Results 1  10
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2,703
From Few to many: Illumination cone models for face recognition under variable lighting and pose
 IEEE Transactions on Pattern Analysis and Machine Intelligence
, 2001
"... We present a generative appearancebased method for recognizing human faces under variation in lighting and viewpoint. Our method exploits the fact that the set of images of an object in fixed pose, but under all possible illumination conditions, is a convex cone in the space of images. Using a smal ..."
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Cited by 754 (12 self)
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conditions. The pose space is then sampled, and for each pose the corresponding illumination cone is approximated by a lowdimensional linear subspace whose basis vectors are estimated using the generative model. Our recognition algorithm assigns to a test image the identity of the closest approximated
Lightness and Retinex Theory
 JOURNAL OF THE OPTICAL SOCIETY OF AMERICA
, 1971
"... Sensations of color show a strong correlation with reflectance, even though the amount of visible light reaching the eye depends on the product of reflectance and illumination. The visual system must achieve this remarkable result by a scheme that does not measure flux. Such a scheme is described as ..."
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Cited by 497 (6 self)
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Sensations of color show a strong correlation with reflectance, even though the amount of visible light reaching the eye depends on the product of reflectance and illumination. The visual system must achieve this remarkable result by a scheme that does not measure flux. Such a scheme is described
Cones of matrices and setfunctions and 01 optimization
 SIAM JOURNAL ON OPTIMIZATION
, 1991
"... It has been recognized recently that to represent a polyhedron as the projection of a higher dimensional, but simpler, polyhedron, is a powerful tool in polyhedral combinatorics. We develop a general method to construct higherdimensional polyhedra (or, in some cases, convex sets) whose projection a ..."
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Cited by 347 (7 self)
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approximates the convex hull of 01 valued solutions of a system of linear inequalities. An important feature of these approximations is that one can optimize any linear objective function over them in polynomial time. In the special case of the vertex packing polytope, we obtain a sequence of systems
What is the Set of Images of an Object Under All Possible Lighting Conditions
 IEEE CVPR
, 1996
"... The appearance of a particular object depends on both the viewpoint from which it is observed and the light sources by which it is illuminated. If the appearance of two objects is never identical for any pose or lighting conditions, then in theory the objects can always be distinguished or recogni ..."
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Cited by 389 (25 self)
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pixel images of a convex object with a Lambertian reflectance function, illuminated by an arbitrary number of point light sources at infinity, forms a convex polyhedral cone in IR " and that the dimension of this illumination cone equals the number of distinct surface normals. Furthermore, we show
Practical conebeam algorithm
 J Opt Soc Am
, 1984
"... A convolutionbackprojection formula is deduced for direct reconstruction of a threedimensional density function from a set of twodimensional projections. The formula is approximate but has useful properties, including errors that are relatively small in many practical instances and a form that le ..."
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Cited by 308 (0 self)
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A convolutionbackprojection formula is deduced for direct reconstruction of a threedimensional density function from a set of twodimensional projections. The formula is approximate but has useful properties, including errors that are relatively small in many practical instances and a form
NonLinear Approximation of Reflectance Functions
, 1997
"... We introduce a new class of primitive functions with nonlinear parameters for representing light reflectance functions. The functions are reciprocal, energyconserving and expressive. They can capture important phenomena such as offspecular reflection, increasing reflectance and retroreflection. ..."
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Cited by 269 (10 self)
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in a scene, through direct illumination and global interreflection effects. Local r...
Illumination cones for recognition under variable lighting: Faces
 In Proc. IEEE Conf. on Comp. Vision and
, 1998
"... Due to illumination variability, the same object can appear dramatically di erent even when viewed in xed pose. To handle this variability, an object recognition system must employ a representation that is either invariant to, or models this variability. This paper presents an appearancebased metho ..."
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Cited by 115 (15 self)
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based method formodeling the variability due to illumination in the images of objects. The method di ers from past appearancebased methods, however, in that a small set of training images is used to generate a representation { the illumination cone { which models the complete set of images of an object
Heuristics for Integer Programming Using Surrogate Constraints
 Decision Sciences
, 1977
"... This paper proposes a class of surrogate constraint heuristics for obtaining approximate, 'near optimal solutions to integer programming problems. These heuris· tics are based on a simple framework that illuminates the character of several carlier heuristic proposals and provides a variety of n ..."
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Cited by 239 (37 self)
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This paper proposes a class of surrogate constraint heuristics for obtaining approximate, 'near optimal solutions to integer programming problems. These heuris· tics are based on a simple framework that illuminates the character of several carlier heuristic proposals and provides a variety
Allfrequency shadows using nonlinear wavelet lighting approximation
 ACM Transactions on Graphics
, 2003
"... We present a method, based on precomputed light transport, for realtime rendering of objects under allfrequency, timevarying illumination represented as a highresolution environment map. Current techniques are limited to small area lights, with sharp shadows, or large lowfrequency lights, with ..."
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Cited by 188 (25 self)
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We present a method, based on precomputed light transport, for realtime rendering of objects under allfrequency, timevarying illumination represented as a highresolution environment map. Current techniques are limited to small area lights, with sharp shadows, or large lowfrequency lights
Illumination
"... Accurately modeling and reproducing realworld materials ’ appearance are crucial for producing photorealistic imagery of digital scenes and subjects. The appearance of many common materials is due to subsurface light transport, which causes the characteristic “soft” appearance and the materials’ ..."
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’ unique coloring. To efficiently model isotropic subsurface light transport, Henrik Jensen and his colleagues introduced the dipolediffusion approximation1 (see the “Diffusion Models ” and “Related Work ” sidebars). The scattering parameters needed to drive this approximation are typically esti
Results 1  10
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2,703