Automatic delineation of buildings in a MDS using the level set method

• Grant number: 14/27265-7
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: June 01, 2015
• End date: May 31, 2017
• Field of knowledge: Physical Sciences and Mathematics - Geosciences - Geodesy
• Principal Investigator: Aluir Porfírio Dal Poz
• Grantee: Melina Brunelli Nunes
• Host Institution: Faculdade de Ciências e Tecnologia (FCT). Universidade Estadual Paulista (UNESP). Campus de Presidente Prudente. Presidente Prudente , SP, Brazil

Abstract

In this research project a method is proposed for the delineation of buildings in airborne laser scanning (ALS) data, using a non-parametric active contour that is known as level set. This method is based on four main steps. In the first step an ALS point cloud is filtered and classified, allowing the selection of only points belonging to the terrain and buildings. In the second step, points classified as belonging to buildings are firstly set to a constant orthometric height, allowing the flattening of the building tops. This preprocessing is necessary for avoiding the extraction of multiple contours for a same building. Points belonging to the terrain and flattened building tops are then merged into a same point cloud. In the third step of the method the resulting point cloud is transformed into a gridded digital surface model (DSM), composed by points representing the terrain and regularized building tops. The DSM generation requires an appropriated interpolation method. In the last step of the method the level set method is used to automatically determine polylines that represent respective contours of buildings in the MDS.