PART SURFACES 3D DIGITISING: An approach to accurate characteristic lines measurements

摘要

The accurate measurement of characteristic lines using contact-less sensors is an important issue for it conditions the further point exploitation. For applications such as surface reconstruction the characteristic lines represent the 3D boundaries of point sets that can be fitted with surface models. The problem combines two specific issues: evaluating the accuracy of data obtained using non-contact sensors and identifying characteristic lines from discrete data. The first problem is solved through the use of quality indicators that are representative of data density, data completeness, and data accuracy. A particular attention is given to the digitising noise that greatly influences the precision of the acquired points. The second problem is solved through the 2D identification of points that are characteristic of 3D contours. The proposed approach relies on a voxel-space representation of the 3D digitised data that allows both the extraction of voxels belonging to the contour and the evaluation of voxels not satisfying the specified index precision. To improve data accuracy a method for rescanning non-accurate zones is detailed on the calculation of new sensor orientations so that the sensor is as normal as possible to the contour voxel and the digitising noise is limited.