Digitised point quality in relation with point exploitation

Abstract

This paper deals with the quality of digitised points obtained with noncontact probes. The digitising system is analysed so that each source of inaccuracy can be isolated. In particular, for systems such as triangulation laser sensors, the use of the CCD camera is not influence free, and generates nonhomogeneous errors. All sources of inaccuracy of the digitising system lead to a point cloud, the quality of which is described through indicators. These indicators correspond to the digitising noise and the density of the data. In addition to those usual indicators, we suggest qualifying the point cloud through completeness and accuracy. The completeness identifies the dimension of the digitising gaps, while the accuracy is associated with the measurement uncertainty of a 3D point. For each indicator, an evaluation method is presented and then applied. However, the use of those quality indicators only makes sense if they are related to the point exploitation.