Directional Derivatives
Sobel Derivative and Custom Filter Sobel derivative calculates the derivative in x and y directions. Thus, I decided to create customized 2D filter to calculate the derivative in the direction of 45 and -45 degree angles, respectively. The customized kernel for 45 degree is: $$ \begin{bmatrix} 0 & 1 & 2 \\ -1 & 0 & 1 \\ -2 & -1 & 0 \end{bmatrix} $$ The kernel for -45 degrees is:...