脉搏信号的特征点提取方法研究
摘 要
脉搏为体表可触摸到的动脉搏动，它的信号特征对研究心血管系统疾病有着极重要的意义。临床上，我们经常通过分析其波形形态的变化，对病患的心血管系统疾病进行初步诊断。这也足以说明脉搏信号在心血管生理病理研究方面占据着重要的地位。而用MATLAB软件工具实现的阈值法，是现在微弱信号特征提取一种比较常见、代码相对简易的算法，但此原始的方法存在着缺陷，分析结果也容易出现较大的偏差。因此本文对传统的阈值算法进行了改进，采用了差分的阈值方法，可以进一步完善脉搏信号特征点的提取。 关键词：脉搏信号；特征提取；差分阈值法；MATLAB软件
ABSTRACT
Pulse is the arterial pulse touched on surface,it has indispensable meaning to reaserch
cardiovascular disease.Clinically we often have a preliminary diagnosis of patients with cardiovascular disease according to analysing the change of waveform morphology.This is enough to prove that pulse signal plays an important role in the research of cardiovascular physiology and pathology. And threshold method based on MATLAB is an usual kind of algorithm that has the relatively simple code in field of weak signal feature extraction recently,but there are several bugs in this method,while its result also appears big deviation.So in this paper we improved the traditional threshold method based on MATLAB with differential threshold algorithm.This method can further improve the pulse signal feature extraction.
Key Words：Pulse signal; feature extraction; Difference threshold algorithm; MATLAB;
目 录
一、 绪论·····················································1
1.1 研究背景·························································1 1.2 脉搏信号基础·····················································2
二、 提取脉搏信号的原因及方法······································4
2.1 提取脉搏信号的原因··············································4 2.2 脉搏信号提取的方法···············································4
三、 脉搏信号的特征值 ········································6
3.1 脉搏信号的特征点·················································6 3.2 K值·····························································7
四、 脉搏信号特征值提取算法········································9
4.1 数据来源·························································9 4.2 阈值法提取特征值 ························ 9
4.2.1 脉搏波的绘制 ························ 9 4.2.2 动态阈值设定 ······················· 10 4.2.3 特征值的提取 ······················· 10
五、 总结与展望 ························· 13
5.1 总结 ···························· 13 5.2 展望 ···························· 13
参考文献 ····························· 14 致 谢 ······························ 16 附 录 ······························ 17
一、 绪论
1.1 研究背景及意义
随着各国学者们对亚健康状态的问题展开更加广泛而深入的研究，现在一致的观点认为，亚健康状态是指机体虽无明确疾病，却呈现活力下降、适应能力减退的一种“生理状态”现象，是介于健康和疾病之间的一种中间状态，也称为第三状态、临界状态、灰色状态、或病前状态
[1]。中医在中国有着悠久的历史，并且很早就已经建立起了学术体系，主要研究人
体的生理和病历以及疾病的预防、诊断和治疗的一门科学，它承载着我国古代人民和疾病作斗争的经验和丰富的理论知识，是在古代朴素的唯物论和自发的辨证法思想指导下，通过长期医疗实践逐步形成并发展成的医学理论体系。中医的四诊（望、闻、问、切）中的切指的就是切脉，从脉搏的信号中获取人的身体健康状况，医者通过切按病人的动脉用右手的食、中、无名指诊病人的左寸、关、尺脉候心、肝、辨别脉搏的速率、节律、强度、位置和形态之脉象,以了解病症
[2]。基于脉搏波能够及时对人体病变做出相应反应的性质，无论是中医
还是西医，对心血管疾病的检查，都离不开对脉搏波的关注，期望从脉搏波的幅值及波形的变化中提取到各种生理和病理信息，脉搏波之所以具有这样的特性，从生理学角度来讲，在脉搏波由心脏向动脉系统传播的过程中，受到波的离散，血液和血管壁的粘滞性对脉搏波的阻力作用，外周反射波的迭加，以及动脉管壁弹性模量的变化等因素的影响，所以脉搏波中包含着丰富的心血管系统的各种信息，是人体活动最直接的体现，能够做出最及时的反应，且其波形特征变化是评价人体心血管系统生理病理状态的重要依据
[3?4]。随着各国学者们对
亚健康状态展开更加广泛而深入的研究，现在比一致的观点认为，亚健康状态是指机体虽无明确疾病，却呈现活力下降、适应能力减退的一种“生理状态”现象，是介于健康和疾病之间的一种中间状态，也称为第三状态、临界状态、灰色状态或病前状态
[5]。早在公元前七
世纪，人类对于人体解剖学还未有成熟的认知之时，我们的祖先就已经从经验中总结出了一套独特的诊断方法——中医脉诊，由于脉象的浮沉变化会受到脏腑气血的变化影响，当脏腑发生病变，血脉运行也会随之产生变化，从而反应在脉象上。这一发现和整理应用为当时的世人所惊叹，更令如今的我们啧啧称奇。脉诊在临床医学的运用十分广泛，涉及到医学很多领域，医生根据脉象的变化，可以测知人体的健康状况，推断病源的出处，以便为开处方提供依据。但是中医的把脉全凭借的是多年的经验的积累，存在主观上因数素，有时候很容易出现失误。如果客观的对人体的脉搏信号进行采集处理，最后送到上位机进行分析，研究就可以尽可能减少人为判断上的主观失误，从而为医学上病理的诊断提供更安全可靠地依据。
1