非侵入式异步脑机接口技术研究综述

Review of Non-invasive Asynchronous Brain-computer Interface Technology

脑-机接口(brain-computer interface,BCI)为大脑提供了直接对外部设备进行控制的信息通路,根据是否存在同步触发信号可分为同步和异步系统。同步BCI设置了同步触发信号,迫使人脑与计算机同步通信,要求用户严格按照计算机发出的同步信号进行操作,约束用户遵循固定的节奏输出指令,从而限制了用户控制外部设备的自主性,难以满足实际应用场景下的操控需求。相比于同步BCI系统,异步BCI无须设置同步触发信号,可实时对脑电信号进行处理及响应。异步BCI通过对用户的控制态和空闲态的检测,使用户可自主支配输出指令的时间。因此异步BCI系统完全由用户控制,在人机交互方面更加自然、实用。目前,异步BCI控制状态检测的实现途径主要可分为两类,即状态切换开关检测和自主控制状态检测。基于状态切换开关检测的异步BCI系统将状态切换开关与BCI系统连接,构成两步混合系统。用户在对设置的独立开关进行选择时会产生相应的开关信号,异步BCI通过检测开关信号实现对系统的控制状态切换。基于自主控制状态检测的异步BCI系统没有独立的状态切换开关,而是直接对采集的脑电信号进行解码,分析是否存在控制信号对应的有效成分,以实现状态检测和切换。本文总结了两种异步BCI系统的基本原理和关键技术,探讨了其未来发展趋势,以期促进异步BCI技术的深入研究和开发应用。

The brain-computer interface provides the brain with an information pathway to directly control external devices,and can be divided into synchronous and asynchronous systems according to whether there is a synchronous trigger signal.Synchronous BCI sets a synchronous trigger signal to force the human brain to communicate synchronously with the computer,requiring the user to operate strictly in accordance with the synchronous signal sent by the computer,and constraining the user to follow a fixed rhythm output command,thus limiting the user’s autonomy in controlling external devices,which is difficult to meet Control requirements in practical application scenarios.Compared with the synchronous BCI system,the asynchronous BCI does not need to set a synchronous trigger signal,and can process and respond to EEG signals in real time.The asynchronous BCI enables the user to independently control the time for outputting instructions by detecting the user’s control state and idle state.Therefore,the asynchronous BCI system is completely controlled by the user,which is more natural and practical in terms of human-computer interaction.At present,the implementation methods of asynchronous BCI control state detection can be mainly divided into two categories,namely state switching switch detection and autonomous control state detection.The asynchronous BCI system based on the detection of the state switching switch connects the state switching switch with the BCI system to form a two-step hybrid system.When the user selects the set independent switch,a corresponding switch signal will be generated,and the asynchronous BCI realizes the switching of the control state of the system by detecting the switch signal.The asynchronous BCI system based on autonomous control state detection does not have an independent state switching switch,but directly decodes the collected EEG signals,and analyzes whether there is an effective component corresponding to the control signal,so as to realize state detection and switching.This paper summarizes the basic principles and key technologies of two asynchronous BCI systems,and discusses their future development trends,in order to promote the in-depth research,development and application of asynchronous BCI technology.