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28ff680 Jul 21, 2012
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#!/usr/bin/env python
# -*- coding: utf-8 -*-
import pylab
import pywt
data1 = pylab.array(range(1, 400) + range(398, 600) + range(601, 1024))
x = pylab.arange(612 - 80, 20, -0.5) / 250.
data2 = pylab.sin(40 * pylab.log(x)) * pylab.sign((pylab.log(x)))
from sample_data import ecg as data3
mode = pywt.MODES.sp1
def plot(data, w, title):
print title
w = pywt.Wavelet(w)
a = data
ca = []
cd = []
for i in xrange(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))
pylab.figure()
ax_main = pylab.subplot(len(rec_a) + 1, 1, 1)
pylab.title(title)
ax_main.plot(data)
pylab.xlim(0, len(data) - 1)
for i, y in enumerate(rec_a):
#print len(data), len(x), len(data) / (2**(i+1))
ax = pylab.subplot(len(rec_a) + 1, 2, 3 + i * 2)
ax.plot(y, 'r')
pylab.xlim(0, len(y) - 1)
pylab.ylabel("A%d" % (i + 1))
for i, y in enumerate(rec_d):
ax = pylab.subplot(len(rec_d) + 1, 2, 4 + i * 2)
ax.plot(y, 'g')
pylab.xlim(0, len(y) - 1)
#pylab.ylim(min(0,1.4*min(x)), max(0,1.4*max(x)))
pylab.ylabel("D%d" % (i + 1))
print "Signal decomposition (S = An + Dn + Dn-1 + ... + D1)"
plot(data1, 'coif5', "DWT: Signal irregularity")
plot(data2, 'sym5', "DWT: Frequency and phase change - Symmlets5")
plot(data3, 'sym5', "DWT: Ecg sample - Symmlets5")
pylab.show()
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