Deformable templates are a mechanism for modeling shape classes, and have been used recently for the identification of structures in medical imagery such as x-rays of hands and magnetic resonance images of brains, and for the identification and tracking of targets in simulated military applications.
Deformations act on templates to produce observable shapes.
The ensemble of presentations of a particular object is thereby modeled as the result of acting on a template with a random deformation. It is important that the deformations are mostly local, because they can then be described by a local random field, and this has essential computational advantages. The framework is quite general. The algorithm, which amounts to an inference engine, is computationally intensive, but implementation on a massively parallel computer has achieved satisfactory convergence times in several applications.