Saginaw Valley State University

University of Michigan

Hsuan S Chen

David S Dilworth

Gregory A Wright

Janis A Valdmanis

Joaquin L Lopez

Emmett N Leith

Ye Chen

A method and apparatus for making a holographic shadowgram of an object are disclosed. The method and apparatus include a light source for generating and expanding a coherent light beam. The method and apparatus also include a reflector for reflecting the coherent light beam to simultaneously produce a diffuse object beam and a coherent reference beam such that differential vibration between the object and reference beams is substantially eliminated, and for illuminating the object with the object beam and creating an interference pattern between the object and reference beams. The method and apparatus further include a recorder for recording the interference pattern to produce the holographic shadowgram.

Method and apparatus for producing a holographic shadowgram

An image of an object embedded in a diffusing medium is formed by propagating a coherent or equivalent light pulse through the diffusing medium and applying a reference pulse so as to gate precisely the first emerging light transmitted through the diffusing medium. An ultra-short pulse, having a duration on the order of 150 fs, insures that only the first emerging light is used to form a hologram. Instability in the diffusing medium, which may be inherent therein, as is the case with living tissue, or artificially induced therein, such as by vibrating the specimen, ensures that a subsequent hologram has a different background noise and speckle pattern. Integration of such holograms causes the background noise to average out, but time-invariant features, such as the object being imaged, become increasingly more visible as more holograms are integrated.

Holographic imaging through scattering media

A HOE for use in a wavelength .lambda..sub.3 is made by recording a holographic corrector plate at a wavelength of .lambda..sub.1. The HOE is then recorded at a wavelength .lambda..sub.2. Aberration caused by differences between the wavelength of recording and the wavelength of HOE usage is compensated for by inserting the holographic corrector plate in one of the beams in used in recording the HOE.

HOE and indirect method of constructing same

Provided is a systemic approach to creating a hologram from a sequential series of two dimensional transparencies each having a differing viewpoint of a scene taken simultaneously by a camera in incoherent light and a projection apparatus using coherent light in combination with said transparencies to form a rainbow hologram of the scene originally photographed. The invention utilizes a lenticular lens array to provide parallax information and a perpendicularly oriented cylindrical lens for focusing, along with additional optical enhancing elements, to obtain high quality rainbow holograms from scenes originally photographed in natural light.

Growing community of inventors

Midland, MI, United States of America

Hsuan S Chen