Methods for Fitting CSG Models to Point Clouds and their Comparison T.Rabbani t.rabbani@citg.tudelft.nl May 14, 2019 Section of Photogrammetry and Remote Sensing Faculty of Aerospace Engineering
CSG Fitting – Why and How? Library of CAD models is useful for industrial scenes CSG is a compact and flexible representation scheme Main problem: Calculation of distance of a point from estimated model surface and its partial derivatives Three methods are compared: ICS (Iterative Closest Surface-point) ICT (Iterative Closest Triangle-point) ICP (Iterative Closest Pointcloud-point) May 14, 2019
Application Domain – Industrial Reconstruction May 14, 2019
Traditional vs CSG Fitting Traditional Approach Scans Segmentation Fitting Editing CAD B-rep Object knowledge CSG Fitting CSG Fitting CAD CSG Object knowledge Scans Segmentation May 14, 2019
Traditional Fitting (Example) May 14, 2019
CSG Fitting (Example) May 14, 2019
Constructive Solid Geometry (CSG) CSG tree: primitives, constraints, operations Flanged T-junction May 14, 2019
Three distance approximations May 14, 2019
Before fitting May 14, 2019
Iterative Closest Surface-point (ICS) May 14, 2019
Iterative Closest Triangle-point (ICT) May 14, 2019
Iterative Closest Point-cloud-point (ICP) May 14, 2019
Fitting – Problem Formulation = shortest distance of a given point from May 14, 2019
Fitting method May 14, 2019
Finite difference approximation of partial derivatives May 14, 2019
Example 1 – Before Fitting May 14, 2019
Example 1 – After ICS May 14, 2019
Example 1 – After ICT May 14, 2019
Example 1 – After ICP May 14, 2019
Example 2 – Before Fitting May 14, 2019
Example 2 – After ICS May 14, 2019
Example 2 – After ICT May 14, 2019
Example 2 – After ICP May 14, 2019
Comparison May 14, 2019
Future: Combined Fitting May 14, 2019
Future plans: Automatic object recognition using a library of CSG objects Combined fitting using images and point clouds May 14, 2019
Questions: May 14, 2019