voice_enhancement.py 文件源码

def compute_by_noise_pow(self, signal, n_pow):
        s_spec = np.fft.fftpack.fft(signal * self._window)
        s_amp = np.absolute(s_spec)
        s_phase = np.angle(s_spec)
        gamma = self._calc_aposteriori_snr(s_amp, n_pow)
        xi = self._calc_apriori_snr(gamma)
        self._prevGamma = gamma
        nu = gamma * xi / (1.0 + xi)
        self._G = (self._gamma15 * np.sqrt(nu) / gamma) * np.exp(-nu / 2.0) *\
                  ((1.0 + nu) * spc.i0(nu / 2.0) + nu * spc.i1(nu / 2.0))
        idx = np.less(s_amp ** 2.0, n_pow)
        self._G[idx] = self._constant
        idx = np.isnan(self._G) + np.isinf(self._G)
        self._G[idx] = xi[idx] / (xi[idx] + 1.0)
        idx = np.isnan(self._G) + np.isinf(self._G)
        self._G[idx] = self._constant
        self._G = np.maximum(self._G, 0.0)
        amp = self._G * s_amp
        amp = np.maximum(amp, 0.0)
        amp2 = self._ratio * amp + (1.0 - self._ratio) * s_amp
        self._prevAmp = amp
        spec = amp2 * np.exp(s_phase * 1j)
        return np.real(np.fft.fftpack.ifft(spec))