Structured light stereo catadioptric scanner based on a spherical mirror. (August 2018) - Barone, S.
Highlights: An omnidirectional structured light stereo catadioptric scanner is presented. The catadioptric arrangement is based on a spherical mirror. An analytical solution for forward and backward reflection is proposed. A sensitivity analysis to different error sources on 3D reconstruction is provided. An experimental validation is carried out by using primitive shapes. Abstract: The present paper describes the development and characterization of a structured light stereo catadioptric scanner for the omnidirectional reconstruction of internal surfaces. The proposed approach integrates two digital cameras, a multimedia projector and a spherical mirror, which is used to project the structured light patterns generated by the light emitter and, at the same time, to reflect into the cameras the modulated fringe patterns diffused from the target surface. The adopted optical setup defines a non-central catadioptric system, thus relaxing any geometrical constraint in the relative placement between optical devices. An analytical solution for the reflection on a spherical surface is proposed with the aim at modelling forward and backward projection tasks for a non-central catadioptric setup. The feasibility of the proposed active catadioptric scanner has been verified by reconstructing various target surfaces. Results demonstrated a great influence of the target surface distance from the mirror's centre on the measurement accuracy. The adopted optical configuration allows the definition of a metrological 3D scanner for surfaces disposed within 120 mm from the mirror centre.