How do I gaussian blur an image without using any in-built gaussian functions?

Question

I want to blur my image using the native Gaussian blur formula. I read the Wikipedia article, but I am not sure how to implement this.

How do I use the formula to de

Answer 1

To use the filter kernel discussed in the Wikipedia article you need to implement (discrete) convolution. The idea is that you have a small matrix of values (the kernel), you move this kernel from pixel to pixel in the image (i.e. so that the center of the matrix is on the pixel), multiply the matrix elements with the overlapped image elements, sum all the values in the result and replace the old pixel value with this sum.

Gaussian blur can be separated into two 1D convolutions (one vertical and one horizontal) instead of a 2D convolution, which also speeds things up a bit.