Method of and apparatus for the positional detection of objects

摘要

A holographic technique for the detection of position of known items so as to be able to reject those samples which do not lie within certain defined spatial parameters. A plate which contains a single exposure of the three dimensional holographic image of an object is illuminated by parallel reference beams from a laser to allow the reconstruction of a real focused image of the object. A displacement translator supports the object and permits displacement thereof in three directions all at right angles to one another. The coincidence of the object and its holographic image are detected either optically by means of a stereoscopic microscope, or electrically by means of a stereoscopic microscope and a photo-diode.