If you are to truly understand thermal imaging for security and safety, you must first understand a simple scientific fact. Visible light, invisible light and radio waves are all fundamentally the same thing: electromagnetic radiation. Each has a unique frequency (the rate at which a wave is created each second) and amplitude (intensity), and each plays an important role in security video imaging.
Differentiating Between Cameras
We have access to several different styles of camera for security video that create images based on different portions of the electromagnetic spectrum.
• Day/night. Many of you may refer to these units as color/black-and-white cameras. They can produce full-color images under good lighting and then switch automatically to black and white in lower light levels.
• Intensified. These units can produce usable, clear images in almost no light through the use of electron excitement and/or pixel enhancement. They often work in less than .000001 fc (.00001 lx).
• Infrared (IR). These units work in that invisible light zone just between visible light and microwaves.
• Radio wave. These cameras are fairly new to the security industry. In simplest, non-technical terms, they project radio waves that penetrate saline-based objects (such as the human body) up to a couple of inches. They give us the ability to detect, see and identify weapons and/or explosives being carried by individuals regardless of the clothing that hides them.
All of these cameras require some sort of light or electromagnetic radiation to be projected or reflected to create an image. If left out in the dark, all these camera styles would be totally blind. So we come to our final category of cameras: thermal.
Thermal cameras are the only cameras available to the security industry that require no reflected light, IR light or radio waves. They work off the principle of radiated energy. That is to say, all objects produce, store, dissipate and/or absorb heat. Therefore, if given a thermometer, all objects, animate or inanimate, could have their temperatures taken. The thermal camera takes the temperature of a scene in micro units and creates an image in which the colds are contrasted with the hots.
Thermal Goes Mainstream
Ten years ago, cumbersome was a polite definition of thermal camera size. The images created by these cameras were a mix of van Gogh and The Twilight Zone —warm-colored bodies moving through a sea of blacks, reds and blues. Even five years ago, the price tags on these units—in the tens of thousands of dollars—left them to the rich and the government. However, modern technology has allowed enhancements and improvements to both the physical and the technical side of these cameras.
Thermal cameras are now the size of large desk phones, and they can be easily placed within any standard analog or IP-based video system. The images are now available in easy-to-look-at, computer-enhanced full color. Thanks to supply and demand and the overall drop in technology cost, the thermal camera has become affordable to everyday industrial security applications. Today, you can pick up a good thermal camera for less than $5,000.
Where Can You Use Them?
OK, so thermal cameras are smaller and more affordable. That doesn't convince you that you need one. Say you have a simple security issue and you have plenty of light on your property. If that's the case, then you're right; you don't need this camera. However, if you are like thousands of others, you have some serious lighting issues in the back confines of your property or buildings. Stop thinking spy networks and mystery shots. Think applications.
I reviewed a job a year or so ago for a company that had to increase the general security around its perimeter fence line in order to comply with new security guidelines passed down from the corporate office. After a complete technical site review, they found that putting up five thermal cameras with good lenses was far less expensive than adding 20 new lights and poles at $15,000 a pop.