脑—机接口及其信号的单次提取
详细信息    本馆镜像全文|  推荐本文 |  |   获取CNKI官网全文
摘要
直接用大脑思维活动的信号与外界进行通信,实现“心与心”的交流,甚至达到对周围环境的控制,是人类自古以来就追求的梦想。脑-机接口(Brain-Computer Interface: BCI)这种新颖的人机交互模式提供了实现这一梦想的科学途径。人们希望这种全新的通信技术能够用于辅助控制交通工具、武器和其它系统,特别为那些神经肌肉受损,不能使用常规通信手段的残疾患者提供与外界进行交流的另一途径。
    所谓脑-机接口,是一个不依靠外周神经和肌肉组织等通常的大脑输出通道的通信系统。近5 年来,这一领域的研究逐渐形成了热点,世界上数十个研究小组已开发出多种形式的BCI 实验系统。其中已有3 种脑控键盘的报道。但它们的共同问题一是以低频闪烁方式提供视觉诱发信息,容易造成使用者的疲劳; 二是通信速度太低,只有5~27 比特/分钟,很难满足实际需要。有鉴如此,我们在国家自然科学基金的资助下,开展了基于“模拟自然阅读”诱发模式的脑控拼写装置的研究。试图使该系统的通信速率达到90 比特/分钟,并以更自然的方式给用户提供一种舒适的使用环境。
    在这个系统中,通信载体、信源编码、虚拟键盘的设计和脑-机接口信号的单次提取是四个最核心的问题。在前两个问题已基本解决的情况下,本文就后两个问题展开了深入的研究。研究内容、结果与创新点如下:
    1. 调研了脑-机接口的起源、意义、定义、分类、信号特点、信号处理及模式识别方法、目前研究的现状及面临的挑战等。进行综合分析后,指出了目前存在的不足及其发展方向,提出了我们的解决方案。成果发表在附录1 的【1】、【2】、【6】中。
    2. 提出了一个新颖的“双页虚拟键盘”方案,并对其按键位置的排布进行了合理的设计。它弥补了常规脑控拼写装置中信源数量增多将导致选择单个信源时程偏长的不足。分析表明,这种设计在原有设计指标的基础上,通信速率将有约70%的提高,可达150 比特/分钟以上,是现有BCI 系统的5~20 倍。这部分的研究成果发表在附录1 的【4】、【5】中。
    3. 对BCI 通信载体信号进行了谱分析,发现非靶刺激与靶刺激所诱发的VEP 信号的相对功率谱,在5Hz 以下有较大的变化,可达15db 以上; 而在10Hz 以上却基本没有变化。这为后续降低特征维数,提高信号处理速度提供了理论
It’s an ancient dream of human that using their mind to control or communicate with peripheral circumstance directly. Brain-Computer Interface (BCI) technologies revealed the scientific approaches to make the dream coming true. This novel method gives a valuable new option for individuals who cannot use conventional communication systems that depend on peripheral muscles and nerves, particularly those with neuromuscular disorders and motor disabilities.
    Brain computer interfaces give their users communication and control channels that do not depend on the brain’s normal output channels of peripheral nerves and muscles. In last five years, BCI is becoming a hotspot and have arisen great interesting of scientists all over the world. There several BCI systems came out, among them three mental controlled keyboard had been reported. These innovatory systems achieved an average speed rate about 5~27bits/min. But there are several aspects to be improved. Firstly, the speed rate is not so high; and secondly, the flash in a low frequency may cause eye fatigue rapidly. To amend these deficient, we investigated an INR SPELLER system based on a so-called Imitating-Natural Reading (INR) paradigm. It was demonstrated that the Exogenous Given Reactions which reduce the signal-to-noise ratio were restrained and spontaneous endogenous potentials were “regularized”significantly with this novel modality. The system is expected to have a speed of 90bits/min, and to give their users comfortable conditions in using it.
    There are four key issues in the system, that is communication carriers, source coding, designation of virtual keyboard, and the single-trial estimation of its message carriers. The present dissertation dedicated to have a thoroughly investigation to the latter two issues. The contexts, results, and innovations of this work are as follows:
    1. By investigating the BCI’s origination, significance, definition, classification, feature of signals, signal processing, pattern recognition, and the development and challenges, etc., the future developments were clarified.
    2. The communication carrier and coding methods were introduced. A dual-page virtual keyboard was proposed based on former works. The analytical results suggested that
    there are 70% higher in communication rate than the former designation target, it could up to a speed of 150bits/min, and will have a speed 5~20 times higher than the current BCIs. 3. The analysis of power spectrum of carriers in EEG showed that, the relative power have a significant change below 5Hz which could up to 15db; whereas, there were no change in the range of higher than 10Hz. The analysis gave theoretical guidelines for the following feature dimensional reducing and boosting the speed of communication. The features embedded in EEG were enhanced by means of AR model and wavelet filtering. This could improve the classification accuracy further more. we did another experiment to extract N2 components using independent component analysis (ICA). Facing the challenge of uncertainty of the polarity in ICs, a new algorithm with N2 bipolar threshold was proposed, and solved the problem. The N2 components were enhanced and made the single-trial estimation of N2 be feasible. 4. The pattern classification algorithm of support vector machine (SVM), which based on statistical learning theory, for the single-trial estimation of carriers was researched. We proposed an new SVM algorithm with AR model and ICA feature extraction. Applying the program written in Matlab6 to the data from three subjects, the effects of single-trial estimation of carriers were investigated thoroughly by means of various montages of multi channels, single-channel, difference time lengths, difference time intervals, etc. finally, a perfect results were gained by combination of P2, N2, and P3 components from two channels. The results also suggested the experiment paradigm of our mental speller is feasible.
引文
[1] 魏景汉等, 认知事件相关脑电位教程[M],经济日报出版社,2002; 2-5.
    [2] 田心. 神经信息学——21 世纪的机遇和挑战. CBME 论文集. 2001.9; pp.53.
    [3] 官金安,林家瑞,脑-机接口技术进展与挑战[J],中国医疗器械杂志,2004,28(3):157-164.
    [4] 官金安,林家瑞,赵婕,直接神经接口与控制技术[J],国外医学生物医学工程分册,2004,27(6):337-341.
    [5] 官金安,林家瑞,影响脑-机接口通信速率的因素分析[C], 第六届CBME会议论文集,武汉,May, 2004, pp.297.
    [6] 华小梅,林家瑞,官金安,“脑-机接口”的研究进展[J],国外医学生物医学工程分册,2004,27(2):94.
    [7] Jinan Guan, Yaguang Chen, Jiarui Lin, Designing a Dual Page Virtual Keyboard for Mental Speller[C], Proc. of the first IEEE EMBS int. conf. on neural interface and control, Wuhan, May, 2005.
    [8] Jinan Guan, Yaguang Chen, Jiarui Lin, et al. N2 Components as Features for Brain Computer Interface[C], Proc. of the first IEEE EMBS int. conf. on neural interface and control, Wuhan, May, 2005.
    [9] Jinan Guan, Jiarui Lin, et al. Single-Trial Estimation of Visual Evoked Potentials in Single-channel[C], Proc.of 27th IEEE EMBS annual conference, sept., Shanghai. Sept., 2005. (submitted)
    [10] 官金安,陈亚光,林家瑞,用支持向量机实现脑-机接口载波成分的单次提取[J].中国生物医学工程(submitted).
    [11] J. R. Wolpaw, et al., Brain–Computer Interface Technology: A Review of the First International Meeting[J]. IEEE Trans. Rehab. Eng. 2000; 8:166–173.
    [12] 姚泰. 生理学(第五版)[M]. 人民卫生出版社. 2001.11; pp.287
    [13] 吴小培. 独立分量分析及其在脑电信号处理中的应用[D]. 中国科学技术大学博士学位论文. 2002.7.
    [14] Sandro Mussa-lvaldi. Real brains for real robots[J]. Nature. 2000; 408(16):305-306.
    [15] THERESA M. VAUGHAN, et al., Guest Editorial Brain–Computer Interface Technology: A Review of the Second International Meeting[J]. IEEE Trans. Neural. Syst. Eng. 2003; 11:94–107.
    [16] P. R. Kennedy et al., Direct control of a computer from the human central nervous system[J]. IEEE Trans. Rehab. Eng. 2000; 8:198–202.
    [17] G. Pfurtscheller, et al., Current trends in Graz brain–computer interface (BCI) research[J]. IEEE Trans. Rehab. Eng. 2000; 8:216–219.
    [18] J. R. Wolpaw, et al., The Wadsworth Center brain–computer interface (BCI) research and development program[J]. IEEE Trans. Neural. Syst. Eng. 2003; 11:204–207.
    [19] E. Donchin, et al., The mental prosthesis:Assessing the speed of a P300-based brain-computer interface[J]. IEEE Trans. Rehab. Eng. 2000; 8:174–179.
    [20] N. Birbaumer, et al., The thought-translation device (TTD): Neurobehavioral mechanisms and clinical outcome[J]. IEEE Trans. Neural. Syst. Eng. 2003; 11:120–123.
    [21] M. Cheng, et al., Design and implementation of a brain computer interface with high transfer rates[J]. IEEE Trans. Biomed. Eng. 2002; 49:1181–1186.
    [22] X. Gao, et al., A BCI-based environmental controller for the motion-disabled[J]. IEEE Trans. Neural. Syst. Eng. 2003; 11:137–140.
    [23] S. G. Mason ,et al., A general framework for brain-computer interface design[J]. IEEE Trans. Neural Syst. Rehab. Eng. 2003; 11:72–87.
    [24] Lehtonen J. EEG-based Brain Computer Interfaces (Master). Espoo , Helsinki Unversity of Technology 2002: 6-14.
    [25] Wolpaw JR, McFarland DJ, Neat GW et al. An EEG -based brain-computer interface for cursor control[J]. Electroencephalography and Clinical Neurophysiology ,1991, 78: 252 -259.
    [26] McFarland DJ, Lefkowicz AT,Wolpaw JR. Design and operation of an EEG-based brain-computer interface (BCI) with digital signal processing technology[J]. Behav Res Meth Instrum Comput 1997,29:337 -345.
    [27] Wolpaw JR, McFarland DJ, Vaughan TM. Brain-computer interface research at the Wadsworth Center [J]. IEEE Transaction on Rehabilitation Engineering ,2000, 8(2):222 -225.
    [28] Farwell LA, Donchin E. Talking off the top of your head: toward a mental prosthesis utilizing event-related brain potentials [J]. Electroencephalography and Clinical Neurophysiology, 1988, 510 -523.
    [29] Middendorf M, McMillan G, Calhoun G et al. Brain-computer interfaces based on steady-state visual evoked response [J]. Transaction on Rehabilitation Engineering ,2000,8:211-213.
    [30] Jonathan R. Wolpaw, et al, Brain–computer interfaces for communication and control[J]. Clinical Neurophysiology. 2002; 113:767–791.
    [31] Santhosh J, Brain Computer Interface, http://www.biomedsociety.com/publication/2002/march2002/article01.htm.
    [32] Bayliss JD. A Flexible Brain-Computer Interface[D]. Rochester ,New York.University of Rochester.2001: 2 -33.
    [33] 孙即祥等. 现代模式识别[M]. 长沙:国防科技大学出版社. 2002. pp2-5.
    [34] R. T. Lauer, et al., Applications of cortical signals to neuroprosthetic control: A critical review[J]. IEEE Trans. Rehab. Eng. 2000; 8:205–208.
    [35] Kennedy PR, et al., Restoration of neural output from a paralyzed patient by a direct brain connection[J]. NeuroReport. 1998; 9:1707–1711.
    [36] Thomas Stieglitz. Implantable Microsystems for Monitoring and Neural Rehabilitation, Part II.m?edical device technology , 2002 .
    [37] Pearson, H., Shocks switch brain on. Nature News Service. Available online: www.nature.com/nsu/021104/021104-13.html, 2002.
    [38] Chapin, J.K, et al., Real-time control of a robot arm using simultaneously recorded neurons in the motor cortex[J]. Nature Neurosciences. 1999; 2:664-670.
    [39] Serruya,M D, et al., Brain-machine interface: Instant neural control of a movement signal[J]. Nature. 2002; 416(6877):141-142.
    [40] Wessberg,Johan, et al., Real-time prediction of hand trajectory by ensembles of cortical neurons in primates[J]. Nature. 2000; 408(6810):361-365.
    [41] Talwar, S.K., et al., Rat navigation guided by remote control[J]. Nature. 2002; 417:37-38.
    [42] L. A. Farwell and E. Donchin, “Talking off the top of your head: Toward a mental prosthesis utilizing event-related brain potentials[J],”Electroenceph. Clin. Neurophysiol., 1988,70: 510–523.
    [43] Ying Xie, and Zhongle Yang. “Event-related Potentials during Imitated Natural Reading[J],”International Journal of Psychophysiology, Vol. 45, pp. 81, July 2002.
    [44] 程正兴,小波分析算法与应用[M],西安:西安交通大学出版社,1998.
    [45] 李世雄、刘家琦编著,小波变换和反演数据基础[M],北京:地质出版社,1994.
    [46] Mallat, S., A theory for multiresolution signal decomposition:the wavelet representation[J], IEEE Trans. Pattern Analysis and machine Intelligence, 1989, Vol. 11, pp. 674-693.
    [47] Daubechies, I., Orthonormal bases of compactly supported wavelets[J], Communications on Pure and Applied mathematics, 1988, Vol. 41, No. 11, pp.909-996.
    [48] 高克芳. 基于小波的脑-计算机接口载波的提取[D]. 中南民族大学硕士学位论文.2004.5
    [49] 杨福生,高上凯.生物医学信号处理[M]. 北京:高等教育出版社.1989.
    [50] Bell, et al., An information-maximization approach to blind separation and blind deconvolution[J], Neural Computation, 7, 1129-1159, 1995
    [51] T-W.Lee, Independent Component Analysis--Theory and application. Kluwer,1998.
    [52] T.W.Lee, et al., A unifying information-theoretic framework for independent component analysis[J], International Journal of Computers and Mathematics with Application, 1999
    [53] S. Amari, A. Cichocki, A new learning algorithm for blind source separation[J]. In Advances in Neural Information Processing 8, pages 757-763. MIT Press, Cambridge, MA, 1996
    [54] M. Girolami ,editor:Advances in Independent Component Analysis. Springer-Verlag 2000.
    [55] E. Oja. The nonlinear PCA learning rule in independent component analysis[J]. Neurocomputing, 17(1):25-46, 1997.
    [56] E. Oja.Nonlinear PCA criterion and maximum likelihood in independent component analysis. In Proc. Int. Workshop on Independent Component Analysis and Signal Separation (ICA'99), pp. 143-148, Aussois, France, 1999.
    [57] A. Hyvarinen, Fast and robust fixed-point algorithms for independent component analysis[J], IEEE Trans. on NN, 1999
    [58] Hyvarinen, A family of fixed-point algorithm for independent component analysis[C], Proc. ICASSP, 3917-3920, 1997
    [59] Aapo Hyvtrinen, et al., Independent Component Analysis[M], Wiley, 2001
    [60] K.-R. Müller, C. W. Anderson, and G. E. Birch, “Linear and nonlinear methods for brain–computer interfaces [J],”IEEE Trans. Neural. Syst. Eng., 2003,11:165–169. [60a] 李凌均.统计学习理论在机械设备智能诊断中的应用研究,西安交通大学博士学位论文[D].2003.09.
    [61] G. Ratsch, T. Onoda, and K.R. AdaBoost , Soft Margins for Machine Learning, Machine Learning 2001.42(3): 287-320
    [62] Vapnik V.N. and Chervonenkis A.J., The necessary and suficient conditions & consistency of the method of empirical risk minimization, Pattern Recogn. And Image Analysis, 1(3):284-305, 1991
    [63] N.Vapnik. The nature of statistical learning theory[M]. Springer-Verlag, New York, 1995.
    [64] Rich C,Steve L, Giles C L. Overfiting in Neural Networks: Backpropagation, Conjugate Gradient, and Early Stopping[A]. Advances in Neural Information Processing Systems 13[C]. Colorado: MIT Press,2001,402-408.
    [65] Steve L, Giles C L,Tsoi A C. Lessons in Neural Network Training:Overfiting May be Harder than Expected[A]. Proceedings of the Fourteenth National Conference on Artificial Intelligence[C]. California:AAAI Press, 1997,545-550.
    [66] Vapnik VN, Chervonenkis AJ, theory of pattern recognition[M]. Nauka, Moscow, 1974.
    [67] 张学工.关于统计学习理论与支持向量机[J].自动化学报.2000,26(1):32-41.
    [68] Vladimir N Vapnik著,张学工译.统计学习理论的本质[M].北京:清华大学出版社,2000.
    [69] M. Kaper, P.Meinicke, U. Gro?ekath?fer, T. Lingner, and H. Ritter, BCI Competition 2003—Data set IIb: Support vector machines for the P300 speller paradigm [J], IEEE Trans. Biomed. Eng., 2004,51:1073–1076.
    [70] S.S. Keerthi et al. Improvements to Platt's SMO Algorithm for SVM Classifier Design.
    [71] Corinna Cortes,V.Vapnik. Support-Vector Network. Machine Learning, 1995, 20:273-297.
    [72] C.-C. Chang, and C.-J. Lin. “Training support vector classifiers: Theory and algorithms [J],”Neural Computation, 2001,13:2119–2147.
    [73] C.-C. Chang and C.-J. Lin. LIBSVM: a library for support vector machines, (2001). Software available at http://www.csie.ntu.edu.tw/?cjlin/libsvm.
    [74] J. Ma, Y. Zhao, and S. Ahalt. (2002) OSU SVM Classifier Matlab Toolbox [Online]http://eewww.eng.ohio-state.edu/~maj/osu_svm/
    [75] J.C.Burges. A Tutorial on Support Vector Machines for Pattern Recognition. Bell Laboratories, Lucent Technologies. 1997.
    [76] P. Sajda, A. Gerson, K.-R. Müller, B. Blankertz, and L. Parra, A data analysis competition to evaluate machine learning algorithms for use in brain-computer interfaces [J], IEEE Trans. Neural Syst. Rehab. Eng., 2003,11:184–185.
    [77] D. Garrett, D. A. Peterson, C. W. Anderson, and M. H. Thaut, Comparison of Linear, Nonlinear, and Feature Selection Methods for EEG Signal Classification [J]. IEEE Trans. Neural Syst. Rehab. Eng., 2003,11:141–144.
    [78] B. H. Jansen, et al., An Exploratory Study of Factors Affecting Single Trial P300 Detection [J]. IEEE Trans. Biomed. Eng., 2004, 51:975–978.
    [79] B. Blankertz, et al. The BCI Competition 2003: Progress and Perspectives in Detection and Discrimination of EEG Single Trials [J ], IEEE Trans. Biomed. Eng., 2004,51:1044–1051.
    [80] N. Xu, et al., BCI Competition 2003—Data set IIb: Enhancing P300 wave detection using ICA-based subspace projections for BCI applications [J], IEEE Trans. Biomed. Eng., 2004,51:1067–1072.
    [81] Y. Wang, Z. Zhang, Y. Li, X. Gao, S. Gao, and F. Yang, BCI Competition 2003—Data Set IV:An Algorithm Based on CSSD and FDA for Classifying Single-Trial EEG [J], IEEE Trans. Biomed. Eng., 2004,51:1081–1086.
    [82] 张辉,费鹏豪,郑崇勋, 基于多通道时频相干的诱发电位单次提取[J], 西安交通大学学报,2003,37(6):638-645
    [83] Q. L. Xie, Z. L. Yang, Y.G. Chen, J.P. He. BCI based on imitating-reading-event-related potentials [J]. Proc.Of 7th world multiconference on systemics,cybernetics and informatics, 2003, XIII:49-54.

© 2004-2018 中国地质图书馆版权所有 京ICP备05064691号 京公网安备11010802017129号

地址:北京市海淀区学院路29号 邮编:100083

电话:办公室:(+86 10)66554848;文献借阅、咨询服务、科技查新:66554700