An active vision sensor system employing adaptive digital fringe pattern generated by SLM pattern projector

Abstract

Nowadays, many kinds of fringe projection method for 3D depth measurements have been researched such as moire method, optical triangulation method and so on. Generally speaking these methods uses the regular vertical fringe pattern. However, by using regular vertical fringe pattern, the shape measurement results especially for symmetric objects are not accurate, because the vertical fringe pattern cannot present the shape of various objects well. In this paper to solve this problem, we introduce a new sensing methodology based on object-adapted fringe projection method. To make a flexible object-adapted fringe pattern we used the projector with spatial light modulator (SLM). Our algorithm mainly consists of three parts. The first part is to generate an object-adapted fringe pattern by applying the moire technique. The second part is image projection of moire image to the projector plane. The final part is to find an absolute depth value of the object by using the optical triangulation method. To verify the performance of our proposed sensing system we conducted a series of experiments for various simple objects. The result shows the feasibility of successful perception for some objects treated herein.