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Accurate Position Sensing of Defocused Beams Using Simulated Beam Templates.

DE200515011393

Publication Date	2004
Personal Author	Awwal, A.; Candy, J.; Haynam, C.; Widmayer, C.; Bliss, E.; Burkhart, S.
Page Count	16
Abstract	In position detection using matched filtering one is faced with the challenge of determining the best position in the presence of distortions such as defocus and diffraction noise. This work evaluates the performance of simulated defocused images as the template against the real defocused beam. It was found that an amplitude modulated phase-only filter is better equipped to deal with real defocused images that suffer from diffraction noise effects resulting in a textured spot intensity pattern. It is shown that the there is a tradeoff of performance dependent upon the type and size of the defocused image. A novel automated system was developed that can automatically select the right template type and size. Results of this automation for real defocused images are presented.
Keywords	Pattern recognition US National Ignition Facility Target tracking Optical alignment Phase-only filter AMPOF(Amplitude modulated phase only filter)
Source Agency	Technical Information Center Oak Ridge Tennessee
Corporate Authors	Lawrence Livermore National Lab., CA.; Department of Energy, Washington, DC.
Supplemental Notes	Sponsored by Department of Energy, Washington, DC.
Document Type	Technical Report
NTIS Issue Number	200601

Accurate Position Sensing of Defocused Beams Using Simulated Beam Templates.

Accurate Position Sensing of Defocused Beams Using Simulated Beam Templates.
DE200515011393

Publication Date	2004
Personal Author	Awwal, A.; Candy, J.; Haynam, C.; Widmayer, C.; Bliss, E.; Burkhart, S.
Page Count	16
Abstract	In position detection using matched filtering one is faced with the challenge of determining the best position in the presence of distortions such as defocus and diffraction noise. This work evaluates the performance of simulated defocused images as the template against the real defocused beam. It was found that an amplitude modulated phase-only filter is better equipped to deal with real defocused images that suffer from diffraction noise effects resulting in a textured spot intensity pattern. It is shown that the there is a tradeoff of performance dependent upon the type and size of the defocused image. A novel automated system was developed that can automatically select the right template type and size. Results of this automation for real defocused images are presented.
Keywords	Pattern recognition US National Ignition Facility Target tracking Optical alignment Phase-only filter AMPOF(Amplitude modulated phase only filter)
Source Agency	Technical Information Center Oak Ridge Tennessee
Corporate Authors	Lawrence Livermore National Lab., CA.; Department of Energy, Washington, DC.
Supplemental Notes	Sponsored by Department of Energy, Washington, DC.
Document Type	Technical Report
NTIS Issue Number	200601