Automatic Pose Generation for Robotic 3-D Scanning of Mechanical Parts

Abstract

In this article, we present an automatic pose generation approach for robotic 3-D scanning systems designed for the reverse engineering of mechanical parts. 3-D scanning of an object is usually a highly complicated process that involves aligning multiple measurements from different viewpoints, fusing the merged data, and finally reconstructing the underlying surface. The reconstruction is often performed in isolation to the acquisition step. In contrast, the measured data often exhibit holes owing to limited viewpoints or noises in measurements, which can be observed after the postprocessing. Previous approaches either use the predefined scan paths without knowledge of the actual surface, or calculate the scan path based on the approximated smooth surface enclosing the incomplete scanned measurement. The need for an accurate 3-D scanning of mechanical parts often arises for reverse engineering purposes, as their shape often exhibits sharp corners or continuous shape of primitives (planes, cylinders, etc.), which the existing pipelines do not consider. We suggest a 3-D scan pipeline specifically designed to generate optimal scan paths of mechanical parts from incomplete data with limited fields of view. Our pipeline detects primitives from the scanned partial data, and utilizes the detection to approximate the underlying shape of the ground truth object; thus, it suggests the next-best-view of the scanner from the scarce measurements. In this regard, the suggested method is the first working pipeline specifically designed for scanning mechanical parts; furthermore, it outperforms previous approaches in terms of an efficient scan path generation.