Real-time and high precision 3D shape measurement method

In this paper, a unique 3D shape measurement method for measurement of nearly plain car body parts is proposed. The main advantage of the system is the high accuracy (about 0.1 mm), the high flexibility and the real-time processing. The primary application of the method is the 100% inspection of press formed car parts in the factory since in these cases the high accuracy and the real-time feature are indispensability. In order to achieve suitable measurement accuracy the camera specifications were carefully inspected. As result, a new type of gray-level marker and a new technique was proposed by the authors for compensating the time variability of marker central points in the camera images. In order to achieve real-time processing, the correspondence matching was devised. Furthermore, since the proposed method is based on processing camera images, i.e. the detection of feature-points on the target (such as screw holes) is also supported. The measured feature-points can easily be compared to CAE data.