and data processing

Fixed Wing Airborne System

The survey aircraft is dedicated to photographic and thermal imaging work and is fitted with stabilised sensor mounts, satellite guidance systems and a computer system linked to the infrared thermal imager / sensors. The photograph below shows our military specification imager under test mobilisation.

The photograph below shows the stabilised camera mount and computer system / digital recording equipment inside the aircraft.

Horton Levi regularly conduct surveys for government of whole cities or boroughs where precise OS grids are recorded with the necessary aid of satellite navigation and professional survey pilots.

We also conducts 'low level' surveys of single sites or small areas with a less sophisticated aircraft than the one above at very cost effective prices. 

Aerial thermal surveys of buildings to record heat loss is usually carried out mid evening at least two hours after sunset. This is considered to be the best time to allow solar dissipation and homes that are only heated during the evening to attain a comfortable heat level.

To make a "thermal map" of a large area, data collection is carried out by flying transects in a grid pattern. An altitude of 2000 ft (615 metres) is normal to comply with regulations and to give very high resolution. This altitude is ideal for image detail and economy. The thermal imaging equipment used in all our aerial thermal surveys is of military specification. All real-time imagery is  time/date/Lat/Long stamped during the survey and hidden if required after processing.

Twin engine dedicated survey aircraft are always used at night over urban areas. The aircraft is fitted with CCNS satellite navigation to enable exact flight lines. Post flight "actual" flight lines are printed to scale to overlay on an O.S. map and for future G.I.S. reference.

Digital images are produced, each having an identity and O.S. map reference in grid strips or line runs. The data necessarily has to be produced into a useable file format prior to geo-rectification. The first stage process data retains all original information and being referenced to an O.S. map can be used on almost any pc with off-shelf software. Thermal data is always recorded in flight in monochrome to retain full resolution, however, simple conversion to colourise the data is useful for some analysis and presentation purposes.

Post Processing

A large scale digital map is configured in strips of numerically referenced images. The digital data although referenced to time and flight location is not normally intended for further use once a digital computer copy has been made. The entire digital map will be contained in memory. Each image will be file referenced to an OS map and the actual flight path of the survey. At this stage, any image of any part of the map can be quickly retrieved by the file or street name and postcode reference.

Geographical sizing or scaling and overlaying on to an OS map (integration to your GIS) is a further stage in processing. The imagery will enable householders or industrial property managers to determine relative energy emissions.

The monochrome infrared image below is of an entire city. The image has been drastically reduced in size and resolution for website insertion. After a map like this has been produced, we then process the data into temperature bands. Each and every property can be clearly viewed for thermal performance. We also provide extra options for having the data correlated to post codes for individual property selection.

From the data above, thermal 'banding' of each and every building is produced. All unwanted background detail is removed.