NCJ Number
206123
Date Published
March 1996
Length
8 pages
Annotation
This report presents information about night vision technology and terminology, new developments in night vision, and factors to consider when evaluating night vision systems.
Abstract
Police departments now face an array of night vision systems from which to chose; there are currently more than 50 companies manufacturing or distributing night vision equipment. To assist local jurisdictions in making informed decisions about night vision systems, this report begins by reviewing basic information about night vision equipment. The history of night vision technology is sketched and a description of how image intensifiers work is offered; the most widely used night vision technology in law enforcement is image intensifier equipment. Current image intensifier night vision equipment is in the form of hand-held viewers for use with one eye or two, thus the first consideration when evaluating night visions systems is the purpose of the system and under what conditions it will be used. If the user will most likely be mobile, binocular goggles are a good choice as they allow the user to walk, run, or pilot a vehicle while using the equipment. Another consideration is the equipment the department already has on hand; night vision equipment can often be adapted to work with photography equipment and video cameras. A third consideration is the location in which the night vision equipment will be used. In rural environments with less residual lighting, generation 3 (Gen3) equipment is best, while in urban environments with a lot of ambient light, generation 2 (Gen2) equipment is the best choice. Performance factors are another important consideration and include the following parameters: photosensitivity, signal-to-noise ratio, gain, equivalent background input, resolution, magnification and field of view, distortion, and weather resistance. Details of each are enumerated in turn. Additional factors to consider include human factors, such as ease of use, and cost. Specific advice is offered on how to evaluate the strengths of systems based on what is included with the system. For example, it is best to avoid reconditioned tubes as their operational life is usually short. Finally, thermal imaging is described as a new development in night vision. How it works, its unique capabilities, and its limitations are explored. Contact information is provided for further information.
Date Published: March 1, 1996