circular high pass filter

Started by enriquefergosa July 7, 2003
Hallo, I need help. I would like to do a 2D circular high pass
filter using the matlab function FSPECIAL('DISK', RADIUS) but, this
function is a low pass filter really. How could I change from low to
high pass filter using this function?.

I tried to do this filter doing my own algorithm with a matrix
and I got to do a rectangular filter easily but my problem was that
I didn't know how to round the squares to get a circular filter.

Could somebody help me. Thank you all very much. Regards.