Conoscopic holography application: multipurpose rangefinders

Abstract

We present a new technology within the scope of distance measurements. It is based upon a particularly rugged holography technique using incoherent light. Unlike the triangulation technique, it resorts to a wavefront reconstruction and thus a limited on-axis optical aperture. These probes enter fields from metres down to nanometres (3D microscopy). They can be conveniently coupled to optical scanners, video cameras, colorimeters, etc. They can access places which are unreachable using conventional techniques and can measure surfaces with up to an angle. Multipurpose rangefinders with a 1/4000 point precision are starting to be manufactured in series for in-line inspection and 3D digitzation.