We describe a simple and robust algorithm for estimating 3D shape given a number of silhouette points obtained from two or more viewpoints and a parametric model of the shape. Our algorithm minimizes (in the least squares sense) the distances from the lines obtained by unprojecting the silhouette points to 3D to their closest silhouette points on the 3D shape. The solution is found using an ite...

We present a new approach to combine two approaches to three-dimensional reconstruction: silhouette-based and correspondence-based approaches. The two approaches have complementary costs and benefits. Silhouette-based approaches deliver volumetric descriptions which often have very few outliers, but they cannot reconstruct concave surfaces. Correspondence-based approaches give surface descripti...

We have revisited the silhouette algorithm developed by Canny, and designed its new symbolic-numeric version. The symbolic-numeric silhouette algorithm do not require the symbolic computation of the determinants of resultant matrices, and can work on oating point arithmetic. Though its combinatorial complexity remains the same, but its algebraic complexity has been improved signi cantly which i...

B.Bones and breast shadows: Inspect the bones for radiographic density, fractures, lytic lesions, or bony deformity. Eval¬ uate the breast shadows for gross asymmetry, evidence of prior surgery, and any gross calcification. C.Cardiac silhouette: Assess the cardiac silhouette for gen¬ eral size and contour. D.Diaphgram: Assess the diaphgram(s) with attention to the contour and costaphrenic angle...

In this work, we introduce a model-based approach to extracting the silhouette of people in motion from stereo video sequences. To this end, we extend a purely stereo-based approach to tracking people proposed in earlier work. This approach is based on an implicit surface model of the body. It lets us accurately predict the silhouette’s location and, therefore, detect them more robustly. In tur...

Human activity recognition is an active research field in computer vision and image processing. In this paper we propose a robust rule-based method for the task of recognition of human activities and scenarios in video image sequences. The methodology uses a context-free grammar based representation scheme to represent human actions. The proposed system consists of three major steps. Initially ...

We present a computationally efficient and robust shape from silhouette method based on topologyadaptive mesh deformation, which can produce accurate, smooth, and topologically consistent 3D mesh models of complex real objects. The deformation scheme is based on the conventional snake model coupled with local mesh transform operations that control the resolution and uniformity of the deformable...