The Sobel operator, typically referred to as the Sobel–Feldman operator or Sobel filter, is used in image process and computer vision, significantly inside edge detection algorithms wherever it creates a picture emphasising edges. Sobel filter computes native image gradient in 3×3 image neighbourhoods…

The data set contains two features. The first describes gradient magnitude and the second its orientation:

In order to highlight larger-scale structures, we may want to filter the image first with a Gaussian:

The result of directional Sobel filters may be extracted using the ‘sobel.x’ and ‘sobel.y’ options, respectively: