Convolution, Sobel and Median filters

My little project for Image Processing clases.

We had to create our own convolution filter with a sharpening 3x3 matrix [0, -1, 0, -1, 5, -1, 0, -1, 0].
Then a Sobel filter using the convolution with two 3x3 edge detection matrices: [-1, 0, 1, -2, 0, 2, -1, 0, 1] and [1, 2, 1, 0, 0, 0, -1, -2, -1]
And finally a Median blurring filter.

It was quite easy and here is a little example of how it worked:

1. Original (Natalie Portman mmm :)):



2. Convolution sharpening filter:



3. Sobel edge detector filter:



4. Median blurring filter with median matrix 7x7