Thermal imaging in protection, next to video analytics, is probably one of the hottest topics. Why? This is in part due to the recent significant increase in the cost of physical protection (implemented by man), and thus the search for solutions that can replace or effectively support this man. The second issue is the fact that thermovision is an area of technology that has recently developed, miniaturized and become unusually advanced. Remember that the first thermal imaging cameras were built in the 1950s - mainly based on individual infrared radiation photon detectors cooled with liquid nitrogen. At the end of the 1990s, a breakthrough occurred because relatively cheap matrices of uncooled thermal detectors were constructed. What we are observing now is the further development of this technology. So it's nothing new.
Replay in physics - how thermovision works.
How thermovision differs from normal cameras and why this difference is so important from the point of view video monitoring systems used in security? Here's a reminder of physics in a nutshell. Question: why do we see "something"? We see because the retina in our eye (which is something like the CCD matrix in the camera), records the light reflected from the observed object. Reflected light, that is, which "flies" from the sun or light bulb towards the object and then is reflected and hits the eye. If there is no light (it is total zero) we will see nothing. And a regular camera won't see either. To see something we have to turn on the light. Simple. In the case of classic CCD cameras, instead of the sun or light bulb, we can also use infrared (IR) lighting. The radiator illuminates the object and the CCD matrix records the reflected radiation. A wider range of frequency sensitivity (than human) allows the camera to process this image and present it to the viewer. The answer to the question: "why do we use IR and not just light" is another matter entirely ...
It's different with thermography. Thermovision registers electromagnetic radiation generated by the object itself. Not reflected, only generated. In this case, it is infrared radiation, invisible to the human eye with a wavelength of 780nm to 1mm, which is commonly referred to as thermal radiation (because it heats). In thermal imaging cameras we only use a section of this band from 7.5μm to 13.5μm. We don't see it but the machine (infrared camera) can see. This is the significant difference between classic cameras and thermal imagers. It is from this that the implementation possibilities in specific applications result. This is why thermovision has a future in protection, especially in solutions for remote video surveillance such as e.g. Safestar monitoring station.
Imagine a sauna, not too hot - one with a temperature of 36.6 degrees Celsius - is the body temperature of a healthy person. Let's put him in there (naked). What should you do to see a man in this sauna through a classic camera? You have to turn on the light. Simple. And what to do to see this man through a thermal imaging camera? Increase or decrease the sauna temperature. Then, against the background of the general temperature prevailing in our sauna, man will be either warmer or colder and then we will see him. Simple? Of course, this is an illustrative example. If anyone would have doubts, I invite you to comment.
This and no other way of observation by a thermal imaging camera is extremely useful in protection. Why? Because the observed silhouette stands out significantly from the average background. Inanimate matter, which is often the background, has a temperature much lower than the human body - unless these are extreme conditions. Therefore, a man with a temperature of 36.6 is clearly visible. It is the same as we should dress bright clothes with reflections so that we are more visible on the road - then we will stand out better from the background in visible light. Let's look at the example below. The same shot from two cameras. Thermal imaging on the left, high sensitivity video camera on the right. Without straining your eyes, you can clearly see a man in the left picture. In this case, video analytics will also work very well, but I will write about this in the next article.
And what's in it for us to protect?
A lot. To more accurately imagine the potential of thermal imaging technology in protection, let's look at an example below. On the left, we see an image from an ordinary video camera, which would most likely lack dynamics to see a man in the middle of the room, not to mention that we would certainly not see him through the smoke. And we don't see. On the right, the same shot from the thermal imaging camera. You can clearly see a man without a doubt. So we stop worrying if it's dark or light, whether it's fog or smoke - we'll notice the intruder.
Let's see another example now. Outdoor areas - perimeter protection. On the left we see the image recorded with a video camera. Good luck to the system operator (and video analytics) to capture the intruder there. In the image of the thermal imaging camera, the intruder is visible.
And so you could show a lot of different examples. However, my goal is not to present individual cases of thermal imaging. Giving you the basis for understanding how thermovision works, I would like you to imagine the specific applications and benefits that you will get from using it. Such an interesting application can be the use of such a camera in the system Safestaras a source of alarms - something like a very advanced detector. Remember, however, that very often you should also install a classic camera in parallel with a thermal imaging camera. In real applications it may turn out that thermovision in protection, although it captures the intruder more efficiently, may not provide enough details needed for its neutralization or identification.
Thermovision in protection will be increasingly used, but it will have to be supported by classic cameras.
The next material I will prepare for you will be an article about the use of video analytics operating on infrared images. I will show you why analyzing thermal imaging from a security point of view is much more efficient and effective than the image from classic video cameras. I cordially greet you, see you, hear or read!
The photos used come from FLIR, HIKVISION and DAHUA advertising materials.