Thermal imaging from the air with drones

Thermal images produced by drones have a much higher relevance than thermal images, which are limited in perspective

Safe and informative thermography for roof inspections, object and plant control

Thermography is of great importance for many areas in industry and private business. From the roof inspection of a photovoltaic system to the survey of buildings and complex technical installations, thermal images can provide meaningful results. The use of drones not only facilitates access, but with thermal imaging from the air, it provides a safe way to deliver accurate results quickly and cost-effectively.

Beyond the photovoltaic plant - where thermal imaging with drones still makes sense

The use of a thermal camera can detect damage and leaks in photovoltaic systems, heating systems, roofs, industrial plants, power plants and many other facilities at a very early stage. In addition to human eyes, normal visual inspection often involves the use of high-resolution cameras, which are not infrequently mounted on drones. Images in the visible light spectrum are expedient in many places and useful for assessing a well-rounded overall picture of the condition of photovoltaic systems and other facilities. However, the additional use of a thermal imaging camera and the in-depth evaluation of such thermography offers enormous advantages. Contrary to popular belief, thermal imaging is not only useful for heat-carrying systems such as heaters or photovoltaic systems, because heat differences exist in the entire temperature spectrum - i.e. also downwards.

Thermal image with drone of a photovoltaic plant in Tyrol

How is the thermal camera different from any other optics?

Humans perceive only part of the electromagnetic spectrum with their eyes - the wavelength range visible to us. We cannot see either ultraviolet light or infrared radiation. The latter plays the decisive role in thermography. Confusion sometimes arises because most video cameras today offer an IR mode for night vision imaging. In combination with natural residual light or an additional infrared spotlight, it is thus possible to "invisibly" illuminate objects at night and make them visible in the camera image. However, night vision is not based on the detection of an actual thermal image like thermography. Whether a camera is IR-capable can be easily tested by using the remote control of your own TV. If the camera shows a flashing LED, it can display infrared wavelengths. A true thermal image sensor, on the other hand, perceives a much broader IR spectrum and can display temperature differences completely independent of residual light or additional IR light sources. The conversion is usually done in a false color display to indicate the temperature differences.

Closeup DJI Matrice M30T drone with thermal camera

A thermal image can also detect cold loss

For example, a roof inspection with a thermal camera not only reveals the obvious thermal bridges in winter, when the heating system is running at full blast and heat escapes through poorly insulated or damaged roofs. A creeping moisture intrusion (e.g. on flat roofs) is also detected more quickly in the context of thermography, because there can be a clear temperature difference from the rest of the masonry. Since heat losses (and incidentally also cold losses, if one thinks of air conditioning systems, industrial plants or chemical production facilities) can often only be detected indirectly, the thermal image is usually the only way to narrow down a problem concretely and precisely without dismantling parts of the plant. In particular, creeping losses often go unnoticed for weeks or months until the irregularity can no longer be ignored due to major consequential damage.

In addition to the roof inspection, thermal images can reveal the most important problem areas of a building in advance during energy refurbishment, so that the refurbishment measures can be sensibly coordinated and planned. It has been shown time and again that the assessment of a thermography made with ground-based thermal cameras is often insufficient. The reason for this is the limited perspectives and viewing angles, which can of course be considerably extended by using a drone.

Roof inspection with drone without endangering people

A drone with a thermal camera can not only provide a quick overview from a bird's eye view, but also combine a photovoltaic system with a roof inspection at close range, for example. For this, no one has to climb onto the roof and unnecessarily put themselves in danger. Depending on the location and orientation of the building, sometimes access to a complete side of the building is not possible at all. In these cases, the drone also helps, because it can scan any roof and photovoltaic system, as well as other facilities from close to all angles.

Aerial photo with drone of real estate roof in the Alps

Major defects can be avoided thanks to drone thermography

Incidentally, a drone can also detect mechanical damage or contamination that initially has nothing to do with thermal imaging. However, defects in technical systems often announce themselves through a creeping overheating of certain areas. In the case of photovoltaic systems, for example, a larger temperature difference between individual solar modules can indicate a functional problem that does not necessarily lead immediately to a failure of the entire system. In the long run, however, the yield of the system can be negatively affected by the decreased efficiency of the damaged areas of the photovoltaic system. If this is not noticed until billing, a lot of time and money has already been wasted. As with all technical equipment, it is of course also true for the photovoltaic system that early detection of problems often avoids greater consequences.

How informative can thermography with drone be?

How meaningful a thermal image is depends on the one hand on the quality of the thermal camera used, and on the other hand on the possibilities for subsequent evaluation of the data. Our customers often require precise information on temperature differences, which can be generated with the help of so-called radiometric thermography. Here we use the possibilities of a highly developed software, which determines precise values from the various data of the drone.

Radiometric evaluation of a photovoltaic system

Radiometric processing in dual mode of the drone

Our drones can use a dual mode in which not only can thermal images be taken with the thermal camera in just one flyover, but high-resolution RGB photos in the visible spectrum are also taken at the same time. So in a flyover where 300 images are taken with each of the cameras, we end up with access to a total of 600 images. In the course of so-called photogrammetry, the software combines the image information of the RGB photos with the results of the thermography. This makes it possible to create high-resolution thermal maps that allow very precise conclusions to be drawn about temperature differences in the areas photographed. In addition, the RGB photos can of course also be used for other purposes, such as the creation of orthophotos after processing.

Photovoltaic inspection with thermal imaging drone - Radiometric

For whom is the inspection with drone and thermal camera interesting?

Costs can be saved by using a drone to create thermal images simply because of the high creation speed and precision. This applies to both private houses and large photovoltaic plants. Of course, the greater the benefit of aerial photography with a drone, the greater the effort would be to carry out the inspection in any other way. The use of drones is always without alternative if there is no sensible way to reach an area in any other way. In industry in particular, there are also areas where humans cannot operate without danger, especially when problems or incidents are suspected. Here, the drone provides a unique way to reliably and safely collect the data needed. If one thinks of facilities in the dangerous oil and gas industry, for example, the benefits of drone thermography become immediately apparent.

Thermal image of a property for thermal insulation

Individual scaling of inspections with drone and thermal camera

Depending on your individual needs, we can offer you viable solutions for the inspection and troubleshooting of your plant, building or other facilities. The flexibility and performance of the drones we use covers a very wide range of applications, which is usually only limited by very unfavorable weather conditions (e.g. storms). Of course, we can provide you with a complete package including professional evaluation of all thermographic data according to your needs. Feel free to contact us for an individual consultation and benefit from the advantages of a modern roof inspection and the support of other maintenance and control tasks by modern drone technology.

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