🚀 go-pugleaf

jle@dam.brown.edu (Jon Elion) writes:

>Would be interested in from anyone who has experience with image
>filtering techniques for noise reduction that simultaneously ENHANCE
>edges.  Normally, these two operations are mutually exclusive (as
>noise reduction can tend to BLUR edges, not sharpen them).  There
>exist non-linear approaches that achieve this goal (although
>tending to be computationally very intensive).

>Application is x-ray fluoroscopy (noise is Poisson).  Goal is to reduce
>the Poisson noise while providing edge enhancement.

>Anecdotes, experience, pointers to articles, etc. would be appreciated.

How about: Edge preserving smoothing
Proc, 4th Int. Conf on Pattern Recognition
Nov 7-10 1978 Kyoto
Nagao & Matsuyama


Basically, compute variance and mean in 4 quadrants in the neighbourhood
around a point and take the mean of the quadrant with the lowest vaariance.
In TCL-Image on a Quadra: 1.9 seconds for a 256*256 image independent of
neighbourhoodsize.

Ben