News & Updates

XCAM arrives in South Africa equipped with Thermal and NIR capabilities

GeoXphere has delivered a new XCAM B Thermal R to Geosense in South Africa ready to tackle aerial survey work in the mining, energy and construction markets.

GeoXphere spent 5 days in Johannesburg providing the training for the installation, survey and processing. Here’s our report.

XCAM

At the time of deployment this was a one-of-a-kind XCAM built to meet the requirements of Geosense and the particular areas of work they wanted to operate it in. It’s an XCAM B (our most common pod form factor) with three sensors onboard. It has:

  • an RGB sensor that you find in other XCAMs to capture true-colour imagery,
  • a NIR sensor which is the same resolution as the RGB but filters for near-infrared wavelengths,
  • and a Thermal sensor which records absolute temperature values.

What makes this pod special is the thermal sensor. Most XCAMs with the thermal add-on produce relative temperature values, so you can see ‘what’s hot and what’s not’ but you can’t see what the actual temperature is without providing some temperature ground control. This is more than sufficient for most applications as it’s the differences in temperature that provide the insight. This sensor, however, includes a thermal sensor that can return the absolute temperature values +/- 5 degrees Celsius. This allows another layer of insight where the analyst can say “ok, that feature is hotter than the surrounding area, and it’s 45.2 degrees Celsius”. This has the potential to allow much more informed decision making when analysing an area mapped with XCAM.

Deployment

The XCAM was delivered in its standard Peli case along with strut mount, battery pack and cable loom. It’s a lightweight package that fits easily into the overhead locker of an Airbus A380 (even in Economy!).

XCAM B in airport
XCAM B as hand luggage at Heathrow Terminal 5

On day one, Chris from GeoXphere arrived at Johannesburg’s OR Tambo International airport in the morning, met the Geosense staff in the Centurion office then headed over to the local airport, Wonderboom, where the XCAM was to be installed for the first time. The installation took longer than normal as training was incorporated into it and there were lots of questions about the pod itself, but it took around 20 minutes in total. A quick ground test was carried out and it was ready for survey.

XCAM installed on Cessna 172 in South Africa
Pilot and operator with the XCAM Thermal

 

Lady Luck
No luck needed for these XCAM surveys!

Survey 1 & 2

The XCAM went up for two surveys the following day. The first was a daytime survey to collect datasets with all three sensors. This provided a true-colour base map that following surveys could be referenced against. The second survey was carried out early evening after dark to capture just the thermal. All sensors were collecting data but as the sun had gone down, the RGB and NIR sensors weren’t much use. This second survey was all about getting a thermal dataset that wasn’t affected by daytime heating by the Sun.

XCAM Thermal
XCAM thermal data ranging from black (cold) through to white (hot)

The area of interest was just outside a small town where subterranean coal mining activity had taken place. The intention was to see whether the thermal sensor could pick up any evidence of underground burning, a big issue in this part of the world. This burning has the potential to compromise the surface soil and create large cavities. It doesn’t take much imagination to see how a big burning hole in the ground could be a danger to people, livestock and buildings! These XCAM datasets will pave the way for organisations to put in remedial action to reduce the risk to people in the area.

XCAM Thermal data in details
Yellow/white areas showing patches of hot surface soil (circa 48 degrees Celsius)

Survey 3 & 4

After the Tuesday daytime and evening surveys the XCAM headed out to Potchefstroom where it was to be used by GyroLAG on a research project linked with the local University. The XCAM was fitted to their aircraft, again in around 20 mins and was immediately sent out to capture two areas.

XCAM Thermal in the air
This area of grass burning was just outside the project area, unfortunately

The datasets were to be used by local University students to analyse the heat response from the roofs of buildings for assessing property insulation and the use of heating. There’s a lot of analysis that can be done using this data, from comparing roof construction methods, through to extrapolating levels of economic deprivation in an area. All useful data that further down the line can be used to provide guidance on policies and funding to improve the lives of the residents.

XCAM orthophoto
Stunning orthophoto mosaic captured over Potchefstroom
XCAM Thermal composite
Orthophoto with semi-transparent thermal overlaid.
School captured in thermal
Vegetation and man-made surfaces show up really well

The thermal data overlaid with the orthophoto really shows up the buildings that are cold (black/grey) and the ones that are hot (yellow/white). As it's a daytime survey you can also see the effect of the heat of the sun on the faces of the roofs and in the shadows of the buildings.

Processing

Both Geosense and GyroLAG carried out their own processing, with a bit of guidance from GeoXphere. They processed the data from all three sensors in Pix4D to produce the orthophoto mosaics of RGB, NIR and Thermal datasets. They also produced NDVI classifications. The RGB data was also processed in Skyline Photomesh to produce a 3D model and terrain dataset.

NDVI Index Map
NDVI produced using the RGB and NIR bands of the XCAM

The speed that this data can be captured and processed in, combined with the low-cost XCAM itself means there is a much lower overhead on survey projects. This was a revelation for both Geosense and GyroLAG who are used to operating more expensive remote sensing equipment. This means their clients can get the data they need faster than was ever possible before.

Summary

The XCAM B with the NIR and Thermal sensors has proven itself as a very capable unit for quickly and easily capturing multi-band data. Not only that, the applications are wide-reaching meaning a small survey company can tackle a variety of jobs in different sectors, expanding their capabilities and client-base. Not only that, they can value-add with processing services such as thermal analysis and NDVI calculations. The GeoXphere team look forward to seeing lots of new and interesting datasets being captured with this XCAM pod.

The XCAM B Thermal R (‘R’ stands for ‘radiometric’) was delivered in May 2017, on lease with Geosense, South Africa. For more information on Geosense or GyroLAG, please visit their websites.


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