Real-time profiling of a pure phase object using an auto-Wigner distribution function

Abstract The reconstruction of a pure phase object is investigated on the basis of an auto-Wigner distribution function (AWDF). A cylindrical lens is used as a typical example of the pure phase object and its profile is successfully obtained in real time using its AWDF. The product of the object function and its conjugated one, which is necessary to yield the AWDF, was generated by a Brenner-Lohmann configuration. The Fourier transform of the product is made by a microcomputer without using the holographic method. This paper shows that this method realizes not only a real-time operation but also much improvement in measurement accuracy by thresholding the product obtained optically as the intensity distribution.