  The major challenges of automatic track counting are distinguishing tracks
and material defects, identifying small tracks and defects of similar size, and
detecting overlapping tracks. Here we address the latter issue using WUSEM, an
algorithm which combines the watershed transform, morphological erosions and
labeling to separate regions in photomicrographs. WUSEM shows reliable results
when used in photomicrographs presenting almost isotropic objects. We tested
this method in two datasets of diallyl phthalate (DAP) photomicrographs and
compared the results when counting manually and using the classic watershed.
The mean automatic/manual efficiency ratio when using WUSEM in the test
datasets is 0.97 +/- 0.11.
