seeed-voicecard-radxazero-a.../tools/coherence.py

45 lines
973 B
Python

"""
Estimate the magnitude squared coherence estimate,
- requirements
sudo apt install python-numpy python-scipy python-matplotlib
"""
import sys
import wave
import numpy as np
from scipy import signal
import matplotlib.pyplot as plt
if len(sys.argv) < 2:
print('Usage: python {} audio.wav'.format(sys.argv[0]))
sys.exit(1)
wav = wave.open(sys.argv[1], 'rb')
channels = wav.getnchannels()
frames = wav.readframes(wav.getnframes())
fs = wav.getframerate()
wav.close()
print("channels: %d" % channels)
print("rate : %d" % fs)
print("frames : %d" % wav.getnframes())
array = np.fromstring(frames, dtype='int16')
ch0 = array[0::channels]
fig, ax = plt.subplots()
for ch in range(1, channels):
f, c = signal.coherence(ch0, array[ch::channels], fs, nperseg=1024)
ax.semilogy(f, c, label="CO 1-%d" % (ch + 1))
legend = ax.legend(loc='lower right', shadow=True, fontsize='small')
plt.xlabel('frequency [Hz]')
plt.ylabel('Coherence')
plt.show()