Abstract: The three-dimensional position of a hole through a workpiece is determined using back lighting or front lighting (feature lighting) to determine the centroid of the hole's image in two-dimensional computer memory image space. The centroid determines a line of sight between the center of the hole's image and the actual center of the hole in real space. Next a crosshair lighting pattern (structured lighting) is projected onto the plane of the workpiece in the neighborhood of the hole. From the reflected crosshair pattern an equation representing the plane containing the hole is determined in image space. The intersection of the plane equation and the line of sight is computed and the three-dimensional, real space position of the hole is determined for comparision with an ideal position established during calibration.
Abstract: A three-dimensional triangulation-type sensor-illumination system adapted for connection to a machine vision computer. The illumination source in the preferred system comprises a unique cross hair light pattern which provides sufficient image data to the computer to enable the computer to make three-dimensional measurements of a wide variety of features, including edges, corners, holes, studs, designated portions of a surface and intersections of surfaces. The illumination source and sensor are both mounted within a single housing in a specific position and orientation relative to one another, thereby permitting the system to be internally calibrated. In addition, the sensor-illuminator unit is preferably mounted in a test fixture so that the light source is substantially normal to the surface of the part to be examined and the sensor is thereby positioned at a perspective angle relative thereto.
September 1, 1983
Date of Patent:
February 24, 1987
Robert Dewar, Jeremy Salinger, Thomas J. Waldecker, Neil E. Barlow
Abstract: Apparatus for optically checking both the gap between two adjacent parts such as the hood-to-fender fit of a vehicle and the surface flushness of the parts employs a hand-held fixture which is adapted to engage edges of the part in order to orient the fixture in a preselected position relative to the gap. A laser and related optical system mounted on the fixture directs a line of collimated light onto the parts and across the gap. The optical system and a television camera on the fixture pick up light reflected from the parts surfaces and generate an image using the triangulation technique which contains measurement information relating to the size of the gap and the degree of surface flushness. A computerized controller converts the image to measurement data that is displayed on a CRT. The control system is used in a part fitting method to select and display the identity of any of a plurality of shims which on an assembly person may employ to create proper fit between the parts.