Implementation of Accelerated Beam-Specific Matched-Filter-Based Optical Alignment

Journal Article · Thu Jan 29 04:00:00 EST 2009 · Applied Optics

OSTI ID:966226

Awwal, A S; Rice, K L; Taha, T M

Accurate automated alignment of laser beams in the National Ignition Facility (NIF) is essential for achieving extreme temperature and pressure required for inertial confinement fusion. The alignment achieved by the integrated control systems relies on algorithms processing video images to determine the position of the laser beam images in real-time. Alignment images that exhibit wide variations in beam quality require a matched-filter algorithm for position detection. One challenge in designing a matched-filter based algorithm is to construct a filter template that is resilient to variations in imaging conditions while guaranteeing accurate position determination. A second challenge is to process the image as fast as possible. This paper describes the development of a new analytical template that captures key recurring features present in the beam image to accurately estimate the beam position under good image quality conditions. Depending on the features present in a particular beam, the analytical template allows us to create a highly tailored template containing only those selected features. The second objective is achieved by exploiting the parallelism inherent in the algorithm to accelerate processing using parallel hardware that provides significant performance improvement over conventional processors. In particular, a Xilinx Virtex II Pro FPGA hardware implementation processing 32 templates provided a speed increase of about 253 times over an optimized software implementation running on a 2.0 GHz AMD Opteron core.

• Research Organization: Lawrence Livermore National Laboratory (LLNL), Livermore, CA
• Sponsoring Organization: USDOE
• DOE Contract Number: W-7405-ENG-48
• OSTI ID: 966226
• Report Number(s): LLNL-JRNL-410446
• Journal Information: Applied Optics, Journal Name: Applied Optics Journal Issue: 27 Vol. 48; ISSN 0003-6935; ISSN APOPAI
• Country of Publication: United States
• Language: English

Related Subjects

42 ENGINEERING
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ALGORITHMS
ALIGNMENT
BEAM POSITION
CONTROL SYSTEMS
DETECTION
IMPLEMENTATION
INERTIAL CONFINEMENT
LASERS
PERFORMANCE
PROCESSING
US NATIONAL IGNITION FACILITY
VELOCITY