There are quite a few different edge detection operators used in image processing algorithms; all of them are discrete (first or second order) differentiation operators and they try to approximate the gradient of the image intensity function (for instance, the Sobel operator, which we discussed previously). The kernels shown in the following diagram are a few popular ones used for edge detection. For example, popular derivative filters approximating the 1st Order image derivatives are Sobel, Prewitt, Sharr, and Roberts filters, whereas a derivative filter approximating the 2nd Order derivatives is the Laplacian:
As discussed in the scikit-image documentation, ...
