In the previous lesson we used the Sobel gradient operators to detect edges. There are several gradient operators used for edge detection, nd variations can be obtained by rotating the kernel values. In this experiment we will use the Roberts, Sobel, Prewitt and Isotropic gradient kernels shown below
The arrow indicates the direction that each gradient kernels evaluates. Also, the small box indicates the kernel origin or "sweet spot".
The image for our experiment is shown below.
The results of the gradient operators are shown below. All of the results used Euclidean distances to determine the final gradient.
Left: Roberts operator, Right: Sobel operator
Left: Prewitt operator, Right: Isotropic operator