linearity and convolution

1.To convolute a image with a filer ,a good way to cut down the magnitude.

QS:Is any matrix can be get by the convolution with two vectors?

2.Devison can be a linear function when the denominator is a constant.

3.Three ways about the boundary issues.

And matlab code are listed below:

4.Sharping filter

5 Median filter to remove the salt and pepper noise,and be noticed that it is not a linear filter

6.In order to avoid bluring the nice sharp in the sec box,median filter 

and the code is here:

cite:

https://classroom.udacity.com/courses/ud810/lessons/3490398568/concepts/34996085510923