CAD-based range sensor placement for optimum 3D data acquisition

The use of laser range sensor allows a very significant improvement in acquisition speed but does not equal the accuracy obtained with a coordinate measuring machine. In order to obtain a quality control close to that obtained in metrology we suggest improving the accuracy of the depth measurements by positioning the sensor's head according to a strategy for optimum 3D data acquisition. We propose such a strategy to automatically produce a sensing plan for completely and accurately acquiring the geometry of a surface or of the whole piece whenever possible. The system requires the exact position and orientation of the part and its CAD model in IGES format. There is no limitation regarding the shape of the part to be digitized. An auto-synchronized range sensor developed at the NRCC was used, and for this sensor, the accuracy of the 3D measured points is a function of the distance and of the incident angle relative to the surface. Our strategy guarantees that the viewpoints found meet the best accuracy conditions in the scanning process.