In-line quality control utilizing close-range photogrammetry and a CAD-model

Abstract

Abstract This paper presents an overview of a measurement system that is designed for in-line shape inspection of metal sheet components in real-time utilizing pre-calibrated close-range photogrammetry and a CAD-model. The system is currently designed to measure parts thrown out on a conveyor belt that moves at about 1 m s−1 at a frequency of 0.5 Hz or less without fixturing. Detected features on the components in the camera images are used to align the CAD-model, describing the nominal shape, to the images from which required deviations are computed using photogrammetry. The measurement volume of the current system is 500 × 800 × 200 mm3 and absolute measurements are performed with an accuracy in the order of 0.1 mm. The in-line functionalities of the system have been verified at several real production sites in Sweden. In this paper, the basic components of the system are described together with a few results from real tests.