Deformable Models

The term Deformable Model describes a group of computer algorithms and techniques widely used in computer vision today. They all share the common characteristic that they model the variability of a certain class of objects (In biometrics this could be the class of all faces, or of all hands, or all eyes, etc.). Today, different representations of the object classes are commonly used. Earlier algorithms modeled shape variations only. The shape, represented as curve or surface, is deformed in order to match a specific example in the object class. Later, the representations were extended to model texture variations in the object classes as well as imaging factors such as perspective projection and illumination effects. For biometrics, deformable models are used for image analysis such as face recognition, image segmentation or classification. The image analysis is performed by fitting the deformable model to a novel image, thereby parametrizing the novel image in terms of the known model.