Rapid and flexible calibration of DFPP using a dual-sight fusion target.

ABSTRACT

The parameter calibration of a digital fringe projection profilometry (DFPP) system is a fundamental step and directly related to 3D measurement accuracy. However, existing solutions based on geometric calibration (GC) suffer from the weakness of limited operability and practicality. In this Letter, a novel, to the best of our knowledge, dual-sight fusion target is designed for flexible calibration. The novelty of this target is the ability to directly characterize control rays for ideal pixels of the projector, and to transform the rays into the camera coordinate system, which replaces the traditional phase-shifting algorithm and avoids the error from the nonlinear response of the system. Attributed to the excellent position resolution of a position-sensitive detector within the target, the geometric relationship between the projector and camera can be easily established by projecting only one diamond pattern. Experimental results demonstrated that the proposed method using only 20 captured images is capable of achieving comparable calibration accuracy to the traditional GC method (20 images versus 1080 images, 0.052 pixels versus 0.047 pixels), which is suitable for rapidly and accurately calibrating the DFPP system in the 3D shape measurement field.