Thermal Camera Installed in the Aircraft Piper Aztec Aircraft FLIR ThermaCam SC 660 Thermal Camera
Winter Nights in Montbéliard Introduction Thermal imaging results are necessary for monitoring thermal leakages in order to uncover construction problems, such as escaping warmth from thermal energy distribution grids or heated objects. Preventing energy loss caused by improper insulation or insulation breakdown should be the priority of property owners and the entire society and one of the key objectives of the European Union. Since 1994, ARGUS GEO SYSTÉM s.r.o., has been offering thermal imaging services. We have implemented projects utilizing various types of thermal cameras, from nitrogen-cooled devices to electronic cameras with a resolution of 320 x 240 pixels and to cameras fitted with uncooled microbolometric mosaic detectors with a resolution of 640 x 480 pixels.
Meeting at the Airport
Montbéliard Project
Thermal Imaging
Thermal imaging is one of the important products among GEODIS GROUP services. GEODIS has completed several thermovision projects in the Czech and Slovak Republics. The following article is dedicated to one such extensive project in France. Its objective was to acquire images -- using a thermal camera -- of Montbéliard buildings in order to identify thermal leakages through roofs. Given the high requirements for the geometric and thermal resolution and the extensive subject area, we used the thermal camera FLIR ThermaCam SC660 with the resolution of 640 x 480 pixels. This thermal camera with a gyro stabilized mount and necessary additional equipment had to be installed in a double-engine Piper Aztec aircraft to comply with aerial regulations applicable in France above cities the size of Montbéliard.
Image acquisition of the entire Montbéliard area took place over four nights with varying climatic conditions, as the weather was quite changeable. The first flight night was from 12 January 2009 to 13 January 2009, the second from 16 January 2009 to 17 January 2009, the third from 20 January 2009 to 21 January 2009, and the last flight night from 21 January 2009 to 22 January 2009. Because the airport was a part of the subject area, no time was lost with commuting. Gaps between the flight days (or nights) were caused by the following two factors. The first was the condition specified by the client – to fly only in workdays, i.e. from Monday to Friday and if possible to avoid localities on Wednesday where schools are located. Pupils and students have a free day on Wednesday, and the heating of these objects is therefore turned down. The second important factor was the weather. The weather significantly influences results of the measurement and requires therefore getting as close to the “ideal” imaging conditions as possible. The first two flight sessions were done with bright weather. However, near the end of the flight (long after midnight), fog started to form, making further work impossible and complicating the landing procedure for the aircraft crew. It is worth noting that all flights were “self-attended”, because airport flight control closed at 6:00 p.m. and our crew had to remotely light up the runway for takeoff and landing, paying special attention to the movement of other aircraft in the area. The remaining two flight sessions were performed under warm front clouds sliding in from the west. The relatively long pauses between flight sessions, caused by unsettled wintertime climatic conditions, hindered project homogeneity, since measuring such an extensive surface was difficult (11.100 ha) and increased the overall demands for our data processing work.
Thermal Imaging Plan The entire Montbéliard area was divided into 4 sections: 76 + 94 + 84 + 32, i.e. 286 flight lines in total. For the thermal camera in use, lenses had a focal distance of 37 mm, and the resolution of source thermal images of 40 cm. The aircraft flew at an altitude of 600 m above the ground, with 150 m gaps between lines. The aerial imaging in the infrared range of 7,5µm – 13,5µm was done with the aim of detecting building surface thermal anomalies. To eliminate impacts of building surface heating by incoming solar radiation, it was necessary to perform the imaging long after sunset, and French winter sunset (evening) began around 3:30 p.m. CET. Conditions needed for thermal imaging and technical equipment descriptions were provided in previous issues of the GEODIS NEWS.
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