Multi-view shape-from-silhouette systems are increasingly used for analysing stones. This thesis presents methods to estimate stone shape and to recognise individual stones from their silhouettes. Calibration of two image capture setups is investigated. First, a setup consisting of two mirrors and a camera is introduced. Pose and camera internal parameters are inferred from silhouettes alone. S...

Silhouette information is important in many applications such as virtual reality and visual hull construction. However, silhouette extraction from images relies on a known background. In this paper, we propose a method for silhouette extraction from an arbitrarily unknown background. To do this, we use multiple calibrated images. Each input image is first segmented in regions. Then, the consist...

This paper presents human body posture estimation methods based on analysis of human silhouette and investigates their characteristics. Two types of estimation method are presented: one method is based on both the heuristically extraction method of estimating the significant points of human body and the contour analysis of the human silhouette, and the other is using artificial neural network. ...

Conspicuous and visually unpleasant polygonal silhouettes are often produced when rendering a polyhedral approximation (i.e. a polygonal mesh) of a smooth surface model, regardless whatever shading method is used to improve the appearance of the interior region. We present in this paper a technique for displaying a coarse polygonal mesh with smooth silhouette. Unlike other existing methods that...

The efficient extraction of model silhouettes is essential in many applications, such as non-photorealistic rendering, backface culling, shadow computation, and computing swept volumes. For dynamically moving viewpoints, efficient silhouette extraction is more important for system performance. Accordingly, this paper presents an incremental update algorithm for computing a perspective silhouett...

A novel approach for human silhouette recognition is presented. The method is based on Fourier descriptors. We made an analysis of which and how many descriptors are enough to have a general human silhouette representation, and concluded that a reduced number of components, low and high frecuency, is sufficient for representing a human silhouette and for its recognition in different posses. Bas...

In this paper we show that diversity-driven widening, the parallel exploration of the model space with focus on developing diverse models, can improve hierarchical agglomerative clustering. Depending on the selected linkage method, the model that is found through the widened search achieves a better silhouette coefficient than its sequentially built counterpart.

Silhouettes arise in a variety of imaging scenarios. Pristine silhouettes are often degraded via blurring, detector sampling, and detector noise. We present a maximum a posteriori estimator for the restoration of parameterized facial silhouettes. Extreme dealiasing and dramatic superresolution, well beyond the diffraction limit, are demonstrated through the use of strong prior knowledge.

Anemia is sometimes the sole cause of enlargement of the so-called cardiac silhouette. Successful treatment of the anemia may then restore the silhouette to normal. The enlargement has been attributed to cardiac dilatation. Because of the recognized difficulty in distinguishing l)ericarlial effusion from cardiac dilatation, direct puncture was attempted in two instances of anemnia with the silh...