#
 PERIMETER ERROR:
 The edge detection method could not find
 a continuous perimeter around the particle
 within the select-block.  This error may
 occur because the particle touches
 the edge of the select-block, because
 the particle has a very irregular edge,
 because the particle is fragmented, or
 because the THRESHOLD is misplaced.
 You may resize the BLOCK SELECT
 (IMAGE menu) and try again.  If the
 image is dark, then move the THRESHOLD
 to a lower value.  If the image is
 light, then move the THRESHOLD
 to a higher value.
#