This book contains both a synthesis and mathematical analysis of a wide
set of algorithms and theories whose aim is the automatic segmen- tation
of digital images as well as the understanding of visual perception. A
common formalism for these theories and algorithms is obtained in a
variational form. Thank to this formalization, mathematical questions
about the soundness of algorithms can be raised and answered. Perception
theory has to deal with the complex interaction between regions and
"edges" (or boundaries) in an image: in the variational seg- mentation
energies, "edge" terms compete with "region" terms in a way which is
supposed to impose regularity on both regions and boundaries. This fact
was an experimental guess in perception phenomenology and computer
vision until it was proposed as a mathematical conjecture by Mumford and
Shah. The third part of the book presents a unified presentation of the
evi- dences in favour of the conjecture. It is proved that the
competition of one-dimensional and two-dimensional energy terms in a
variational for- mulation cannot create fractal-like behaviour for the
edges. The proof of regularity for the edges of a segmentation
constantly involves con- cepts from geometric measure theory, which
proves to be central in im- age processing theory. The second part of
the book provides a fast and self-contained presentation of the
classical theory of rectifiable sets (the "edges") and unrectifiable
sets ("fractals").