#!/usr/bin/python3 # -*- coding: utf-8 -*- import numpy as np import matplotlib.pyplot as plt import pywt import pywt.data ecg = pywt.data.ecg() data1 = np.concatenate((np.arange(1, 400), np.arange(398, 600), np.arange(601, 1024))) x = np.linspace(0.082, 2.128, num=1024)[::-1] data2 = np.sin(40 * np.log(x)) * np.sign((np.log(x))) mode = pywt.Modes.smooth def plot_signal_decomp(data, w, title): """Decompose and plot a signal S. S = An + Dn + Dn-1 + ... + D1 """ w = pywt.Wavelet(w) a = data ca = [] cd = [] for i in range(5): (a, d) = pywt.dwt(a, w, mode) ca.append(a) cd.append(d) rec_a = [] rec_d = [] for i, coeff in enumerate(ca): coeff_list = [coeff, None] + [None] * i rec_a.append(pywt.waverec(coeff_list, w)) for i, coeff in enumerate(cd): coeff_list = [None, coeff] + [None] * i rec_d.append(pywt.waverec(coeff_list, w)) fig = plt.figure() ax_main = fig.add_subplot(len(rec_a) + 1, 1, 1) ax_main.set_title(title) ax_main.plot(data) ax_main.set_xlim(0, len(data) - 1) for i, y in enumerate(rec_a): ax = fig.add_subplot(len(rec_a) + 1, 2, 3 + i * 2) ax.plot(y, 'r') ax.set_xlim(0, len(y) - 1) ax.set_ylabel("A%d" % (i + 1)) for i, y in enumerate(rec_d): ax = fig.add_subplot(len(rec_d) + 1, 2, 4 + i * 2) ax.plot(y, 'g') ax.set_xlim(0, len(y) - 1) ax.set_ylabel("D%d" % (i + 1)) plot_signal_decomp(data1, 'coif5', "DWT: Signal irregularity") plot_signal_decomp(data2, 'sym5', "DWT: Frequency and phase change - Symmlets5") plot_signal_decomp(ecg, 'sym5', "DWT: Ecg sample - Symmlets5") plt.show()