A vision system is described for depalletizing steel cylindrical billets for a forging application. An algorithm for accurately locating and measuring the billets is described in some detail. Highlights of this discussion include an algorithm for adaptive threshold selection to accommodate changing image brightnesses and a special robot calibration procedure that enables inference of depth using only a single camera view combined with prior knowledge about the scene. Experimental results show that the system provides accurate measurements in spite of poor, inconsistent contrast.
Arthur V. Forman, Jr.,
J. Ronald Clark,
"Robot Vision System For Depalletizing Steel Cylindrical Billets," Optical Engineering 25(3), 253402 (1 March 1986). https://doi.org/10.1117/12.7973837