Scientists warn against using drone footage for environment monitoring
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Spanish researchers have found inconsistencies in 3D models of natural environments made from images taken by low-cost drones.
Relying on drone imagery to measure surface movement over time could result in significant deformation of maps used for environmental research, a study has found.
Natural heritage studies often leverage drone imagery and photogrammetric techniques in order to map and monitor geomorphological objects. Some of the characteristics that make this technology so popular are the affordability of the drones, as well as the ease with which these images can be used to generate 3D models of large areas of terrain.
However, scientists from the Centro Nacional de Investigación sobre la Evolución Humana (CENIEH), in Spain have found that variations in the lens profiles of images taken by low-cost drones could have a significant influence on the deformations quantified, thereby affecting analyses of movement of surfaces over time.
Not all 3D models made with this technique are affected by these deformations. The team stressed that low-cost drone imagery is still very accurate when producing the majority of 3D models, as long as these are not used to measure surface movement.
“While drones have become tools of great utility in studies relating to the geosciences, it is a good idea to possess some knowledge of the principles of photogrammetry and to analyse the resulting models judiciously," said Adrián Martínez Fernández, the technician in charge of the Digital Mapping and 3D Analysis Laboratory and lead author of the paper.
"This is because even one of the main components of the technique, namely, the images, can affect the results and how we interpret them later.”
The study was conducted at the rocky glacier La Paúl, in the Pyrenees in Aragón, which is an icy body undergoing constant movement because of interior melting processes. The glacier is of particular interest to environmental researchers, as it can provide useful information about the progression of climate change.
As drone technology develops and becomes more accessible, its number of use cases also increases. Recently, the UK has trialled the use of drones for the delivery of life-saving medication, while California-based DroneSeed has leveraged these devices to spray seeds from the sky in an effort to fight deforestation.
The findings of the CENIEH study were published in the journal Remote Sensing.
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