Calibration of the Stripe Projecting 3D-Measurement System

With various stripe projecting 3D-measurement methods, e.g. coded light approach, phase-shift method and Moiré method, the projector needs to be precalibrated, since the projector parameters are directly involved in the object point determination. If we like to make use of the camera model and calibration algorithm also for the projector, the projector must image the target points field, despite it having no sensing ability. Consequently, we need a special operation method, the virtual imaging. A regular grid pattern will be projected onto the target surface, and each projected quadrangle on the target surface can be regarded as the projection of a single virtual pixel of the projector image plane. Thus, if we locate a target center within the projected grid pattern, it may be said that the projector has imaged the target center.