Abstract: In order to determine the position and orientation of an object on a conveyor, two planes of light intersect at a single transverse line on the conveyor surface, the planes of light each being at an acute angle to the conveyor. A linear diode array aligned with the single line of light on the conveyor detects light from that line. An object on the conveyor moving through the line of light intercepts the light above the conveyor at positions spaced laterally from the line of light. The linear array senses only the line segments on the conveyor beyond the object boundaries. By electronic sampling of the illumination of the linear array, the object boundaries are determined and the object shape and orientation are thus detected.