Question

I am using .NET AForge libraries to sharpen and image. The “Sharpen” filter uses the following matrix.

 0  -1   0
-1   5  -1
 0  -1   0

This in fact does sharpen the image, but I need to sharpen the image more aggressively and based on a numeric range, lets say 1-100.

Using AForge, how do I transform this matrix with numbers 1 through 100 where 1 is almost not noticeable and 100 is very noticeable.

Thanks in advance!

Answer 1

The one property of a filter like this that must be maintained is that all the values sum to 1. You can subtract 1 from the middle value, multiple by some constant, then add 1 back to the middle and it will be scaled properly. Play around with the range (100 is almost certainly too large) until you find something that works.

You might also try using a larger filter matrix, or one that has values in the corners as well.

I would also suggest looking at the GaussianSharpen class and adjusting the sigma value.