Real-time neutron coded aperture imaging: A technique for nondestructive three-dimensional imaging
Neutron Coded Aperture Imaging is a nondestructive imaging technique that utilizes neutrons scattered from an object through specially designed apertures. Coded Aperture Imaging is an alternative technique to Computed Tomography for three-dimensional imaging. Coded Aperture Imaging has the advantage that all of the three-dimensional information is contained in a single image, whereas Computed Tomography requires several images or projections. This technique has been implemented by other using photographic film as an image recording medium and optical reconstruction or decoding of the images. In this work, the possibility of using a real-time neutron video camera to record the images, followed by digital decoding methodology has been investigated. Because only a small fraction of the neutrons incident on the object are scattered to the neutron camera, a new neutron beamport facility, with a larger neutron flux (7.3 x 10[sup 7] n/cm[sup 2]/s) than the previous facility was constructed. A real-time imaging system has been assembled that also allows for image integration directly on the video tube for low flux applications. A technique for aperture fabrication has been developed. This technique utilizes vapor deposition of neutron absorbing material (Gadolinium) onto a substrate followed by photolithographic etching of the coded aperture pattern. Various method for digital decoding have been examined including a novel use of the Wiener filter for direct image decoding. These methods have been successfully implemented on simulated images to insure that they function properly. Algorithms for decoding multiple planes to exploit the three-dimensional information have been developed and tested. In addition, a method to remove the contributions due to out-of-focus planes from a given reconstructed or decoded image was developed. Coded images were successfully recorded using the real-time imaging system with integration times of approximately 5 minutes.
- Research Organization:
- Virginia Univ., Charlottesville, VA (United States)
- OSTI ID:
- 7266883
- Country of Publication:
- United States
- Language:
- English
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