Information about the project

Frequently asked questions about the unique thermal images taken from the air
(Publicised in the Technical magazine)

1. Why did Tepelné hospodářství Hradec Králové, a.s. take the thermal images of the city?
Answer: The project of air thermal images comes from the task ''To improve the prevention of accidents of our technologies '' and it is based on the evaluation of the documents ''Company strategy for the year 2009''. The result is a system of procedures and measures, which in combination gives very good results. This system includes a variety of advanced technologies, such as a micro-camera system. In the future there will be a detector for discovering the micro suction on hot pipes based on the refractive optical fibre (this system is very good for our economy, because after implementation of the project MOSHK we will have penetration into the heat pipes at levels of 90-95%). For the free-channel route there is a technology for measuring electrical impulses on pre-insulated pipes and the analysis of changes will find the location of leaks. One of the many technologies that identify the thermal changes and temperature gradients on the best level are the air thermal images.

2. Who, how and to what extent carries them out?
Answer: The tender for this project was won by the company Argus Geo System, which is a local company. The company has a base and an airport in Hradec Králové.

3. How long will the thermal images take and how will their results be used in everyday practice?
Answer: Because of the requirements, it is appropriate that the images be taken under same weather and flight conditions. We succeeded and the thermal images were finished during one evening in late November. The following important weather conditions were met:

  • The coolest air temperature, at least - 5 °C.
  •  Dry without snow
  •  Elimination of sunshine (night hours)
  •  No wind
  •  Elimination of clouds and shadows

Currently the thermal images are taking place and over 2 months will be evaluated and combined into maps. We would like to have final results at the end of February or early March.

These are the specific expectations:
a) Verification and identification of possible variations of network against data of internal GIS environment. Our company manages about 70 km of old routes, for which there is no documentation or geometric orientation and many routes are only deduced. Thermo images will help us to locate these very accurately.

b) Identification of covered shafts that are very important for the maintenance. At present we are finding these shafts only randomly. We hope that by the increased loss of heat in these shafts we will find them easily and restore them to their former glory.

c) Identification of thermal losses, which may indicate an inrush channel and thereby very important to prevent accidents. This is a key benefit of this project, as we know that solving a medium size accident costs around 0.5 million CZK. With regards to the cost of this pilot project, this project is in fact paid immediately. Further benefits are discovering thermal leaks and their locating. So we can actually lower the costs of thermal losses.

Synergistic outcomes for the wider public:
The published map of thermal images can be useful to other organizations. The change of sensitivity in the special software can show heterogeneity of the underlay consistency of a particular site. Linear structures pinpoint utility lines and surface formations can be useful for archaeologists.
Also this information can be useful for property owners, who can identify an increase or decrease of the heat loss through the roof of their building. It is necessary to highlight the importance of more detailed analysis. Identification of the heat losses from the thermal map must contain an analysis of roof materials emissivity. However, this principle applies generally. After the identification of the heterogeneous thermal space it is necessary to look closer at construction and materials, and after analyzing all the information state the point of interest.

4. Your conception will undoubtedly interest a number of other cities. What would you (using your experience) recommend for the preparation of analogous projects? What should they avoid?
Answer: It is too early to state any recommendations. The thermal images are now being processed and the results will show to what extent the outputs of the project are relevant and if they correspond with our expectations. Given the investment costs to implement this technology, our management chose a cautious approach and implemented only a pilot project, which was limited to Slezské předměstí, Velké Square, Eliščino nábřeží and part of Pouchov. If the project is evaluated as beneficial, we are prepared to cooperate with the council and extend the project to the whole territory of Hradec Králové.
In conclusion, a few words about the technology of photography.
The flight photography uses strict lines of areas of special interest that are kept by sensitive GPS navigation system. On individual lines with a selected interval, which corresponds with the altitude and the focal length of a camera lens, the images are taken so the desired overlay of images is realized. For each picture the GPS information is known, and therefore very precise pinpointing with an ortho-photomap and the location of the point of interest. The part of the project is a very precise ortho-photomap 10 x 10 cm /pixel. So we will have information about a point of interest that will be very accurate - thermal information accurate to a tenth of a degree and locating information accurate to centimetres.
The plane, from which the imaging is performed is a Piper Aztec. The thermostatic camera has no lens cover, because any ''Plexiglas'' prevents the rays against the infrared spectrum. The camera is placed on a special parallelogram, which balances and allows measurements of the camera angle. This is important for software parallel corrections with the ground.

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