A two pass Zone Of Influence (ZOI) creation method creates a Zone Of
Influence (ZOI) image. The two pass ZOI creation method performs a first
pass scan to create a first pass intermediate distance image and a
shortest distance component label image. It then performs a second pass
scan using the first pass intermediate distance image and the shortest
distance component label image to create a background distance transform
image and a updated shortest distance component label image. An adaptive
image region partition method allows distance lengths of the two pass
adaptive ZOI creation method depend on their associated component labels.