keras_yolo.py 文件源码

def space_to_depth_x2_output_shape(input_shape):
    """Determine space_to_depth output shape for block_size=2.

    Note: For Lambda with TensorFlow backend, output shape may not be needed.
    """
    return (input_shape[0], input_shape[1] // 2, input_shape[2] // 2, 4 *
            input_shape[3]) if input_shape[1] else (input_shape[0], None, None,
                                                    4 * input_shape[3])