Methods: withdraw the envelope of heat sounds by using Mathematic Morphology and normalized Shannon energy, extract first heartsound and the secondheartsound.
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。
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Results: Their main cause to colour Doppler echocardiography were murmur, cyanosis, panting, asphyxia, feeding-difficulty, Loud pulmonary valve secondheartsound.
The clinical experiments have indicated that the first and secondheartsound can be almost acquired by the microphone, but it is difficult for the third and fourth, w…