Mr. James A. Dawson Profile

James A. Dawson

Sr. Principal Electrical Engineer at Aviation & Missile Solutions, LLC

SPIE Involvement:

Conference Program Committee | Author

Proceedings Article | 27 May 2022 Presentation + Paper

Uncertainty considerations for determining variability in detector noise for staring imaging devices

James Dawson, Katherine Sherer

Proceedings Volume 12106, 121060P (2022) https://doi.org/10.1117/12.2630878

KEYWORDS: Sensors, Imaging devices, Photons, Image sensors, Monte Carlo methods, Error analysis, Received signal strength, Manufacturing, Imaging systems, Systems modeling

Read Abstract +

Proceedings Article | 5 June 2013 Paper

Compensation for instrument anomalies in imaging infrared measurements

Christopher Dobbins, James Dawson, Jay Lightfoot, William Edwards, Ryan Cobb, Amanda Heckwolf

Proceedings Volume 8706, 870606 (2013) https://doi.org/10.1117/12.2015473

KEYWORDS: Sensors, Thermography, Black bodies, Temperature metrology, Staring arrays, Calibration, Quantum efficiency, Infrared imaging, Nonuniformity corrections, Infrared radiation

Read Abstract +

Infrared imaging is commonly used for performing thermography based on field calibration that simply relates image levels to apparent temperature levels using field blackbodies. Under normal conditions, the correlation between the image levels and blackbody temperature is strong, allowing conversion of the raw data into units of blackbody-equivalent temperature without consideration of other factors. However, if certain instrument anomalies are present, a compensation procedure that involves more in-depth sensor characterization may be required. The procedure, which uses an analysis of temperature-dependent dark current, optical emissions, and detector response, is described along with results for a specific case. The procedure involves first cold soaking a thermal camera and then observing the cooldown behavior of the sensor under non-stressing conditions. Variations in environmental temperature levels are then used to observe cooler performance and dark current levels. A multi-variate linear regression is performed that allows temperature-dependent dark current, lens emission, lens transmission, and detector quantum efficiency to be fully characterized. The resulting data describe for each image pixel a relationship between the scene temperature and the observed values of image signal, detector temperature, and camera temperature. The procedure has been applied successfully to a thermal imager used to collect field data while suffering from instrument anomalies due to a faulty cooler. Using the resulting characterization data for the pixel-dependent dark current, image data collected with the thermal imager was compensated. The compensation involved using spatial filtering to determine temperature shifts caused by the faulty cooler based on the predictable pattern of pixel-to-pixel variations in dark current. The estimated temperature shift was used to compute a compensation offset for each pixel based on its known dark current coefficient. The compensated image data, while still degraded, was sufficiently corrected for the predictable effects of dark current variations to allow valid thermography to be performed.

Proceedings Article | 26 August 1998 Paper

Laboratory testing of dithered infrared imaging systems

James Dawson, Mark Chambliss, Carrie Kimbel, Philip Owen

Proceedings Volume 3377, (1998) https://doi.org/10.1117/12.319371

KEYWORDS: Modulation transfer functions, Imaging systems, Infrared imaging, Sensors, Scanning electron microscopy, Fourier transforms, Error analysis, Image analysis, Optical components, Missiles

Read Abstract +

Proceedings Article | 7 July 1998 Paper

Analysis and synthesis of inhomogeneous infrared clutter images

Keith Olree, James Dawson, Joe DeBlaquiere

Proceedings Volume 3375, (1998) https://doi.org/10.1117/12.327154

KEYWORDS: Image segmentation, Image processing, Infrared imaging, Infrared radiation, Sensors, Image filtering, Fourier transforms, Statistical analysis, Imaging infrared seeker, Infrared sensors

Read Abstract +

Proceedings Article | 16 June 1997 Paper

Improved acquisition capabilities of tactical IR seekers modeled with the infrared sensor performance analysis model

MeLisa Cannon, Ronald Passmore, Keith Olree, James Dawson

Proceedings Volume 3063, (1997) https://doi.org/10.1117/12.276068

KEYWORDS: Signal processing, Performance modeling, Thermal modeling, Imaging infrared seeker, Detection and tracking algorithms, Target acquisition, Infrared sensors, Filtering (signal processing), Statistical analysis, Computer simulations

Read Abstract +

Proceedings Article | 22 May 1995 Paper

Measuring the MTF of undersampled staring IRFPA sensors using 2D discrete Fourier transform

Mark Chambliss, James Dawson, Eric Borg

Proceedings Volume 2470, (1995) https://doi.org/10.1117/12.210058

KEYWORDS: Modulation transfer functions, Sensors, Fourier transforms, Modulation, Imaging systems, Infrared imaging, Staring arrays, Target detection, Infrared radiation, Spatial frequencies

Read Abstract +

Proceedings Article | 22 May 1995 Paper

Applications of stochastic multidimensional models of noise and clutter to design and analysis of digital processors for imaging IR sensors

James Dawson, Mark Moellenhoff

Proceedings Volume 2470, (1995) https://doi.org/10.1117/12.210047

KEYWORDS: Filtering (signal processing), Signal to noise ratio, Signal processing, Optical filters, Electronic filtering, Stochastic processes, Sensors, Modulation transfer functions, Image processing, Infrared imaging

Read Abstract +

Imaging IR devices, particularly two-dimensional staring FPAs, are capable of providing large amounts of data applicable to target detection and tracking. This information is received as dynamic imagery of the subject scene, with commercial sensors currently delivering digital data at rates above 35 megabits per second. Currently, due to these high data rates, system performance is limited by the processor throughput and performance. Efficient methods are needed to suppress the deleterious effects of clutter and noise in order to achieve operability against low-signature targets in high-clutter conditions while maintaining real-time operation. To accommodate this, fundamental Wiener filter concepts were applied to design several digital processing concepts. These concepts used noise models that were based on recent progress in representing background clutter. Although not implemented, the general technique is applicable to additional disturbances such as fixed-pattern noise, assuming the noise power spectrum is known. The IR background was modeled using a three-parameter Gauss-Markov power spectral density. Four digital processors were designed using finite impulse response (FIR) kernels of varying size, assuming a fixed-size circular target in each case. A simple band-pass kernel tuned to the target was also considered as a baseline non-Wiener filter. These filters were compared based on their realized transfer functions compared to the ideal Wiener transfer function. The detection processing was accomplished by convolving single-frame imagery with the FIR kernels. Using the filtered imagery, varying thresholds were applied to derive the receive operating curve relating detection and false-alarm probabilities. The processor details and design parameters derived from the noise and clutter parameters are described. Empirical and analytical assessments of filter performance were obtained in clutter backgrounds. Applicability to real-world IR backgrounds is demonstrated through evaluation against real scenes. The analytical model supports assessments of processor performance against extended targets, including quantifying the performance penalties due to imposition of realistic processing constraints.

Proceedings Article | 8 July 1994 Paper

Proposed standard for infrared focal-plane array nonuniformity measurements

James Dawson, Eric Borg, Gill Duykers

Proceedings Volume 2224, (1994) https://doi.org/10.1117/12.180088

KEYWORDS: Sensors, Surface plasmons, Nonuniformity corrections, Imaging systems, Spatial frequencies, Missiles, Image quality standards, 3D image processing, 3D modeling, Performance modeling

Read Abstract +

Proceedings Article | 31 August 1993 Paper

Integrated approach to the modeling of system-level performance for autonomous imaging IR systems

Brian Brackney, James Dawson

Proceedings Volume 1969, (1993) https://doi.org/10.1117/12.154735

KEYWORDS: Imaging systems, Systems modeling, Detection and tracking algorithms, Performance modeling, Image processing, Sensors, Phase modulation, Target detection, Target acquisition, Composites

Read Abstract +

Proceedings Article | 13 August 1993 Paper

Multispectral infrared measurements and analysis of terrain and sky backgrounds using novel parameters defined by a regionalized power spectrum model

Emily Vandiver, James Dawson, Wanda Fluhler, Eric Borg, Kimberly Eubank

Proceedings Volume 1967, (1993) https://doi.org/10.1117/12.151056

KEYWORDS: Sensors, Performance modeling, Databases, Image processing, Black bodies, Temperature metrology, Modulation transfer functions, Chlorine, Radiometry, Target detection

Read Abstract +

Proceedings Article | 16 September 1992 Paper

Resolving the differences in oversampled and undersampled imaging sensors: updated target acquisition modeling strategies for staring and scanning FLIR systems

Philip Owen, James Dawson

Proceedings Volume 1689, (1992) https://doi.org/10.1117/12.137957

KEYWORDS: Forward looking infrared, Sensors, Imaging systems, Systems modeling, Infrared imaging, Performance modeling, Radiometry, Staring arrays, Target detection, Target acquisition

Read Abstract +

Proceedings Article | 1 September 1991 Paper

Solutions to modeling of imaging IR systems for missile applications: MICOM imaging IR system performance model-90

Philip Owen, James Dawson, Eric Borg

Proceedings Volume 1488, (1991) https://doi.org/10.1117/12.45795

KEYWORDS: Systems modeling, Sensors, Imaging systems, Thermal modeling, Performance modeling, Electro optical modeling, Modulation transfer functions, Infrared imaging, Visual process modeling, Thermography

Read Abstract +

Showing 5 of 12 publications

Conference Committee Involvement (13)

Infrared Imaging Systems: Design, Analysis, Modeling, and Testing XXXVI

13 April 2025 | Orlando, Florida, United States

Infrared Imaging Systems: Design, Analysis, Modeling, and Testing XXXV

23 April 2024 | National Harbor, Maryland, United States

Infrared Imaging Systems: Design, Analysis, Modeling, and Testing XXXIV

3 May 2023 | Orlando, Florida, United States

Infrared Imaging Systems: Design, Analysis, Modeling, and Testing XXXIII

6 April 2022 | Orlando, Florida, United States

Infrared Imaging Systems: Design, Analysis, Modeling, and Testing XXXII

12 April 2021 | Online Only, Florida, United States

Showing 5 of 13 Conference Committees

Keywords/Phrases

Search In:

Publication Years