imgZonePlate

 imgZonePlate - Make a zone plate image

 img = ieZonePlate([SZ], [AMP], [PHASE])

 The zone plate function is  AMP * cos( r^2 + PHASE) + 1
 
 SZ   -- image size (default = 256)
 AMP  --  (default = 1) 
 PHASE (default = 0) 

 Examples:
   img = imgZonePlate(256);  imagesc(img); axis image; colormap(gray(256)); 
   img = imgZonePlate([384,384],255); imagesc(img);    colormap(gray(256));   axis image
   img = imgZonePlate([384,384],255,pi/2); imagesc(img); colormap(gray(256)); axis image

 Copyright ImagEval Consultants, LLC, 2005.