Estimating Plant Nitrogen Concentration of Rice through Fusing Vegetation Indices and Color Moments Derived from UAV-RGB Images

Estimating plant nitrogen concentration (PNC) has been conducted using vegetation indices (VIs) from UAV-based imagery, but color features have been rarely considered as additional variables. In this study, the VIs and color moments (color feature) were calculated from UAV-based RGB images, then par...

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Main Authors: Haixiao Ge, Haitao Xiang, Fei Ma, Zhenwang Li, Zhengchao Qiu, Zhengzheng Tan, Changwen Du
Format: Article
Language:English
Published: MDPI AG 2021-04-01
Series:Remote Sensing
Subjects:
Online Access:https://www.mdpi.com/2072-4292/13/9/1620
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author Haixiao Ge
Haitao Xiang
Fei Ma
Zhenwang Li
Zhengchao Qiu
Zhengzheng Tan
Changwen Du
author_facet Haixiao Ge
Haitao Xiang
Fei Ma
Zhenwang Li
Zhengchao Qiu
Zhengzheng Tan
Changwen Du
author_sort Haixiao Ge
collection DOAJ
description Estimating plant nitrogen concentration (PNC) has been conducted using vegetation indices (VIs) from UAV-based imagery, but color features have been rarely considered as additional variables. In this study, the VIs and color moments (color feature) were calculated from UAV-based RGB images, then partial least square regression (PLSR) and random forest regression (RF) models were established to estimate PNC through fusing VIs and color moments. The results demonstrated that the fusion of VIs and color moments as inputs yielded higher accuracies of PNC estimation compared to VIs or color moments as input; the RF models based on the combination of VIs and color moments (R<sup>2</sup> ranging from 0.69 to 0.91 and NRMSE ranging from 0.07 to 0.13) showed similar performances to the PLSR models (R<sup>2</sup> ranging from 0.68 to 0.87 and NRMSE ranging from 0.10 to 0.29); Among the top five important variables in the RF models, there was at least one variable which belonged to the color moments in different datasets, indicating the significant contribution of color moments in improving PNC estimation accuracy. This revealed the great potential of combination of RGB-VIs and color moments for the estimation of rice PNC.
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spelling doaj.art-4e1005816690413baa457db03b446df42023-11-21T16:33:04ZengMDPI AGRemote Sensing2072-42922021-04-01139162010.3390/rs13091620Estimating Plant Nitrogen Concentration of Rice through Fusing Vegetation Indices and Color Moments Derived from UAV-RGB ImagesHaixiao Ge0Haitao Xiang1Fei Ma2Zhenwang Li3Zhengchao Qiu4Zhengzheng Tan5Changwen Du6The State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science Chinese Academy of Sciences, Nanjing 210008, ChinaThe State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science Chinese Academy of Sciences, Nanjing 210008, ChinaThe State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science Chinese Academy of Sciences, Nanjing 210008, ChinaThe State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science Chinese Academy of Sciences, Nanjing 210008, ChinaThe State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science Chinese Academy of Sciences, Nanjing 210008, ChinaYuan Longping High-Tech Agriculture Co., Ltd., Changsha 410001, ChinaThe State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science Chinese Academy of Sciences, Nanjing 210008, ChinaEstimating plant nitrogen concentration (PNC) has been conducted using vegetation indices (VIs) from UAV-based imagery, but color features have been rarely considered as additional variables. In this study, the VIs and color moments (color feature) were calculated from UAV-based RGB images, then partial least square regression (PLSR) and random forest regression (RF) models were established to estimate PNC through fusing VIs and color moments. The results demonstrated that the fusion of VIs and color moments as inputs yielded higher accuracies of PNC estimation compared to VIs or color moments as input; the RF models based on the combination of VIs and color moments (R<sup>2</sup> ranging from 0.69 to 0.91 and NRMSE ranging from 0.07 to 0.13) showed similar performances to the PLSR models (R<sup>2</sup> ranging from 0.68 to 0.87 and NRMSE ranging from 0.10 to 0.29); Among the top five important variables in the RF models, there was at least one variable which belonged to the color moments in different datasets, indicating the significant contribution of color moments in improving PNC estimation accuracy. This revealed the great potential of combination of RGB-VIs and color moments for the estimation of rice PNC.https://www.mdpi.com/2072-4292/13/9/1620UAVplant nitrogen concentrationRGB-VIscolor momentsPLSRRF
spellingShingle Haixiao Ge
Haitao Xiang
Fei Ma
Zhenwang Li
Zhengchao Qiu
Zhengzheng Tan
Changwen Du
Estimating Plant Nitrogen Concentration of Rice through Fusing Vegetation Indices and Color Moments Derived from UAV-RGB Images
Remote Sensing
UAV
plant nitrogen concentration
RGB-VIs
color moments
PLSR
RF
title Estimating Plant Nitrogen Concentration of Rice through Fusing Vegetation Indices and Color Moments Derived from UAV-RGB Images
title_full Estimating Plant Nitrogen Concentration of Rice through Fusing Vegetation Indices and Color Moments Derived from UAV-RGB Images
title_fullStr Estimating Plant Nitrogen Concentration of Rice through Fusing Vegetation Indices and Color Moments Derived from UAV-RGB Images
title_full_unstemmed Estimating Plant Nitrogen Concentration of Rice through Fusing Vegetation Indices and Color Moments Derived from UAV-RGB Images
title_short Estimating Plant Nitrogen Concentration of Rice through Fusing Vegetation Indices and Color Moments Derived from UAV-RGB Images
title_sort estimating plant nitrogen concentration of rice through fusing vegetation indices and color moments derived from uav rgb images
topic UAV
plant nitrogen concentration
RGB-VIs
color moments
PLSR
RF
url https://www.mdpi.com/2072-4292/13/9/1620
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