Combining spectral and texture feature of UAV image with plant height to improve LAI estimation of winter wheat at jointing stage
IntroductionLeaf area index (LAI) is a critical physiological and biochemical parameter that profoundly affects vegetation growth. Accurately estimating the LAI for winter wheat during jointing stage is particularly important for monitoring wheat growth status and optimizing variable fertilization d...
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Frontiers Media S.A.
2024-01-01
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| Series: | Frontiers in Plant Science |
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| Online Access: | https://www.frontiersin.org/articles/10.3389/fpls.2023.1272049/full |
| _version_ | 1797367759763406848 |
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| author | Mengxi Zou Mengxi Zou Yu Liu Maodong Fu Cunjun Li Cunjun Li Zixiang Zhou Haoran Meng Enguang Xing Yanmin Ren |
| author_facet | Mengxi Zou Mengxi Zou Yu Liu Maodong Fu Cunjun Li Cunjun Li Zixiang Zhou Haoran Meng Enguang Xing Yanmin Ren |
| author_sort | Mengxi Zou |
| collection | DOAJ |
| description | IntroductionLeaf area index (LAI) is a critical physiological and biochemical parameter that profoundly affects vegetation growth. Accurately estimating the LAI for winter wheat during jointing stage is particularly important for monitoring wheat growth status and optimizing variable fertilization decisions. Recently, unmanned aerial vehicle (UAV) data and machine/depth learning methods are widely used in crop growth parameter estimation. In traditional methods, vegetation indices (VI) and texture are usually to estimate LAI. Plant Height (PH) unlike them, contains information about the vertical structure of plants, which should be consider.MethodsTaking Xixingdian Township, Cangzhou City, Hebei Province, China as the research area in this paper, and four machine learning algorithms, namely, support vector machine(SVM), back propagation neural network (BPNN), random forest (RF), extreme gradient boosting (XGBoost), and two deep learning algorithms, namely, convolutional neural network (CNN) and long short-term memory neural network (LSTM), were applied to estimate LAI of winter wheat at jointing stage by integrating the spectral and texture features as well as the plant height information from UAV multispectral images. Initially, Digital Surface Model (DSM) and Digital Orthophoto Map (DOM) were generated. Subsequently, the PH, VI and texture features were extracted, and the texture indices (TI) was further constructed. The measured LAI on the ground were collected for the same period and calculated its Pearson correlation coefficient with PH, VI and TI to pick the feature variables with high correlation. The VI, TI, PH and fusion were considered as the independent features, and the sample set partitioning based on joint x-y distance (SPXY) method was used to divide the calibration set and validation set of samples.ResultsThe ability of different inputs and algorithms to estimate winter wheat LAI were evaluated. The results showed that (1) The addition of PH as a feature variable significantly improved the accuracy of the LAI estimation, indicating that wheat plant height played a vital role as a supplementary parameter for LAI inversion modeling based on traditional indices; (2) The combination of texture features, including normalized difference texture indices (NDTI), difference texture indices (DTI), and ratio texture indices (RTI), substantially improved the correlation between texture features and LAI; Furthermore, multi-feature combinations of VI, TI, and PH exhibited superior capability in estimating LAI for winter wheat; (3) Six regression algorithms have achieved high accuracy in estimating LAI, among which the XGBoost algorithm estimated winter wheat LAI with the highest overall accuracy and best results, achieving the highest R2 (R2 = 0.88), the lowest RMSE (RMSE=0.69), and an RPD greater than 2 (RPD=2.54).DiscussionThis study provided compelling evidence that utilizing XGBoost and integrating spectral, texture, and plant height information extracted from UAV data can accurately monitor LAI during the jointing stage of winter wheat. The research results will provide a new perspective for accurate monitoring of crop parameters through remote sensing. |
| first_indexed | 2024-03-08T17:21:52Z |
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| institution | Directory Open Access Journal |
| issn | 1664-462X |
| language | English |
| last_indexed | 2024-03-08T17:21:52Z |
| publishDate | 2024-01-01 |
| publisher | Frontiers Media S.A. |
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| series | Frontiers in Plant Science |
| spelling | doaj.art-7f4024ebaa6a44c4877f6a64a355b1282024-01-03T04:31:01ZengFrontiers Media S.A.Frontiers in Plant Science1664-462X2024-01-011410.3389/fpls.2023.12720491272049Combining spectral and texture feature of UAV image with plant height to improve LAI estimation of winter wheat at jointing stageMengxi Zou0Mengxi Zou1Yu Liu2Maodong Fu3Cunjun Li4Cunjun Li5Zixiang Zhou6Haoran Meng7Enguang Xing8Yanmin Ren9College of Geomatics, Xi’an University of Science and Technology, Xi’an, ChinaResearch Center of Information Technology, Beijing Academy of Agriculture and Forestry Science, Beijing, ChinaResearch Center of Information Technology, Beijing Academy of Agriculture and Forestry Science, Beijing, ChinaHebei Maodong Xingteng Agricultural Technology Service Co., Ltd, Cangzhou, ChinaResearch Center of Information Technology, Beijing Academy of Agriculture and Forestry Science, Beijing, ChinaQingyuan Smart Agriculture and Rural Research Institute, Qingyuan, ChinaCollege of Geomatics, Xi’an University of Science and Technology, Xi’an, ChinaResearch Center of Information Technology, Beijing Academy of Agriculture and Forestry Science, Beijing, ChinaResearch Center of Information Technology, Beijing Academy of Agriculture and Forestry Science, Beijing, ChinaResearch Center of Information Technology, Beijing Academy of Agriculture and Forestry Science, Beijing, ChinaIntroductionLeaf area index (LAI) is a critical physiological and biochemical parameter that profoundly affects vegetation growth. Accurately estimating the LAI for winter wheat during jointing stage is particularly important for monitoring wheat growth status and optimizing variable fertilization decisions. Recently, unmanned aerial vehicle (UAV) data and machine/depth learning methods are widely used in crop growth parameter estimation. In traditional methods, vegetation indices (VI) and texture are usually to estimate LAI. Plant Height (PH) unlike them, contains information about the vertical structure of plants, which should be consider.MethodsTaking Xixingdian Township, Cangzhou City, Hebei Province, China as the research area in this paper, and four machine learning algorithms, namely, support vector machine(SVM), back propagation neural network (BPNN), random forest (RF), extreme gradient boosting (XGBoost), and two deep learning algorithms, namely, convolutional neural network (CNN) and long short-term memory neural network (LSTM), were applied to estimate LAI of winter wheat at jointing stage by integrating the spectral and texture features as well as the plant height information from UAV multispectral images. Initially, Digital Surface Model (DSM) and Digital Orthophoto Map (DOM) were generated. Subsequently, the PH, VI and texture features were extracted, and the texture indices (TI) was further constructed. The measured LAI on the ground were collected for the same period and calculated its Pearson correlation coefficient with PH, VI and TI to pick the feature variables with high correlation. The VI, TI, PH and fusion were considered as the independent features, and the sample set partitioning based on joint x-y distance (SPXY) method was used to divide the calibration set and validation set of samples.ResultsThe ability of different inputs and algorithms to estimate winter wheat LAI were evaluated. The results showed that (1) The addition of PH as a feature variable significantly improved the accuracy of the LAI estimation, indicating that wheat plant height played a vital role as a supplementary parameter for LAI inversion modeling based on traditional indices; (2) The combination of texture features, including normalized difference texture indices (NDTI), difference texture indices (DTI), and ratio texture indices (RTI), substantially improved the correlation between texture features and LAI; Furthermore, multi-feature combinations of VI, TI, and PH exhibited superior capability in estimating LAI for winter wheat; (3) Six regression algorithms have achieved high accuracy in estimating LAI, among which the XGBoost algorithm estimated winter wheat LAI with the highest overall accuracy and best results, achieving the highest R2 (R2 = 0.88), the lowest RMSE (RMSE=0.69), and an RPD greater than 2 (RPD=2.54).DiscussionThis study provided compelling evidence that utilizing XGBoost and integrating spectral, texture, and plant height information extracted from UAV data can accurately monitor LAI during the jointing stage of winter wheat. The research results will provide a new perspective for accurate monitoring of crop parameters through remote sensing.https://www.frontiersin.org/articles/10.3389/fpls.2023.1272049/fullplant heightfeature fusionmachine learningdeep learningUAVLAI |
| spellingShingle | Mengxi Zou Mengxi Zou Yu Liu Maodong Fu Cunjun Li Cunjun Li Zixiang Zhou Haoran Meng Enguang Xing Yanmin Ren Combining spectral and texture feature of UAV image with plant height to improve LAI estimation of winter wheat at jointing stage Frontiers in Plant Science plant height feature fusion machine learning deep learning UAV LAI |
| title | Combining spectral and texture feature of UAV image with plant height to improve LAI estimation of winter wheat at jointing stage |
| title_full | Combining spectral and texture feature of UAV image with plant height to improve LAI estimation of winter wheat at jointing stage |
| title_fullStr | Combining spectral and texture feature of UAV image with plant height to improve LAI estimation of winter wheat at jointing stage |
| title_full_unstemmed | Combining spectral and texture feature of UAV image with plant height to improve LAI estimation of winter wheat at jointing stage |
| title_short | Combining spectral and texture feature of UAV image with plant height to improve LAI estimation of winter wheat at jointing stage |
| title_sort | combining spectral and texture feature of uav image with plant height to improve lai estimation of winter wheat at jointing stage |
| topic | plant height feature fusion machine learning deep learning UAV LAI |
| url | https://www.frontiersin.org/articles/10.3389/fpls.2023.1272049/full |
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