Gradient Boosting Estimation of the Leaf Area Index of Apple Orchards in UAV Remote Sensing

The leaf area index (LAI) is a key parameter for describing the canopy structure of apple trees. This index is also employed in evaluating the amount of pesticide sprayed per unit volume of apple trees. Hence, numerous manual and automatic methods have been explored for LAI estimation. In this work,...

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Main Authors: Zhijie Liu, Pengju Guo, Heng Liu, Pan Fan, Pengzong Zeng, Xiangyang Liu, Ce Feng, Wang Wang, Fuzeng Yang
Format: Article
Language:English
Published: MDPI AG 2021-08-01
Series:Remote Sensing
Subjects:
Online Access:https://www.mdpi.com/2072-4292/13/16/3263
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author Zhijie Liu
Pengju Guo
Heng Liu
Pan Fan
Pengzong Zeng
Xiangyang Liu
Ce Feng
Wang Wang
Fuzeng Yang
author_facet Zhijie Liu
Pengju Guo
Heng Liu
Pan Fan
Pengzong Zeng
Xiangyang Liu
Ce Feng
Wang Wang
Fuzeng Yang
author_sort Zhijie Liu
collection DOAJ
description The leaf area index (LAI) is a key parameter for describing the canopy structure of apple trees. This index is also employed in evaluating the amount of pesticide sprayed per unit volume of apple trees. Hence, numerous manual and automatic methods have been explored for LAI estimation. In this work, the leaf area indices for different types of apple trees are obtained in terms of multispectral remote-sensing data collected with an unmanned aerial vehicle (UAV), along with simultaneous measurements of apple orchards. The proposed approach was tested on apple trees of the “Fuji”, “Golden Delicious”, and “Ruixue” types, which were planted in the Apple Experimental Station of the Northwest Agriculture and Forestry University in Baishui County, Shaanxi Province, China. Five vegetation indices of strong correlation with the apple leaf area index were selected and used to train models of support vector regression (SVR) and gradient-boosting decision trees (GBDT) for predicting the leaf area index of apple trees. The best model was selected based on the metrics of the coefficient of determination (<i>R</i><sup>2</sup>) and the root-mean-square error (RMSE). The experimental results showed that the gradient-boosting decision tree model achieved the best performance with an <i>R</i><sup>2</sup> of 0.846, an RMSE of 0.356, and a spatial efficiency (SPAEF) of 0.57. This demonstrates the feasibility of our approach for fast and accurate remote-sensing-based estimation of the leaf area index of apple trees.
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spelling doaj.art-d795626eccbd46de93955c56ff48bfc52023-11-22T09:34:44ZengMDPI AGRemote Sensing2072-42922021-08-011316326310.3390/rs13163263Gradient Boosting Estimation of the Leaf Area Index of Apple Orchards in UAV Remote SensingZhijie Liu0Pengju Guo1Heng Liu2Pan Fan3Pengzong Zeng4Xiangyang Liu5Ce Feng6Wang Wang7Fuzeng Yang8College of Mechanical and Electronic Engineering, Northwest A&F University, Yangling 712100, ChinaCollege of Mechanical and Electronic Engineering, Northwest A&F University, Yangling 712100, ChinaCollege of Mechanical and Electronic Engineering, Northwest A&F University, Yangling 712100, ChinaCollege of Mechanical and Electronic Engineering, Northwest A&F University, Yangling 712100, ChinaCollege of Mechanical and Electronic Engineering, Northwest A&F University, Yangling 712100, ChinaCollege of Mechanical and Electronic Engineering, Northwest A&F University, Yangling 712100, ChinaCollege of Mechanical and Electronic Engineering, Northwest A&F University, Yangling 712100, ChinaCollege of Mechanical and Electronic Engineering, Northwest A&F University, Yangling 712100, ChinaCollege of Mechanical and Electronic Engineering, Northwest A&F University, Yangling 712100, ChinaThe leaf area index (LAI) is a key parameter for describing the canopy structure of apple trees. This index is also employed in evaluating the amount of pesticide sprayed per unit volume of apple trees. Hence, numerous manual and automatic methods have been explored for LAI estimation. In this work, the leaf area indices for different types of apple trees are obtained in terms of multispectral remote-sensing data collected with an unmanned aerial vehicle (UAV), along with simultaneous measurements of apple orchards. The proposed approach was tested on apple trees of the “Fuji”, “Golden Delicious”, and “Ruixue” types, which were planted in the Apple Experimental Station of the Northwest Agriculture and Forestry University in Baishui County, Shaanxi Province, China. Five vegetation indices of strong correlation with the apple leaf area index were selected and used to train models of support vector regression (SVR) and gradient-boosting decision trees (GBDT) for predicting the leaf area index of apple trees. The best model was selected based on the metrics of the coefficient of determination (<i>R</i><sup>2</sup>) and the root-mean-square error (RMSE). The experimental results showed that the gradient-boosting decision tree model achieved the best performance with an <i>R</i><sup>2</sup> of 0.846, an RMSE of 0.356, and a spatial efficiency (SPAEF) of 0.57. This demonstrates the feasibility of our approach for fast and accurate remote-sensing-based estimation of the leaf area index of apple trees.https://www.mdpi.com/2072-4292/13/16/3263leaf area indexgradient-boosting decision treesUAV remote sensingapple orchardsvegetation index
spellingShingle Zhijie Liu
Pengju Guo
Heng Liu
Pan Fan
Pengzong Zeng
Xiangyang Liu
Ce Feng
Wang Wang
Fuzeng Yang
Gradient Boosting Estimation of the Leaf Area Index of Apple Orchards in UAV Remote Sensing
Remote Sensing
leaf area index
gradient-boosting decision trees
UAV remote sensing
apple orchards
vegetation index
title Gradient Boosting Estimation of the Leaf Area Index of Apple Orchards in UAV Remote Sensing
title_full Gradient Boosting Estimation of the Leaf Area Index of Apple Orchards in UAV Remote Sensing
title_fullStr Gradient Boosting Estimation of the Leaf Area Index of Apple Orchards in UAV Remote Sensing
title_full_unstemmed Gradient Boosting Estimation of the Leaf Area Index of Apple Orchards in UAV Remote Sensing
title_short Gradient Boosting Estimation of the Leaf Area Index of Apple Orchards in UAV Remote Sensing
title_sort gradient boosting estimation of the leaf area index of apple orchards in uav remote sensing
topic leaf area index
gradient-boosting decision trees
UAV remote sensing
apple orchards
vegetation index
url https://www.mdpi.com/2072-4292/13/16/3263
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