Mr. David W. Roberts Profile

David W. Roberts

Senior Research Scientist at Georgia Tech Research Institute

SPIE Involvement:

Author

Publications (26)

Proceedings Article | 9 June 2014 Paper

The integrated atmospheric characterization system (IACS)

D. Roberts, K. Albers, E. Brown, T. Craney, M. Hosain, R. James, N. Meraz, A. Mercer, K. Nielson, R. Ortman, T. Pool, J. Wood, J. Stewart, T. Strike, G. Gimmestad, D. Whiteman

Proceedings Volume 9080, 90801E (2014) https://doi.org/10.1117/12.2050600

KEYWORDS: LIDAR, Aerosols, Turbulence, Atmospheric particles, Raman spectroscopy, Receivers, Profiling, Water, Computing systems, Backscatter

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SPIE Journal Paper | 20 September 2012

Development of a lidar technique for profiling optical turbulence

Gary Gimmestad, David Roberts, John Stewart, Jack Wood

OE, Vol. 51, Issue 10, 101713, (September 2012) https://doi.org/10.1117/12.10.1117/1.OE.51.10.101713

KEYWORDS: LIDAR, Turbulence, Profiling, Optical turbulence, Atmospheric optics, Stars, Receivers, Optical engineering, Motion measurement, Optical simulations

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Proceedings Article | 25 May 2011 Paper

Characterizing aerosol extinction in the UV-NIR spectral range

Gary Gimmestad, David Roberts

Proceedings Volume 8038, 803806 (2011) https://doi.org/10.1117/12.883455

KEYWORDS: LIDAR, Aerosols, Atmospheric particles, Optical parametric oscillators, Profiling, Avalanche photodetectors, Imaging systems, Optical testing, Mineralogy, Computing systems

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Proceedings Article | 7 May 2009 Paper

Integrated atmospheric characterization system

David Roberts, Gary Gimmestad, John Stewart, David Whiteman, Frank Eaton

Proceedings Volume 7324, 73240O (2009) https://doi.org/10.1117/12.820238

KEYWORDS: LIDAR, Aerosols, Turbulence, Atmospheric particles, Profiling, Raman spectroscopy, Computing systems, System integration, Receivers, Stars

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Proceedings Article | 18 April 2008 Paper

Testing of LIDAR system for turbulence profiles

Gary Gimmestad, David Roberts, John Stewart, Jack Wood, Frank Eaton

Proceedings Volume 6951, 695109 (2008) https://doi.org/10.1117/12.792204

KEYWORDS: LIDAR, Turbulence, Mirrors, Stars, Receivers, Telescopes, Algorithm development, Aerosols, Cameras, Astronomy

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Proceedings Article | 4 May 2007 Paper

Hands-free focus night vision technology demonstration

Terence Haran, J. Christopher James, David Roberts, Michael Knotts, Anthony Wasilewski, Leanne West, William Robinson, Gisele Bennett

Proceedings Volume 6557, 65570R (2007) https://doi.org/10.1117/12.720970

KEYWORDS: Sensors, Image sensors, Contrast transfer function, Image processing, Eye, Image resolution, Wavefronts, Signal to noise ratio, CMOS sensors, Imaging systems

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Proceedings Article | 4 May 2007 Paper

Improved night vision demonstrator program status

Terence Haran, J. Christopher James, David Roberts, Michael Knotts, Anthony Wasilewski, Leanne West, William Robinson, Gisele Bennett

Proceedings Volume 6538, 653821 (2007) https://doi.org/10.1117/12.720971

KEYWORDS: Sensors, Image sensors, Contrast transfer function, Image processing, Eye, Image resolution, Wavefronts, Night vision, Signal to noise ratio, CMOS sensors

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Proceedings Article | 4 May 2007 Paper

Lidar system for monitoring turbulence profiles

Gary Gimmestad, David Roberts, John Stewart, Jack Wood

Proceedings Volume 6551, 65510H (2007) https://doi.org/10.1117/12.720805

KEYWORDS: LIDAR, Turbulence, Laser guide stars, Optical simulations, Receivers, Laser scattering, Astronomy, Stars, Atmospheric modeling, Mirrors

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Proceedings Article | 30 June 2006 Paper

LIDAR for measuring atmospheric extinction

M. Dawsey, G. Gimmestad, D. Roberts, J. McGraw, P. Zimmer, J. Fitch

Proceedings Volume 6270, 62701F (2006) https://doi.org/10.1117/12.673110

KEYWORDS: LIDAR, Focus stacking software, Receivers, Telescopes, Observatories, Transmitters, Eye, Aerosols, Astronomy, Atmospheric particles

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Proceedings Article | 23 June 2006 Paper

LIDAR system for monitoring turbulence profiles

Gary Gimmestad, Martha Dawsey, David Roberts, John Stewart, Jack Wood, Frank Eaton

Proceedings Volume 6267, 62671V (2006) https://doi.org/10.1117/12.672222

KEYWORDS: LIDAR, Turbulence, Adaptive optics, Laser guide stars, Telescopes, Astronomy, Wavefronts, Optical simulations, Receivers, Atmospheric modeling

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Proceedings Article | 25 May 2005 Paper

Field validation of optical turbulence lidar technique

G. Gimmestad, M. Dawsey, D. Roberts, J. Stewart, J. Wood, F. Eaton, M. Jensen, R. Welch

Proceedings Volume 5793, (2005) https://doi.org/10.1117/12.603058

KEYWORDS: LIDAR, Data acquisition, Motion measurement, Optical turbulence, Turbulence, Statistical analysis, Stars, Algorithm development, Astronomy, Motion analysis

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Proceedings Article | 19 May 2005 Paper

1.5 microns and the future of unattended aerosol lidar

Gary Gimmestad, David Roberts

Proceedings Volume 5791, (2005) https://doi.org/10.1117/12.602582

KEYWORDS: LIDAR, Aerosols, Sensors, Receivers, Ultraviolet radiation, Eye, Avalanche photodetectors, Indium gallium arsenide, Clouds, Safety

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Proceedings Article | 20 October 2004 Paper

Target edge response

Mikhail Belen'kii, Patti Gillespie, Gary Gimmestad, Kevin Hughes, David Roberts, Vincent Rye, John Stewart, Jack Wood

Proceedings Volume 5550, (2004) https://doi.org/10.1117/12.566077

KEYWORDS: Imaging systems, Image quality, Modulation transfer functions, Cameras, Data acquisition, Point spread functions, Visible radiation, Scintillation, Atmospheric optics, Spatial resolution

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Proceedings Article | 27 January 2004 Paper

Measurement of tilt anisoplanatism with discrete and extended sources

Mikhail Belen'kii, Kenneth Burgi, Patti Gillespie, Gary Gimmestad, Kevin Hughes, David Roberts, John Stewart, Jack Wood

Proceedings Volume 5160, (2004) https://doi.org/10.1117/12.507952

KEYWORDS: Imaging systems, Turbulence, Visible radiation, Sensors, Projection systems, Statistical analysis, Cameras, Data acquisition, Optical sensors, Scintillation

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A dual-band imaging system with variable aperture diameter was constructed and horizontal and vertical atmospheric tilt components were measured on a 1-km near-the-ground horizontal path using discrete and extended visible and JR sources. The spatial and temporal tilt statistics were estimated from the recorded data. Tilt structure function, which also characterizes v ariance of the p ointing error caused by anisoplanatism of t he track point to the aim point in the 1 aser projection system, for small angular separation decreases inverse proportionally to the aperture diameter D1 . The tilt structure function is insensitive to sensor vibration. For a point ahead angle of 0.45 mrad the daytime rms pointing enor caused by tilt anisoplanatism is 12 prad for D= 6 cm, and it is 5 prad for D= 40 cm. The tilt power spectral density agrees well with theory. Jt has the "-2/3" power slope, and the ratio of the two knee frequencies is equal to the inverse ratio of the aperture diameters. The tilt temporal conelation increases with the aperture diameter. The temporal conelation scale is 0.25 sec for D=6 cm and it is 1 sec for D= 40 cm. The C measurements made with discrete JR sources and an optical imager agree well with the measurements made with a scintillometer. The structure function for the lateral (Y) tilt exceeds that for the longitudinal (X) tilt, which is inconsistent with the theoretical prediction. We believe that heat-induced turbulence from the JR sources and a wind component parallel to the optical path degraded the measurements of the vertical tilt. Three mitigation techniques were considered including an increase of the aperture diameter, integration of the image edge over the edge angular extent, and averaging of multiple frames. A multi-frame averaging technique is known to be efficient for mitigation of the effects of turbulence induced scintillation and laser speckle. We found that by averaging multiple image frames one can mitigate the effects of tilt anisoplanatism as well. We also found that the edge response for a multi frame averaged image and a single frame image is the same. This allows us to conclude that a multi frame averaging technique for an extended object does not affect the system angular resolution.

Proceedings Article | 22 September 2003 Paper

Covert camera for screening of vehicle interiors and HOV enforcement

Jack Wood, Gary Gimmestad, David Roberts

Proceedings Volume 5071, (2003) https://doi.org/10.1117/12.498755

KEYWORDS: Cameras, Imaging systems, Fiber optic illuminators, Infrared imaging, Eye, Photography, Infrared radiation, Homeland security, Safety, Standards development

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Proceedings Article | 12 September 2003 Paper

Photoactivated methods for enabling cartilage-to-cartilage tissue fixation

Valerie Sitterle, David Roberts

Proceedings Volume 4949, (2003) https://doi.org/10.1117/12.476397

KEYWORDS: Tissues, Cartilage, Collagen, Tissue optics, Adhesives, Natural surfaces, Bone, In vivo imaging, Oxygen, FT-IR spectroscopy

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Proceedings Article | 21 August 2003 Paper

Augmenting the micropulse lidar concept

David Roberts, Gary Gimmestad

Proceedings Volume 5086, (2003) https://doi.org/10.1117/12.501114

KEYWORDS: LIDAR, Receivers, Transmitters, Aerosols, Photometry, Polarization, Sun, Light emitting diodes, Telescopes, Photomultipliers

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Proceedings Article | 21 August 2003 Paper

System verification of an unattended DIAL lidar

John Stewart, Gary Gimmestad, Peter Haugen, David Roberts, Leanne West, Jack Wood

Proceedings Volume 5086, (2003) https://doi.org/10.1117/12.499055

KEYWORDS: Ozone, LIDAR, Aerosols, Receivers, Prototyping, Clouds, Sun, Photometry, Signal to noise ratio, Light emitting diodes

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Proceedings Article | 21 August 2003 Paper

Laser remote sensing of atmospheric turbulence

G. Gimmestad, D. Roberts

Proceedings Volume 5087, (2003) https://doi.org/10.1117/12.500088

KEYWORDS: LIDAR, Motion measurement, Analog electronics, Sensors, Atmospheric turbulence, Remote sensing, Turbulence, Laser scattering, Scintillation, Scattering

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Proceedings Article | 29 July 2002 Paper

Eye-safe lidar as an undergraduate research experience

Gary Gimmestad, Arthur Bowling, David Roberts, John Stewart, Leanne West, Jack Wood, Edward Patterson

Proceedings Volume 4723, (2002) https://doi.org/10.1117/12.476410

KEYWORDS: LIDAR, Clouds, Aerosols, Eye, Receivers, Backscatter, Geometrical optics, Atmospheric optics, Physics, Atmospheric sciences

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Proceedings Article | 29 July 2002 Paper

Optimizing lidar dynamic range by engineering the crossover region

David Roberts, Gary Gimmestad

Proceedings Volume 4723, (2002) https://doi.org/10.1117/12.476403

KEYWORDS: Receivers, LIDAR, Transmitters, Pulsed laser operation, Image transmission, Photodetectors, Beam splitters, Optical design, Absorption, Scattering

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Proceedings Article | 29 July 2002 Paper

NEXLASER: an unattended tropospheric aerosol and ozone lidar

John Stewart, Gary Gimmestad, David Roberts, Leanne West, Jack Wood

Proceedings Volume 4723, (2002) https://doi.org/10.1117/12.476409

KEYWORDS: Aerosols, Ozone, Atmospheric modeling, Signal to noise ratio, LIDAR, Prototyping, Atmospheric particles, Backscatter, Absorption, Receivers

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Proceedings Article | 19 September 2001 Paper

Experimental validation of the differential image motion lidar concept

Mikhail Belen'kii, David Roberts, John Stewart, Gary Gimmestad, W. Dagle

Proceedings Volume 4377, (2001) https://doi.org/10.1117/12.440118

KEYWORDS: LIDAR, Turbulence, Sensors, Scintillation, Receivers, Analog electronics, Laser scattering, Scattering, Motion measurement, Image transmission

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Proceedings Article | 14 October 1996 Paper

Single-ended laser wind sensor

Mikhail Belen'kii, Gary Gimmestad, David Roberts

Proceedings Volume 2828, (1996) https://doi.org/10.1117/12.254199

KEYWORDS: Sensors, Wind measurement, Prototyping, Laser development, Telescopes, Signal detection, Receivers, Chlorine, Speckle pattern, Fringe analysis

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Proceedings Article | 3 June 1994 Paper

Boundary layer height measurements with an eyesafe Lidar

Gary Gimmestad, Edward Patterson, David Roberts, Susan Gimmestad

Proceedings Volume 2112, (1994) https://doi.org/10.1117/12.177298

KEYWORDS: LIDAR, Aerosols, Receivers, Sensors, Atmospheric chemistry, Data acquisition, Chemistry, Nd:YAG lasers, Indium gallium arsenide, PIN photodiodes

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SPIE Journal Paper | 1 January 1991

Design and performance of a 100 inch lidar facility

David Roberts, Gary Gimmestad, Allen Garrison, Edward Patterson, Susan Gimmestad, J. Michael Cathcart, Raymond DuVarney, Gerald Grams, Jan Servaites

OE, Vol. 30, Issue 01, (January 1991) https://doi.org/10.1117/12.10.1117/12.55774

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Showing 5 of 26 publications

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