Dimensional measurement of hot, large forgings with stereo vision structured light system

Non-contact dimensional measurements are desirable in several hot-working processes, such as hot forging processes. A dimensional measurement method, used to reduce scrap and waste during forming processes, is presented, based on a spectrum selective method and stereo vision structured light technique. Using the spectrum selective method, the image of the hot forging can be obtained without interference by self-emitted radiation. A coded single pattern is projected towards the hot forging to label characteristic lines, and simplify the process of finding correspondences between image pairs. The depth can be estimated by triangulation. An ellipse is fitted to the reconstructed 3D data for calculating the diameter of the forging. Experiments in a forging workshop are conducted to measure the diameters of round forgings. The results verify the effectiveness of the presented method.