Processing thermal images - PIX4Dfields

Thermal supported cameras

The thermal bands of the Altum, Altum-PT, and Sentera 6x cameras have full thermal support.

The unit of the thermal band is defined by the original images.

Process dataset from Micasense Altum/Altum-PT

The Micasense Altum is a camera with 6 bands: Blue, green, red, red edge, near-infrared (NIR) and thermal infrared (LWIR). The Altum-PT has an extra Panchromatic band.

1. Import all images together and process. 
2. To convert the LWIR Centikelvin pixel values to Celsius, use the formula:
Thermal_ir=(lwir/100)-273.15

There is a demo dataset of this camera on the Micasense website.

RGB thermal supported cameras

PIX4Dfields can process .jpg thermal imagery, but it will be treated as RGB images.
The resulting orthomosaic is colored-mapped of temperatures and contains only a visual representation of the temperature. This allows the detection of areas with high and low temperatures relative to the scene. It will not be possible to extract the temperature value of a particular object or pixel from the resulting map. 

How to capture thermal images?

For a better reconstruction of the captured scene in a thermal project, some recommendations should be followed during the image acquisition:

• Have very high overlap: 90% front and side image overlap.
• The images have been taken at a resolution of at least 640x480.
• The images do not suffer from motion blur. An increased flight speed may cause a blurred image.