Wang, Lihui Matlab code for computing image gradient. Raw images and the Matlab code for computing image gradient. Imaging Systems, Microscopy, and Displays 2018-11-07
    https://opticapublishing.figshare.com/articles/software/Matlab_code_for_computing_image_gradient_/7048784
10.6084/m9.figshare.7048784.v1