Path planning of multi-patched freeform surfaces for laser scanning

In this paper, a new method for scanning a complex surface model with multiple patches is proposed. In scanning of freeform-shaped models, it is difficult to generate a measuring plan by human intuition due to the complexity of the part. The developed method calculates the number of scans, scan direction, and scan path for a stripe-type laser scanner. The user can designate the surface patches that need to be scanned. In generating the scan plan, surface information is first extracted from the CAD model automatically. Other information such as, design knowledge, functionality and machine parameters are provided interactively. Based on this information, the original surface model is sampled in the u, v parameter domain and the sampled points are grouped using the view angle of the laser scanner. The scan direction is determined by calculating the global mean vector of the sampled points that belong to a group. The range of the view angle can be varied to enhance the quality of captured point data. The optical scan paths for each scan direction are calculated by projecting the sampled points onto a 2D plane. The optical constraints are also verified to guarantee the generated scan plan.