高采样率下简单整系数工频陷波器的设计

目的 解决心电信号分析中高采样频率下工频窄带陷波器设计难题.方法 本文提出了一种基于零极点抵消和插值理论结合的带阻滤波器的设计方法,设计出滤波器系数为简单整系数,带宽可任意调整,而且可满足高采样率下工频陷波的要求.同时为了消除窄带滤波器的吉布思现象,本文吸取前人的经验,提出了在信号线性段采用平均滤波的方法消除吉布思现象.结果 该方法设计的滤波器能有效去除高采样频率下50 Hz工频干扰,且系数为整数,实现简单.结论 基于零极点抵消和插值理论结合的带阻滤波器,可以有效地解决高采样率下窄带工频陷波器的设计难题,滤除了工频干扰信号,同时最大程度地保留了信号的有用成分,满足心电分析的要求.     

心电信号的实时数字预处理

本文根据心电实时监护的要求,应用整系数线性相位数字滤波器对心电信号作预处理,包括50Hz 工频干扰的陷波(带阻滤波)及高频噪声抑制(低通滤波)。文章叙述了整系数数字滤波器的设计过程,在实际滤波效果与计算量的减省方面均取得了较好的效果。     

滤除ECG中肌电和宽频率范围工频干扰的小波算法

目的 设计小波去除噪声方法消除心电内肌电和宽频率范围的工频干扰。方法 根据QRS波群含有的最高频率成分较高,T波和P波含有的最高频率成分较低的特性,选取双正交小波将原始信号分解,将各尺度上系数重新组合,然后再重构,得到消噪后的心电。结果 受肌电干扰的心电信号分别叠加幅度为20%的49Hz和61Hz工频干扰的心电信号,经小波消噪算法后49Hz至61Hz工频干扰和肌电干扰已消除,结论 该方法可以很好地去除肌电干扰和工频干扰的基频和谐波成分,而对工频干扰的频率变化并不敏感,对于50/60Hz的工频干扰可用同样的算法。     

周期平均法消除心电图中50Hz干扰

在使用一般的带道滤波器时都程度不等的有“振铃”现象,影响对心电波形的正确分析判断,我们研究实验了一种新的周期平均法技术,可以用它来消除心电波中50Hz(60Hz)的工频干扰而不引入“振铃”现象。周期平均法针对50Hz(或60HZ)的工频为周期性信号的特点,采用平均技术,方法简便,效果明显。可以很方便的应用于心电图和向量心电图的实时监测及数据分析处理。     

基于小波变换和K-means聚类算法的心电信号特征提取

目的研究一种基于小波变换和K-means聚类算法的心电信号特征提取方法,根据特征点信息判断心电是否正常。方法利用小波变换和形态学滤波方法去除工频干扰、肌电干扰和基线漂移等主要的噪声之后,利用K-Means聚类算法提取出心电信号的QRS波群,P波和T波这3个主要的特征点,实现心电智能诊断。结果实验数据取自MIT-BIH数据库,多次实验结果显示QRS波群的阳性检测度(P+)达到99.68%和灵敏度(Se)达到99.21%,P波和T波的检测准确度分别达91.43%和97.01%。结论相对于其它方法,本文心电特征提取方法准确度较高,具有一定参考价值;在移动医疗和临床医疗方面具有一定实用价值。     

航天飞行中心电信号去噪方法研究

目的 寻找适合载人航天需要的心电信号去噪方法。方法 通过研究载人航天过程中心电信号的噪声特性，提出将小波变换和形态滤波级联的去噪方法。结果 通过实际应用和仿真对比实验结果表明，本文提出的将小波变换和形态滤波级联的方法，能有效地去除载人航天过程中心电信号的噪声。结论 将小波变换级联形态滤波的去噪方法应用到载人航天过程中是可行的。     

动态环境血氧饱和度监测的运动干扰分离自适应对消方法

目的为解决动态环境中脉搏血氧饱和度监测容易受到运动干扰的问题,提出一种新的运动干扰分离自适应对消方法。方法在对动态环境光电容积脉搏波信号干扰分析的基础上,首先通过计算信号包络提取出红光和红外光光电容积脉搏波信号的交流分量,并分离出与干扰相关的信号,然后将其作为参考信号进行自适应滤波,去除运动干扰。结果采用本文提出的方法可有效抑制运动干扰对血氧饱和度结果的影响。结论本方法充分利用了光电容积脉搏波信号包含的信息,具有结果准确、稳定,运算量小的特点,可应用于动态环境血氧饱和度的监测。     

可穿戴电容耦合式电极在载人航天心电检测中的应用

目的研究可穿戴的小尺寸电容耦合式电极在载人航天中的应用问题。方法针对电极尺寸减小对信号幅值和噪声带来的影响,在系统设计中采用动态驱动屏蔽的电极结构、噪声性能优良的阻抗转换放大器等措施提高信噪比,并采用小波阈值滤波算法去噪。结果相比直径4 cm电极,直径2 cm电容耦合式电极采集的信号幅值减小,但心电信号P波、QRS波、T波均得到完整检测,并在降低界面噪声方面具有一定的优势。小波阈值滤波有效消除噪声。结论本文所设计的使用小尺寸电容耦合式电极的心电检测系统实现了隔着衣服对心电信号的非接触式检测,信号波形清晰完整,可以满足航天医学监护要求。     

基于能量变换与小波分解的QRS波群检测算法

目的 使用能量变换与小波分解的联合算法检测心电信号QRS波群的特征点,为心电信号的自动分析提供新的手段.方法 能量变换是基于信号的局部特征的,可以有效地突出信号的峰点或谷点;小波分解对信号做多分辨率分解,可以突出信号的特征信息;两种方法的结合更利于QRS波群的检测.结果 使用30例样本检测算法性能,证明联合算法能够提高信噪比,对特征点的定位准确可靠.经MIT/BIH心电数据库的检测验证,其R波定位的正确率高达99.79%.使用心率趋势图分析计算结果,不仅可以完全纠正误检和漏检,而且能够定位异常的心搏.结论 本算法能够准确、实时地识别被噪声严重干扰的心电信号的QRS波群,因而在心电信号的自动分析中有很好的应用前景.     

心电基线漂移去除方法的比较研究

基线漂移可严重影响心电信号的分析与处理.滤波法和拟合基漂法是去除心电基线漂移的两类主要算法.本文讨论了形态滤波、中值滤波、线性相位FIR滤波、小波变换、形态和小波相结合、中值滤波和小波相结合等去除基漂的滤波方法,并与导数法与坐标法这两类基漂拟合方法进行了对比.实验结果表明,滤波法实现简单,但精度较低;分段拟合法去除基漂的效果更好,有自适应的特性而且失真较小.无论是实时性还是准确性,基漂拟合法都比滤波法更有优势;但某些场合下,基漂拟合点的提取十分困难,此时只能使用滤波法.本文比较了基漂去除的常用方法,从而为基漂去除方法的选择提供参考.     

Eigenimage filtration of intravenous digital subtraction angiograms of the heart. Work in progress

The authors developed a postprocessing technique, eigenimage filtering, to extract phase-dependent information from digital subtraction angiograms of the heart. This technique suppresses the interference from the right ventricle and left atrium and produces an image of the left ventricle and aorta that is substantially free of these overlap artifacts. The resultant eigenimages of the heart appear more like conventional ventriculograms than do digital subtraction angiograms and matched filtered images.     

Eddy current correction in volume-localized MR spectroscopy

The quality of volume-localized magnetic resonance spectroscopy is affected by eddy currents caused by gradient switching. Eddy currents can be reduced with improved gradient systems; however, it has been suggested that the distortion due to eddy currents can be compensated for during postprocessing with a single-frequency reference signal. The authors propose modifying current techniques for acquiring the single-frequency reference signal by using relaxation weighting to reduce interference from components that cannot be eliminated by digital filtering alone. Additional sequences with T1 or T2 weighting for reference signal acquisition are shown to have the same eddy current characteristics as the original signal without relaxation weighting. The authors also studied a new eddy current correction method that does not require a single-frequency reference signal. This method uses two free induction decays (FIDs) collected from the same volume with two sequences with opposite gradients. Phase errors caused by eddy currents are opposite in these two FIDs and can be canceled completely by combining the FIDs. These methods were tested in a phantom. Eddy current distortions were corrected, allowing quantitative measurement of structures such as the –CH?CH– component, which is otherwise undetectable.     

眼动信号处理研究

对基于红外光反射法的眼动测试仪,从两只光敏管中所接受到的信号是非常微弱的,并含有大量的随机噪声。本文针对该系统的这种特性,提出了诸如相敏检波,非线性滤波、低通数字滤波等一系列硬软件的信号处理技术,并在实际系统中加以实现,结果得到了较好的输出信号。经过处理的输出信号和眼球的运动之间仍存在非线性问题,对此,我们采用了基于加权最小二乘的多项式曲线拟合。在完成系统的基础上,我们在其实用化方面作了一些工作,并取得了一些效果。     

一种视频眼震数据的计算机自动识别方法

目的 判断一组招飞学员视频眼震信号样本的分布,去除眼震图中由于眨眼、主观扫视等异常眼动引起的严重偏离值和干扰值,建立眼震波的计算机自动识别法.方法 采集200例男性招飞学生的眼震数据,采用直方图和Q-Q概率图鉴别样本的分布是否近似于某种类型的分布;通过分析样本的中位数、极差和四分位极差等数字特征,计算数据的上、下截断点...     

A novel method for dendritic spines detection based on directional morphological filter and shortest path

Dendritic spines are tiny membranous protrusions from neuron's dendrites. They play a very important role in the nervous system. A number of mental diseases such as Alzheimer's disease and mental retardation are revealed to have close relations with spine morphologies or spine number changes. Spines have various shapes, and spine images are often not of good quality; hence it is very challenging to detect spines in neuron images. This paper presents a novel pipeline to detect dendritic spines in 2D maximum intensity projection (MIP) images and a new dendrite backbone extraction method is developed in the pipeline. The strategy for the backbone extraction approach is that it iteratively refines the extraction result based on directional morphological filtering and improved Hessian filtering until a satisfactory extraction result is obtained. A shortest path method is applied along a backbone to extract the boundary of the dendrites. Spines are then segmented from the dendrites outside the extracted boundary. Touching spines will be split using a marker-controlled watershed algorithm. We present the results of our algorithm on real images and compare our algorithm with two other spine detection methods. The results show that the proposed approach can detect dendrites and spines more accurately. Measurements and classification of spines are also made in this paper.     

Adaptive sensitivity encoding incorporating temporal filtering (TSENSE).

A number of different methods have been demonstrated which increase the speed of MR acquisition by decreasing the number of sequential phase encodes. The UNFOLD technique is based on time interleaving of k-space lines in sequential images and exploits the property that the outer portion of the field-of-view is relatively static. The differences in spatial sensitivity of multiple receiver coils may be exploited using SENSE or SMASH techniques to eliminate the aliased component that results from undersampling k-space. In this article, an adaptive method of sensitivity encoding is presented which incorporates both spatial and temporal filtering. Temporal filtering and spatial encoding may be combined by acquiring phase encodes in an interleaved manner. In this way the aliased components are alternating phase. The SENSE formulation is not altered by the phase of the alias artifact; however, for imperfect estimates of coil sensitivities the residual artifact will have alternating phase using this approach. This is the essence of combining temporal filtering (UNFOLD) with spatial sensitivity encoding (SENSE). Any residual artifact will be temporally frequency-shifted to the band edge and thus may be further suppressed by temporal low-pass filtering. By combining both temporal and spatial filtering a high degree of alias artifact rejection may be achieved with less stringent requirements on accuracy of coil sensitivity estimates and temporal low-pass filter selectivity than would be required using each method individually. Experimental results that demonstrate the adaptive spatiotemporal filtering method (adaptive TSENSE) with acceleration factor R = 2, for real-time nonbreath-held cardiac MR imaging during exercise induced stress are presented.     

感冒灵胶囊质量标准的研究

目的进一步完善感冒灵胶囊的质量标准。方法采用薄层色谱法鉴别感冒灵胶囊中的三叉苦、岗梅、野菊花;采用HPLC法测定该药中对乙酰氨基酚的含量。结果在薄层色谱中可见各个鉴别斑点清晰,阴性对照无干扰。对乙酰氨基酚在0.19894～2.4925μg范围内线性关系良好r,=0.9999,平均回收率为100.0%,RSD=0.83%。结论本方法简便易行,重现性好,适于感冒灵胶囊质量控制。     

非叠加法体表逐搏检测His束电图的研究

目的　研究非叠加无屏蔽体表逐搏检测His束电位在临床上的应用价值。方法　使用极低噪声三通道高增益放大器 ,16位A/D转换 ,通过USB接口与微机连接 ;应用模式识别加数字滤波方法对微信号进行处理 ,记录时受检者取仰卧位。结果　 46个志愿者用逐搏体表His束检测仪清晰地记录到心房与心室之间的His束电活动 ,即A波、H波与V波 ;8例患者体表检测与心内导管电极记录进行对照 ,两种方法获得的参数基本一致。结论　无创体表逐搏检测His束电活动有广泛临床价值 ,对心脏电生理研究和对房室传导阻滞的诊断有高度实用性。     

扁咽口服液质量标准研究

目的建立扁咽口服液的质量标准。方法用TLC法对扁咽口服液中所含的玄参、连翘、冰片进行鉴别,HPLC法测定玄参中肉桂酸含量。结果 TLC法斑点清晰,无干扰。肉桂酸进样量在1.000～20.00μg/ml范围内,线性关系良好(r=0.9999),平均加样回收率为101.26%,RSD为1.38%(n=6)。结论本方法操作简便,结果准确,能够有效控制扁咽口服液的质量。     

动态浊度法检测盐酸普鲁卡因注射液中的细菌内毒素

目的　建立盐酸普鲁卡因注射液中细菌内毒素的定量检测方法。方法　采用动态浊度法和“二点法”测定计算内毒素回收率。结果　将样品原液进行 1→ 16稀释 (1.2 5mg·ml-1)可消除其对鲎试验的抑制作用。结论　用“二点法”计算内毒素回收率 ,具有良好的可操作性和较强的可靠性。