Pre-Processing of Point-Data from Contact and Optical 3D Digitization Sensors

Igor Budak,Mirko Soković,Drago Bračun,Djordje Vukelić,Janko Hodolič

doi:10.3390/s120101100

Igor Budak, Mirko Soković + Show 3 more

Open Access

https://doi.org/10.3390/s120101100

Copy DOI

Abstract

Contemporary 3D digitization systems employed by reverse engineering (RE) feature ever-growing scanning speeds with the ability to generate large quantity of points in a unit of time. Although advantageous for the quality and efficiency of RE modelling, the huge number of point datas can turn into a serious practical problem, later on, when the CAD model is generated. In addition, 3D digitization processes are very often plagued by measuring errors, which can be attributed to the very nature of measuring systems, various characteristics of the digitized objects and subjective errors by the operator, which also contribute to problems in the CAD model generation process. This paper presents an integral system for the pre-processing of point data, i.e., filtering, smoothing and reduction, based on a cross-sectional RE approach. In the course of the proposed system development, major emphasis was placed on the module for point data reduction, which was designed according to a novel approach with integrated deviation analysis and fuzzy logic reasoning. The developed system was verified through its application on three case studies, on point data from objects of versatile geometries obtained by contact and laser 3D digitization systems. The obtained results demonstrate the effectiveness of the system.

Highlights

Engineering (RE) an extremely popular technique, to the point of being practically indispensable in some design problems
The 3D digitization process is very often plagued by measuring errors, which can be attributed to the very nature of measuring systems, various characteristics of the digitized objects and subjective errors by the operator, which contribute to problems in the CAD model generation process [12,13,14,15]
Building on the weak spots and deficiencies of current approaches to reduction of point data by sampling methods—i.e., the lack of information on the level of deviation in reduced point clouds and necessity to employ parameters which are abstract to user—a novel approach was developed for analysis of the level of deviation of the reduced point cloud in comparison with the initial point cloud

Summary

Introduction

Engineering (RE) an extremely popular technique, to the point of being practically indispensable in some design problems. The market today dictates sudden and frequent re-design of products with emphasis on aesthetic and ergonomic features, which, in turn, require the ever more complex organic forms and shapes. These are most often very difficult—sometimes even impossible—to model using conventional CAD tools, which is why they first have to be modelled by sculpting (using clay, plaster, wood, etc.), and subsequently translated into CAD models using RE [1,2,3,4,5]. The huge number of point data, generated in the course of 3D digitization, can become a serious practical problem, later on, when the CAD model is generated. The 3D digitization process is very often plagued by measuring errors, which can be attributed to the very nature of measuring systems, various characteristics of the digitized objects and subjective errors by the operator, which contribute to problems in the CAD model generation process [12,13,14,15]

Objectives

Results

Discussion

Conclusion