Automatic close-up drone photos of tropical trees скачать в хорошем качестве

Automatic close-up drone photos of tropical trees

Tropical forest canopies contain many tree and liana species, and the foliar or reproductive features to guide taxonomic identification can be hidden away high above the forest floor and thus difficult for botanists to access. As such, taxonomic identification often becomes a bottleneck in tropical forest inventories. Here we show a drone-based workflow to automatically acquire close-up, ultra-high resolution photos of tree crowns (or canopies more broadly) to support tropical botanical and ecological work. Our workflow is based around the DJI Mavic 3 Enterprise (M3E) drone that is equipped with a wide-angle and a telephoto camera. This drone is portable, accessible to many small organisations, and relatively easy to use. Our workflow is as follows: on day one, the pilot first maps up to ~200 ha of forest (with the wide-angle camera) and generates an RGB orthomosaics and digital surface model (DSM) using structure-from-motion (Sfm) photogrammetry. On subsequent days, the pilot can then acquire close-up photos (with the telephoto camera) from up to 400 selected canopy trees per day. These close-up photos are acquired at 6 m above the canopy and contain a high level of visual detail that allows expert botanists to reliably identify many tree and liana species. The photos are geolocated with survey-grade accuracy using RTK, thus facilitating spatial co-registration with other data sources, including the photogrammetry products. The primary operational challenge of our workflow is the need to maintain RTK corrections with the drone to ensure that close-up photos are acquired exactly at the predefined locations; we present different solutions to this problem. The maximum operational range we obtained was 3 km, which would allow the pilot to reach any tree within a ~2800 ha area from the take-off point. Although our workflow was developed to support taxonomic identification of tropical trees and lianas, it could be extended to any other forest or vegetation type to support floristic and phenological studies. We provide an open-source Python library to program these automatic close-up photo missions (https://github.com/traitlab/harpia). This video was acquired at Tiputini Biodiversity Station (Ecuador) by Adrian Buenano.