5.3. Image Segmentation. When looking at an image, a human observer cannot
help seeing structures which often may be identified with objects. However, digital
images as the raw retinal input of local intensities are not structured. Segmentation
is the process of creating a structured visual representation from an unstructured
one. The problem was first studied in the 1920’s by psychologists of the Gestalt
school (see Kohler [54] and the references therein), and later by psychophysicists [49,
95] 14. In its modern formulation, image segmentation is the problem of partitioning
an image into homogeneous regions that are semantically meaningful, i.e., that
correspond to objects we can identify. Segmentation is not concerned with actually
determining what the partitions are. In that sense, it is a lower level problem than
object recognition