image.py 文件源码

def upscale(image, ratio):
    """
    return upscaled image array
    Arguments:
    image -- a (H,W,C) numpy.ndarray
    ratio -- scaling factor (>1)
    """
    if not isinstance(image, np.ndarray):
        raise ValueError('Expected ndarray')
    if ratio < 1:
        raise ValueError('Ratio must be greater than 1 (ratio=%f)' % ratio)
    width = int(math.floor(image.shape[1] * ratio))
    height = int(math.floor(image.shape[0] * ratio))
    channels = image.shape[2]
    out = np.ndarray((height, width, channels), dtype=np.uint8)
    for x, y in np.ndindex((width, height)):
        out[y, x] = image[int(math.floor(y / ratio)), int(math.floor(x / ratio))]
    return out