Absolute optical contouring

The authors describe a method which represents a development of several optical contouring techniques. The authors choose to call it absolute contouring. By absolute range is meant the distance from the hologram or camera to a point in the field; as opposed to the distance between one contour fringe and the next. Absolute contouring is effected in real time by varying the contour depth of a system from infinity to some chosen value. During this continuous variation the intensity output trace is then processed to produce a value for absolute distance