Thermal systems are excellent for locating people in wooded areas. Photo: FLIR Systems
If your only tool is a hammer, all your problems will look like nails. That's a huge mistake when it comes to the work we do in law enforcement. Whether it's bullets, protective vests, uniforms, duty firearms, or night vision devices, we need the right tools for a particular job.
Quite a few procurement officers have absolutely no idea what the folks in the field really need when it comes to night vision. Nor do they understand the different uses of thermal imaging versus light amplification and when they should be deployed.
There's a reason for this lack of interest and lack of knowledge. Night vision technology is complicated and at one time it was prohibitively expensive, the stuff that only a few agencies and the military could afford. So let's demystify the stuff, discuss its benefits, and talk about how and where you can get it, and why the price is dropping into your affordability range.
Scientists have been studying thermal energy for hundreds of years. Back in the 1700s astronomer William Herschel started identifying the infrared part of the spectrum, invisible to the human eye, by looking at the sun with his telescope using different colored filters. There wasn't much practical application of this science until shortly after World War II when the U.S. Air Force began using downward-looking infrared cameras for reconnaissance missions.
Thermal energy comes from a combination of sources. Some things, including people, engines, and machinery create their own heat, either biologically or mechanically. Other things such as land, rocks, and vegetation absorb heat from the sun during the day and then radiate it off during the night.
Thermal cameras are actually sensors that see and measure thermal energy emitted from an object. Thermal or infrared energy is light that's not visible because its wavelength is too long to be detected by the human eye; it's the part of the electromagnetic spectrum we perceive as heat. Everything with a temperature above absolute zero (-459.67 degrees Fahrenheit) emits heat. So even ice cubes emit infrared energy.
What we see when we look through a thermal camera or scope is a representation in the visible spectrum of the infrared energy emitted by objects. Some thermal camera systems present this image in black and white while other more expensive systems present it in colors that differentiate between temperatures. The color aspect is critical to the fire services so firefighters can make decisions on entering a structure fire safely and maybe even determining the origin of the burn. But we cops mostly deal with people, so color output isn’t a huge factor; it’s nice to have but not mission critical.
Many people think night vision devices were first developed in the 1960s and were a product of the Vietnam War. Not so. The Allgemeine Elektrizitäts-Gesellschaft or German Electricity Company developed the first usable systems in 1939.
During World War II some German Sturmgewehr 44 assault rifles were equipped with a "Vampyr" active night vision system. These earliest, man-portable, Generation 0 devices consisted of a 30-pound battery in a wooden case for the main light and another smaller battery for the image converter. The light was a 35-watt tungsten spotlight equipped with an infrared filter. The battery system was strapped to a pack frame and the light and scope were attached to the rifle. Imagine having to lug that monstrosity around during your regular patrol shift. Thankfully, you won’t have to do so. Today's night vision systems are passive—not requiring any external light source—and can fit into the palm of your hand.
Those old systems were Generation 0. Gen 1 systems used in Vietnam were true "starlight" systems that required no external IR light because they amplified existing ambient light, hence their nickname "Starlight Scopes."
Later, Gen 2 systems incorporated a micro channel plate consisting of a wafer manufactured from thousands of hollow glass tubes to boost light amplification to 30,000 times. Increasing layers of wafers can achieve 1 million times amplification.