隐性注意下视听双通道脑控字符输入系统关键问题研究

发布时间：2018-05-26 17:56

本文选题：隐性注意 + 视听联合　；参考：《天津大学》2015年博士论文

【摘要】：脑控字符输入系统可以帮助重症残障病人通过虚拟键盘信息实现对外自主交流,但传统的显性注意输入范式很大程度上依赖于使用者的注视转移水平,并不适用于眼动控制受限的重症残障病人。为了解决这一问题,研究者逐渐转向寻求一些基于隐性注意的脑机交互新方法,尤其是在视觉与听觉双通路联合刺激方面给予了较高期望,相应研究亟待深入开展。基于上述背景,本文首先设计了三类独立于眼动控制的隐性注意刺激范式,分别是:视觉刺激范式、听觉刺激范式以及视听联合刺激范式。通过对不同刺激范式诱发出的事件相关电位各成分特征、分类正确率的时空分布特性以及溯源结果的分析,探究了视觉刺激和听觉刺激在不同控制条件下的作用机制和大脑对不同刺激范式的响应特性,并且通过对在线字符输入速度和实验中任务负荷的分析,证明了视听联合刺激范式是一种低任务负荷的高效字符输入范式。在此基础上,研究中设计并实现了五种视-听呈现时间差的视听联合刺激范式下的隐性注意脑控字符输入系统。通过对其诱发出的事件相关电位进行分析发现,视听联合刺激早期成分与视觉和听觉均显著相关,而事件相关电位的潜伏期主要与视觉刺激的呈现时刻相关。呈现时间差在一定范围内(小于100 ms)的视-听联合刺激范式均可取得较高的分类正确率,且不存在显著性差异。这一方面显示了文中采用的分类算法的鲁棒性,另一方面也说明只要保证视-听刺激的刺激呈现时间差在一定范围内并配以合适的分类器就可以得到较高的分类正确率,而不必对硬件系统和配准时刻有过高的要求。最后本文还提出了一种新颖的隐性注意视听双通道刺激范式,即视听并行刺激范式。实现了利用视觉刺激与听觉刺激并行完成对目标任务的选择。文中从事件相关电位的特性与分类识别的结果分析了视听并行字符输入的可能性,结果表明并行范式下可诱发产生稳定的事件相关电位,并具有较强的可分性。有超过70%的被试可以达到输入字符正确率在80%以上。总之,本文设计实现了多种隐性注意视听刺激范式,探讨了视听联合刺激中视觉刺激与听觉刺激的作用机制,并证明了视听联合刺激范式的优势及视听并行刺激范式的可行性,研究成果有望在重症瘫痪脑-机接口康复系统中得到进一步的推广应用。
[Abstract]:The brain-controlled character input system can help the severely disabled patients to communicate autonomously through virtual keyboard information, but the traditional explicit attention input paradigm largely depends on the user's fixation transfer level. Not suitable for severely disabled patients with limited eye movement control. In order to solve this problem, researchers have gradually turned to seek some new methods of brain-computer interaction based on recessive attention, especially in the combination of visual and auditory stimuli. Based on the above background, three types of implicit attention stimuli are designed, which are visual stimulation paradigm, auditory stimulus paradigm and audio-visual combined stimulation paradigm. The characteristics of the components of event-related potentials induced by different stimulus paradigms, the temporal and spatial distribution of classification accuracy and the traceability results were analyzed. This paper explores the mechanism of visual and auditory stimuli under different control conditions and the characteristics of brain response to different stimuli patterns, and analyzes the speed of online character input and the task load in the experiment. It is proved that the Audio-visual combined stimulation paradigm is an efficient character input paradigm with low workload. On the basis of this, we design and implement five implicit attention control character input systems under the visual and auditory time-delay combined stimulation paradigm. It was found that the early components of the combined audiovisual stimulation were significantly related to the visual and auditory components, while the latency of the event-related potentials was mainly related to the presentation time of the visual stimuli. In a certain range (less than 100 Ms), the visual and auditory stimulus paradigm with time difference can achieve a higher classification accuracy, and there is no significant difference. On the one hand, it shows the robustness of the classification algorithm used in this paper. On the other hand, it also shows that the classification accuracy can be obtained by ensuring that the time difference of visual and auditory stimuli is within a certain range and matching with a suitable classifier. There is no need for the hardware system and registration time to have too high requirements. Finally, this paper proposes a novel implicit attention audiovisual dual channel stimulation paradigm, that is, audiovisual parallel stimulation paradigm. The choice of target task by visual stimulation and auditory stimulation is realized. In this paper, the possibility of audio-visual parallel character input is analyzed from the characteristics of event-related potentials and the results of classification and recognition. The results show that the event-related potentials can be induced in parallel paradigm and have strong separability. More than 70% of the subjects can achieve the input character accuracy of more than 80%. In a word, this paper designs and implements a variety of implicit audio-visual stimulation paradigms, probes into the mechanism of visual stimulation and auditory stimulation in combination with audio-visual stimulation, and proves the advantages of audio-visual co-stimulation paradigm and the feasibility of audio-visual parallel stimulation paradigm. The research results are expected to be further applied in the rehabilitation system of severe paralysis brain-computer interface.
【学位授予单位】：天津大学
【学位级别】：博士
【学位授予年份】：2015
【分类号】：R496;TH789

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