Night Vision Store Terminology

HOW NIGHT VISION WORKS

2005-12-21T18:35:00.000-08:00

HOW NIGHT VISION WORKS

Author - C. J. Boedeker - The Night Vision Store & The
Opticstore

http://www.nightvisionstore.com

http://www.opticstore.com

During the history of warfare, operations at night have always
been degraded significantly, if not totally avoided. Typically,
soldiers fighting at night have had to resort to artificial
illumination, e.g., at first fire and later with light sources
such as searchlights. The use of light sources on the
battlefield had the detrimental result of giving away tactical
positions and information about maneuvers. The advent of new
technologies initially in the 1950's and continuing into the
present time has changed this situation. The engineers and
scientists at the Night Vision & Electronic Sensors Directorate
(NVESD) have discovered ways to capture available
electro-magnetic radiation outside that portion of the spectrum
visible to the human eye and have developed equipment to enable
the American soldier to fight as well at night as during the day
in order to "Own the Night".

Image Intensification: Image intensifiers capture ambient light
and amplify it thousands of times by electronic means to display
the battlefield to a soldier via a phosphor display such as
night vision goggles. This ambient light comes from the stars,
moon or sky glow from distant manmade sources, such as cities.
A soldier can conduct his combat missions without any active
illumination sources using only image intensifiers. The main
advantages of image intensifiers as night vision devices are
their small size, light weight, low power requirements and low
cost. These attributes have enabled image intensifier goggles
for head-worn, individual soldier applications and resulted in
hundreds of thousands of night vision goggles to be procured by
the US Army. Research and development continues today on image
intensifiers in the areas of longer wavelength spectral
response, higher sensitivity, larger fields of view, increased
resolution, advanced displays and image fusion.

Night Vision technology consists of two major types: image
intensification (light amplification) and thermal imaging
(infrared). Most consumer night vision products are light
amplifying devices.

Light amplification technology takes the small amount of light,
such as moonlight or starlight, that is in the surrounding area,
and converts the light energy (scientists call it photons), into
electrical energy (electrons). These electrons pass through a
thin disk that's about the size of a quarter and contains over
10 million channels. As the electrons travel through and strike
the walls of the channels, thousands more electrons are
released. These multiplied electrons then bounce off of a
phosphor screen which converts the electrons back into photons
and let you see an impressive nighttime view even when it's
really dark. All image intensified night vision products on the
market today have one thing in common: they produce a green
output image. In the night vision world there are generations
that reflect the level of technology used. The higher the
generation, the more sophisticated the night vision technology.

Generation 0 - The earliest (1950's) night vision products were
based on image conversion, rather than intensification. They
required a source of invisible infrared (IR) light mounted on or
near the device to illuminate the target area.

Generation 1 - The "starlight scopes" of the 1960's (Vietnam
Era) have three image intensifier tubes connected in a series.
These systems are larger and heavier than Gen 2 and Gen 3. The
Gen 1 image is clear at the center but may be distorted around
the edges. (Low-cost Gen 1 imports are often mislabeled as a
higher generation.

Generation 2 - The microchannel plate (MCP) electron multiplier
prompted Gen 2 development in the 1970s. The "gain" provided by
the MCP eliminated the need for back-to-back tubes - thereby
improving size and image quality. The MCP enabled development of
hand held and helmet mounted goggles.

Generation 3 - Two major advancements characterized development
of Gen 3 in the late 1970s and early 1980s: the gallium arsenide
(GaAs) photocathode and the ion-barrier film on the MCP. The
GaAs photocathode enabled detection of objects at greater
distances under much darker conditions. The ion-barrier film
increased the operational life of the tube from 2000 hours (Gen
2) to 10,000 (Gen 3), as demonstrated by actual testing and not
extrapolation.

Thermal Imaging:

Most objects in natural scenes, as well as human beings and
manmade objects emit electro-magnetic radiation in the form of
heat. Thermal imagers or infrared viewers (also known as FLIRs)
gather the infrared radiation and form an electronic image for
the soldier. Since they do not rely on reflected ambient light,
thermal imagers are totally light-level independent. They also
have significant penetration capabilities through obscurants
such as fogs, hazes, and conventional battlefield smokes. There
are two varieties of thermal imaging systems: cooled and
uncooled. Cooled thermal imaging requires cryogenic cooling.
Lower performing uncooled thermal imaging systems require no
detector cooling but have sufficient performance to provide the
low to medium performance required by individual soldier sights,
infantry vehicles, navigation, robotics and missile seekers.
Present research and development in cooled thermal imaging are
pursuing multi-spectral imaging, improved sensitivity and
resolution, and embedded signal processing to aid the soldier in
target acquisition missions. Current uncooled research is
directed at smaller size packages and power consumption with
lower cost and increased sensitivity, resolution and field of
view. Small, palm-sized uncooled thermal imagers are now
available.

About the author:
C. J. Boedeker provides Night Vision equipment and Consulting
for both Professional and Hobbyist applications. He is the VP of Sales for The Night Vision Store & The Opticstore

Professional Spy Stuff

2005-12-08T16:52:00.000-08:00

Professional Spy Stuff
Author: Kingston Y. Amadan
Brought to you by The Night Vision Store

http://www.nightvisionstore.com

And The OpticStore

http://www.opticstore.com

Article:
There are plenty of spies stuff around that is in use for amateurs and regular consumers. However, if one is serious about starting a private investigator business, or about offering professional surveillance services, it is essential to have some professional spy stuff. Clients won't take you seriously if you do not have the proper equipment. While it can be fun and useful to have some the smaller stuff, the truth is that there is plenty of high tech equipment, available at a reasonable price, that can help you get your professional business off the ground.

Professional grade listening devices are a must in any arsenal of professional spy stuff. These go beyond the pens outfitted with mics and get into some serious listening ability. Listening devices that can allow you to hear what is being said 300 yards away are ideal for many professional jobs. Simply hook your device into a high tech recorder and listen and record at the same time. It is even possible to use devices that cancel our background noise, allowing you to hear the object of your surveillance much clearer.

Another piece of spy stuff is some sort of night vision accessory. Many operations are done under cover of darkness, and it is important to be able to see without creating a light that could draw attention to your location. Night vision is not just about those goggles that you wear on your head; it is also possible to get binoculars and monocular that can aid you in seeing at night. The best devices do not rely on stars or the moon. This means that you can do surveillance in any kind of weather, no matter how cloudy or dark.

There is no reason why you can't have a professional business with professional grade spy stuff. There are plenty of Web sites that offer equipment at reasonable prices that are affordable to the start up surveillance professional. While such equipment will cost a little more, you will show clients that you can handle any job when you have professional equipment that proclaims that you only use the best when it comes to your spy stuff.
(c) 2005 Copyright www.spyassociates.com. This article is about:
Spy Stuff.
About the author:
To learn more about Spy and Surveillance Products visit
http://www.spyassociates.com

Distortion in Night Vision

2005-11-13T06:39:00.000-08:00

Distortion There are two types of distortion found in night vision systems. One type is caused by the design of the optics, or image intensifier tube, and is classical optical distortion. The other type is associated with manufacturing flaws in the fiber optics used in the image intensifier tube.
Classical Optical Distortion: Classical optical distortion occurs when the design of the optics or image intensifier tube causes straight lines at the edge of the field of view to curve inward or outward. This curving of straight lines at teh edge will cause a square grid pattern to start to look like a pincushion or barrel. This distortion is the same for all systems with the same model number. Good optical design normally makes this distortion so low that the typical user will not see the curving of the lines.
Fiber Optics Manufacturing Distortions: Two types of fiber optics distortions are most significant to night vision devices:
S-distortion and shear distortion: S-Distortion: Results from the twisting operation in manufacturing fiber-optic inverters. Usually S-distortion is very small and is difficult to detect with the unaided eye.
Shear Distortion: Can occur in any image tube that use fiber-optic bundles for the phospor screen. It appears as a cleavage or dislocation in a straight line viewed in the image area, as though the line were "sheared".

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