utils.py 文件源码

def pcnn_norm(x, colorspace="RGB", reverse=False):
    """Normalize the input from and to [-1, 1].

    Args:
      x: input image array (3D or 4D)
      colorspace (str): Source/target colorspace, depending on the value of `reverse`
      reverse (bool, optional): If False, converts the input from the given colorspace to float in the range [-1, 1].
      Otherwise, converts the input to the valid range for the given colorspace. Defaults to False.

    Returns:
      x_norm: normalized input
    """
    if colorspace == "RGB":
        return np.cast[np.uint8](x * 127.5 + 127.5) if reverse else np.cast[np.float32]((x - 127.5) / 127.5)
    elif colorspace == "lab":
        if x.shape[-1] == 1:
            return (x * 50. + 50.) if reverse else np.cast[np.float32]((x - 50.) / 50.)
        else:
            a = np.array([50., +0.5, -0.5], dtype=np.float32)
            b = np.array([50., 127.5, 127.5], dtype=np.float32)
            return np.cast[np.float64](x * b + a) if reverse else np.cast[np.float32]((x - a) / b)
    else:
        raise ValueError("Unknown colorspace" % colorspace)