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Proceedings Paper

Avoiding the false peaks in correlation discrimination
Author(s): Abdul A. S. Awwal
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Paper Abstract

Fiducials imprinted on laser beams are used to perform video image based alignment of the 192 laser beams in the National Ignition Facility (NIF) of Lawrence Livermore National Laboratory. In many video images, matched filtering is used to detect the location of these fiducials. Generally, the highest correlation peak is used to determine the position of the fiducials. However, when the signal to-be-detected is very weak compared to the noise, this approach totally breaks down. The highest peaks act as traps for false detection. The active target images used for automatic alignment in the National Ignition Facility are examples of such images. In these images, the fiducials of interest exhibit extremely low intensity and contrast, surrounded by high intensity reflection from metallic objects. Consequently, the highest correlation peaks are caused by these bright objects. In this work, we show how the shape of the correlation is exploited to isolate the valid matches from hundreds of invalid correlation peaks, and therefore identify extremely faint fiducials under very challenging imaging conditions.

Paper Details

Date Published: 1 September 2009
PDF: 8 pages
Proc. SPIE 7442, Optics and Photonics for Information Processing III, 74421F (1 September 2009); doi: 10.1117/12.830518
Show Author Affiliations
Abdul A. S. Awwal, Lawrence Livermore National Lab. (United States)

Published in SPIE Proceedings Vol. 7442:
Optics and Photonics for Information Processing III
Khan M. Iftekharuddin; Abdul Ahad Sami Awwal, Editor(s)

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