Rapid in-situ accuracy evaluation and exposure optimization method for fringe projection profilometry

Abstract

Fringe projection profilometry (FPP) has become one of the most powerful techniques for three-dimensional (3D) non-contact measurement. However, in practical scenarios, the various reflectivity of the unknown measured objects often greatly makes the system unable to achieve the theoretical precision under the same system parameter settings. Therefore, the adaptively system parameter setting is essential to be developed. In this paper, we propose a novel metric model, i.e. the accuracy quality function, for initial accuracy evaluation using in-situ acquired images under the current parameter settings. The causes that potentially affects the ultimate accuracy are analyzed via theoretical derivation and further adopted within the evaluation model. In addition, an optimal exposure selection method based just two images is carried out to fast adjusting. Experimental results demonstrated that the proposed accuracy quality model aligns well with the actual condition. Under optimal exposure, it achieved a significant reduction in phase error by 36.15% and by 21.39% in low- and high- exposure, highlighting its strong performance and potential for high-accuracy and in-situ 3D shape measurement applications.