共查询到16条相似文献,搜索用时 93 毫秒
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针对异步脑机接口(BCI)中空闲状态难以检测的问题,提出将近似熵与公共空间模式(CSP)综合的方法来处理. 在采用二级分类策略的前提下,通过近似熵与CSP方法分别从时间复杂度和空间模式上提取不同类型的脑电特征,利用这些特征训练出不同的分类器,然后使用多分类器投票的方法将它们综合以提高判断空闲状态的正确率. 将本文的方法运用到BCI竞赛数据中,得到最终具体想象任务的命中率(TPR)普遍比通过阈值法得到的结果要高. 数据处理的结果说明了本文方法对空闲状态检测的有效性. 相似文献
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本文设计了基于事件关联电位脑机接口的脑电信号预处理、特征提取、分类识别实时算法,开发了具有通讯功能的遥控器,实现了脑机接口电视遥控的异步系统.受试者可以用脑电波来遥控电视选择频道和调整音量,这为重症瘫痪病人拓展其与自然的直接交流开辟了新的通道.5位健康的受试者参与了训练实验和在线实验,实验结果表明经过特定的训练,受试者均可有效控制该脑机接口电视遥控系统,其统计平均准确率达87%,平均传输速率(ITR)达35 bits/min. 相似文献
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基于ECoG的运动想象脑-机接口分类方法 总被引:1,自引:0,他引:1
脑—机接口BCI(Brain-Computer Interface)技术是近年来国际上的研究热点之一,它通常利用脑电EEG(electroencephalo-gram)来实现无动作的人机交互,运动想象是其中一种重要的BCI实验范式。有关研究表明,脑皮层电位ECoG(electrocorticogram)具有更好的信噪比与频带特性。研究基于ECoG的运动想象BCI系统,针对ECoG信号的特点,改进了信号处理方法,提取数据的公共空间模式CSP(Common Spatial Pattern)特征,并利用支持向量机SVM(Support Vector Machines)进行分类器设计,提高了运动意向的识别正确率。用相应方法处理2005年脑-机接口竞赛中的一组实验数据,正确率达到92%,相比于当时参赛时所用的方法提高了6%。实验还发现,支持向量机在克服"维数灾难"和"过拟合"方面具有更好的鲁棒性。 相似文献
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基于虚拟仪器LabVIEW的脑—机接口系统 总被引:2,自引:0,他引:2
给出了基于瞬态视觉诱发电位的脑-机接口系统在LabVIEW环境下的实现方案。该方案的关键部分是视觉刺激器的设计和脑电信号的提取两部分。不同的刺激模块代表了多种可能的选择,受试者注视屏幕上其中一个目标,分析诱发电位可判别试者所注视的目标。采用累加平均和滤波的方法提高信噪比,用于提取微弱的脑电信号。该方案能有效地诱发出可识别的具有特征性的视觉诱发电位,并且通过离线的信号处理能够提取出所诱发的视觉诱发电位。 相似文献
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针对基于EEG的脑-机接口(BCI)实验数据分布不明朗的特点,双滤波模式(DFP)算法利用样本模式相似性来优化BCI的分类特征——运动相关电位(MPPs) 特征的空间(即电极位置)和时间投影方向,使得映射后异类样本模式差异性与同类相似性的比值最大化。该算法考虑MRPs特征对时间、空间的敏感性,并以自适应的方式挖掘它们适合分类的信息;优化时不需要进行样本数据分布假设,符合BCI数据特点。最后,DFP算法对BCI competition I、II两组数据进行实验,识别效果均高于相关比赛的最好成绩,这表明DFP算法能有效提取MRPs特征。 相似文献
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For the problem of low classification accuracy and poor real-time performance during the traditional common spatial patterns (CSP) algorithm for motor imagery EEG signal processing, a new analysis method of CSP EEG signal based on time space frequency domain is put forward. Firstly, the wavelet packet is used to decompose the original signal of EEG, the motor imagery EEG rhythm is extracted according to the frequency distribution of EEG signal, and the spatial features of EEG are extracted by improving CSP algorithm. Then, we introduce the time window to filter the EEG signals, and eliminate the influence of EEG fluctuation at the beginning and end of the motion imagery. Lastly, according to the characteristics of the physiological distribution of EEG signals in the brain cortex, the method based on spindle channel is used to process the EEG signal and analyze computational time of different algorithms and the classification results. The experimental results show that, the running time of the algorithm is 1.562 s, which is 67% shorter than the traditional method, and the average classification accuracy is up to 97.5% when the number of spindle channels is 29 and the time window is 2 s. In the meantime, the results show that the proposed method can effectively improve the classification accuracy and the real-time performance of motor imagery EEG. 相似文献
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Breast cancer continues to be a significant public health problem in the world. Approximately, 182,000 new cases of breast cancer are diagnosed and 46,000 women die of breast cancer each year in the United States. Even more disturbing is the fact that one out of eight women in US will develop breast cancer at some point during her lifetime. Primary prevention seems impossible since the causes of this disease still remain unknown. Early detection is the key to improving breast cancer prognosis. Mammography is one of the reliable methods for early detection of breast carcinomas. There are some limitations of human observers, and it is difficult for radiologists to provide both accurate and uniform evaluation for the enormous number of mammograms generated in widespread screening. The presence of microcalcification clusters (MCCs) is an important sign for the detection of early breast carcinoma. An early sign of 30–50% of breast cancer detected mammographically is the appearance of clusters of fine, granular microcalcification, and 60–80% of breast carcinomas reveal MCCs upon histological examinations. The high correlation between the appearance of the microcalcification clusters and the diseases show that the CAD (computer aided diagnosis) systems for automated detection/classification of MCCs will be very useful and helpful for breast cancer control. In this survey paper, we summarize and compare the methods used in various stages of the computer-aided detection systems (CAD). In particular, the enhancement and segmentation algorithms, mammographic features, classifiers and their performances are studied and compared. Remaining challenges and future research directions are also discussed. 相似文献
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This paper presents a new recursive method for system analysis via double-term triangular functions (DTTF) in state space environment. The proposed method uses orthogonal triangular function sets and proves to be more accurate as compared to single term Walsh series (STWS) method with respect to mean integral square error (MISE). This has been established theoretically and comparison of error with respect to MISE is presented for clarity. A numerical example is treated to establish the proposed method. Relevant curves for the solutions of states of the dynamic system are also presented with plots of percentage error for DTTF-based analysis. 相似文献