丽大学
开课时间: 2012-12-03
课程语种: 英语
中文简介:
在对运动图像的单次试验脑电图进行分类时,存在两个具有挑战性的问题。一种是谱滤波器优化——频率频段,其中ERD/ERS模式反映了运动和感觉运动皮层上节律活动的激活和失活,在不同的受试者之间,甚至在同一受试者的试验中,都高度可变。另一个问题是空间滤波器优化——脑电图电极测量来自大脑不同来源的叠加信号,而脑电图信号通常被人为干扰和噪声污染,从而导致模式分类性能下降。本文提出了一种新的基于脑-机接口的贝叶斯框架下优化空间-光谱滤波器的类识别特征提取方法。在我们的方法中,优化空间光谱滤波器的问题被表述为后验概率密度函数的估计(pdf)。摘要为了估计未知的后验pdf,提出了一种基于粒子的近似方法,扩展了一种带扩散过程的因子采样技术。提出了一种基于信息论的观测模型,用于测量类间特征的分辨能力。通过对结果的分析和在公共数据库上的成功应用,验证了该方法的可行性和有效性。
课程简介: There are two challenging problems in classifying a single-trial EEG of motor imagery. One is spectral filter optimization - The frequency bands, in which ERD/ERS patterns reflect activation and deactivation of rhythmic activity over motor and sensorimotor cortices, are highly variable across subjects and across even trials for the same subject. The other problem is spatial filter optimization - The EEG electrodes measure the superimposed signals that originated from various sources in the brain and the EEG signals are generally contaminated with artifacts and noise that can cause performance degradation in pattern classification. In this work, we propose a novel method for class-discriminative feature extraction by means of optimizing spatio-spectral filters in a Bayesian framework for EEG-based Brain-Computer Interfaces. In our method, the problem of optimizing spatio-spectral filter is formulated as estimation of a posterior probability density function (pdf). In order to estimate the unknown posterior pdf, about which, in this paper, there is no functional assumption, a particle-based approximation method is proposed by extending a factored-sampling technique with a diffusion process. An information-theoretic observation model is also devised to measure discriminative power of features between classes. The feasibility and effectiveness of the proposed method are demonstrated by analyzing the results and its success on public databases.
关 键 词: 脑电图; 脑磁图; 反演方法; 频谱滤波器优化; 空间-光谱滤波器
课程来源: 视频讲座网
最后编审: 2019-10-22:cwx
阅读次数: 69