The Slow Sobel Filter Macro..
       An exercise in macro programming only slightly less insane than FFTs.  However, if you
need the information....

The macro Slow Sobel calculates the sobel filter magnitude and phase of an image.  The 
macro is SLOW!!! Taking 98 s on a Centris 650 for a 128 x 128 image.  

Version 1.1  21 Apr 1994
    Now supports ROI selection of an image.   Presently I do not mask non-rectangular ROI's
    in the ROI image so the filter will need some interpretation before the results can be
    used.   Additionally, a timing routine has been added with a status window to allow
    one to keep up with how long the calculation should take and the actual elapsed time.
    This thing is not a speed demon.  Be prepared to go get some coffee.

Version 1.0 17 Apr 1994

Doug Morris
University of Illinois
Biomedical Magnetic Resonance Lab
dmorris@bmrl.med.uiuc.edu