Practical Measurement and Analysis of the Nonuniformity of Thermal Imaging Cameras for First Responders

Published

March 17, 2008

Author(s)

Andrew J. Lock, Francine K. Amon, Anthony P. Hamins

Abstract

Police, firefighters, and emergency medical personnel are some of the first responders that are utilizing thermal imaging cameras in a very practical way every day. However, few performance metrics have been developed to assist first responders in evaluating thermal imaging technology. This paper describes one possible metric for evaluating the nonuniformity of commercial thermal imaging cameras. Several commercially available uncooled focal plane array cameras are examined. Because of the proprietary property issues, each camera is considered as a black box . A well defined thermally uniform target is imaged with the focal plane array, and then the resulting National Television Systems Committee (NTSC) standard output signal is digitized. In these experiments a large area surface black body (18 cm square) is placed very close to the objective lens of the thermal imaging camera. The resultant NTSC output from the camera is digitized at a resolution of 640x480 and a grayscale depth of 10 bits. The nonuniformity is calculated as the standard deviation of each digitized image pixel intensities divided by the mean of the pixel intensities. This procedure is repeated for each camera at several blackbody temperatures in the range from 30 C to 300 C. It is observed that the nonuniformity of each camera increases linearly with temperature for the operational range (30 C to 230 C) of temperatures and then asymptotically approaches a second maximum value. The testing procedures described herein are being developed as a suite of tests to be incorporated into a performance standard covering thermal imaging cameras for first responders.

Citation

SPIE Defense and Security Conference

Pub Type

Journals

Keywords

fire, first responders, nonuniformity, thermal imaging camera, uniformity

Citation

Lock, A. , Amon, F. and Hamins, A. (2008), Practical Measurement and Analysis of the Nonuniformity of Thermal Imaging Cameras for First Responders, SPIE Defense and Security Conference (Accessed July 10, 2025)