Computer Holographic Reconstruction System Implementing Integrated Three Dimensional Multi-Image Technique

Abstract

This paper describes a computer (Fresnel/Fourier transform) holographic reconstruction system used in the inspection of nuclear pressure vessels. The computer system can generate quasi-real-time (128x128) holographic reconstructions using an array processor and FFT program.

The display software has the unique capability of integrating up to ten holographic images taken of one defect at different viewing angles or positions, and displaying a single composite true three dimensional image. The image can then be rotated or tilted to assist the operator in interpretation and analysis.

Additionally, the computer reconstruction system provides an image spatial frequency filtering program for image enhancement and object characterization. This program has the ability to catalog and store in disk memory spatial frequency signatures which can be then used for classification and identification analysis.

Experimental results are presented that uniquely demonstrate the capabilities of the holographic reconstruction system.

The work described in this paper was performed in its entirety at Holosonics, Inc., in Richland, Washington, for the Electric Power Research Institute. Mr. Hall and Dr. Collins are currently employed at Battelle, while Mr. Wilson is self-employed at 20 Nuclear Lane, Richland, Washington 99352.