gradients.py 文件源码

def main():
    """Load image, compute derivatives, plot."""
    img = data.camera()
    imgy_np, imgx_np = np.gradient(img)
    imgx_ski, imgy_ski = _compute_derivatives(img)

    # dx
    util.plot_images_grayscale(
        [img, dx_symmetric(img), dx_forward(img), dx_backward(img), imgx_np, imgx_ski],
        ["Image", "dx (symmetric)", "dx (forward)", "dx (backward)",
         "Ground Truth (numpy)", "Ground Truth (scikit-image)"]
    )

    # dy
    util.plot_images_grayscale(
        [img, dy_symmetric(img), dy_forward(img), dy_backward(img), imgy_np, imgy_ski],
        ["Image", "dy (symmetric)", "dy (forward)", "dy (backward)",
         "Ground Truth (numpy)", "Ground Truth (scikit-image)"]
    )