Night Vision
Why Use a Night Vision Device?
Many nights in the backcountry are far from dark. A bright moon and a sky full of stars can throw off enough light to allow for reading a book, but add cloud cover, mountains or trees and it gets dark awfully fast. When you need to see in the dark, you have two choices - you either turn on a light, or use one of the many available night vision devices (NVD). The NVD could be the ultimate backcountry toy.
Like choosing many other types of technology, choosing the correct NVD is all about how you are going to use it. When most people think of night vision capabilities, they think about spy movies, the military or law enforcement - applications where it is vital for the good guys to see without being seen by the bad guys. A drop in pricing over the past few years has made a NVD affordable for campers, hunters, hikers and a wide variety of other outdoor enthusiasts. However, high-end devices used for specialized purposes remain quite expensive.
There are two broad categories of NVD. Image Enhancement devices collect small amounts of light and amplify them to the point where the human eye can observe the object. Infrared Imaging devices capture the infrared light spectrum which is emitted as heat by objects. Image Enhancement devices will provide a much crisper image with detail while Infrared Imaging devices show regions of infrared light. Currently, five Generations of NVD exist. Generations 0 and 1 are less expensive and typically produce a poor image quality. Generations 2, 3 and 4 have increasingly better image quality and an equally increasing price to match.
Applications for NVD are actually quite diverse. They include but are not limited to: military, law enforcement, hunting, wildlife observation, surveillance, security, navigation, hidden-object detection, spelunking and entertainment. NVD can be found on helicopters, rifles, camcorders, cameras, boats….just about anywhere. A new craze found at up-scale gatherings is called “A Dinner in the Dark Party” where guests wear an NVD throughout their dining experience.
Many outdoor enthusiasts are beginning to discover the wonderful world that can be found after darkness falls in the backcountry. If you like to camp, hike or hunt, chances are good an NVD will be perfect for you.
Types of Night Vision:
Currently there are two different types of night vision technology. One is traditional image intensifier tube technology and the other is pure digital night vision technology.
Image Intensifier Tube Technology:
A Night Vision Device can be either a 1st, 2nd, 3rd or 4th generation unit. What this stands for is what type of light intensifier tube is used for that particular device The light intensifier tube is the heart and soul of an traditional NVD.
1st Generation is currently the most popular type of night vision in the world. Utilizing the basic principles described earlier, a 1st generation will amplify the existing light several thousand times letting you clearly see in the dark. These units provide a bright and sharp image at a low cost, which is perfect, whether you are boating, observing wildlife, or providing security for your home. You may notice the following when you are looking through a 1st gen unit
- A slight high-pitched whine when the unit is on.
- The image you see may be slightly blurry around the edges. This is known as Geometric Distortion.
- When you turn a 1st gen off it may glow green for some time.
- These are inherent characteristics of a 1st gen and are normal.
2nd Generation is primarily used by law enforcement or for professional applications. This is because the cost of a 2nd gen unit is approximately $500.00 to $1000.00 more then a 1st gen. The main difference between a 1st and a 2nd generation unit is the addition of a micro-channel plate, commonly referred to as a MCP. The MCP works as an electron amplifier and is placed directly behind the photocathode. The MCP consists of millions of short parallel glass tubes. When the electrons pass through these short tubes, thousands more electrons are released. This extra process allows 2nd generation units to amplify the light many more times then 1st generation giving you a brighter and sharper image.
3rd Generation By adding a sensitive chemical, gallium arsenide to the photocathode a brighter and sharper image was achieved over 2nd generation. An ion barrier film was also added to increase tube life. Gen. 3 provides the user with good to excellent low light performance.
4th Generation (Gated Filmless technology) represents the biggest technological breakthrough in image intensification of the past 10 years. By removing the ion barrier film and "Gating" the system Gen 4 demonstrates substantial increases in target detection range and resolution, particularly at extremely low light levels.
The use of filmless technology and auto-gated power supply in 4th generation image intensifiers result in:
- Up to 100% improvement in photo response.
- Superb performance in extremely low light level (better S/N and EBI)
- At least triple high light level resolution
With significant improvement in contrast level and in performance under all light conditions, 4th generation represents the top of the line performance in the night vision market.
Gen 4 technology improves night operational effectiveness for military users of night vision goggles and other night vision devices. The filmless MCP provides a higher signal-to-noise ratio than Gen 3, resulting in better image quality (less scintillation) under low-light conditions. The gated power supply further improves image resolution under high light conditions, and the reduced halo minimizes interference from bright light sources. These improvements also substantially increase the detection range of the systems.
Pure Digital Night Vision Technology: The pure digital night vision device takes the advantages of the latest CMOS or CCD sensors technology which can work in a low light environment with IR Illuminator. It collect existing light through the objective lens, which is then processed through a highly sensitive sensors and then transferred to a micro-display.
Digital night vision is a newer consumer technology that gives results similar to image intensifier technology with some additions and advantages. The positive side is that this technology can give results that are comparable to Generation 1 and 2 devices at less cost and without the distortions
The technology for this type of night vision is quite different from standard night vision and generally works like this. The light comes into the device through an objective lens and is then processed through a highly sensitive charged coupling device (CCD) and then sent to a Liquid Crystal Display (LCD) where you can view the image. This can vary a bit and there might be an eyepiece to look into to view the output rather than a LCD screen.
One great advantage of Digital Night Vision is that you can also look through these devices in the daylight without the concerns of damaging it. They are amplify available light and require an IR illuminator to see in dark areas. Most digital night vision devices are equipped with IR illuminator (a bank of small IR lights). They also often come with multiple filters so that the image can be viewed in shades of green, red or gray. The green filters give you the greatest image contrast and detail and appear similar to standard night vision devices.
Infrared (IR) Illuminator: All NVD need some light to amplify. This means that if you were in complete darkness you could not see. Due to this we have a built in infra-red illuminator (IRI) on all of our scopes. Basically what an IR Illuminator does is throw out a beam of infra-red light that is near invisible to the naked eye but your NVD can see it. This allows you to use your scope even in total darkness. The IR Illuminator works like a flashlight and the distance you can see with it will be limited. We do use the most powerful eye-safe illuminator on the market. This allows our IR Illuminator to extend out to 100 yards However, because of the power at a short distance the IRI may cover only 40-60% of the viewing area.
Micro-Display: A type of LCD flat-panel display screen in which each pixel is controlled by from one to four transistors. The micro-display technology provides the best resolution of all the flat-panel techniques.
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