Prof. Patricia A. Howell Profile

Prof. Patricia A. Howell

Engineer at NASA Langley Research Ctr

SPIE Involvement:

Author

Publications (16)

Proceedings Article | 4 May 2020 Presentation + Paper

Quadrupole simulations of three-dimensional structures

William Winfree, Joseph Zalameda, Patricia Howell

Proc. SPIE. 11409, Thermosense: Thermal Infrared Applications XLII

KEYWORDS: Thermography, Matrices, Composites, Interfaces, Diffusion, Resistance, Inspection, Finite element methods, Heat flux, Chemical elements

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Proceedings Article | 2 May 2019 Presentation + Paper

Quadrupole simulations of thermographic inspections of impacted composites

William Winfree, Joseph Zalameda, Patricia Howell

Proc. SPIE. 11004, Thermosense: Thermal Infrared Applications XLI

KEYWORDS: Thermography, X-ray computed tomography, Composites, Inspection, Computed tomography

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Proceedings Article | 11 May 2016 Paper

Simulation of thermographic responses of delaminations in composites with quadrupole method

William Winfree, Joseph Zalameda, Patricia Howell, K. Elliott Cramer

Proc. SPIE. 9861, Thermosense: Thermal Infrared Applications XXXVIII

KEYWORDS: Thermography, Data modeling, Composites, Interfaces, Resistance, Computer simulations, Solids, Finite element methods, Computed tomography, Chemical elements

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Proceedings Article | 12 May 2015 Paper

Measurement of flaw size from thermographic data

William Winfree, Joseph Zalameda, Patricia Howell

Proc. SPIE. 9485, Thermosense: Thermal Infrared Applications XXXVII

KEYWORDS: Thermography, Image processing, Error analysis, Composites, Time metrology, Finite element methods, Computed tomography, Convolution, Chemical elements, Binary data

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Proceedings Article | 12 May 2015 Paper

Principal component analysis of thermographic data

William Winfree, K. Elliott Cramer, Joseph Zalameda, Patricia Howell, Eric Burke

Proc. SPIE. 9485, Thermosense: Thermal Infrared Applications XXXVII

KEYWORDS: Thermography, Principal component analysis, Data modeling, Composites, Resistance, Inspection, Nondestructive evaluation, Data acquisition, Data processing, Thermal modeling

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Proceedings Article | 21 May 2014 Paper

Computational reduction of specimen noise to enable improved thermography characterization of flaws in graphite polymer composites

William Winfree, Patricia Howell, Joseph Zalameda

Proc. SPIE. 9105, Thermosense: Thermal Infrared Applications XXXVI

KEYWORDS: Thermography, Infrared imaging, Radon, Polymers, Image processing, Composites, Inspection, Nondestructive evaluation, Data acquisition, Infrared radiation

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Proceedings Article | 22 May 2013 Paper

Improved sizing of impact damage in composites based on thermographic response

William Winfree, Patricia Howell, Cara A. Leckey, Matthew Rogge

Proc. SPIE. 8705, Thermosense: Thermal Infrared Applications XXXV

KEYWORDS: Thermography, Carbon, Composites, Diffusion, Inspection, Nondestructive evaluation, Ultrasonics, Data acquisition, Time metrology, Fiber reinforced polymers

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Proceedings Article | 10 May 2011 Paper

Improved flaw detection and characterization with difference thermography

William Winfree, Joseph Zalameda, Patricia Howell

Proc. SPIE. 8013, Thermosense: Thermal Infrared Applications XXXIII

KEYWORDS: Thermography, Infrared imaging, Polymers, Composites, Resistance, Inspection, Image registration, Data acquisition, Infrared radiation, Thermal modeling

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Proceedings Article | 18 April 2006 Paper

Development of an extra-vehicular (EVA) infrared (IR) camera inspection system

Michael Gazarik, Dave Johnson, Ed Kist, Frank Novak, Charles Antill, David Haakenson, Patricia Howell, John Pandolf, Rusty Jenkins, Rusty Yates, Ryan Stephan, Doug Hawk, Michael Amoroso

Proc. SPIE. 6205, Thermosense XXVIII

KEYWORDS: Infrared cameras, Thermography, Infrared imaging, Imaging systems, Cameras, Manufacturing, Inspection, Electronic components, Infrared radiation, Thermal modeling

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Proceedings Article | 18 August 2005 Paper

Infrared on-orbit inspection of shuttle orbiter reinforced carbon-carbon using solar heating

P. Howell, W. Winfree, K. Elliott Cramer

Proc. SPIE. 5880, Optical Diagnostics

KEYWORDS: Infrared cameras, Thermography, Signal to noise ratio, Infrared imaging, Principal component analysis, Cameras, Inspection, Nondestructive evaluation, Infrared radiation, Heat flux

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Proceedings Article | 28 March 2005 Paper

Compression techniques for improved algorithm computational performance

Joseph Zalameda, Patricia Howell, William Winfree

Proc. SPIE. 5782, Thermosense XXVII

KEYWORDS: Signal to noise ratio, Principal component analysis, Image compression, Data modeling, Image processing, Composites, Inspection, Nondestructive evaluation, Data processing, Temperature metrology

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Proceedings Article | 10 November 2003 Paper

Computational analysis for thermal NDE of composites

Patricia Howell, Joseph Zalameda

Proc. SPIE. 5191, Optical Diagnostics for Fluids, Solids, and Combustion II

KEYWORDS: Staring arrays, Microbolometers, Infrared cameras, Detection and tracking algorithms, Cameras, Composites, Diffusion, Inspection, Nondestructive evaluation, Anisotropic diffusion

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Proceedings Article | 28 March 1995 Paper

Quantitative thermal imaging of aircraft structures

K. Elliott Cramer, Patricia Howell, Hazari Syed

Proc. SPIE. 2473, Thermosense XVII: An International Conference on Thermal Sensing and Imaging Diagnostic Applications

KEYWORDS: Thermography, Infrared imaging, Imaging systems, Image processing, Skin, Inspection, Corrosion, Nondestructive evaluation, Infrared radiation, Aluminum

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Aircraft structural integrity is a major concern for airlines and airframe manufacturers. To remain economically competitive, airlines are looking at ways to retire older aircraft, not when some fixed number of flight hours or cycles has been reached, but when true structural need dictates. This philosophy is known as `retirement for cause.' The need to extend the life of commercial aircraft has increased the desire to develop nondestructive evaluation (NDE) techniques capable of detecting critical flaws such as disbonding and corrosion. These subsurface flaws are of major concern in bonded lap joints. Disbonding in such a joint can provide an avenue for moisture to enter the structure leading to corrosion. Significant material loss due to corrosion can substantially reduce the structural strength, load bearing capacity and ultimately reduce the life of the structure. The National Aeronautics and Space Administration's Langley Research Center has developed a thermal NDE system designed for application to disbonding and corrosion detection in aircraft skins. By injecting a small amount of heat into the front surface of an aircraft skin, and recording the time history of the resulting surface temperature variations using an infrared camera, quantitative images of both bond integrity and material loss due to corrosion can be produced. This paper presents a discussion of the development of the thermal imaging system as well as the techniques used to analyze the resulting thermal images. The analysis techniques presented represent a significant improvement in the information available over conventional thermal imaging due to the inclusion of data from both the heating and cooling portion of the thermal cycle. Results of laboratory experiments on fabricated disbond and material loss samples are presented to determine the limitations of the system. Additionally, the results of actual aircraft inspections are shown, which help to establish the field applicability for this technique. A recent application of this technology to aircraft repairs using boron/epoxy patches is shown illustrating the flexibility of the technology.

Proceedings Article | 6 April 1993 Paper

Quantitative thermal depth imaging of subsurface damage in insulating materials

K. Elliott Cramer, Patricia Howell, William Winfree

Proc. SPIE. 1933, Thermosense XV: An International Conference on Thermal Sensing and Imaging Diagnostic Applications

KEYWORDS: Thermography, Infrared imaging, Imaging systems, Image processing, Video, Composites, Diffusion, Data acquisition, Video processing, Radiometry

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Proceedings Article | 1 April 1992 Paper

Thermographic imaging of cracks in thin metal sheets

K. Elliott Cramer, William Winfree, Patricia Howell, Hazari Syed, Keith Renouard

Proc. SPIE. 1682, Thermosense XIV: An Intl Conf on Thermal Sensing and Imaging Diagnostic Applications

KEYWORDS: Infrared imaging, Imaging systems, Metals, Image processing, Video, Image analysis, Image filtering, Aluminum, Radiometry, Heat flux

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Proceedings Article | 1 March 1990 Paper

Material property measurements with post-processed thermal image data

Christopher Welch, William Winfree, D. Michele Heath, K. Elliott Cramer, Patricia Howell

Proc. SPIE. 1313, Thermosense XII: An International Conference on Thermal Sensing and Imaging Diagnostic Applications

KEYWORDS: Thermography, Signal to noise ratio, Statistical analysis, Data modeling, Imaging systems, Video, Nondestructive evaluation, Interference (communication), Convolution, Thermal modeling

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Showing 5 of 16 publications

Conference Committee Involvement (2)

Optical Diagnostics

3 August 2005 | San Diego, California, United States

Optical Diagnostics for Fluids, Solids, and Combustion II

3 August 2003 | San Diego, California, United States

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