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Exact Shape from Shading and Integrability
1992We propose a new method for solving the image irradiance equation for the reconstruction of shape from shading. This partial differential equation is reduced to a nonlinear algebraic equation if the surface is represented in gradient space. Since the solution in gradient space is underconstrained, we enforce the integrability of the computed vector ...
Bert Janfeld, Hanspeter A. Mallot
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A fast linear shape from shading
Proceedings 1992 IEEE Computer Society Conference on Computer Vision and Pattern Recognition, 2003A method for computing depth from a single shaded image is presented. Discrete approximations for p and q using finite differences are used, and the reflectance in Z/sub ij/ is linearized. The method is faster, since each operation is purely local. In addition, it gives good results for spherical surfaces, in contrast to other linear methods. >
Tsai, P. S., Shah, M.
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2004
One of the earliest problems in computer vision is the “shape from shading problem” [87, 89, 88]. The question is how to reconstruct the shape of a smooth “Lambertian” object from a given single gray-level image. Excluding interreflections and specularities, the shading image of a Lambertian object is a function of the projection of the surface normal ...
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One of the earliest problems in computer vision is the “shape from shading problem” [87, 89, 88]. The question is how to reconstruct the shape of a smooth “Lambertian” object from a given single gray-level image. Excluding interreflections and specularities, the shading image of a Lambertian object is a function of the projection of the surface normal ...
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Perception of solid shape from shading
Biological Cybernetics, 1986Observers judged the slants and tilts of numerous regions within shaded images of ellipsoid surfaces that varied in shape, orientation, surface reflectance, and direction of illumination. The perceived three-dimensional structure of each surface was calculated from these judgments.
E, Mingolla, J T, Todd
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Perceptual Grouping in Shape from Shading
Perception, 2004We report on the reversal of asymmetry in visual-search tasks with shaded items. Previous studies have suggested that the target of a bottom-lit disk among distractors of top-lit disks is detected in a rapid and parallel manner, but not vice versa. However, in this study, we have shown that the compound items of top-lit disks were searched more quickly
Takahiro, Kawabe, Kayo, Miura
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Uniqueness in Shape from Shading Revisited
Journal of Mathematical Imaging and Vision, 1997<p>We analyse the problem of representing solutions of first-order partial differential equations in terms of complete integrals and envelopes. In this context, we revisit the uniqueness results already existing in the shape-from-shading literature that concern eikonal equations corresponding to the images of a Lambertian hemi-sphere and ...
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Invariants for recovering shape from shading
1994The image formed by shading depends on many variables, including the shape of the object, the lighting characteristics, the imaging system, etc. Most of these variables are not known in advance, so the calculation of shape from shading is difficult. The problem could be greatly simplified if we could find invariants of the situation, namely quantities ...
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