In previous attempts to record holograms of incoherent objects, the fringe contrast has been quite low, often barely exceeding the photographic grain noise. A method is presented which improves the fringe contrast by allowing only a limited number of object points to contribute to any local fringe pattern in the hologram. The number of object points is reduced by taking the holographic transformation in only one direction while imaging the object onto the hologram plane in the orthogonal direction, using an astigmatic lens system. An interferometric device divides the wavefront and inverts one leg about a line in the imaging direction. The interference patterns from corresponding points are then incoherently superimposed on the hologram. Some experimental results are shown. The objects were illuminated with spatially incoherent light; a rotating diffuser was introduced in a laser beam.
O. BRYNGDAHL and A. LOHMANN, "One-Dimensional Holography with Spatially Incoherent Light," J. Opt. Soc. Am. 58, 625-625 (1968)