def show_plt(image):
    """

    Use matplotlib to display an image (which is represented as a matrix).

    :param image: an image represented as a matrix.
    :type image: ``ndarray``
    """
    from matplotlib import pyplot as plt
    fig, ax = plt.subplots()
    ax.imshow(image, interpolation='nearest', cmap=plt.cm.gray)
    plt.show()
