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Grant number: 13/21647-2
Support Opportunities:Scholarships in Brazil - Doctorate
Effective date (Start): May 01, 2014
Effective date (End): April 30, 2016
Field of knowledge:Physical Sciences and Mathematics - Geosciences
Principal Investigator:Aluir Porfírio Dal Poz
Grantee:Henrique Cândido de Oliveira
Host Institution: Faculdade de Ciências e Tecnologia (FCT). Universidade Estadual Paulista (UNESP). Campus de Presidente Prudente. Presidente Prudente , SP, Brazil
Associated scholarship(s):14/15332-1 - The use of laser data for occlusion determination using height gradient from a polyhedral surface, for true orthophoto generation, BE.EP.DR


The usage of spatial information is found from a simple pedestrian walk using his mobile phone up to surveying locations on big engineering projects. Cartographic products (maps) need a high level of accuracy and precision, depending on the application. There are various ways to create a map and one is by the science of extracting qualitative and quantitative information from photographs, most of the time from aerial photos (photogrammetry). One of the products created by the photogrammetry is the orthophoto. This product has a single scale allowing the use of its content as if it was a map, with no distortions due to relief displacement. However, in urban areas where there are a great many high buildings, aerial photographs may have some surface portions occluded by the buildings (occlusions areas), depending on the point of view from which they are taken. Due this problem, the need for a new product arose - the true-orthophoto. This product includes all features above the surface, such as buildings and bridges, in orthogonal projection, without hiding other information such as streets, property boundaries, parks, etc. The main aim of this project is to propose a new method for occlusion detection using LASER data, together with high resolution aerial images. This new approach uses height gradient calculated from a polyhedric surface (TIN obtained from LASER data) for the identification of occlusion areas instead of interpolated regular grids or digital building model (DBM), as can be found in the literature. Surface representation using a polyhedric shape avoids interpolation problems and does not need a DBM related to all the buildings in the image.

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Scientific publications
(References retrieved automatically from Web of Science and SciELO through information on FAPESP grants and their corresponding numbers as mentioned in the publications by the authors)
DE OLIVEIRA, HENRIQUE CANDIDO; GALO, MAURICIO; DAL POZ, ALUIR PORFIRIO. Height-Gradient-Based Method for Occlusion Detection in True Orthophoto Generation. IEEE Geoscience and Remote Sensing Letters, v. 12, n. 11, p. 2222-2226, . (13/21647-2)
DE OLIVEIRA, HENRIQUE CANDIDO; DAL POZ, ALUIR PORFIRIO; GALO, MAURICIO; HABIB, AYMAN FAWZY. Surface Gradient Approach for Occlusion Detection Based on Triangulated Irregular Network for True Orthophoto Generation. IEEE JOURNAL OF SELECTED TOPICS IN APPLIED EARTH OBSERVATIONS AND REMOTE SENSING, v. 11, n. 2, p. 443-457, . (13/21647-2, 14/15332-1)
Academic Publications
(References retrieved automatically from State of São Paulo Research Institutions)
OLIVEIRA, Henrique Cândido de. Occlusion detection by surface-gradient-based method for true-orthophoto generation. 2016. Doctoral Thesis - Universidade Estadual Paulista (Unesp). Faculdade de Ciências e Tecnologia. Presidente Prudente Presidente Prudente.

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