  Distance transformation is an image processing technique used for many
different applications. Related to a binary image, the general idea is to
determine the distance of all background points to the nearest object point (or
vice versa). In this tutorial, different approaches are explained in detail and
compared using examples. Corresponding source code is provided to facilitate
own investigations. A particular objective of this tutorial is to clarify the
difference between arbitrary distance transforms and exact Euclidean distance
transformations.
