Dr. Alan Weidemann Profile

Dr. Alan Weidemann

Oceanographer at US Naval Research Lab

SPIE Involvement:

Author

Publications (40)

SPIE Journal Paper | 29 March 2017 Open Access

Special Section Guest Editorial: Remote Sensing for Investigating the Coupled Biogeophysical and Biogeochemical Process of Harmful Algal Blooms

Ni-Bin Chang, Alan Weidemann

JARS, Vol. 11, Issue 01, 012001, (March 2017) https://doi.org/10.1117/12.10.1117/1.JRS.11.012001

KEYWORDS: Remote sensing, Synthetic aperture radar, Water, Environmental sensing, LIDAR, Unmanned aerial vehicles, Clouds, Image fusion, Satellites, Analytical research

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Proceedings Article | 16 October 2013 Paper

Evaluation of ocean color data processing schemes for VIIRS sensor using in-situ data of coastal AERONET-OC sites

S. Ahmed, A. Gilerson, S. Hlaing, A. Weidemann, R. Arnone, M. Wang

Proceedings Volume 8888, 88880H (2013) https://doi.org/10.1117/12.2028821

KEYWORDS: Calibration, Sensors, MODIS, Satellites, Data processing, Water, Avalanche photodetectors, Ocean optics, Atmospheric modeling, Aerosols

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In the processing of Ocean Color (OC) data from sensor data recorded by Visible Infrared Imaging Radiometer Suite (VIIRS) aboard JPSS-Suomi satellite, NASA Ocean Biology Processing Group (OBPG) is deriving a continuous temporal calibration based on the on-board calibration measurements for the visible bands, and then reprocessing the full mission to produce a continuously calibrated sensor data record (SDR) product. In addition, a vicarious calibration during SDR to OC Level-2 processing is applied. In the latest processing the vicarious calibration is derived from the Marine Optical Buoy (MOBY) data, whereas in the initial processing it was derived from a sea surface reflectance model and a climatology of chlorophyll-a concentration. Furthermore, NASA has recently reprocessed the OC data for the entire VIIRS mission with lunar-based temporal calibration and updated vicarious gains. On the other hand, in fulfilling the mission of the U.S. National Oceanic and Atmospheric Administration (NOAA), the Interface Data Processing Segment (IDPS) developed by Raytheon Intelligence and Information Systems, for the processing of the environmental data products from sensor data records, has gained beta status for evaluation. As these processing schemes continue to evolve, monitoring the validity and assessments of the related VIIRS ocean color products are necessary, especially for coastal waters, to evaluate the consistency of these processing and calibration schemes. The ocean color component of the Aerosol Robotic Network (AERONET-OC) has been designed to support long-term satellite ocean color investigations through cross-site measurements collected by autonomous multispectral radiometer systems deployed above water. As part of this network, the Long Island Sound Coastal Observatory (LISCO) near New York City and WaveCIS in the Gulf of Mexico expand those observational capabilities with continuous monitoring as well as (for the LISCO site) additional assessment of the hyper-spectral properties of coastal waters. In the investigations carried out over a one and half year period dataset of VIIRS, based on the data from two coastal AERONET-OC sites, it has been observed that the VIIRS sensor captures well the seasonal and temporal variations in the nLw data, exhibiting significant correlation with in-situ data (R = 0.929 and 0.985 for LISCO and WaveCIS respectively). For the WaveCIS site, VIIRS nLw data retrievals are seen to be enhanced with each incremental adjustments of vicarious and calibration procedures. However, that is not the case for the LISCO site which exhibits more frequent occurrences of negative water-leaving radiances, while underestimation in VIIRS nLw data is further exacerbated. Strong consistency between the time-series nLw data retrieved from the VIIRS and MODIS sensors was also observed.

Proceedings Article | 3 June 2013 Paper

Measurements of turbulent dissipation during the Bahamas Optical Turbulence Experiment

Silvia Matt, Weilin Hou, Sarah Woods, Ewa Jarosz, Wesley Goode, Alan Weidemann

Proceedings Volume 8724, 872405 (2013) https://doi.org/10.1117/12.2018303

KEYWORDS: Turbulence, Optical turbulence, Temperature metrology, Intelligence systems, Error analysis, Tongue, Velocity measurements, Tin, Ocean optics, Optical properties

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Proceedings Article | 3 June 2013 Paper

Bathymetry estimations using vicariously calibrated HICO data

David Lewis, Richard Gould, Alan Weidemann, Sherwin Ladner, Zhongping Lee

Proceedings Volume 8724, 87240N (2013) https://doi.org/10.1117/12.2017864

KEYWORDS: Calibration, Reflectivity, Sensors, Atmospheric corrections, Absorption, Spatial resolution, Remote sensing, In situ remote sensing, Near infrared, Data processing

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Proceedings Article | 3 June 2013 Paper

Evaluation of VIIRS ocean color data using measurements from the AERONET-OC sites

Samir Ahmed, Alex Gilerson, Soe Hlaing, Ioannis Ioannou, Menghua Wang, Alan Weidemann, Robert Arnone

Proceedings Volume 8724, 87240L (2013) https://doi.org/10.1117/12.2017756

KEYWORDS: MODIS, Satellites, Aerosols, Sensors, Calibration, Statistical analysis, Atmospheric corrections, Avalanche photodetectors, Data processing, Ocean optics

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SPIE Journal Paper | 5 December 2012 Open Access

Airborne lidar detection and characterization of internal waves in a shallow fjord

James Churnside, Richard Marchbanks, Jennifer Lee, Joseph Shaw, Alan Weidemann, Percy Donaghay

JARS, Vol. 6, Issue 01, 063611, (December 2012) https://doi.org/10.1117/12.10.1117/1.JRS.6.063611

KEYWORDS: LIDAR, Scattering, Polarization, Wave propagation, Photography, Turbulence, Receivers, Dielectric polarization, Transmitters, Signal attenuation

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Proceedings Article | 12 June 2012 Paper

Scattered photons as useable signal for underwater imaging

Walton McBride, Alan Weidemann, Linda Mullen, Alan Laux, Derek Alley

Proceedings Volume 8372, 837204 (2012) https://doi.org/10.1117/12.920469

KEYWORDS: Receivers, Photons, Signal attenuation, Laser scattering, Scattering, Imaging systems, Chromium, Laser sources, Underwater imaging, Electrons

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Proceedings Article | 12 June 2012 Paper

Bahamas Optical Turbulence Exercise (BOTEX): preliminary results

Weilin Hou, Ewa Jorosz, Fraser Dalgleish, Gero Nootz, Sarah Woods, Alan Weidemann, Wesley Goode, Anni Vuorenkoski, B. Metzger, B. Ramos

Proceedings Volume 8372, 837206 (2012) https://doi.org/10.1117/12.920740

KEYWORDS: Turbulence, Optical turbulence, Ocean optics, Sensors, Scattering, Imaging systems, Particles, Water, Image transmission, High speed cameras

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The Bahamas Optical Turbulence Exercise (BOTEX) was conducted in the coastal waters of Florida and the Bahamas from June 30 to July 12 2011, onboard the R/V FG Walton Smith. The primary objective of the BOTEX was to obtain field measurements of optical turbulence structures, in order to investigate the impacts of the naturally occurring turbulence on underwater imaging and optical beam propagation. In order to successfully image through optical turbulence structures in the water and examine their impacts on optical transmission, a high speed camera and targets (both active and passive) were mounted on a rigid frame to form the Image Measurement Assembly for Subsurface Turbulence (IMAST). To investigate the impacts on active imaging systems such as the laser line scan (LLS), the Telescoping Rigid Underwater Sensor Structure (TRUSS) was designed and implemented by Harbor Branch Oceanographic Institute. The experiments were designed to determine the resolution limits of LLS systems as a function of turbulence induced beam wander at the target. The impact of natural turbulence structures on lidar backscatter waveforms was also examined, by means of a telescopic receiver and a short pulse transmitter, co-located, on a vertical profiling frame. To include a wide range of water types in terms of optical and physical conditions, data was collected from four different locations. . Impacts from optical turbulence were observed under both strong and weak physical structures. Turbulence measurements were made by two instruments, the Vertical Microstructure Profiler (VMP) and a 3D acoustical Doppler velocimeter with fast conductivity and temperature probes, in close proximity in the field. Subsequently these were mounted on the IMAST during moored deployments. The turbulence kinetic energy dissipation rate and the temperature dissipation rates were calculated from both setups in order to characterize the physical environments and their impacts. Beam deflection by multiple point patterns are examined, using high speed camera recordings (300 to 1200 fps), in association with measured turbulence structures. Initial results confirmed our hypothesis that turbulence impacted optical transmissions. They also showed that more research will be needed to better quantify and mitigate such effects, especially for the U.S. Navy's next generation EO systems, including active imaging, lidar and optical communications.

Proceedings Article | 12 June 2012 Paper

Airborne lidar sensing of internal waves in a shallow fjord

James Churnside, Richard Marchbanks, Jennifer Lee, Joseph Shaw, Alan Weidemann, Percy Donaghay

Proceedings Volume 8372, 83720P (2012) https://doi.org/10.1117/12.918099

KEYWORDS: LIDAR, Polarization, Wave propagation, Wave sensors, Receivers, Light scattering, Scattering, Telescopes, Analytical research, Mouth

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Proceedings Article | 12 June 2012 Paper

Biological thin layers: history, ecological significance and consequences to oceanographic sensing systems

James Sullivan, Michael Twardowski, Percy Donaghay, Jan Rines, Malcolm McFarland, Siddharth Talapatra, Joseph Katz, James Churnside, Alan Weidemann

Proceedings Volume 8372, 83720U (2012) https://doi.org/10.1117/12.921156

KEYWORDS: Acoustics, Organisms, Ocean optics, Scattering, Sensing systems, Particles, Defense and security, Backscatter, Neodymium, Imaging systems

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Proceedings Article | 12 June 2012 Paper

Evaluation of atmospheric correction procedures for ocean color data processing using hyper- and multi-spectral radiometric measurements from the Long Island Sound Coastal Observatory

S. Ahmed, A. Gilerson, T. Harmel, S. Hlaing, A. Tonizzo, A. Weidemann, R. Arnone

Proceedings Volume 8372, 83720M (2012) https://doi.org/10.1117/12.919900

KEYWORDS: Satellites, Aerosols, Atmospheric corrections, MODIS, Atmospheric particles, Data processing, Atmospheric optics, Reflectivity, Atmospheric modeling, Sensors

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Proceedings Article | 8 October 2011 Paper

Uncertainties assessment and satellite validation over 2 years time series of multispectral and hyperspectral measurements in coastal waters at Long Island Sound Coastal Observatory

S. Ahmed, T. Harmel, A. Gilerson, A. Tonizzo, S. Hlaing, A. Weidemann, R. Arnone

Proceedings Volume 8175, 817505 (2011) https://doi.org/10.1117/12.898299

KEYWORDS: Satellites, MODIS, Aerosols, Atmospheric optics, Data processing, Atmospheric particles, Atmospheric corrections, Remote sensing, Ocean optics, Calibration

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Proceedings Article | 8 October 2011 Paper

Bidirectional reflectance function in coastal waters: modeling and validation

Alex Gilerson, Soe Hlaing, Tristan Harmel, Alberto Tonizzo, Robert Arnone, Alan Weidemann, Samir Ahmed

Proceedings Volume 8175, 81750O (2011) https://doi.org/10.1117/12.898449

KEYWORDS: Reflectivity, Remote sensing, Magnesium, Bidirectional reflectance transmission function, Water, Computer simulations, Coastal modeling, Backscatter, Sensors, Data modeling

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Proceedings Article | 5 May 2011 Paper

Hyperspectral and multispectral above-water radiometric measurements to monitor satellite data quality over coastal area

Samir Ahmed, Tristan Harmel, Alexander Gilerson, Soe Hlaing, Alberto Tonizzo, Curtiss Davis, Alan Weidemann, Robert Arnone

Proceedings Volume 8030, 803002 (2011) https://doi.org/10.1117/12.884674

KEYWORDS: Satellites, Sun, Data processing, Calibration, Sensors, Atmospheric corrections, Radiometry, Remote sensing, MODIS, Reflectivity

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Proceedings Article | 5 May 2011 Paper

Impacts of optical turbulence on underwater imaging

Weilin Hou, S. Woods, W. Goode, E. Jarosz, A. Weidemann

Proceedings Volume 8030, 803009 (2011) https://doi.org/10.1117/12.883114

KEYWORDS: Turbulence, Modulation transfer functions, Optical turbulence, Scattering, Water, Optical transfer functions, Underwater imaging, Optical properties, Laser scattering, Data modeling

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Proceedings Article | 5 May 2011 Paper

Quantifying turbulence microstructure for improvement of underwater imaging

Sarah Woods, Weilin Hou, Wesley Goode, Ewa Jarosz, Alan Weidemann

Proceedings Volume 8030, 80300A (2011) https://doi.org/10.1117/12.887607

KEYWORDS: Turbulence, Scattering, Underwater imaging, Light scattering, Sensors, Visibility, Temperature metrology, Target detection, Optical turbulence, Water

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SPIE Journal Paper | 1 January 2011

Ocean color patterns help to predict depth of optical layers in stratified coastal waters

Martín Montes-Hugo, Alan Weidemann, Richard Gould, Robert Arnone, James Churnside, Ewa Jaroz

JARS, Vol. 5, Issue 1, 053548, (January 2011) https://doi.org/10.1117/12.10.1117/1.3634055

KEYWORDS: Ocean optics, Water, Reflectivity, Optical properties, Remote sensing, Optical testing, Biomedical optics, Geometrical optics, Scattering, In situ metrology

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Proceedings Article | 20 April 2010 Paper

Glider optical measurements and BUFR format for data QC and storage

Weilin (Will) Hou, Michael Carnes, Derek Burrage, Bob Arnone, Alan Weidemann, Danielle Bryant, Ken Grembowicz, Samuel Mangin, Kevin Mahoney, Marc Torres

Proceedings Volume 7678, 76780F (2010) https://doi.org/10.1117/12.851361

KEYWORDS: Ocean optics, Data storage, Sensors, Optical testing, Remote sensing, Binary data, Data modeling, Environmental sensing, Optical sensors, Algorithm development

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Proceedings Article | 7 May 2009 Paper

Defining the uncertainty of electro-optical identification system performance estimates using a 3D optical environment derived from satellite

S. Ladner, R. Arnone, B. Casey, A. Weidemann, D. Gray, I. Shulman, K. Mahoney, T. Giddings, J. Shirron

Proceedings Volume 7317, 731705 (2009) https://doi.org/10.1117/12.821724

KEYWORDS: 3D modeling, Ocean optics, Satellites, Optical properties, Electro optical modeling, Sensors, Image quality, 3D acquisition, 3D metrology, 3D image processing

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Proceedings Article | 29 April 2009 Paper

Diver visibility: Why one cannot see as far?

Weilin Hou, Alan Weidemann

Proceedings Volume 7317, 73170I (2009) https://doi.org/10.1117/12.820810

KEYWORDS: Scattering, Turbulence, Visibility, Underwater imaging, Optical transfer functions, Particles, Spatial frequencies, Data modeling, Visual process modeling, Modulation

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Proceedings Article | 29 April 2009 Paper

Polarization characteristics of coastal waters and their impact on in-water visibility

Jing Zhou, Alberto Tonizzo, Alex Gilerson, Michael Twardowski, Deric Gray, Alan Weidemann, Robert Arnone, Barry Gross, Fred Moshary, Sam Ahmed

Proceedings Volume 7317, 73170H (2009) https://doi.org/10.1117/12.820738

KEYWORDS: Polarization, Scattering, Light scattering, Monte Carlo methods, Visibility, Ocean optics, Submerged target modeling, Cameras, Polarizers, Point spread functions

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SPIE Journal Paper | 1 December 2007

Water and bottom properties of a coastal environment derived from Hyperion data measured from the EO-1 spacecraft platform

Zhongping Lee, Brandon Casey, Robert Arnone, Alan Weidemann, Rost Parsons, Marcos Montes, Bo-Cai Gao, Wesley Goode, Curtiss Davis, Julie Dye

JARS, Vol. 1, Issue 01, 011502, (December 2007) https://doi.org/10.1117/12.10.1117/1.2822610

KEYWORDS: Water, LIDAR, Sensors, Reflectivity, Absorption, Sun, Remote sensing, In situ metrology, Environmental sensing, Atmospheric corrections

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Proceedings Article | 24 September 2007 Paper

Imagery-derived modulation transfer function and its applications for underwater imaging

Weilin Hou, Alan Weidemann, Deric Gray, Georges Fournier

Proceedings Volume 6696, 669622 (2007) https://doi.org/10.1117/12.734953

KEYWORDS: Modulation transfer functions, Scattering, Imaging systems, Absorption, Point spread functions, Cameras, Optical properties, Polarization, Spatial frequencies, Signal to noise ratio

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The main challenge working with underwater imagery results from both rapid decay of signals due to absorption, which leads to poor signal to noise returns, and the blurring caused by strong scattering by the water itself and constituents within, especially particulates. The modulation transfer function (MTF) of an optical system gives the detailed and precise information regarding the system behavior. Underwater imageries can be better restored with the knowledge of the system MTF or the point spread function (PSF), the Fourier transformed equivalent, extending the performance range as well as the information retrieval from underwater electro-optical system. This is critical in many civilian and military applications, including target and especially mine detection, search and rescue, and diver visibility. This effort utilizes test imageries obtained by the Laser Underwater Camera Imaging Enhancer (LUCIE) from Defense Research and Development Canada (DRDC), during an April-May 2006 trial experiment in Panama City, Florida. Imaging of a standard resolution chart with various spatial frequencies were taken underwater in a controlled optical environment, at varying distances. In-water optical properties during the experiment were measured, which included the absorption and attenuation coefficients, particle size distribution, and volume scattering function. Resulting images were preprocessed to enhance signal to noise ratio by averaging multiple frames, and to remove uneven illumination at target plane. The MTF of the medium was then derived from measurement of above imageries, subtracting the effect of the camera system. PSFs converted from the measured MTF were then used to restore the blurred imageries by different deconvolution methods. The effects of polarization from source to receiver on resulting MTFs were examined and we demonstrate that matching polarizations do enhance system transfer functions. This approach also shows promise in deriving medium optical properties including absorption and attenuation.

Proceedings Article | 25 April 2007 Paper

Objectively assessing underwater image quality for the purpose of automated restoration

Weilin Hou, Alan Weidemann

Proceedings Volume 6575, 65750Q (2007) https://doi.org/10.1117/12.717789

KEYWORDS: Image quality, Scattering, Modulation transfer functions, Image restoration, Wavelets, Image enhancement, Image compression, Wavelet transforms, Edge detection, Signal to noise ratio

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Proceedings Article | 13 April 2007 Paper

Restoring number of suspended particles in ocean using satellite optical images and forecasting particle fields

Vladimir Haltrin, Robert Arnone, Peter Flynn, Brandon Casey, Alan Weidemann, Dong-Shang Ko

Proceedings Volume 6615, 661504 (2007) https://doi.org/10.1117/12.740435

KEYWORDS: Particles, Scattering, Satellites, Ocean optics, Backscatter, Satellite imaging, Refractive index, Earth observing sensors, Water, Remote sensing

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Proceedings Article | 23 August 2005 Paper

Measurement of ocean water optical properties and seafloor reflectance with scanning hydrographic operational airborne lidar survey (SHOALS): II. Practical results and comparison with independent data

Grady Tuell, Viktor Feygels, Yuri Kopilevich, Alan Weidemann, A. Grant Cunningham, Reza Mani, Vladimir Podoba, Vinod Ramnath, J. Y. Park, Jen Aitken

Proceedings Volume 5885, 58850E (2005) https://doi.org/10.1117/12.619215

KEYWORDS: Reflectivity, Avalanche photodetectors, LIDAR, Calibration, Water, Receivers, Pulsed laser operation, Optical properties, Scattering, Signal attenuation

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Proceedings Article | 1 June 2005 Paper

Megacollect 2004: hyperspectral collection experiment over the waters of the Rochester Embayment

R. Raqueno, N. Raqueno, A. Weidemann, S. Effler, M. Perkins, A. Vodacek, J. Schott, W. Philpot, M. Kim

Proceedings Volume 5806, (2005) https://doi.org/10.1117/12.605856

KEYWORDS: Absorption, Sensors, Optical testing, Water, Remote sensing, Data modeling, Absorption filters, Optical properties, Light scattering, Particles

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Proceedings Article | 25 May 2005 Paper

Development, validation, and fusion of high resolution active and passive optical imagery

W. Bissett, Sharon DeBra, Mubin Kadiwala, David Kohler, Curtis Mobley, Robert Steward, Alan Weidemann, Curtiss Davis, Jeff Lillycrop, Robert Pope

Proceedings Volume 5809, (2005) https://doi.org/10.1117/12.603751

KEYWORDS: LIDAR, Reflectivity, Ocean optics, Water, Sensors, Databases, Error analysis, Calibration, Signal to noise ratio, Data fusion

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Proceedings Article | 19 May 2005 Paper

In harbor underwater threat detection/identification using active imaging

Alan Weidemann, Georges Fournier, Luc Forand, Pierre Mathieu

Proceedings Volume 5780, (2005) https://doi.org/10.1117/12.603601

KEYWORDS: Cameras, Imaging systems, Scattering, Image enhancement, Polarization, Zoom lenses, Eye, Absorption, Visibility, Particles

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Proceedings Article | 28 October 1999 Paper

Meeting Navy needs with the generic lidar model

Walton McBride, Alan Weidemann, J. Todd Shoemaker

Proceedings Volume 3761, (1999) https://doi.org/10.1117/12.366471

KEYWORDS: Modulation transfer functions, Receivers, LIDAR, Imaging systems, Scattering, Ocean optics, Laser scanners, 3D scanning, Signal attenuation, Spatial frequencies

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