For the first upgrade, I decided to try filters of the form
f(x,y) = cos( 2*pi*dot( (r,theta), (R,THETA) ) ) * exp( -r*r / (2*SIGMA*SIGMA) )
where r and theta are the coordinates of a pixel in polar coordinates. This is a strange family of filters
whose localization is inspired by the Gabor filter, but whose shapes aim to capture local symmetries.
These filters have no precedent, I just thought it would be interesting to try them. They are pictured below.
Shuriken Filters:
Performance:
