Projected fringe profilometry of a high speed moving object using a time delay and integration imaging

Abstract

A novel technique is presented for measurement of surface profile, dynamic inspection of surface quality and nondestructive detection of a motion object at highly constant speed in this paper. In practice, a sinusoidal grating pattern with a common LCD projector is projected onto a moving object. Then, grating patterns which are deformed according to the object shape are acquired by a CCD camera operating in time delay and integration (TDI) mode. When the charges in TDI camera are shifted row by row at a specified speed which is the same as the object speed, a clear and bright image is easily obtained. Because of this advantage in the application of TDI camera, it is proved to be an effective and straightforward approach to avoid blurred image in high speed 3D projection grating patterns profilometry. In our experiment, Fourier transform algorithm is used for projected fringe profilometry. Upon that, absolute 3D surface profile is perfectly achieved. Finally, several factors which will induce measurement errors are respectively discussed, such as the speed disharmony between the object and TDI charges transfer and orientation disorder between the fringe pattern and motion object.