0


一个基于P300拥有最小校准时间的高效脑-机接口

An Efficient P300-based Brain-Computer Interface with Minimal Calibration Time
课程网址: http://videolectures.net/nips09_lotte_epb/  
主讲教师: Fabien Lotte
开课单位: INRIA研究机构
开课时间: 2010-01-19
课程语种: 英语
中文简介:
脑-机接口(BCI)是一种通信系统,使受试者仅通过大脑活动向计算机发送命令[1]。大多数现有的BCI都是基于脑电图(EEG)来测量大脑活动[1]。到目前为止,BCI已被证明是非常有前途的残疾人通信和控制工具[1]。设计残疾人辅助BCI时使用的一种很有前景的脑信号是p300,一种在罕见的相关刺激后约300毫秒出现的正波形[1,2]。为了使用基于p300的BCI,受试者必须将注意力集中在随机出现在许多其他刺激中的给定刺激上,每个刺激对应于一个给定的命令。所需刺激的出现是罕见且相关的,预计会触发受试者大脑活动中的p300。因此,检测p300使系统能够识别所需的刺激,从而识别所需的命令。有趣的是,基于p300的BCI已经成功地用于控制轮椅(见,例如[3])或使严重残疾的用户能够拼写单词[2,4]。然而,目前基于p300的BCI以及其他BCI系统仍然存在一些限制,阻碍了它们的广泛应用[1]。其中一个限制是,要使用BCI,必须记录受试者的许多脑电图信号示例,以便校准BCI,这是不可靠和耗时的。此外,通常必须定期(例如从一天到另一天)重复此校准过程,以适应电极位置变化或受试者精神状态和疲劳程度变化等变化源。因此,校准时间应尽可能短。到目前为止,文献中还很少涉及到缩短基于p300的BCI的校准时间。例外情况是Li等人[5]和Lu等人[6]的作品。Li等人建议最初使用一个校准了少量训练样本的BCI,然后通过半监督学习逐步在线调整该BCI[5]。Lu等人建议使用独立于受试者的BCI,之前从许多其他受试者的数据中学习过,随后还进行在线改编[6]。然而,这两种方法的主要局限性在于,这种BCI最初的检测性能较差,只有在适应后才能变得有效。一个理想的基于p300的BCI最初会有很高的性能,即使只是用很少的例子来训练。在本文中,我们提出了一种新的基于p300的BCI设计,它可以使用比当前的BCI设计更少的示例进行训练,而不会牺牲检测性能。
课程简介: Brain-Computer Interfaces (BCI) are communication systems that enable subjects to send commands to computers by using only their brain activity [1]. Most existing BCI are based on ElectroEncephaloGraphy (EEG) as the measure of brain activity [1]. So far, BCI have been proven to be very promising communication and control tools for disabled people [1]. A promising brain signals used in the design of assistive BCI for disabled people is the P300, a positive waveform occuring roughly 300 ms after a rare and relevant stimulus [1, 2]. In order to use a P300-based BCI, subjects have to focus their attention on a given stimulus randomly appearing among many others, each stimulus corresponding to a given command. The appearance of the desired stimulus being rare and relevant, it is expected to trigger a P300 in the subject’s brain activity. As such, detecting the P300 enables the system to identify the desired stimulus and hence the desired command. Interestingly enough, P300-based BCI have been successfully used to control a wheelchair (see, e.g., [3]) or to enable severely disabled users to spell words [2, 4]. However, current P300-based BCI as well as other BCI systems still suffer from several limitations which prevent them from being widely used [1]. One of these limitations is that to use a BCI, many examples of the subject’s EEG signals must be recorded in order to calibrate the BCI, which is unconvenient and time consuming. Moreover, this calibration process generally has to be repeated at regular intervals (e.g., from one day to the other) in order to accomodate sources of variations such as changes in electrode positions or changes in the subject’s mental state and fatigue level. Therefore, the calibration time should be maintained as brief as possible. Until now, reducing the calibration time of P300-based BCI has been scarcely addressed by the literature. Exceptions are the works of Li et al [5] and Lu et al [6]. Li et al suggested to use initially a BCI calibrated with few training samples, and then to incrementally adapt this BCI online, thanks to semi-supervised learning [5]. Lu et al proposed to use a subject-independent BCI, previously learnt from the data of many other subjects, also followed by online adaptation [6]. However, the main limitiation of these two approaches is that such BCI would have initially poor detection performances, becoming efficient only after adaptation. An ideal P300-based BCI would have initially high performances, even if trained with very few examples. In this paper, we propose a new P300-based BCI design which can be trained using much fewer examples than current BCI designs, without sacrifying the detection performances.
关 键 词: 脑机接口; 通信系统; 残疾人辅助; 脑电信号
课程来源: 视频讲座网
最后编审: 2020-07-31:yumf
阅读次数: 39