A novel method of generating phase-shifting sinusoidal fringes for 3D shape measurement

Abstract

In this paper, a new generating technique of sinusoidal fringes for 3D shape measurement is presented. Specifically, a sinusoidal fringe is generated by expanding the inverted image of a filled binary sinusoidal pattern in a specified direction, and further, the phase shift is realized by switching the backlight sources of a set of sinusoidal patterns. In theory, sinusoidal fringes can be formed whether the projection is focused or defocused. Moreover, the technique has the potential for high frame rates due to the way the phase shift is performed. In particular, since the high shape precision of the binary sinusoidal pattern and the high accuracy of the phase shift can be easily realized by the photolithography process, the technique is very easy to implement.