"In the United States today, there are more than 50 companies that either manufacture or distribute night vision equipment. Departments considering a purchase of this equipment will encounter a potentially confusing array of technical specifications and terminology, and mistakes can be costly. To help departments evaluating night vision systems to make informed decisions, this bulletin of the National Law Enforcement and Corrections Technology Center (NLECTC) presents basic information on night vision technology and terminology, factors to consider when evaluating night vision systems, and new developments in night vision."
National Institute of Justice (U.S.): http://www.nlectc.org/pdffiles/nitevisn.pdf
National Law Enforcement Corrections Technology Center Bulletin (March 1996)