共查询到19条相似文献,搜索用时 531 毫秒
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本文在建立了一个脑电信号源模型的基础上,仔细分析了脑电信号放大器的干扰与噪声,并且提出了抑制干扰与噪声的一系列措施.然后根据脑电信号的特点着重讨论了前置放大器的设计,介绍了整个脑电信号采集系统的组成,以及软件设计方面的任务分析、数字滤波器以及关键的数据结构,最后讲解了诱发事件与诱发脑电信号的同步关系和数据的封装. 相似文献
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提出了利用分形理论对高压电机定子绕组局部放电信号进行处理的方法,得到局部放电信号的关联维数,并将其作为特征参量对几种典型的局部放电信号进行模式识别。局部放电信号是非线性、非平稳随机信号。因此采用非线性理论中的分形理论对其进行分析,即计算关联维数。考虑到相空间重构中嵌入维数和时间延迟对关联维数精度的影响,采用联合算法确定2个参数。仿真结果表明,关联维数用于局部放电信号模式识别是行之有效的。 相似文献
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基于图论理论的脑网络分析方法近年来在认知脑科学研究中起到了非常重要的作用,而基于事件相关电位(Event-Related Potentials,ERP)的传统测谎方法一直都专注于对某一特定通道上的脑电信号进行分析,针对传统方法中使用少数通道并不能够全面的反映人在说谎状态下大脑整体认知功能特征的缺点,本文提出了基于脑网络特征的测谎方法,通过听觉刺激诱发事件相关电位ERP,记录脑区多通道脑电信号,通过讨论各导联之间的相位延迟指数来构建脑功能网络,计算7类脑网络特征参数作为判别指标。分析被试在说谎和无辜状态下的网络特征参数,使用支持向量机对实验数据进行分类判断,结果表明:本文提出的方法有较高的判别准确率,优于目前判别方法的平均值,证明了本方法的测谎有效性。 相似文献
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《中国无线电电子学文摘》2004,(2)
TN一051 2004021276荃于状态空间的EEG信号分析/游荣义,徐慎初(厦门大学)11厦门大学学报.一2003,42(6)一736一740为录求脑电(Eleetroeneephalogram,EEG)分析的新途径,提出了一种基于状态空间的脑电分析的新方法.利用状态空间点间的欧氏距离来计算脑电状态空间的态密度和态方差.实验表明,态密度和态方差不仅计算简单,而且与脑电的关联维数和Lyapunov指数相比,更能有效地反映混沌系统非线性动力学的特征.此外,还计算了基于距离协方差的脑电信号的奇异谱,并对结果作了分析.图7参11(木)发现人脑16导EEG信号具有不同强度的分形特性且存在稳… 相似文献
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人类对大脑的探索已进入了数字化时代,随着脑信号检测技术的日益成熟以及人工智能算法的研究进展,脑信号的解读研究也展现出越来越多的成果.本文首先介绍当下大脑信号获取的医学方法,而后简述脑电信号的特征提取以及分类识别方法,接着列举脑电识别的前沿研究,最后对脑电信号识别的数据应用领域进行展望. 相似文献
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《电子科技文摘》2006,(7)
0618940X线乳腺图像中微钙化检测的快速排除无病变区域法〔刊,英〕/贾新华//南京航空航天大学学报(英文版).—2006,23(1).—52-58(E)0618941脑信息处理动态特征研究〔刊,中〕/陈冬冰//北京理工大学学报.—2006,26(3).—221-225(L)为提取脑信息处理过程中的动态特征参数,提出运用基于相空间重构的思想的时间序列分维算法(G-P算法)。讨论了G-P算法的3个重要参数(即无标度域、嵌入维数和延时)的确定规则,记录大脑在不同状态下的EEG信号并计算其关联维数。实验结果表明,EEG关联维数能够反映脑信息处理过程中的神经元群活动状态,可作为脑信… 相似文献
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Hansson M. Gansler T. Salomonsson G. 《IEEE transactions on bio-medical engineering》1998,45(3):323-334
Describes a method to measure changes in the mid-latency auditory evoked potential (MLAEP) during anesthesia. It is claimed that the position of the Nb-trough of the MLAEP indicates the level of consciousness. The component shows graded changes corresponding to the dose of anesthetic and it exhibits stable reproducible properties between different subjects. The authors propose a system that reduces the disturbances in an averaged MLAEP using fewer realizations than in the standard averaging procedure. The resulting smoothing error is reduced if the number of stimulus is decreased. Unfortunately, the variance of the waveform estimate is, thereby, increased. An improved method must be used in order to estimate the Nb-trough within a prescribed time interval of one minute. The procedure is based on inherent properties of the MLAEP and the noise. A simulation and examples of the performance on real data recorded during surgery are shown 相似文献
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单通道信号分离一直是信号处理领域中的重要问题,当观测数据较少时,该问题尤其困难。本文提出一种以时间自相关函数作为目标函数的最优化分离方法。先使用小波模极大值法来估计出迭代初始值与源信号的时间自相关函数,然后得到的最优解就是对待分离信号的估计。实验结果表明,该方法能够较好地应用于诱发电位信号的单通道单次提取。 相似文献
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Presents a novel approach to solving the single-trial evoked-potential estimation problem. Recognizing that different components of an evoked potential complex may originate from different functional brain sites and can be distinguished according to their respective latencies and amplitudes, the authors propose an estimation approach based on identification of evoked potential components on a single-trial basis. The estimation process is performed in 2 stages: first, an average evoked potential is calculated and decomposed into a set of components, with each component serving as a subtemplate for the next stage; then, the single measurement is parametrically modeled by a superposition of an emulated ongoing electroencephalographic activity and a linear combination of latency and amplitude-corrected component templates. Once optimized, the model provides the 2 assumed signal contributions, namely the ongoing brain activity and the single evoked brain response. The estimator's performance is analyzed analytically and via simulation, verifying its capability to extract single components at low signal-to-noise ratios typical of evoked potential data. Finally, 2 applications are presented, demonstrating the improved analysis capabilities gained by using the proposed approach. The first application deals with movement related brain potentials, where a change of the single evoked response due to external loading is detected. The second application involves cognitive event-related brain potentials, where a dynamic change of 2 overlapping components throughout the experimental session is detected and tracked 相似文献
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《IEEE transactions on bio-medical engineering》1999,46(1):71-81
A fully automated system was developed for the depth of anesthesia estimation and control with the intravenous anesthetic, Propofol. The system determines the anesthesia depth by assessing the characteristics of the mid-latency auditory evoked potentials (MLAEP). The discrete time wavelet transformation was used for compacting the MLAEP which localizes the time and the frequency of the waveform. Feature reduction utilizing step discriminant analysis selected those wavelet coefficients which best distinguish the waveforms of those responders from the nonresponders. A total of four features chosen by such analysis coupled with the Propofol effect-site concentration were used to train a four-layer artificial neural network for classifying between the responders and the nonresponders. The Propofol is delivered by a mechanical syringe infusion pump controlled by Stanpump which also estimates the Propofol effect-site and plasma concentrations using a three-compartment pharmacokinetic model with the Tackley parameter set. In the animal experiments on dogs, the system achieved a 89.2% accuracy rate for classifying anesthesia depth. This result was further improved when running in real-time with a confidence level estimator which evaluates the reliability of each neural network output. The anesthesia level is adjusted by scheduled incrementation and a fuzzy-logic based controller which assesses the mean arterial pressure and/or the heart rate for decrementation as necessary. Various safety mechanisms are implemented to safeguard the patient from erratic controller actions caused by external disturbances. This system completed with a friendly interface has shown satisfactory performance in estimating and controlling the depth of anesthesia 相似文献
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在辐射源个体识别(SEI)技术中,能量较高的主信号往往导致微弱个体特征稳定性降低,进而影响最终的个体识别效果。为了解决该问题并提升辐射源个体识别性能,该文提出基于同步压缩小波变换的主信号抑制技术。首先,利用静态小波变换完成对带噪信号的去噪预处理;然后,利用同步压缩小波变换完成对主信号的检测和抑制,并以均方根误差和皮尔逊相关系数为数值指标,验证算法的有效性;最后,在主信号抑制的基础上,利用分形理论中盒维数完成对信号的特征提取,并利用单核支持向量机验证个体识别性能。实验结果表明,与主信号抑制之前相比,主信号抑制算法下个体识别率提升了10%左右,验证了同步压缩小波变换的主信号抑制算法对辐射源个体识别率提升的有效性。 相似文献
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为了提高铁路激光器驱动电源监控信号自动识别能力,实现铁路信号的激光器驱动电源集中监控,提出一种基于铁路信号激光器驱动电源集中监控方法。采用传感器进行铁路信号电源集中监控信息采集,对采集的信号模型采用空间阵列分布式设计方法进行空间信源模型构建,对采集的铁路信号采用相干检测法进行滤波检测,提取铁路信号功率谱密度特征,采用小波分析方法进行铁路激光器驱动电源监控信号的多元尺度分解,实现铁路激光器驱动电源信号的自动检测和集中监控。仿真结果表明,采用该方法进行的铁路信号激光器驱动电源集中监控能力较强,误码率低于10-1,下降幅度较大且迅速,信号传输延迟缩短了30%,提高了信号的自动检测和识别能力。 相似文献
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Neurological injuries occurring during high-risk surgical procedures can be detected by monitoring intraoperative evoked potential signals. In this communication, an automatic injury detection algorithm is proposed in which the EP signal is modeled as a pole-zero filter and then the model parameters are applied as inputs to a classifier type neural network. A recognition rate of 96% is achieved using an experimental model of brain injury. 相似文献