When I started this review I was immediately reminded of one of my favorite movies – Terminator 2, or rather not the whole movie, but the little bit where Terminator, Sarah Conor and John are driving in a car in complete darkness with the lights off. And a surprised John asks the Terminator with childlike directness if he can see anything. And the Terminator, with the directness of a Terminator, answers that he sees everything. And then on the screen we see an image of what the terminator sees, which is very similar to the images from the thermal imaging camera.
Not long ago it seemed like science fiction and today if your security guard suddenly tells you that he can see everything in total darkness, don’t think he’s watched Terminator 2, he probably already has thermal imaging cameras installed in the place. Just a little bit of theory.
All objects with a temperature above absolute zero (-273 ℃) are sources of thermal radiation. Invisible to the human eye, this type of radiation can be detected by special devices, thermal imaging cameras.
It is these devices that formed the basis of thermal surveillance cameras, which can operate as an independent standalone system, as well as part of a classic video surveillance system.
Thermal imaging cameras capture images in the visible part of the spectrum by determining the temperature difference between an object and its surroundings.
The higher the temperature of an object the more intense the radiation. The greater the temperature differences between different objects, the brighter and more contrasting the images will be.
Benefits of thermal imaging cameras
1) Operating in total darkness
Thermal imaging cameras can operate effectively in much more challenging conditions than conventional CCTV cameras. The sensor is designed to withstand the toughest weather conditions and operates in complete darkness.
2) Operation in harsh environments
Smoke, fog, snow, rain, sandstorms, heavy vegetation – no matter what the challenges, thermal imaging is a reliable and effective solution for round-the-clock video surveillance.
3) Giant detection ranges
Traditionally classic CCTV systems can have three aims – Detection, Recognition, Identification.
Depending on the model, distances can be up to:
For humans
Detection – up to 1500 meters
Recognition – up to 400 meters
Identification – up to 190 meters
For cars
Detection – up to 5000 meters
Recognition – up to 1500 meters
Identification – up to 600 meters
Thermal imaging cameras, despite the low resolution of their sensors, perform much better for these traditional surveillance applications.
With thermal imaging cameras the first two tasks are defined in exactly the same way as in a classic thermal imaging camera.
Detection is the process of capturing the appearance of an object.
Recognition is when you can already classify an object, such as whether it is a person or a car.
Identification, on a thermal imaging camera, means being able to assess the height of a person or the size of a car, for instance. That means there is a limited amount of identification available for thermal imaging cameras.
4) Reducing false alarms.
The peculiarity of using motion detectors in traditional CCTV cameras is a large number of false alarms. It could be snow or rain, tree branches moving in the wind, or a plastic bag or leaves also moving in the wind.
All these false alarms are almost impossible to cut off in traditional CCTV systems.
Thermal video surveillance cameras do not have this disadvantage. The number of false alarms is greatly reduced, as well as the workload of the personnel who somehow have to handle alarm messages.
5) No problem with backlighting
Achilles’ heel of the classic video surveillance systems is ambient light. The most common type of backlighting is sunlight, depending on the location of the sun’s rays can both significantly degrade image quality and completely blind the camera.
And if modern cameras can effectively cope with insignificant backlighting. But intensive illumination is a problem. By the way, the intruders know about it and actively use this method to temporarily disable individual cameras. Thermal surveillance cameras are completely devoid of this disadvantage.
6) High detection accuracy
Built-in smart features such as area intrusion and line cross detection can automatically send an alarm, as well as automatically set the rotation and zoom to get more detailed information on the required area, these solutions are most effectively used for perimeter security
7) Concealed location
Conventional CCTV cameras working in darkness are always supplemented with powerful light sources – infrared or conventional. Naturally these light sources clearly indicate the location of the camera.
Thermal imaging cameras do not use any light source and their location can thus not be detected in total darkness.
Applications
The advantage of thermal imaging cameras is that they can be used with standard IP-Surveillance cameras on the same software.
Perimeter Security
Prevent intrusion into sensitive areas
Quick video target acquisition and alarm trigger even in total darkness and adverse conditions such as rain, snow, dust and smoke
Fire prevention
Fire alarms are usually perfectly capable of announcing fires, but only if they are used indoors.
As you understand modern large industrial enterprises are including a very decent area in the open air. Including such areas can often be used for the storage of inventory.
Or it could be construction projects not yet put into operation, which means they also usually can not apply a classic fire alarm system.
And of course natural forest or peat fires are quite common, including in our latitudes.
Thermal imaging cameras in case of fire automatically detect deviation from temperature range and automatically sends an alarm to the guard’s monitor or cell phone of responsible person.
Equipment temperature measurement
High precision temperature measurement that CCTV thermal imaging cameras can provide allows very widespread use in manufacturing plants for fixing the temperature changes of equipment. Changes in equipment temperature usually clearly indicate a malfunction. With the help of a thermal imaging CCTV camera this can be diagnosed in time and prevent a breakdown.
For the use of thermal imaging CCTV cameras in industry, manufacturers have allocated a separate class of thermometric equipment.
Thermometric equipment allows to solve two big problems temperature deviations and so-called precision thermometry
Temperature deviations
It allows you to set the exact temperature above which you will receive an alarm message The software allows you to set the critical temperature above which the system sends an alarm. Responding to it in time avoids excessive wear and tear and prevents accidents.
Accurate thermometry
It is not always necessary to monitor critical temperatures and send out an alarm, in many cases it is necessary to monitor the temperature of different objects online. Precise thermometry is used for this purpose.
Allows a frame received from the camera to set points or areas where it will reflect the exact temperature to be fixed by the camera at these points or in this area.
Disadvantages of IP-camera with infrared illumination
The first and most enormous disadvantage is the range of detection, thermal imaging cameras human detection distance – up to 1500 meters.
Most IP-cameras with IR illumination IR illumination range is on average 20-50 meters.
But in most cases this range can also be achieved by using a collimator lens. Therefore, the most important indicator for IR illumination is the angle of illumination, the greater the angle the smaller the range.
Infrared illumination is the light and heat, and both are known to attract a variety of insects, and where insects there and spiders, the problem of spider web control is one often enough discussed on the forums of “experienced” installers.
And the only correct way to fight, is the use of a camera without built-in IR illumination and freestanding IR illuminator. But even the most powerful IR illuminators have a limited range.
All these disadvantages are deprived thermal imaging cameras, all that sees such a camera will be evenly illuminated, and of course there will be no cobwebs.
And the cherry on the cake of IP-cameras with IR-illumination in comparison with thermal surveillance cameras – will be impossible to detect anything whatever it was in the conditions – snow, rain, smoke, fog, backlighting, both natural sunlight and artificial, for example with a flashlight). All these are not a problem for thermal imaging cameras at all.
Cloaking from thermal imaging cameras
A common misconception, dating back to the classic movie Predator, starring Arnold Schwarzenegger. Arnold’s character becomes invisible to the Predator’s thermal vision by covering himself in mud.
In practice, the mud will instantly warm up and will be perfectly visible in the thermal imager. But even if we assume that the person will be in a spacesuit made of insulating material, to assume, because at the moment there are no such, such a spacesuit will still let some heat through, at the moment there are almost no materials that do not let the heat radiation through. Which means it will be discovered.
There are only two materials that are impermeable to thermal radiation – glass and water. And both are not suitable for the creation of a spacesuit.
Any other camouflage will only reduce the contrast of the image, but it will not make the object invisible to the thermal imager.
Become invisible to a thermal imaging camera
There’s only one way to become invisible to a thermal imaging camera and that’s with some reservations, as the human body temperature is known to be 36.6 degrees Celsius, it’s also known that the ambient temperature could well reach the same value. In theory, this would mean invisibility, i.e. indistinguishability of the temperature of the object and the environment.
In practice, the temperature of the human body differs from one part of the body to another, just as the temperature of environmental objects is heterogeneous. It is due to this heterogeneity of the human body temperature, both visually by the operator and by the motion detector, the person will be detected. However, the detection distance will be reduced by reducing the contrast of the human image.
The conclusion is still recommended to use an ordinary IP camera at the same time as a thermal imaging camera for particularly important objects.
Can thermal imaging cameras see through walls?
No they can’t, if there’s a heat source behind the wall it will heat up the wall and you’ll be able to see the wall’s temperature.
Can IR cameras see through clothes?
Also no, thermal imaging cameras, just like in the previous answer, will see the clothes heated by the body and emitting their own thermal radiation.
Can the thermal imaging camera be blinded in any way?
In theory, a powerful heat source can blind a thermal imaging camera, but considering that an open fire has a temperature of about 1000 degrees Celsius and it’s for detecting fires that infrared cameras are often used and there’s not even a hint of blinding. So, the heat source should have a multiple of the temperature to dazzle the thermal imager, from the sources I know, the thermonuclear bomb could do that. So you see, in practice you can’t blind the thermal imaging camera.
Installing a thermal imaging camera
Thermal imaging cameras are somewhat larger than classic cameras so the assembly and installation is a bit more complicated, but in general experienced installers don’t have any problems at all.