第二心音

目的本文介绍一种在心音图（PCG）中定位第一心音（S1）和第二心音（S2）的算法。

Objective An algorithm located the first sound ( S 1 ) and the second sound ( S 2 ) on phonocardiogram ( PCG ) was introduced .

部分第二心音S2可能已经被噪声等杂音信号淹没，同时也可能是传输过程中数据的丢包导致S2无法正常采集到。

Partial the second heart sound S2 may have been covered by noises , and the data packets losing in the transmission process may also make S2 not normally collected .

基于心音包络信号的第一心音S1、第二心音S2波峰提取和定位；

Thirdly , the peaks of S1 and S2 are picked up and detected based on the extracted envelope of heart sound signal ;

本文提出一种基于数学形态学的心音包络提取方法，并在提取出的心音包络信号中识别第一心音（S1）与第二心音（S2）。

This study put forward a heart sound envelope detection method based on the mathematical morphology . Then on the heart sound envelope , S1 and S2 were recognized .

利用特征线法对第二心音的一维数学模型进行了数值计算，计算结果与Stein的计算结果吻合良好，并且提出了第二心音的二维轴对称物理模型。

In the present article , characteristic line method is used to solve numerically the problem of the second heart sound of one-dimensional model . The result obtained coincides with that of stein 's.

本文采用经验模态分解（EMD）包络算法进行心音包络的提取，为第一心音和第二心音的定位以及时域特征的提取奠定了基础。

This paper uses the Empirical Mode Decomposition ( EMD ) envelope algorithm for the extraction of heart sound envelope . It lays a foundation for the positioning and time-domain characteristics extraction of the first and second heart sound . 3 .

第二心音信号的瞬时功率和功率谱极大值分析

Instantaneous power maxima and power spectrum maxima analysis of second heart sounds signals

第二心音的数学模型和数值计算

Mathematical Model and Numerical Calculation of Second Heart Sound

第一和第二心音产生的原理、特点及其生理意义；心电图各波的意义；

The principles , characters and physiological meaning of first heart sound and second heart sound .

基于小波多分辨分析的第一第二心音提取

Extraction of the First and the Second Heart Sounds Based on Multi-resolution Analysis of Wavelet Transform

说明这2例心脏病患者的第一心音正常，第二心音不正常。

This indicated that the S , of 2 patients was normal while the S2 was abnormal .

利用数学形态学和归一化香农能量两种方法分别提取了心音的包络，突出了第一心音、第二心音等特征。

Methods : withdraw the envelope of heat sounds by using Mathematic Morphology and normalized Shannon energy , extract first heart sound and the second heart sound .

结果：进行心脏彩超检查的原因以心脏杂音、紫绀、宫内窘迫或新生儿窒息、呼吸急促、肺动脉瓣第二心音亢进最常见。

Results : Their main cause to colour Doppler echocardiography were murmur , cyanosis , panting , asphyxia , feeding-difficulty , Loud pulmonary valve second heart sound .

本文进行了3项工作。（1）提出了基于血流动力的第一心音和第二心音产生模型。

The main work of this paper is focused on three aspects as follows . ( 1 ) A hemodynamics-based first and second heart sound generation model is proposed .

结果表明：5例中3例正常人和2例心脏病患者的第一心音辨识区域重合，而第二心音辨识区域不重合。

The results showed that in the 5 participants , the S1 recognition area of 3 normal subjects and 2 patients with heart diseases overlapped , though the S2 area did not .

以3例正常人6个心动周期的第一和第二心音辨识置信区域为判别标准，对2例心脏病患者进行对比辨识讨论。

The S1 and S2 recognition areas of 6 cardiac cycles of 3 normal subjects were employed as discrimination standard so as to compare and analyze the recognition results of 2 patients with heart diseases .

传统意义上讲，第一心音、第二心音的产生被认为是心脏瓣膜在开合过程中碰撞所产生的振动信号，这些信号包含多种瞬态非平稳成分。

The first heart sound and the second heart sound are considered to be the vibration signals which are generated by the collision in the process of value opening and closing . All of the vibration signals contain many kinds of transient non-steady ingredients .