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A study of surface geometry via projection orthogonal: Koenderink's theorem and extensions

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Author(s):
Mateus Pereira Araujo
Total Authors: 1
Document type: Master's Dissertation
Press: São José do Rio Preto. 2022-01-28.
Institution: Universidade Estadual Paulista (Unesp). Instituto de Biociências Letras e Ciências Exatas. São José do Rio Preto
Defense date:
Advisor: Luciana de Fátima Martins
Abstract

Let M be a surface in R³ and consider the orthogonal projection of its points on a plane along a direction v. This map is singular when v is a tangent direction to M and is important to classify the type of contact between M and lines parallel to v. The singular set of the orthogonal projection restricted to M is called contour generator and its projection is called apparent contour. We gather in this work results about orthogonal projections of regular and singular surfaces in R³ . We study the classification of its singularities and we relate the singularity classes to differential geometry of M, when M is a regular surface or a cuspidal edge. Koenderink’s Theorem is a result that relates the Gaussian curvature of M with the curvatures of the normal section of M along the direction v and of the apparent contour, when this is regular. We present the proof of this theorem and also study extensions of this result considering apparent contours with (2,3)-cusps. We also studied a version of this result when M is a singular surface, namely a cuspidal edge. (AU)

FAPESP's process: 19/19714-0 - Apparent contour of surfaces in R3 and extensions of Koenderink's formula
Grantee:Mateus Pereira Araujo
Support Opportunities: Scholarships in Brazil - Master