Hi, I'm working on a programming assignment dealing with edge detection of an image. I'm supposed to use the Laplacian of Gaussian method to generate a mask for a 7x7 matrix using the sigma = 1.4. I searched google and found a 9x9 matrix with the same sigma of 1.4 and this matrix was generated

what method do I use to generate these numbers into the matrix? If any more information is needed just let me know, thanks.