Using auxiliary mirrors for improved surface coverage in depth scanning

Abstract

Depth cameras have become an integral part of a wide range of applications, including industrial inspection, reverse engineering, human–robot collaboration, and biomechanical analysis. Their practical use, however, is limited by a narrow field of view and self-occlusions, which often prevent complete surface coverage of the scanned object. This paper introduces a methodology for systematically determining the optimal placement of a depth camera and an auxiliary planar mirror to maximize surface visibility. To this end, a simulation tool was developed that models camera rays, their reflections from the mirror, and their intersections with objects. The proposed method combines geometric visibility analysis with an optimization procedure that searches for configurations with maximum coverage. Validation was performed on a set of twenty objects ranging from simple geometric primitives to complex reference models. While a standalone camera achieved an average coverage of 51.68 %, the addition of a single planar mirror increased this value to 85.46 %, with complete coverage achieved for several objects. A complementary user study demonstrated that manually chosen configurations exhibit high variability and do not outperform the algorithmic design. The results confirm that the use of mirrors provides a cost-effective solution for overcoming occlusion-related limitations without resorting to multi-camera systems, and that the proposed methodology delivers consistent performance across diverse object geometries. The approach is particularly applicable in industrial inspection, robotic vision, and other domains where complete geometric information is essential.