image.py 文件源码

def to_grayscale(image):
    """Converts a colored image to a grayscaled one.
    Parameters
    ----------
    image: ndarray()
        An image with the shape of [height, width, 3].
    Returns
    ---------
    image: ndarray(uint8)
        Returns a grayscaled image with shape [height, width, 1].
    """
    img_channels = np.shape(image)[2]
    if img_channels == 3:
        image = cast(image)
        image = cv2.cvtColor(image, cv2.COLOR_RGB2GRAY)
        image = np.expand_dims(image, axis=2)
    # introduce a 1-channel dimension to handle the indexing
    # of color and gray images the same way
    return image