This paper presents a new deformable modeling strategy aimed at integrating shape and appearance in a unified space. If we think traditional deformable models as "active contours" or "evolving curve fronts", the new deformable shape and appearance models we propose are "deforming disks or volumes". Each model has not only boundary shape but also interior appearance. The model shape is implicitly embedded in a higher dimensional space of distance transforms, thus represented by a distance map "image". In this way, both shape and appearance of the model are defined in the pixel space. A common deformation scheme, the Free Form Deformations (FFD), parameterizes warping deformations of the volumetric space in which the model is embedded in, hence deforming both model boundary and interior simultaneously. When applied to segmentation, a Metamorphs model can be initialized covering a seed region far-away from object boundary and efficiently evolve and...
Xiaolei Huang, Dimitris N. Metaxas