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We address the visual ambiguities that arise in estimating object and scene structure from a set of images when the viewpoint and lighting are unknown. We obtain a novel viewpoint–lighting ambiguity called the KGBR that corresponds to a group of three-dimensional affine transformations on the object or scene geometry combined with transformations on the object or scene albedo. Our analysis assu...

This examination of the role and potential for replication in economics points out the paucity of both pure replication – checking on others’ published papers using their data – and scientific replication – using data representing different populations in one’s own work or in a comment. Several controversies in empirical economics are used to illustrate how and how not to behave when replicatin...

Object Detection is the task of identifying the existence of an object class instance and locating it within an image. Difficulties in handling high intra-class variations constitute major obstacles to achieving high performance on standard benchmark datasets (scale, viewpoint, lighting conditions and orientation variations provide good examples). Suggested model aims at providing more robustne...

Cardiovascular disease (CVD), associated with vascular atherosclerosis, is the major cause of death in Western societies. Current risk estimation tools, such as Framingham Risk Score (FRS), based on evaluation of multiple standard risk factors, are limited in assessment of individual risk. The majority (about 70%) of the general population is classified as low FRS where the individual risk for ...

| Recent work 1] has demonstrated the GBR ambiguity which is inherent in the perception of depth from shading and shadow cues. The purpose of this paper is rstly to extend the GBR transform to allow for diierent viewpoints. We demonstrate how this can be done by using image warping. This enables us to generalize the GBR to deal with situations where objects are viewed from diierent viewpoints (...

System engineering often states that respecting diversity during the upstream stages of a system designing is an unavoidable feature of the designing process. In the field of Information Systems, the ability to evolve is a pivotal quality of its computer aided components. A framework is presented to view an Information System as a designing place where viewpoints interact with each other on obj...

In this paper we present the geometry and the algorithms for organizing a viewer-centered representation of the occluding contour of polyhedra. The contour is computed from a polyhedral boundary model as it would appear under orthographic projection into the image plane from every viewpoint on the view sphere. Using this representation , we show how to derive constraints on regions in viewpoint...

This is a survey on our work generalizing the classical Dehn-Sommerville equations (analogous to Poincaré duality, see [10]) for f -vectors of triangulations of manifolds without boundary to general polyhedra. Our key observation is that the exact data needed for the generalization is the classification of points of polyhedra by the Euler characteristics of their links. From this viewpoint, a p...

This study assesses the role of the human medial temporal lobe (MTL) structures in the coordination of spatial information across perspective change and, in particular, in visual perspective taking--namely the capacity to know what another individual is seeing on the visual scene. Fourteen patients with unilateral temporal lobe resection and 21 control subjects performed two tasks, called 'obje...