Automated laser scanning based on orthogonal cross sections

To reversely engineer a clay model or industrial part, a laser scanner is often used to acquire surface data points, which must be processed to created a CAD model. Complete surface definition requires an operator to obtain a number of scans from various viewpoints and orientations. This introduces two difficulties to the reverse-engineering process: (1) the data are difficult to visualize, as scan lines appear at various angles, and (2) the surface is irregularly sampled, with large regions sampled by several scans, and occasionally a small region is missed completely (a result of the visualization problem). We have developed an automated scanning system to overcome these problems. The system utilizes an intermediate data model that consists of three orthogonal cross sections and is built from the triangulated scan data. The resultant model is easily visualized, which facilitates further interactive operation on the data. The system has been successful in autonomously modeling several typical industrial objects.