CAD-based View Planning with Globally Consistent Registration for Robotic Inspection

In robotic 3D inspection systems, it is essential to obtain precise measurement results by covering the entire surface area of the target objects. To this end, various view planning methods have been proposed to guarantee complete coverage in order to ensure precise measurements of the target object. However, for precise inspection, in addition to the coverage of the object, globally consistent registration should also be considered. If the target object has a complex shape, occlusions may occur and registration often fails. Therefore, this study proposes a computer-aided design-based automatic inspection system that simultaneously guarantees both the coverage and globally consistent registration model for objects with complex shapes. To this end, view planning that covers all areas of the complex-shaped objects without occlusions and guarantees globally consistent registration is proposed. Experiments were performed on a piston head, casting mold for a smartphone case, and gear; these objects were inspected using an error map and a quantitative error report. Experimental results show that complex-shaped objects can be successfully inspected without unscanned areas and registration failure by using the proposed method.