灰度图像添加噪声，去除噪声,并计算图像的SNR值-add noise, denoise and count SNR

从心电波形提取出呼吸波形，计算呼吸基频，通过HRV曲线来得到该频谱，最后计算LFa，RFa参数值-get the results of respiratory waveform ,and count the fundamental respiratory frequency.lastly,get the LFa,RFa by frequency spectrum of HRV