Abstract: Automatic equipment, in which each of a plurality of identical devices is positioned automatically to co-operate with processing means and/or test probes, has a TV camera considered as being arranged to move in a raster scan over each device, and to provide signals in response to detecting boundaries of an orthogonal pattern of device features. Initially, with a unique pattern of feature boundaries having been determined, and possibly by reference to the representation, provided by a display unit driven by the camera, of a manually, accurately, located device, there is caused to be generated, in each frame scan period, pairs of signals, individually corresponding to, and representative of a defined location for, a determined feature boundary, each signal representing a marker boundary as if detected by the camera.