A MODEL FOR COMPRESSION AND CLASSIFICATION OF FACE DATA-STRUCTURES

In this paper we present a 3-D model with physical properties which si mplifies the analysis and the synthesis of deformable faces and solids . Our model presents three relevant particularities. First, it describ es the external envelope of faces with 1-D finite elements assembled w ith a new 3-connected mesh topology. Second, the mesh deformations are analysed with a modal analysis. Because our model associates these tw o particularities, the number of rigid modes given by the modal analys is is equal to the number of I-D finite elements, which is also the ha lf of the number of Degrees of Freedom (DOF). This number of rigid mod es is a basic characteristic of our model. The second half of modes co nstitutes the nonrigid modes. Third, we use these rigid modes and the first nonrigid mode to synthesize a mean face named a photo-fit identi kit or class, around which we synthesize face varieties by action on s econdary nonrigid modes. Our physical 3-D model allows compression of face data structures because a greater number of secondary nonrigid mo des can be suppressed to define a class or its varieties, and because the synthesis of varieties does not need more information storage than their classes. Our physical 3-D model allows classification of face d ata structures because we can associate an objective measure to each s ynthesized face. We can measure the deformation between a variety and its photo-fit identikit. Copyright (C) 1996 Elsevier Science Ltd.