The University of Edinburgh -
Division of Informatics
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PhD Thesis #9607

Title:An Analysis of the Inspection of Mechanical Parts Using Dense Range Data
Authors:Bispo,EM
Date: 1996
Presented:
Keywords:
Abstract:More than ever, efficiency and quality are key words in modern industry.This situation enhances the importance of quality control and creates agreat demand for cheap and reliable automatic inspection systems. Takinginto account these facts and the demand for systems able to inspect thefinal shape of machined parts, we decided to investigate the viability ofautomatic model-based inspection of mechanical parts using the dense rangedata produced by laser stripers.Given a part to be inspected and a corresponding model of the part stored inthe model data base, the first step of inspecting the part is theacquisition of data corresponding to the part, in our case this means theacquisition of a range image of it. In order to be able to compare the part image and its stored model, it is necessary to align the model with the range image of the part. This process, called registration, corresponds to finding the rigid transformation that superposes model and image. After the image and model are registered, the actual inspection uses the range image to verify if all the features predicted in the model are present and have the right pose and dimensions. Therefore, besides the acquisition of range images, the inspection of machined parts involves three main issues: modelling, registration and inspection diagnosis.The application for inspection purposes of the main representational schemes for modelling solid objects is discussed and it is suggested the use of EDT models (see [Zeid 91]). A particular implementation of EDT models is presented.A novel approach for the verification of tolerances during the inspection is proposed. The approach allows not only the inspection of the most common tolerances described in the tolerancing standards, but also the inspection of tolerances defined according to Requicha's theory of tolerancing (see[Requicha 83])
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