In winter, short daylight hours (and in some regions, polar night) can create problems for security services and industrial enterprises. Many specialists, faced with the need to conduct surveys and inspections in the cold season, have found a way out of the situation in the use of thermal imagers. However, thermography has only become truly accessible in recent years, thanks to drones. For a number of companies, drones have become an indispensable tool that can shoot both conventional and thermal cameras at the same time – and from any height and from any angle.
How a thermal imager works
Thermal cameras can be used most effectively with a full understanding of the principles of thermal imaging.
Heat, that is, infrared radiation, is simply the vibration of atoms. Depending on the speed of the atoms (the higher it is, the warmer the object), the objects leave a different thermal footprint. Thermography is the process of analyzing thermal traces in order to further use these data in practice.
A person feels heat, but is not able to see infrared radiation: its waves are in that part of the electromagnetic spectrum that is inaccessible to our vision. Thus, a thermal imager is, in fact, a tool that makes heat visible to a person.
Thermal imaging cameras use special lenses that capture the infrared wavelength range, as well as sensors and image analyzers, which together make it possible to visualize the data on the display. In drones, a thermal imager is usually mounted on a gimbal to stabilize the image and allow the lens to rotate 360 degrees in all directions.
Today’s sensors in thermal imaging cameras are affordable technology: so-called microbolometers no longer need the exotic cooling methods used in early devices.
At the same time, users of thermal imagers may face some limitations. Reflective materials (such as those with a shiny surface) have low emissivity—they absorb less heat and may be less visible to a thermal imaging camera. Objects with high emissivity made of wood or concrete (as well as people!) appear much better in images taken with a thermal imager.
Where drones with a thermal imager are used
Although the accuracy and quality of a thermal imaging camera may vary slightly depending on a number of external factors (humidity, time of day, etc.), in general, thermal drones have a wide range of use cases. You certainly won’t have to wait for a cloudless day (and even more so to rent a helicopter).
If we talk about specific areas of possible application of drones with a thermal imager, then we can name three main ones:
- Inspections in the oil and gas industry. Engineers are forced to regularly check the condition of (often huge) oil and gas facilities for corrosion and leaks of hazardous substances. In this case, there is no way to do without process automation. Drones with a thermal imager help to identify infrastructure shortcomings in real time – there is no need to stop production or put the health of employees at risk.
- Rescue operations. As noted above, people (and animals) are objects with a high emissivity for a thermal imager. Rescuers from different countries are actively using drones with thermal imaging cameras to find missing people. Especially in difficult conditions – at night, in winter or in heavy fog – the effectiveness of a UAV with a thermal imager exceeds all other methods of conducting search operations.
- Extinguishing forest fires. If you attach a bucket of water to the drone, you will not be able to put out the fire. But if you install a thermal imager on it, with a high probability, firefighters will be able to quickly determine the sources of fire and plan the course of the operation. For the first time, the potential of the technology was truly appreciated when extinguishing forest fires near Chernobyl in 2020 and in California in 2021. Then it was UAVs with a thermal imager that were able to best convey the picture of the situation even through thick smoke.
How to choose the best model
DJI has the most extensive experience in the production of drones with a thermal imager. Unfortunately, it is impossible to name only one “best” DJI model: it all depends on the specific user requests. Some people may want a compact drone that is easy to transport, while others may want the most durable drone that will accept additional payloads. Therefore, below are three drones that currently deserve the most attention.
1. DJI Matrice 300 RTK
The Matrice 300 RTK is the most advanced commercial drone available, capable of launching three payloads at once. By installing a gimbal with a Zenmuse H20T (or H20N for night vision) thermal imager on the drone, users will be able to get the most detailed data about the object in high resolution.
2. DJI Matrix 30T
The Matrice 30T (M30T) has a rugged housing and is able to withstand headwinds up to 15 m/s and temperatures from -20 to +50 °C. Nevertheless, the drone is quite compact (36.5 x 21.5 x 19.5 cm when folded), weighs less than 4 kg and is suitable for quick transportation from place to place. M30T includes RC Plus professional remote control (with 7-inch screen); Piloting simultaneously with 2 consoles is possible.
3. DJI Mavic 3T
The newest drone listed, the Mavic 3T (M3T), features a 640×512 pixel thermal imager (standard on all DJI models) and a high-quality 48MP wide-angle camera. In split-screen mode, operators can receive a picture simultaneously from a thermal imaging camera and a conventional camera; synchronous 28x image scaling is also supported. It is especially impressive that, despite the decent performance, the drone weighs only 920 g.
It is important to note that all of the above UAVs are compatible with the RTK module, which provides centimeter real-time positioning accuracy and works with 4 global positioning systems (GPS, Galileo, BeiDou and GLONASS). An equally significant advantage is the presence of proprietary software: the DJI Thermal Analysis Tool 3.0 program simplifies the analysis of temperature anomalies in images taken by drones.
And this is what sets DJI apart from all other drone manufacturers. A single unmanned solution that eliminates the need to search, buy and connect components to each other (a drone with a thermal imager, and a thermal imager with software) is the most powerful argument in favor of choosing DJI models.
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