MultiSpectral imaging

Multispectral imaging captures data at specific frequencies across the electromagnetic spectrum, including frequencies which are not visible to the human eye. As different types of land cover reflect to varying degrees at different frequencies, this technique is particularly useful for gathering data on land cover and land cover change. Changes in land cover can have an impact on the propensity of an area for flooding so monitoring change is an essential precautionary measure. Preprogrammable flight paths mean that a UAV survey can be carried out repeatedly with precision over the same area capturing changes accurately.

Multispectral imaging was originally developed for space-based imaging, but by mounting these systems on our UAVs we are able to capitalise on the range of unique solutions this method presents.

This is a cost effective alternative to gathering multispectral data through the more conventional methods such as manned aircraft and satellites. Using a UAV has lower operational costs, faster repeat times (for example, in instances where the weather does not allow for the capture of optimum quality imagery) and no data redundancy.

UAV based multispectral surveys are ideal for a wide range of applications, including identifying areas of crop failure, land cover change and organic content in water.

Conventional methods of multispectral imaging typically require a large amount of compromise on a number of factors affecting data quality, most notably spatial and temporal resolutions. For example, the AVHRR sensor has a fast repeat time of 12 hours but a coarse spatial resolution of 1100m. Conversely, the Landsat TM sensor has a much finer spatial resolution of 30m but a much slower repeat time of 16 days. Gathering multispectral imagery by using a UAV does not require this sort of compromise – we can gather imagery with very fine spatial resolutions (up to 4cm) and can obtain repeat times as fast as the UAVs batteries can be replaced and its safety checks completed, which can be achieved in a matter of minutes. These characteristics make UAVs the far more suitable option for completing small-scale multispectral aerial surveys.

 

Our very high specification multispectral imaging system allows us to perform aerial surveys of the highest quality. Our system collects data in the green, red and near infrared frequencies of the electromagnetic spectrum which are approximately equal to Landsat wavebands TM2, TM3 and TM4. It can capture stills, continuous stills (2-5 photos per second) and video. The sensor collects 3.2 MP imagery, with ground resolutions of 4-48mm (altitude dependent). 

 

To find out more call us on 01444 401840 or email pilot@remoteaerialsurveys.co.uk