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We address the problem of deformable shape and motion recovery from point correspondences in multiple perspective images. We use the low-rank shape model, i.e. the 3D shape is represented as a linear combination of unknown shape bases. We propose a new way of looking at the low-rank shape model. Instead of considering it as a whole, we assume a(More)
Mineralized biological tissues offer insight into how nature has evolved these components to optimize multifunctional purposes. These mineral constituents are weak by themselves, but interact with the organic matrix to produce materials with unexpected mechanical properties. The hierarchical structure of these materials is at the crux of this enhancement.(More)
This paper deals with shading and AAMs. Shading is created by lighting change. It can be of two types: self- shading and external shading. The effect of self-shading can be explicitly learned and handled by AAMs. This is not however possible for external shading, which is usually dealt with by robustifying the cost function. We take a different approach: we(More)
Automatic extraction of facial feature deformations (either due to identity change or expression) is a challenging task and could be the base of a facial expression interpretation system. We use Active Appearance Models and the simultaneous inverse compositional algorithm to extract facial deformations as a starting point and propose a modified version(More)
An Active Appearance Model (AAM) is a variable shape and appearance model built from annotated training images. It has been largely used to synthesize or fit face images. Person-independent face AAM fitting is a challenging open issue. For standard AAMs, fitting a face image for an individual which is not in the training set is often limited in accuracy,(More)
Fitting a single generic AAM on an unseen face (that is not in the training set) under any pose and expression is very difficult. The variability of the data is so high that the fitting process usually gets stuck into one of the numerous local minima. We show that a solution to this problem consists to separate the variability sources. We build a pool of(More)
Le travail présenté ici s'inscrit dans le domaine de l'analyse assistée d'expressions faciales observées sur des séquences vidéos de langue des signes. Dans ce contexte, le visage du signeur est fréquemment occulté, principalement par ses mains. Nous utilisons un mo-dèle à apparence active (AAM) pour modéliser le vi-sage et ses déformations expressives. Un(More)