misc.py 文件源码

def preprocess(image, use_rgb=False, use_hsv=False, norm=True):
    """
    Preprocesses a RGB image before extracting super-regions from it. Improves
    the quality of the super-regions by transforming to the L*a*b colorspace
    and normalizing the image.

    Args:
        image: numpy (H, W) or (H, W, 3) array
            RGB image to be preprocessed.
        use_rgb: bool
            Wether to append RGB channels to the L*a*b channels.
        use_hsv: bool
            Wether to append HSV channels to the L*a*b channels.
        norm:
            Wether to standardize individual channels.
    Result:
        result: numpy (H * W, K) array
            Where K is 3, 6 or depending on `use_rgb` and `use_hsv`. channel
            specific normalization to enhance distances.
    """
    if image.ndim == 2 or image.shape[2] == 1:
        data = (np.squeeze(image) - image.mean()) / image.std()
        return data

    assert image.shape[2] == 3, 'Error: invalid image format'

    result = color.rgb2lab(image).reshape(-1, 3)
    if use_rgb:
        result = np.column_stack(result, image.reshape(-1, 3))
    if use_hsv:
        result = np.column_stack(result, color.rgb2hsv(data).reshape(-1, 3))

    # Standardize channels and reshape in-place
    if norm:
        result = (result - result.mean(0)) / result.std(0)

    return result.astype(np.float32)