First commit after changed file framework

pyat/OANPd.py

@@ -0,0 +1,89 @@
+import numpy as np
+from scipy.fft import fft
+import soundfile as sf
+from numpy import log10
+import math
+
+# Average Noise Spectral Level
+def ANSL(u, fs, M, A=0, N=None, D=None, w=None):
+    """
+    :param u: Voltage data (Unit: V)
+    :param fs: Sampling rate (Unit: Hz)
+    :param M: Sensitivity (Unit: dBV re 1uPa)
+    :param A: Preamplifier (Unit: dB)
+    :param N: Segment length
+    :param D: Overlap length
+    :param w: Window
+    :return: Spectral level
+    """
+    L = len(u)
+    if N == None:
+        if L >= fs:
+            N = round(fs)
+        else:
+            N = L
+    elif N > L:
+        raise Exception("Segment length is larger than data length.")
+
+    if D == None:
+        D = 0
+
+    if w is None:
+        w = np.hamming(N)
+    G = np.mean(np.square(abs(w)))
+
+    K = 1 + math.floor((L-N) / (N-D))
+
+    T = N / fs
+    df = 1 / T
+    X2 = np.zeros(N)
+    for k in range(K):
+        X = fft(w * u[round(k*(N-D)):round(k*(N-D)+N)])
+        X2 += np.square(abs(X))
+
+    spl = 10 * log10(X2) - 10 * log10(N*fs*G*K/2) - M - A
+    freq = np.arange(0, fs/2, df)
+    spl = spl[0:len(freq)]
+
+    return freq, spl
+
+
+# 1/3 Octave Spectral Level
+def OneThirdOct_SPL(freq, spl, f_start, Npoints):
+    """
+    :param freq: Frequency
+    :param spl: 1 Hz bandwidth spectral level
+    :param f_start: Starting frequency of the 1/3 octave
+    :param Npoints: The number of frequency points
+    :return: 1/3 Octave Spectral Level
+    """
+    fC = f_start * np.power(2, np.arange(Npoints)/3)
+    fL = f_start * np.power(2, np.arange(Npoints)/3 - 1.0/6)
+    fH = f_start * np.power(2, np.arange(Npoints)/3 + 1.0/6)
+
+    spl_oct = np.zeros(Npoints)
+    for it in range(Npoints):
+        # idx = (freq >= fL[it]) & (freq <= fH[it])
+        idx = np.where((freq >= fL[it]) & (freq <= fH[it]))
+        # print(idx)
+        # print(spl[idx])
+        spl_oct[it] = 10 * log10(np.mean(np.power(10, spl[idx]/10)))
+        # print(spl_oct[it])
+
+    return fC, spl_oct
+
+def call_oanp(soundFile, M, A=0):
+    [x, fs] = sf.read(soundFile)
+    u = 3 * x           # Voltage data
+    # M = -164.0          # Sensitivity
+    # A = 0               # Preamplifier
+    N = fs              # Segment length
+    D = N/2             # Overlap length
+    w = np.hanning(N)   # Window
+
+    # Average Noise Spectral Level
+    [freq, spl] = ANSL(u, fs, M, A, N, D, w)
+    # 1/3 Octave Spectral Level
+    [fC, spl_oct] = OneThirdOct_SPL(freq, spl, f_start=20, Npoints=28)
+
+    return [freq, spl, fC, spl_oct]