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1.
基于改进的维奥拉积分方法提取心音信号包络   总被引:1,自引:0,他引:1       下载免费PDF全文
郭兴明  蒋鸿  郑伊能 《仪器仪表学报》2016,37(10):2352-2358
心音是评价人体心脏功能的重要生理信号之一,分析心音信号特征对心脏疾病的早期诊断和治疗具有重要意义。分别采用希尔伯特黄变换、归一化香农能量以及维奥拉积分方法提取心音信号的特征包络,并针对维奥拉积分法存在的不足,结合香农能量方法可抑制高、低强度信号的特性,提出了一种改进的心音信号特征包络提取方法,最后采用阈值法实现了对心音信号的分段。采用改进的维奥拉积分方法对55例心音信号提取特征包络并进行分段处理,经验证该方法能有效的提取心音信号特征包络,对正常信号分段正确率达到了100%,异常信号分段正确率平均达到了95.32%,适合于心音信号分段。  相似文献   

2.
针对传统阶比频率分析不能有效提取滚动轴承早期故障的不足,提出一种将阶比分析、复杂度分析相结合的故障诊断新方法。通过转速传感器和振动传感器同步采集轴承的信号,运用计算阶比跟踪实现了轴承时变振动信号的等角度重采样,再计算经过重采样处理后的角域信号复杂度,将其作为故障识别的依据。最后,通过轴承实测数据的诊断与对比试验验证了该方法的正确性。  相似文献   

3.
基于数据融合的三段式心音身份识别技术   总被引:1,自引:0,他引:1  
提出了一种新的基于多特征提取的心音身份识别技术。在分析心音信号特性的基础上,采用独立子波函数表征个体心音特征信息,通过建立"第一心音s1、第二心音s2和周期-功率-频率(T-P-F)图"的三段式识别模型和应用相似距离的模式匹配方法,以及采用单路心音信号多周期段的数据层融合和改进的D-S数据决策层融合算法,有效地实现了单路心音信号多特征提取的身份识别。另外还介绍了一种双听诊头的心声检测装置。实际实验结果表明,该方法具有很好的识别率和可行性。  相似文献   

4.
利用柴油机排气噪声来检测各缸失火故障状态,通过提取排气噪声的复杂度指标来判断信号的随机性,用计算机语言的长度来衡量排气噪声的特征,分析得到正常、掉1缸和掉2缸等工作状态下的复杂度参数,进而判断各种故障现象。实验证明该方法简单易行,诊断可靠,说明复杂度是非线性动力学参数在机械故障诊断中的新应用。  相似文献   

5.
目的:实现低负荷心冲击信号提取,方法:使用固体振动传感器提取心音信号,使用双向检波及低通滤波实现心音包络的提取,结果:与心电信号的同步对照显示该方法能够有效提取心冲击信号,结论:基于固体振动传感器的心音检测的技术能够有效提取心冲击信号,是低负荷心冲击信号提取的有效途径。  相似文献   

6.
针对单一故障模式下轴承内、外圈损伤程度的区分问题,提出了一种基于相关分析的Lempel-Ziv指标评估方法。通过相关分析在保留信号中频率成分的基础上来降低信号中噪声对Lempel-Ziv指标的影响。首先,该方法对原始信号进行自相关分析,将信号进行降噪;其次,对降噪处理后的信号进行0-1编码,得到信号的编码序列;最后,对编码后的序列计算Lempel-Ziv指标,得到信号的复杂度。通过仿真和轴承故障实验数据验证了所提方法的有效性。与传统的Lempel-Ziv指标及滤波后的Lempel-Ziv指标相比,在噪声环境下,所提方法能较好地识别噪声中轴承故障信号的复杂程度,能够有效的区分单一故障模式下轴承内、外圈的损伤严重程度。  相似文献   

7.
目的:实现低负荷心冲击信号提取,方法:使用固体振动传感器提取心音信号,使用双向检波及低通滤波实现心音包络的提取,结果:与心电信号的同步对照显示该方法能够有效提取心冲击信号,结论:基于固体振动传感器的心音检测的技术能够有效提取心冲击信号,是低负荷心冲击信号提取的有效途径。  相似文献   

8.
S变换兼具了小波变换和快速傅里叶变换各自的优势,具有良好的时频聚集性.灰度共生矩阵能够通过研究灰度的空间相关特性来描述图像纹理.归一化信息熵能够定量的度量信号分布的复杂程度.经S变换取其模后得到S时频谱图,通过灰度共生矩阵对滚动轴承全寿命周期内不同状态进行特征提取并对其进行复杂度度量,提出了一种S-GLCM熵特征指标来反映滚动轴承的退化过程.通过对滚动轴承内圈、轴承外圈、轴承滚动体三种故障分别进行3种不同损伤程度数学模型仿真数据分析,提取各自S-GLCM指标进行对比,验证了该方法的可行性.通过对滚动轴承加速疲劳寿命周期内的数据进行分析,与工程中常用的时域指标有效值进行对比,结果表明了该方法的有效性.  相似文献   

9.
一种基于主成分分析和支持向量机的发动机故障诊断方法   总被引:1,自引:0,他引:1  
提出一种新型的基于主成分分析(PCA)和支持向量机(SVM)的故障诊断方法。首先提取振动信号的多项时域指标,并利用小波包分解提取频域特征;再利用PCA从提取的时域、频域特征中选取敏感特征,实现降维处理,减小数据处理复杂度;最后利用SVM进行特征子集的训练和测试,实现故障分离。该方法在柴油机的失火、撞缸、小头瓦磨损等典型实际故障中的诊断准确率高达98%,证实了该方法的有效性。  相似文献   

10.
针对风电齿轮箱传动结构复杂、所处工况恶劣,难以提取有效振动信号特征进行性能衰退分析的问题,提出多传感器数据融合的风电齿轮箱性能衰退评估方法。该方法将自适应完全集合经验模态分解(CEEM-DAN)、核主分量分析(KPCA)和Hotelling T2统计量相结合,先对风电齿轮箱全寿命的非线性、非平稳振动信号进行CEEMDAN-KPCA降噪处理,再利用KPCA对降噪后的多组振动信号进行融合分析,提取连续的T2值(C-T2)及其时域特征作为评估指标,建立风电齿轮箱性能衰退模型。实验结果表明,该方法对风电齿轮箱振动信号降噪效果显著,C-T2特征有效解决了多组振动信号特征维数膨胀问题,且C-T2时域特征模型比振动信号时域特征模型能更准确地评估风电齿轮箱性能的衰退过程。  相似文献   

11.
Improvements in current heart monitoring techniques could reduce the number of heart attacks and resulting deaths. The potential for using time intervals measured between waveforms of the electrocardiogram (ECG), phonocardiogram (PCG), and peripheral blood flow pulse (PP) for heart monitoring was studied. The waveform locations identified in the simultaneously recorded signals included the R- and T-wave peaks of the ECG, the first (S1) and second (S2) sounds of the PCG, and the systolic peak of the PP. The signals were found to be highly consistent from one cardiac cycle to the next. Further, the time intervals measured between the different signals were stable with time. Strong relationships were found between the intervals R to T and R to S2 and the R to R interval. In contrast, R to PP and R to S1 correlated poorly with the R to R but strongly with each other. Additional differences between the measured intervals were revealed by studying changes due to exercise and different body positions. The relationships between the measured intervals were found to be independent of PCG recording location. This study demonstrates the feasibility and potential of using the electrical-contractile indices of heart function for monitoring heart patients. Design of a computer-based monitor using the techniques specified in this study is discussed along with relative strengths and weaknesses of such a system.  相似文献   

12.
基于关联维数的心音分析研究   总被引:2,自引:0,他引:2  
周静  何为 《现代科学仪器》2007,898(2):56-59
本文提出利用关联维数来定量地对心音信号的复杂程度进行描述。对四种状态下的心音信号进行关联维数计算,结果表明:心音信号为确定的非线性动力系统并且不同的病变心音关联维数有显著区别,因此关联维数可以作为心音识别的重要依据,对心音的检测以及心血管疾病的诊断具有重要的意义。  相似文献   

13.
This study proposes an integrated optimization system to find out the optimal parameter settings of multi-input multi-output (MIMO) plastic injection molding (PIM) process. The system is divided into two stages. In the first stage, the Taguchi method and analysis of variance (ANOVA) are employed to perform the experimental work, calculate the signal-to-noise (S/N) ratio, and determine the initial process parameters. The back-propagation neural network (BPNN) is employed to construct an S/N ratio predictor and a quality predictor. The S/N ratio predictor and genetic algorithms (GA) are integrated to search for the first optimal parameter combination. The purpose of this stage is to reduce the process variance. In the second stage, the quality predictor is combined with particle swarm optimization (PSO) to find the final optimal parameters. The quality characteristics, product length and warpage, are dedicated to finding the optimal process parameters. After the numerical analysis, the optimal parameters can meet the lowest variance and the product quality requirements simultaneously. Experimental results show that the proposed optimization system can not only satisfy the quality specification but also improve stability of the PIM process.  相似文献   

14.
Stark RW  Drobek T  Heckl WM 《Ultramicroscopy》2001,86(1-2):207-215
We have calculated the thermal noise of a v-shaped AFM cantilever (Microlever, Type E, Thermomicroscopes) by means of a finite element analysis. The modal shapes of the first 10 eigenmodes are displayed as well as the numerical constants, which are needed for the calibration using the thermal noise method. In the first eigenmode, values for the thermomechanical noise of the z-displacement at 22 degrees C temperature of square root of u2(1) = A/square root of c(cant) and the photodiode signal (normal-force) of S2(1) = A/square root of c(cant) were obtained. The results also indicate a systematic deviation ofthe spectral density of the thermomechanical noise of v-shaped cantilevers as compared to rectangular beam-shaped cantilevers.  相似文献   

15.
16.
The familiar cracking sounds produced by distraction of the metacarpophalangeal joints were studied using accelerometers and a computerized signal analysis system. The joints were distracted in a controlled manner using a motorized device which simultaneously monitored the load on the joint and its extension. The load and extension parameters and those from the signal analysis were used to examine diurnal variation, the effects of multiple distractions, distraction speed, hand temperature and loading between distractions, and to show that in many cases, the energy contained in a crack signal, expressed as a ratio of the articular cartilage volume, exceeded a known level needed to produce articular cartilage damage.  相似文献   

17.
The first and second signals observed during ultrasonic testing of a cylindrical article with a normal probe set on the article’s end surface are studied. The amplitude of the second pulse caused by a reflection from a lateral wall with transformation of elastic waves is estimated relative to the amplitude of the first (ordinary bottom-reflected) pulse. It is ascertained that, under certain conditions, the amplitude of the second pulse can be comparable to or even exceed the amplitude of the first pulse. The effect of a change in the specimen radius-to-length ratio on the amplitude of the bottom signal is estimated.  相似文献   

18.
基于声发射和关联维数的空气压缩机故障诊断技术研究   总被引:1,自引:0,他引:1  
针对空气压缩机的结构复杂、振动激励源众多、故障诊断与状态检测难度大的问题,提出一种空气压缩机声发射信号的关联维数故障诊断方法.在分析关联维数计算的参数选择基础上,采用奇异值分析的嵌入维数计算法和平均位移的延迟时间计算法等获取声发射信号的关联维数.利用现场往复式压缩机模拟吸气阀座松动、吸气阀弹簧片变形、吸气阀弹簧片失效、阀片变形和阀片失效等五种典型故障.声发射信号的关联维数计算分析结果表明,设计方法能有效诊断压缩机气阀的故障模式.  相似文献   

19.
The new age advancements in information technology due to materials and integrated circuit (IC) technologies and their applications in biomedical sciences have made the healthcare facilities more compact and affordable for the aging population. Market trends in healthcare and related devices indicate a sharp rise in their demand. Hence the researchers have converged the efforts on designing more smart and advanced medical devices using IC technology. Among these devices, cardiac pacemakers have become a recurrent biomedical device which is engrafted in the human body to detect and monitor a person's heart beating rate. The data thus generated is processed for various medical usages and devices via wireless methods. Cardiovascular diseases (CVDs) or diseases related to the heart are due to abnormalities or disorders of the heart and blood vessels. Till date, limited literature is available which focuses on a single technique that can perform all of the ECG signal denoising, ECG detection, lossless data compression and wireless transmission. In this work, a joint approach for denoising, detection, compression, and wireless transmission of ECG signal is proposed. The modified biorthogonal wavelet transform is used for denoising, detection and lossless compression of ECG signal. To reduce the circuit complexity, biorthogonal wavelet transform is realized using linear phase structure. Further, it is found in this work that the usage of modified biorthogonal wavelet transform increases the detection accuracy and CR of the proposed design. Also, in this work, the Wi-Fi-based wireless protocol is used for compressed data transmission. The proposed ECG detector achieves the highest sensitivity and positive predictivity of 99.95% and 99.92%, respectively, with the MIT-BIH arrhythmia database. The use of modified biorthogonal 3.1 wavelet transform and run-length encoding (RLE) for the compression of ECG data achieves a higher compression ratio (CR) of 6.271. To justify the effectiveness of the proposed algorithm, which uses modified biorthogonal wavelet 3.1transform, the results are compared with the existing methods, namely, Huffman coding/simple predictor, Huffman coding/adaptive, and slope predictor/fixed length packaging.  相似文献   

20.
基于DDS算法的12导联心电信号发生器设计   总被引:5,自引:1,他引:4  
心电信号发生器是研发智能心电仪器的关键设备,心率连续可变是心电信号发生器研究的难点。提出了一种用DDS(direct digital frequently synthesis)算法合成心率连续可变的多导联心电信号的方法,并在基于ARM的嵌入式实时操作系统uC/OS-II上用软件实现了该方法。首先证明了用软件实现DDS算法产生心电信号的可行性;针对心电信号的频率特点给出了算法的基本参数;并根据DDS算法思想给出了一种查找表(LUT)长度调整的方法;最后分析了本方法误差的主要来源,通过理论推导得出系统误差为26×10-6。实验结果证明本方法行之有效,具有理论和实际意义。  相似文献   

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