High-Resolution Airborne UAV Imagery to Assess Olive Tree Crown Parameters Using 3D Photo Reconstruction: Application in Breeding Trials

Abstract

Abstract:The development of reliable methods for the estimation of crown architecture parameters is a key issue for the quantitative evaluation of tree crop adaptation to environment conditions and/or growing system. In the present work, we developed and tested the performance of a method based on low-cost unmanned aerial vehicle (UAV) imagery for the estimation of olive crown parameters (tree height and crown diameter) in the framework of olive tree breeding programs, both on discontinuous and continuous canopy cropping systems. The workflow involved the image acquisition with consumer-grade cameras on board a UAV and orthomosaic and digital surface model generation using structure-from-motion image reconstruction (without ground point information). Finally, geographical information system analyses and object-based classification were used for the calculation of tree parameters. Results showed a high agreement between remote sensing estimation and field measurements of crown parameters. This was observed both at the individual tree/hedgerow level (relative RMSE from 6% to 20%, depending on the particular case) and also when average values for different genotypes were considered for OPEN ACCESS Remote Sens. 2015, 7 4214 phenotyping purposes (relative RMSE from 3% to 16%), pointing out the interest and applicability of these data and techniques in the selection scheme of breeding programs.

Estimating evaporation with thermal UAV data and two-source energy balance models

“…Here we hypothesise that UAV data can substitute satellite images and, in combination with the presented heat flux models, can be used to generate spatially detailed heat flux maps that provide insight into different evaporation rates and plant stress at decimetre scale. There is a rapidly growing interest in the potential of data collection with UAVs, particularly in the science of precision agriculture but also in a range of different scientific and commercial communities (Díaz-Varela et al, 2015;Gonzalez-Dugo et al, 2014;Swain et al, 2010;Zarco-Tejada et al, 2013. As scientists strive to understand the potential of UAVs and the new applications to which they are suited, the development of efficient workflows, operational systems, and improved software that capture and process UAV data are continuing (Harwin and Lucieer, 2012;Lucieer et al, 2014;Turner et al, 2012;Wallace et al, 2012).…”

High Throughput Phenotyping of Blueberry Bush Morphological Traits Using Unmanned Aerial Systems

“…Points below the bottom of the bush Remote Sens. 2017, 9, 1250 8 of 19 and above the desired harvester catch pan height are removed. The remaining points are projected onto a plane.…”

Cicada (<i>Magicicada</i>) Tree Damage Detection Based on UAV Spectral and 3D Data

“…An example of surface reconstruction has been in forest structure [29]. Studies have shown that UAVs can help with species identification [30,31], tree height [26,32], crown delineation [26,33,34], and forest health [35][36][37]. The use of UAVs has great potential for analyzing tree branch conditions as an early detection of tree health [35].…”