filtering.py 文件源码

def fwd_filter(img, S):
    img_w, img_h, ch = img.shape
    F = pad2(img)
    F.data[F.mask] = 0.  # make sure its zero-filled!

    # Forward transform
    specF = np.fft.fft2(F.data.astype(float), axes=(0, 1))
    specN = np.fft.fft2(1. - F.mask.astype(float), axes=(0, 1))
    specS = np.fft.fft2(S[::-1, ::-1])
    out = np.real(np.fft.ifft2(specF * specS[:, :, np.newaxis], axes=(0, 1)))
    norm = np.real(np.fft.ifft2(specN * specS[:, :, np.newaxis], axes=(0, 1)))
    eps = 1e-15
    norm = np.maximum(norm, eps)
    out /= norm
    out = out[-img_w:, -img_h:]
    out[img.mask] = 0.
    return np.ma.MaskedArray(data=out, mask=img.mask)