markback -- mark regions in the background for performing statistics on
calnicb style association input file with list of images to be processed and
labels boxes with numbers on image display
number of boxes to mark. Only the first 2 boxes will be used by asncombine.
image in association to use for marking the boxes.
markback displays one image of an association (the nmem'th image), and allows
the to mark nbox regions on the image display. The first 2 of those regions
will be used by asncombine to evaluate the quality of the background subtraction.
Two region should be marked which contain no objects. The boxes will be stored
in the table header.