Blobs or Objects with Holes

Lispix ignores holes in objects.  This is because the boundary is saved as a simple, connected curve.  For our applications to date, this has been a desirable characteristic.  It may not be so for yours.  This illustrates the consequences:

This is a synthesized image with two circles of exactly the same size, but one has a hole or an area of reduced intensity.  (This image is hole-demo.tif in the lx-images folder.)  The image can be thresholded for blobbing, with this internal area either selected or not: