tf_methods.py 文件源码

def GLA(wsz, hop, N=4096):
        """ LSEE-MSTFT algorithm for computing the synthesis window used in
        inverse STFT method below.
        Args:
            wsz :   (int)    Synthesis window size
            hop :   (int)    Hop size
            N   :   (int)    DFT Size
        Returns :
            symw:   (array)  Synthesised windowing function

        References :
            [1] Daniel W. Griffin and Jae S. Lim, ``Signal estimation from modified short-time
            Fourier transform,'' IEEE Transactions on Acoustics, Speech and Signal Processing,
            vol. 32, no. 2, pp. 236-243, Apr 1984.
        """
        synw = hamming(wsz)/np.sqrt(N)
        synwProd = synw ** 2.
        synwProd.shape = (wsz, 1)
        redundancy = wsz/hop
        env = np.zeros((wsz, 1))
        for k in xrange(-redundancy, redundancy + 1):
            envInd = (hop*k)
            winInd = np.arange(1, wsz+1)
            envInd += winInd

            valid = np.where((envInd > 0) & (envInd <= wsz))
            envInd = envInd[valid] - 1
            winInd = winInd[valid] - 1
            env[envInd] += synwProd[winInd]

        synw = synw/env[:, 0]
        return synw