Locating polyhedral features from sparse light-stripe data

A light-stripe vision system which quickly and accurately locates polyhedral part features is presented. An image of three line segments generated by the intersection of a plane of light and a polyhedral feature is used to localize the feature. Sufficient conditions for six degree-of-freedom positional constraint are discussed and the solution for determining the rigid transformation of a general polyhedral feature is presented. The accuracy of a prototype sensing system in locating a right corner feature is 0.1 degrees (1.5 milliradians) per standard deviation in rotation and 0.002 inches (0.055 mm) per standard deviation in translation. The time required for the measurements is 2.5 to 3 seconds. Much shorter times are also realizable.