ORCID Profile
0000-0003-4496-2028
Current Organisations
Beihang University
,
University of York
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Publisher: IEEE Comput. Soc
Date: 2001
Publisher: IEEE
Date: 2004
Publisher: Elsevier BV
Date: 03-2007
Publisher: IEEE
Date: 2004
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 07-2004
Abstract: In this paper, we explore how graph-spectral methods can be used to develop a new shape-from-shading algorithm. We characterize the field of surface normals using a weight matrix whose elements are computed from the sectional curvature between different image locations and penalize large changes in surface normal direction. Modeling the blocks of the weight matrix as distinct surface patches, we use a graph seriation method to find a surface integration path that maximizes the sum of curvature-dependent weights and that can be used for the purposes of height reconstruction. To smooth the reconstructed surface, we fit quadrics to the height data for each patch. The smoothed surface normal directions are updated ensuring compliance with Lambert's law. The processes of height recovery and surface normal adjustment are interleaved and iterated until a stable surface is obtained. We provide results on synthetic and real-world imagery.
Publisher: Elsevier BV
Date: 11-2005
Publisher: IGI Global
Date: 2013
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 2020
Publisher: Elsevier BV
Date: 12-2023
Publisher: Elsevier BV
Date: 08-2002
Publisher: Elsevier BV
Date: 08-2002
Publisher: IEEE
Date: 2004
Publisher: Elsevier BV
Date: 03-2018
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 2007
Abstract: This paper offers two new directions to shape-from-shading, namely the use of the heat equation to smooth the field of surface normals and the recovery of surface height using a low-dimensional embedding. Turning our attention to the first of these contributions, we pose the problem of surface normal recovery as that of solving the steady state heat equation subject to the hard constraint that Lambert's law is satisfied. We perform our analysis on a plane perpendicular to the light source direction, where the z component of the surface normal is equal to the normalized image brightness. The x - y or azimuthal component of the surface normal is found by computing the gradient of a scalar field that evolves with time subject to the heat equation. We solve the heat equation for the scalar potential and, hence, recover the azimuthal component of the surface normal from the average image brightness, making use of a simple finite difference method. The second contribution is to pose the problem of recovering the surface height function as that of embedding the field of surface normals on a manifold so as to preserve the pattern of surface height differences and the lattice footprint of the surface normals. We experiment with the resulting method on a variety of real-world image data, where it produces qualitatively good reconstructed surfaces.
Publisher: Elsevier BV
Date: 07-2019
Publisher: IEEE
Date: 06-2010
Publisher: Springer Science and Business Media LLC
Date: 15-06-2006
Publisher: IEEE
Date: 2004
Publisher: Elsevier BV
Date: 08-2005
Publisher: IEEE
Date: 2004
Publisher: Springer International Publishing
Date: 2018
Publisher: Elsevier BV
Date: 06-2019
Publisher: Springer Science and Business Media LLC
Date: 29-06-2012
Location: United Kingdom of Great Britain and Northern Ireland
Location: United Kingdom of Great Britain and Northern Ireland
Location: United Kingdom of Great Britain and Northern Ireland
Location: United Kingdom of Great Britain and Northern Ireland
Location: United Kingdom of Great Britain and Northern Ireland
Location: United Kingdom of Great Britain and Northern Ireland
No related grants have been discovered for Edwin Hancock.