The price of night vision is coming down, and the quality/performance is going up. So let’s talk a little about the various options in night vision so you end up buying what works best for you. There are three main categories of night vision; Digital, Intensified, and Thermal.
Digital Night Vision is the newcomer so lets start there. Digital night vision works basically like a digital video camera. Sensors magnify light onto a viewing screen and microprocessors auto adjust the resolution and pixels to provide fairly clear images in nearly complete darkness. Like standard amplifying night vision, InfraRed (IR) Illuminators can be used to increase the amount of light to enhance and/or brighten the image.
Digital night vision is fairly inexpensive and provides results similar to 1st Generation amplifying night vision devices. Rather than the tradition green hue of amplifying night vision, you get a gray-scale or black and white image. For the money, Digital night vision is probably a better choice than 1st Generation traditional devices. The resolution and clarity will be a little better – especially when using the IR illuminator.
Unlike an Intensifier tube, “Ultra Bright” digital scopes do not have to worry about exposure to bright light. These issues simply do not exist in the digital products. This means digital night vision devices can be used during the day as well.
Digital devices offer the ability to adjust brightness levels according to your need. Most Intensified systems do not offer that ability. Many of the digital systems offer various ways to record what you see. With classical Intensified systems is also possible to record night time scenes but require additional camera equipment that is attached via camera adapter to the device.
Here are a couple of comparison images:
The first image, of each set of pictures, is 1st Generation Intensified and the second is from a Digital System.
Intensified Night Vision is what most people are familiar with. They give you the green hued images seen in the movies and on CNN. Intensified Night Vision does exactly as its name implies. It intensifies existing light and produces the image on a screen. A Night Vision Device can be either a 1st, 2nd, 3rd or 4th generation unit. What this stands for is what type of image intensifier tube is used for that particular device; the image intensifier tube is the heart and soul of an NVD.
1st generation is currently the most popular type of night vision in the world. Utilizing the basic principles described earlier, a 1st generation unit 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.
2nd generation is primarily used by law enforcement or for professional applications. 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 systems add a light sensitive chemical that greatly enhances light magnification over and above 2nd generation systems. 3rd Generation is the standard for the U.S. military. Additionally, resolution increases with each generation as well. 3rd generation systems are very expensive… generally starting around $3,000.
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. Filmless inverting image intensifier tubes improve night operational effectiveness for users of night vision goggles and other night vision devices. The filmless micro channel plate provides a higher signal-to-noise ratio than standard 3rd Gen. tubes, resulting in better image quality under low-light conditions. An Autogated power supply further improves image resolution under high light conditions and a reduced halo effect that minimizes interference from bright light sources. The reduced Halo maximizes the effectiveness of the Night Vision device in dynamic lighting conditions such as those experienced, for example, in night operations in urban areas.
1st Gen 2nd Gen 3rd Gen 4th Gen
Thermal Night Vision – All objects, both natural and manmade, emit infrared energy as heat. By detecting very subtle temperature differences of everything in view, infrared (or thermal imaging) technology reveals what otherwise would be invisible to the naked eye. Even in complete darkness and challenging weather conditions, thermal imaging gives users the ability to see the unseen.
First developed for military purposes, thermal imaging has since been adopted by law enforcement, fire and rescue teams and security professionals.
For law enforcement and security staff, thermal imaging detects suspicious activity over long distances in total darkness and through fog, smoke, dust, and foliage. This allows officers to approach in stealth mode and make better informed decisions more quickly. Cameras may be handheld, vehicle-mounted, tripod-mounted, or weapon-mounted.
For security and surveillance systems, thermal imaging cameras complement CCTV cameras to provide comprehensive threat detection and integrate seamlessly with larger networks. For predictive maintenance, thermal imaging reveals “hot spots” where failure may be imminent in many electrical and industrial facilities and installations.
In order to understand thermal imaging, it is important to understand something about light. The amount of energy in a light wave is related to its wavelength: Shorter wavelengths have higher energy. Of visible light, violet has the most energy, and red has the least. Just next to the visible light spectrum is the infrared spectrum.
Infrared light can be split into three categories:
- Near-infrared (near-IR) – Closest to visible light, near-IR has wavelengths that range from 0.7 to 1.3 microns, or 700 billionths to 1,300 billionths of a meter.
- Mid-infrared (mid-IR) – Mid-IR has wavelengths ranging from 1.3 to 3 microns. Both near-IR and mid-IR are used by a variety of electronic devices, including remote controls.
- Thermal-infrared (thermal-IR) – Occupying the largest part of the infrared spectrum, thermal-IR has wavelengths ranging from 3 microns to over 30 microns.
The key difference between thermal-IR and the other two is that thermal-IR is emitted by an object instead of reflected off it. Infrared light is emitted by an object because of what is happening at the atomic level.
A special lens of thermal scope focuses the infrared light emitted by all of the objects in view. The focused light is scanned by a phased array of infrared-detector elements. The detector elements create a very detailed temperature pattern called a thermogram. It only takes about one-thirtieth of a second for the detector array to obtain the temperature information to make the thermogram. This information is obtained from several thousand points in the field of view of the detector array.
The thermogram created by the detector elements is translated into electric impulses. The impulses are sent to a signal-processing unit, a circuit board with a dedicated chip that translates the information from the elements into data for the display. The signal-processing unit sends the information to the display, where it appears as various colors depending on the intensity of the infrared emission. The combination of all the impulses from all of the elements creates the image.
Unlike traditional most night-vision equipment which uses image-enhancement technology, thermal imaging is great for detecting people or working in near-absolute darkness with little or no ambient lighting (i.e. stars, moonlight, etc, )
So, what’s the best night vision for you? If you need to detect things like people, animals, etc, then Thermal devices are your best choice. They’re also the most expensive. Cost is going to be a major determining factor. You can get a good Digital Night Vision Monocular for around $250. Thermal is going to start out around $2,500! Standard night vision is tougher and generally more durable than Thermal systems. Additionally, you get longer battery life from standard night vision.