周期互补序列在多焦视觉诱发电位提取中的应用
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摘要
多焦视觉电生理检查技术是近年来发展起来的，它可以同时对视网膜多个区域进行检测，检查时间较短，并可比较视网膜不同部位的视功能，不但在临床应用和生物视觉系统的探索及研究中有着重要的价值，而且代表着视觉电生理检测的国际最高水平和发展趋势。我国在这方面的研究起步较晚，目前尚无成功的仪器推出。由于进口设备的价格非常昂贵，在很大程度上限制了该技术在我国临床上的应用，同时也极不利于我国视觉电生理的研究和发展。因此，对多焦视网膜电图检测设备的研究势在必行。另外，该技术在对面状目标不同区域低信噪比微弱信号的提取中也有很好的利用价值。
多焦视网膜电图信号非常微弱(＜1μV)，且淹没在强大的背景噪声之中，因此检测多焦视网膜电图是一项非常困难的工作。目前多焦视网膜电图的产生均采用m-序列选取若干个不同的起始点同时分别控制刺激视网膜不同部位，记录混合反应信号，再经计算机快速Walsh变换，把各部位的波形分离提取出来。
控制序列是产生视网膜电图刺激过程和结果分析的核心部分，它必须满足以下两个条件：①在任何时刻刺激野有光刺激与无光刺激接近相等；②视网膜各局部反应互不相关(或称正交)。m序列由于其良好的自相关特性容易满足条件②的要求，但是为了满足条件①就要从m序列中寻找出多个符合条件的不同起始点。对于mfERG控制序列2~(13)～2~(15)长度来说，要寻找符合条件的几十到几百个不同起始点则相当困难。另外，由于m序列的自相关特性并不等于零，对测试结果势必有一定的影响。
针对产生视网膜电图中的m-序列起始点的选取中存在的困难，本文提出了采用周期互补序列产生测试控制序列的一种方法。该方法所产生的测试序列严格满足mfERG测试序列的要求，可以作为多焦视诱发电位提取中的测试序列加以应用，与目前使用的m二元伪随机序列比较，其产生方法简单，且自相关与互相关特性更具优越性。
本文介绍了多焦视觉电生理学的产生、发展、目前状况和周期互补序列的概念、性质、产生方法；对多焦视觉电生理的基本原理进行了简要阐述；对m-序列、周期互补序列等几种序列的特性进行了分析和比较，提出了周期互补序列的改进方法；给出了序列的重复测试法和补偿法两种修正方法以及序列在多焦电生理信号的测试和提取中的模拟方法和编程实现，同时对模拟结果进行了分析和比较。
The multifocal visaul electrophysiology check technique is developed in recent years , which can examine several retina districts simultaneously, shorten the check time, and can compare the function of different part of retina. It not only has very important value for clinical applying and for exploring and researching the visual system, but also represents international highest level and the development trend of visaul electrophysiology. It is later that research developed in our country, and has no successful instrument to be released still currently. It is restricted to this new technique for clinical application, and extremely disadvantageous to research and development of visual electrophysiology in our country, because the prices of the equipments imported are very expensive. Therefore, the research of examination equipments for mfERG (multifocal electroretinogram) Be going necessarily. In addition, that technique has good exploitation value for extracting response signal of different district in plane target from mixture signal with low amplitude and low signal-to-noise ratio.
The signal of mfERG is very weak (<1μ V), and drowned into the strong background noice, so the examination is a very difficult work. Currently, The mfERG selects different start points from m-sequence to control stimulating different parts of retina respectively at one time, recording a mixture reaction signal, calculated through fast Walsh transform by computer, and separate the corresponding wave of each part.
The control sequence is the core part of producing mfERG incitement process and analyzing the result. It must satisfy the following two conditions: ① the light incitement is nearly equal to the no-light incitement inside the stimulation wild at any time; ② the responding of each retina district is not related with each other(orthogonal). The m-sequence is easily satisfy the request of the condition ② by its characteristic of correlation, but we have to look for many different start points from the m-sequence in order to satisfy the condition ① . It is very difficult to look for tens or hundreds different starts from such a sequence as 2~(12)~2~(15) long for controlling mfERG stimulation. In addition, it certainly will influence the test result because of the auto-correlation function between each different starting point of m-sequence is not equal to zero absolutely.
This paper put forward another way for producing test sequence by periodic complementary sequence to put the axe in the helve in looking-for starting points from
多焦视网膜电图信号非常微弱(＜1μV)，且淹没在强大的背景噪声之中，因此检测多焦视网膜电图是一项非常困难的工作。目前多焦视网膜电图的产生均采用m-序列选取若干个不同的起始点同时分别控制刺激视网膜不同部位，记录混合反应信号，再经计算机快速Walsh变换，把各部位的波形分离提取出来。
控制序列是产生视网膜电图刺激过程和结果分析的核心部分，它必须满足以下两个条件：①在任何时刻刺激野有光刺激与无光刺激接近相等；②视网膜各局部反应互不相关(或称正交)。m序列由于其良好的自相关特性容易满足条件②的要求，但是为了满足条件①就要从m序列中寻找出多个符合条件的不同起始点。对于mfERG控制序列2~(13)～2~(15)长度来说，要寻找符合条件的几十到几百个不同起始点则相当困难。另外，由于m序列的自相关特性并不等于零，对测试结果势必有一定的影响。
针对产生视网膜电图中的m-序列起始点的选取中存在的困难，本文提出了采用周期互补序列产生测试控制序列的一种方法。该方法所产生的测试序列严格满足mfERG测试序列的要求，可以作为多焦视诱发电位提取中的测试序列加以应用，与目前使用的m二元伪随机序列比较，其产生方法简单，且自相关与互相关特性更具优越性。
本文介绍了多焦视觉电生理学的产生、发展、目前状况和周期互补序列的概念、性质、产生方法；对多焦视觉电生理的基本原理进行了简要阐述；对m-序列、周期互补序列等几种序列的特性进行了分析和比较，提出了周期互补序列的改进方法；给出了序列的重复测试法和补偿法两种修正方法以及序列在多焦电生理信号的测试和提取中的模拟方法和编程实现，同时对模拟结果进行了分析和比较。
The multifocal visaul electrophysiology check technique is developed in recent years , which can examine several retina districts simultaneously, shorten the check time, and can compare the function of different part of retina. It not only has very important value for clinical applying and for exploring and researching the visual system, but also represents international highest level and the development trend of visaul electrophysiology. It is later that research developed in our country, and has no successful instrument to be released still currently. It is restricted to this new technique for clinical application, and extremely disadvantageous to research and development of visual electrophysiology in our country, because the prices of the equipments imported are very expensive. Therefore, the research of examination equipments for mfERG (multifocal electroretinogram) Be going necessarily. In addition, that technique has good exploitation value for extracting response signal of different district in plane target from mixture signal with low amplitude and low signal-to-noise ratio.
The signal of mfERG is very weak (<1μ V), and drowned into the strong background noice, so the examination is a very difficult work. Currently, The mfERG selects different start points from m-sequence to control stimulating different parts of retina respectively at one time, recording a mixture reaction signal, calculated through fast Walsh transform by computer, and separate the corresponding wave of each part.
The control sequence is the core part of producing mfERG incitement process and analyzing the result. It must satisfy the following two conditions: ① the light incitement is nearly equal to the no-light incitement inside the stimulation wild at any time; ② the responding of each retina district is not related with each other(orthogonal). The m-sequence is easily satisfy the request of the condition ② by its characteristic of correlation, but we have to look for many different start points from the m-sequence in order to satisfy the condition ① . It is very difficult to look for tens or hundreds different starts from such a sequence as 2~(12)~2~(15) long for controlling mfERG stimulation. In addition, it certainly will influence the test result because of the auto-correlation function between each different starting point of m-sequence is not equal to zero absolutely.
This paper put forward another way for producing test sequence by periodic complementary sequence to put the axe in the helve in looking-for starting points from
引文
[1] 吴乐正 吴德正等著“临床多焦视觉电生理学”．北京．北京科学技术出版社．2004
[2] 田继锋，郭黎利“一种基于周期互补序列的CDMA系统模型”．哈尔滨工程大学学报．2001，10(5)-0078-05
[3] 查光明 熊贤祚著“扩频通信”．西安．西安电子科技大学出版社．1990
[4] Marcus A. Bearse, Jr.,and Erich E. Sutter, "Imaging localized retinal dysfunction with the multifocal electroretinogram", The Smith-Kettlewell Eye Research Institute, 1995,5
[5] Erich E. SuRer, Dudong Tran, "The Field Topography of ERG Components in Man—Ⅰ. The Photopic Luminance Response". The Smith-Kettlewell Eye Research Institute. 1991,2
[6] 林金贤(Jin-Xian Lin)“互補码分码多工系统之研究”．台北．鼋机工程学系研究所(Electrical Engineering)．1991
[7] 赵崇侃 袁孝如等著“多焦视网膜电图局部反应的提取技术”．南京．南京医科大学学报．第23卷 第6期．2003
[8] 张泾周 刘园园 戴冠中“多焦技术及其在mfERG中的应用”．北京．北京生物医学工程．第24卷 第6期．2005
[9] 谷万章“视觉电生理”．航空航天医药．第10卷第3期．1999
[10] 吴德正“临床视觉电生理的进展”．广州用艮科．第10卷第1期．2001
[11] 郭兴明 张思杰 袁松 彭承琳“多焦视觉电生理分析系统的研制”．重庆．中国医疗器械杂志．第27卷第1期．2003
[12] 张思杰 郭兴明 彭承琳 盛得“基于快速M变换的多焦视觉电生理检查系统的设计”．重庆．生物医学工程杂志．2005
[13] 邓亲恺 郭云波 冯前进“视觉电生理信号检测方法研究”．广州．中国医学物理学杂志．第16卷 第4期．1999
[14] 沈允春著“扩频技术”．北京．国防工业出版社．1995
[15] H.A.Baseler, E.E.Sutter, S.A.klein and T.Carney "The topography of Visual evoked response properties across the visual field".San Francisco. Electroencephalography and clinical neurophysiology. 1994
[16] Erich E.Sutter "The FAST m-TRANSFORM:A FAST COMPUTATION OF CROSS-CORRELATIONS WITH BINARY m-SEQUENCES".Society for Industrial and Applied Mathematics. 1991
[17] Erich E.Sutter and Vaegan "LATERAL INTERACTION COMPONENT AND LOCAL LUMINANCE NONLINEARITIES IN THE HUMAN PATTERN REVERSAL ERG".Great Britain.Pergamon press plc.1990
[18] Erich E.Sutter, Marcus A.Bearse Jr. "The Retinal Topography of Local and Lateral Gain Control Mechanisms".San Francisco. 1991
[19] Erich E.Sutter, Duong tran "The Topography of ERG Components in Man—Ⅰ. The photopic Luminance".Great Britain.Pergamon press plc. 1992
[20] Poloschek CM, Sutter EE. "The fin structure of multifocal ERG topographies[J].Joumal of Vision.2002
[21] 樊昌信 詹道庸 徐炳祥 吴成柯著“通信原理”．北京．国防工业出版社．1995
[22] 贺元才 林财兴 阵东帆“眼电生理诊疗信的原理研究及系统设计方案”．上海．计算机辅助工程．2004
[23] 曹志刚 钱亚生著“现代通信原理”．北京．清华大学出版社．1992
[24] 张贤达 保铮著“通信信号处理”．北京．国防工业出版社．2000
[25] 飞 思科技产品研发中心著“MATLAB7基础与提高”．北京．电子工业出版社．2005
[26] 薛松山 吕威“CDMA通信编码研究”．哈尔滨．信息技术．第28卷第8期．2004
[27] 李贺敏著“眼科学”．北京．人民军医出版社．1999
[28] 飞思科技产品研发中心著“MATLAB 7辅助信号处理技术与应用”．北京．电子工业出版社．2005
[29] 黄永安 马唛 刘慧敏著“MATLAB 7.0／Simulink 6.0建模仿真开发与高级工程应用”．北京．清华大学出版社．2005
[30] 肖国镇 卿斯汉著“编码理论”．北京．国防工业出版社．1993
[31] 万旺根 余小清著“信息与编码理论基础”．上海．上海大学出版社．2000
[32] 刘妍“多焦视觉诱发电位检测和分析精确性的研究及其在青光眼病人视功能检测中的应用探讨”．广州．中山大学博士学位论文．2004
[33] 喻央央“电生理诊断中实时数字滤波器的设计与实现”．上海．华东工业大学学报．第17卷第4期．1995
[34] 张伟 综兴 赵堪兴“多焦视网膜电图及其应用”．北京．中国实用眼科杂志．第20卷第4期．2002
[35] 刘园园“多焦视电信号检测与分离算法研究”．西安．西北工业大学硕士学位论文．2005
[36] 邢军智“多焦视网膜电图检测系统研究与设计”．西安．西北工业大学硕士学位论文．2005
[37] Keating D, parks S, Evans A . "Technical aspects of multifocal ERG recording". Doc Ophthalmol. 2000. 240:874-875.
[38] 朱豫 高永峰 万光明“眼科诊疗新技术”．科学出版社．2001
[39] 王煊 郭守一“临床视电生理学”．陕西科学技术出版社．1993
[40] Smith Keating Parks "An instrument to investigate temporal processing mechanicsms with the multifocal ERG". Journal of Medical Engineering Technology. 2002.26(4): 147-151
[41] Sano M, Tazawa Y, Nabshima T, et al "A new wavelet in the multifocal ERG probably originating from ganglion cells. Invest Ophthalmol Vis Sci. 2002.43:1666-1672
[42] S. Parks, D Keating, T.H. Williamson, A.L. Evans, A.T. Elliot and J.L. Jay "Functional imaging of the retina using the multifocal electroretinograph: a control study". Br J Ophthalmol . 80. 1996
[43] 林家瑞 朱帆三 陈瑞红 邓东云“强背景噪声下微弱生理信号的检洲与处理”．华中理工大学学报．第22卷 第9期．1994
[2] 田继锋，郭黎利“一种基于周期互补序列的CDMA系统模型”．哈尔滨工程大学学报．2001，10(5)-0078-05
[3] 查光明 熊贤祚著“扩频通信”．西安．西安电子科技大学出版社．1990
[4] Marcus A. Bearse, Jr.,and Erich E. Sutter, "Imaging localized retinal dysfunction with the multifocal electroretinogram", The Smith-Kettlewell Eye Research Institute, 1995,5
[5] Erich E. SuRer, Dudong Tran, "The Field Topography of ERG Components in Man—Ⅰ. The Photopic Luminance Response". The Smith-Kettlewell Eye Research Institute. 1991,2
[6] 林金贤(Jin-Xian Lin)“互補码分码多工系统之研究”．台北．鼋机工程学系研究所(Electrical Engineering)．1991
[7] 赵崇侃 袁孝如等著“多焦视网膜电图局部反应的提取技术”．南京．南京医科大学学报．第23卷 第6期．2003
[8] 张泾周 刘园园 戴冠中“多焦技术及其在mfERG中的应用”．北京．北京生物医学工程．第24卷 第6期．2005
[9] 谷万章“视觉电生理”．航空航天医药．第10卷第3期．1999
[10] 吴德正“临床视觉电生理的进展”．广州用艮科．第10卷第1期．2001
[11] 郭兴明 张思杰 袁松 彭承琳“多焦视觉电生理分析系统的研制”．重庆．中国医疗器械杂志．第27卷第1期．2003
[12] 张思杰 郭兴明 彭承琳 盛得“基于快速M变换的多焦视觉电生理检查系统的设计”．重庆．生物医学工程杂志．2005
[13] 邓亲恺 郭云波 冯前进“视觉电生理信号检测方法研究”．广州．中国医学物理学杂志．第16卷 第4期．1999
[14] 沈允春著“扩频技术”．北京．国防工业出版社．1995
[15] H.A.Baseler, E.E.Sutter, S.A.klein and T.Carney "The topography of Visual evoked response properties across the visual field".San Francisco. Electroencephalography and clinical neurophysiology. 1994
[16] Erich E.Sutter "The FAST m-TRANSFORM:A FAST COMPUTATION OF CROSS-CORRELATIONS WITH BINARY m-SEQUENCES".Society for Industrial and Applied Mathematics. 1991
[17] Erich E.Sutter and Vaegan "LATERAL INTERACTION COMPONENT AND LOCAL LUMINANCE NONLINEARITIES IN THE HUMAN PATTERN REVERSAL ERG".Great Britain.Pergamon press plc.1990
[18] Erich E.Sutter, Marcus A.Bearse Jr. "The Retinal Topography of Local and Lateral Gain Control Mechanisms".San Francisco. 1991
[19] Erich E.Sutter, Duong tran "The Topography of ERG Components in Man—Ⅰ. The photopic Luminance".Great Britain.Pergamon press plc. 1992
[20] Poloschek CM, Sutter EE. "The fin structure of multifocal ERG topographies[J].Joumal of Vision.2002
[21] 樊昌信 詹道庸 徐炳祥 吴成柯著“通信原理”．北京．国防工业出版社．1995
[22] 贺元才 林财兴 阵东帆“眼电生理诊疗信的原理研究及系统设计方案”．上海．计算机辅助工程．2004
[23] 曹志刚 钱亚生著“现代通信原理”．北京．清华大学出版社．1992
[24] 张贤达 保铮著“通信信号处理”．北京．国防工业出版社．2000
[25] 飞 思科技产品研发中心著“MATLAB7基础与提高”．北京．电子工业出版社．2005
[26] 薛松山 吕威“CDMA通信编码研究”．哈尔滨．信息技术．第28卷第8期．2004
[27] 李贺敏著“眼科学”．北京．人民军医出版社．1999
[28] 飞思科技产品研发中心著“MATLAB 7辅助信号处理技术与应用”．北京．电子工业出版社．2005
[29] 黄永安 马唛 刘慧敏著“MATLAB 7.0／Simulink 6.0建模仿真开发与高级工程应用”．北京．清华大学出版社．2005
[30] 肖国镇 卿斯汉著“编码理论”．北京．国防工业出版社．1993
[31] 万旺根 余小清著“信息与编码理论基础”．上海．上海大学出版社．2000
[32] 刘妍“多焦视觉诱发电位检测和分析精确性的研究及其在青光眼病人视功能检测中的应用探讨”．广州．中山大学博士学位论文．2004
[33] 喻央央“电生理诊断中实时数字滤波器的设计与实现”．上海．华东工业大学学报．第17卷第4期．1995
[34] 张伟 综兴 赵堪兴“多焦视网膜电图及其应用”．北京．中国实用眼科杂志．第20卷第4期．2002
[35] 刘园园“多焦视电信号检测与分离算法研究”．西安．西北工业大学硕士学位论文．2005
[36] 邢军智“多焦视网膜电图检测系统研究与设计”．西安．西北工业大学硕士学位论文．2005
[37] Keating D, parks S, Evans A . "Technical aspects of multifocal ERG recording". Doc Ophthalmol. 2000. 240:874-875.
[38] 朱豫 高永峰 万光明“眼科诊疗新技术”．科学出版社．2001
[39] 王煊 郭守一“临床视电生理学”．陕西科学技术出版社．1993
[40] Smith Keating Parks "An instrument to investigate temporal processing mechanicsms with the multifocal ERG". Journal of Medical Engineering Technology. 2002.26(4): 147-151
[41] Sano M, Tazawa Y, Nabshima T, et al "A new wavelet in the multifocal ERG probably originating from ganglion cells. Invest Ophthalmol Vis Sci. 2002.43:1666-1672
[42] S. Parks, D Keating, T.H. Williamson, A.L. Evans, A.T. Elliot and J.L. Jay "Functional imaging of the retina using the multifocal electroretinograph: a control study". Br J Ophthalmol . 80. 1996
[43] 林家瑞 朱帆三 陈瑞红 邓东云“强背景噪声下微弱生理信号的检洲与处理”．华中理工大学学报．第22卷 第9期．1994