The Inversion of SPAD Value in Pear Tree Leaves by Integrating Unmanned Aerial Vehicle Spectral Information and Textural Features
Chlorophyll is crucial for pear tree growth and fruit quality. In order to integrate the unmanned aerial vehicle (UAV) multispectral vegetation indices and textural features to realize the estimation of the SPAD value of pear leaves, this study used the UAV multispectral remote sensing images and gr...
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2025-01-01
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| author | Ning Yan Yasen Qin Haotian Wang Qi Wang Fangyu Hu Yuwei Wu Xuedong Zhang Xu Li |
| author_facet | Ning Yan Yasen Qin Haotian Wang Qi Wang Fangyu Hu Yuwei Wu Xuedong Zhang Xu Li |
| author_sort | Ning Yan |
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| description | Chlorophyll is crucial for pear tree growth and fruit quality. In order to integrate the unmanned aerial vehicle (UAV) multispectral vegetation indices and textural features to realize the estimation of the SPAD value of pear leaves, this study used the UAV multispectral remote sensing images and ground measurements to extract the vegetation indices and textural features, and analyze their correlation with the SPAD value of leaves during the fruit expansion period of the pear tree. Finally, four machine learning methods, namely XGBoost, random forest (RF), back-propagation neural network (BPNN), and optimized integration algorithm (OIA), were used to construct inversion models of the SPAD value of pear trees, with different feature inputs based on vegetation indices, textural features, and their combinations, respectively. Moreover, the differences among these models were compared. The results showed the following: (1) both vegetation indices and textural features were significantly correlated with SPAD values, which were important indicators for estimating the SPAD values of pear leaves; (2) combining vegetation indices and textural features significantly improved the accuracy of SPAD value estimation compared with a single feature type; (3) the four machine learning algorithms demonstrated good predictive ability, and the OIA model outperformed the single model, with the model based on the OIA inversion model combining vegetation indices and textural features having the best accuracy, with <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msup><mrow><mi>R</mi></mrow><mrow><mn>2</mn></mrow></msup></mrow></semantics></math></inline-formula> values of 0.931 and 0.877 for the training and validation sets, respectively. This study demonstrated the efficacy of integrating multiple models and features to accurately invert SPAD values, which, in turn, supported the refined management of pear orchards. |
| format | Article |
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| language | English |
| publishDate | 2025-01-01 |
| publisher | MDPI AG |
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| series | Sensors |
| spelling | doaj-art-b2d646f2d3a648948c5f2a33678818f22025-08-20T02:12:29ZengMDPI AGSensors1424-82202025-01-0125361810.3390/s25030618The Inversion of SPAD Value in Pear Tree Leaves by Integrating Unmanned Aerial Vehicle Spectral Information and Textural FeaturesNing Yan0Yasen Qin1Haotian Wang2Qi Wang3Fangyu Hu4Yuwei Wu5Xuedong Zhang6Xu Li7College of Information Engineering, Tarim University, Alaer 843300, ChinaCollege of Information Engineering, Tarim University, Alaer 843300, ChinaCollege of Information Engineering, Tarim University, Alaer 843300, ChinaCollege of Information Engineering, Tarim University, Alaer 843300, ChinaCollege of Information Engineering, Tarim University, Alaer 843300, ChinaCollege of Information Engineering, Tarim University, Alaer 843300, ChinaCollege of Information Engineering, Tarim University, Alaer 843300, ChinaCollege of Information Engineering, Tarim University, Alaer 843300, ChinaChlorophyll is crucial for pear tree growth and fruit quality. In order to integrate the unmanned aerial vehicle (UAV) multispectral vegetation indices and textural features to realize the estimation of the SPAD value of pear leaves, this study used the UAV multispectral remote sensing images and ground measurements to extract the vegetation indices and textural features, and analyze their correlation with the SPAD value of leaves during the fruit expansion period of the pear tree. Finally, four machine learning methods, namely XGBoost, random forest (RF), back-propagation neural network (BPNN), and optimized integration algorithm (OIA), were used to construct inversion models of the SPAD value of pear trees, with different feature inputs based on vegetation indices, textural features, and their combinations, respectively. Moreover, the differences among these models were compared. The results showed the following: (1) both vegetation indices and textural features were significantly correlated with SPAD values, which were important indicators for estimating the SPAD values of pear leaves; (2) combining vegetation indices and textural features significantly improved the accuracy of SPAD value estimation compared with a single feature type; (3) the four machine learning algorithms demonstrated good predictive ability, and the OIA model outperformed the single model, with the model based on the OIA inversion model combining vegetation indices and textural features having the best accuracy, with <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msup><mrow><mi>R</mi></mrow><mrow><mn>2</mn></mrow></msup></mrow></semantics></math></inline-formula> values of 0.931 and 0.877 for the training and validation sets, respectively. This study demonstrated the efficacy of integrating multiple models and features to accurately invert SPAD values, which, in turn, supported the refined management of pear orchards.https://www.mdpi.com/1424-8220/25/3/618pear tree leafSPADUAV multispectraltextural featuresmachine learning |
| spellingShingle | Ning Yan Yasen Qin Haotian Wang Qi Wang Fangyu Hu Yuwei Wu Xuedong Zhang Xu Li The Inversion of SPAD Value in Pear Tree Leaves by Integrating Unmanned Aerial Vehicle Spectral Information and Textural Features Sensors pear tree leaf SPAD UAV multispectral textural features machine learning |
| title | The Inversion of SPAD Value in Pear Tree Leaves by Integrating Unmanned Aerial Vehicle Spectral Information and Textural Features |
| title_full | The Inversion of SPAD Value in Pear Tree Leaves by Integrating Unmanned Aerial Vehicle Spectral Information and Textural Features |
| title_fullStr | The Inversion of SPAD Value in Pear Tree Leaves by Integrating Unmanned Aerial Vehicle Spectral Information and Textural Features |
| title_full_unstemmed | The Inversion of SPAD Value in Pear Tree Leaves by Integrating Unmanned Aerial Vehicle Spectral Information and Textural Features |
| title_short | The Inversion of SPAD Value in Pear Tree Leaves by Integrating Unmanned Aerial Vehicle Spectral Information and Textural Features |
| title_sort | inversion of spad value in pear tree leaves by integrating unmanned aerial vehicle spectral information and textural features |
| topic | pear tree leaf SPAD UAV multispectral textural features machine learning |
| url | https://www.mdpi.com/1424-8220/25/3/618 |
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