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This is a technical historical chronicle of the past and on-going development of performance models for electro-opticalsensors carried out by the U.S. Army CECOM NVESD, the original Night Vision Laboratory. The emphasis has been onthermal imaging models and is also the focus ofthis paper. The origin ofthe Johnson criteria is shown and the resultingmodels that have evolved from the original concept proposed by John Johnson. The present formulations ofthe models aredetailed and the newest developments are introduced. The force that drives the various improvements in the models is thedevelopment ofmore sophisticated thermal imagers whose performance must be described and predicted. Backgroundsupporting developments in laboratory measurements and field validation are indicated.Keywords: FLIR modeling; thermal imagers; Johnson criteria; Minimum resolvable temperature; Mmimum detectabletemperature; detection; recognition; identification. 1. Introduction The development and fielding ofthermal imaging, or Forward Looking Infrared (FLIR), systems by the U.S. Army over thelast 30 years has been led by the development and exercise ofvalidated performance models. These models were and still arebeing improved by the U.S. Army Communications-Electronics Command (CECOM) Research, Development &Engineering Center's (RDEC) Night Vision & Electronic Sensors Directorate (NVESD) at Ft. Belvoir, VA. This modelingapproach has been adopted by the other services, NATO and industry to optimize designs, predict operational performance,select contractor proposals and generate performance specifications. The modeling approach is based upon the uniqueconcept ofJohn Johnson ofNVESD that relates a laboratory measurement of"resolvable cycles across a target" to targetacquisition performance in the field. This innovative concept when coupled with extensive validation data from thelaboratory and the field has provided a powerful tool for the infrared and thermal imaging community. Models have alsobeen developed based on this same principle for otherelectro-optical imaging systems, such as image intensifiers andtelevision. This paper will concentrate primarily on the FLIR modeling. |
