Real-time 3D shape inspection system of automotive parts based on structured light pattern

Abstract

The non-contact 3D area sensor technology has achieved many successes in a variety of offline measurements. However, it has not been implemented for online measurement in the automotive production lines. The biggest challenge is the capability of simultaneously satisfying the efficiency, reliability, and accuracy requirements. For this purpose, a real-time 3D area sensor based on structured light pattern is proposed. To satisfy the requirement of online measurement, a one-shot pattern using monochromatic light is proposed. Compared with the previous patterns, this pattern is more robust because it can avoid the influence of the ambient light and the inspected part reflective property. Moreover, the requirement of the accuracy performance is achieved by the pattern primitive which is similar to the corner of the checkerboard since it can provide high accuracy performance even when the occlusion occurs; also, the pixel-to-pixel calibration strategy is utilized to increase the accuracy of the inspection system. Such a real-time shape measurement system has been successfully developed in our laboratory. Last, the evaluation experiments are conducted. The experiment results demonstrate the robustness and accuracy of the approach on automotive parts with different surface properties. © 2010 Elsevier Ltd. All rights reserved.