Fourier Transform Techniques for Imaging Performance Evaluations of Thermal Imaging Cameras Used by the Fire Service.
Fourier Transform Techniques for Imaging Performance
Evaluations of Thermal Imaging Cameras Used by the Fire
Service.
(155 K)
Amon, F. K.; Ducharme, A.
Volume 2;
Interflam 2007. (Interflam '07). International
Interflam Conference, 11th Proceedings. Volume 2.
September 3-5, 2007, London, England, 1537-1542 pp,
2007.
Keywords:
fire departments; fire investigations; FT-IR; thermal
imaging; evaluation; fire fighting; methodology; fire
fighters; first responders
Abstract:
Infrared (IR) technology for fire fighting applications
has matured to the point that most first responder
organizations in the U. S. either have purchased or are
considering the purchase of thermal imaging cameras.
Thermal imagers can provide first responders with
critical information to size up a fire incident, track
fire growth, and to locate victims, other first
responders, and egress routes. While these devices
represent a significant investment, typically on the
order of $10 K per camera, first responders have little
guidance on instrument performance beyond manufacturer
literature and recommendations from other users. These
issues are further complicated because the demands
placed on thermal imagers are application dependent. The
end users may have very different ideas about which
imaging properties are most important: sharp image
contrast may be sufficient for some fire fighting
applications, such as finding the source of a fire, but
high thermal sensitivity may be required to locate a
person or structural component when flames and water are
in the imager's field of view. Currently, there are no
standardized performance guidelines available to aid end
users in making purchasing decisions. Over the past
several years, the Fire Research Division at the
National Institute of Standards and Technology has been
developing a suite of performance metrics and test
methods for inclusion in a national consensus-based
standard on thermal imaging cameras used by first
responders. The performance metrics are related
directly to the environment in which the imagers are
used and taskstypically performed by first responders.
Measurements of contrast, effective temperature range,
spatial resolution, image uniformity, thermal
sensitivity, and the ability to penetrate obscuring
media such as smoke and water vapor are currently
included in the draft standard. The test methods
associated with two of these performance metrics, e.g.,
spatial resolution and effective temperature range, may
benefit from a careful analysis of the frequency content
of the images that appear on the imager's display
screen. As a subset of the overall project, NIST is
working with the College of Optics and Photonics at the
University of Central Florida to investigate two
techniques for transferring the essential
characteristics of complex images generally seen in the
fire environment to relatively simple bench top target
configurations for use in standardized performance
tests.
Building and Fire Research Laboratory
National Institute of Standards and Technology
Gaithersburg, MD 20899