System and method for holographic imaging with discernible image of an object

• US 5,777,742 A
• Filed: 02/04/1994
• Issued: 07/07/1998
• Est. Priority Date: 03/11/1993
• Status: Expired due to Term

• Current Assignee: Coherix Incorporated
• Original Assignee: Environmental Research Institute of Michigan
• Inventors: Marron, Joseph C.
• Primary Examiner(s): Turner, Samuel A.
• Application Number:
  US08/282,781
• Time in Patent Office: 1,614 Days
• Field of Search: 356/359, 356/360, 356/361, 356/345, 356/346, 359/32
• US Class Current: 356/458
• CPC Class Codes: G01B 9/021 using holographic techniques

Abstract

A system and method for three-dimensional imaging utilize a lens to perform a two-dimensional Fourier transform of an interference pattern while focusing the pattern on a two-dimensional detector array which is positioned in the image plane of the lens. This allows immediate previewing of the imaged object for proper positioning. Coherent energy beams are utilized to create a series of interference patterns, or image-plane holograms, each at a different frequency of the source energy beams. Furthermore, at each frequency, the relative phase between an object and a reference energy beam is varied to capture the complex values associated with the interference patterns. After capturing and storing the various interference patterns, a computer performs a one-dimensional Fourier transform, or other simplified processing to generate the three-dimensional image of the object. The image resolution extends to the micron range making this system and method easily adaptable to a variety of three-dimensional inspection applications.

Claims