Bitte benutzen Sie diese Referenz, um auf diese Ressource zu verweisen: doi:10.22028/D291-26499
Titel: Perspective shape from shading for Phong-type non-Lambertian surfaces
Verfasser: Breuß, Michael
Vogel, Oliver
Weickert, Joachim
Sprache: Englisch
Erscheinungsjahr: 2008
DDC-Sachgruppe: 510 Mathematik
Dokumentart : Preprint (Vorabdruck)
Kurzfassung: The shape-from-shading (SfS) problem in computer vision is to compute at hand of the shading variation in a given 2-D image the 3-D structure of depicted objects. We introduce an efficient numerical method for a new perspective SfS model for general non-Lambertian surfaces. First, the modelling process is given in detail. The model is based on the perspective model for Lambertian surfaces recently studied by Prados et al., which we extend by use of the Phong reflection model incorporating ambient, diffuse and specular components. The arising partial differential equation (PDE) is a non-linear time-independent Hamilton-Jacobi equation. In order to compute the sought viscosity supersolution of the PDE, we introduce an artificial time into the equation and solve for the steady state. Based on a multi-scale analysis of the PDE, we construct a fully explicit numerical method and elaborate on its stability. In order to achieve fast convergence of the resulting iterative scheme, a coarse-to-fine strategy combined with a sweeping technique is employed. Numerical experiments show the benefits of our approach: While computational times stay reasonable even for quite large images, a substantial qualitative gain can be achieved by use of the new model. Moreover, the computational technique is relatively easy to implement compared to other approaches in the field.
Link zu diesem Datensatz: urn:nbn:de:bsz:291-scidok-47460
Schriftenreihe: Preprint / Fachrichtung Mathematik, Universität des Saarlandes
Band: 216
SciDok-Publikation: 5-Jun-2013
Fakultät: MI - Fakultät für Mathematik und Informatik
Fachrichtung: MI - Mathematik
Fakultät / Institution:SciDok - Elektronische Dokumente der UdS

Dateien zu dieser Ressource:
Datei Beschreibung GrößeFormat 
preprint_216_08.pdf444,23 kBAdobe PDFÖffnen/Anzeigen

Alle Ressourcen in diesem Repository sind urheberrechtlich geschützt.