{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,6,9]],"date-time":"2026-06-09T12:21:45Z","timestamp":1781007705379,"version":"3.54.1"},"reference-count":39,"publisher":"MDPI AG","issue":"1","license":[{"start":{"date-parts":[[2021,12,28]],"date-time":"2021-12-28T00:00:00Z","timestamp":1640649600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100001809","name":"National Natural Science Foundation of China","doi-asserted-by":"publisher","award":["31901154"],"award-info":[{"award-number":["31901154"]}],"id":[{"id":"10.13039\/501100001809","id-type":"DOI","asserted-by":"publisher"}]},{"name":"the research team project of Anhui Academy of Agricultural Sciences","award":["2021YL0085"],"award-info":[{"award-number":["2021YL0085"]}]},{"name":"the Provincial Science and Technology Innovation Park Demonstration Project","award":["201907d06020011"],"award-info":[{"award-number":["201907d06020011"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>Chlorophyll content is an important indicator of plant photosynthesis, which directly affects the growth and yield of crops. Using hyperspectral imaging technology to quickly and non-destructively estimate the soil plant analysis development (SPAD) value of pepper leaf and its distribution inversion is of great significance for agricultural monitoring and precise fertilization during pepper growth. In this study, 150 samples of pepper leaves with different leaf positions were selected, and the hyperspectral image data and SPAD value were collected for the sampled leaves. The correlation coefficient, stability competitive adaptive reweighted sampling (sCARS), and iteratively retaining informative variables (IRIV) methods were used to screen characteristic bands. These were combined with partial least-squares regression (PLSR), extreme gradient boosting (XGBoost), random forest regression (RFR), and gradient boosting decision tree (GBDT) to build regression models. The developed model was then used to build the inversion map of pepper leaf chlorophyll distribution. The research results show that: (1) The IRIV-XGBoost model demonstrates the most comprehensive performance in the modeling and inversion stages, and its Rcv2, RMSEcv, and MAEcv are 0.81, 2.76, and 2.30, respectively; (2) The IRIV-XGBoost model was used to calculate the SPAD value of each pixel of pepper leaves, and to subsequently invert the chlorophyll distribution map of pepper leaves at different leaf positions, which can provide support for the intuitive monitoring of crop growth and lay the foundation for the development of hyperspectral field dynamic monitoring sensors.<\/jats:p>","DOI":"10.3390\/s22010183","type":"journal-article","created":{"date-parts":[[2021,12,28]],"date-time":"2021-12-28T06:55:03Z","timestamp":1640674503000},"page":"183","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":33,"title":["Study on the Optimization of Hyperspectral Characteristic Bands Combined with Monitoring and Visualization of Pepper Leaf SPAD Value"],"prefix":"10.3390","volume":"22","author":[{"given":"Ziran","family":"Yuan","sequence":"first","affiliation":[{"name":"Soil and Fertilizer Research Institute, Anhui Academy of Agricultural Sciences, Hefei 230031, China"},{"name":"Key Laboratory of Nutrient Cycling and Resources Environment of Anhui Province, Anhui Academy of Agricultural Sciences, Hefei 230031, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yin","family":"Ye","sequence":"additional","affiliation":[{"name":"Soil and Fertilizer Research Institute, Anhui Academy of Agricultural Sciences, Hefei 230031, China"},{"name":"Key Laboratory of Nutrient Cycling and Resources Environment of Anhui Province, Anhui Academy of Agricultural Sciences, Hefei 230031, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Lifei","family":"Wei","sequence":"additional","affiliation":[{"name":"Faculty of Resources and Environmental Science, Hubei University, Wuhan 430062, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Xin","family":"Yang","sequence":"additional","affiliation":[{"name":"Soil and Fertilizer Research Institute, Anhui Academy of Agricultural Sciences, Hefei 230031, China"},{"name":"Key Laboratory of Nutrient Cycling and Resources Environment of Anhui Province, Anhui Academy of Agricultural Sciences, Hefei 230031, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Can","family":"Huang","sequence":"additional","affiliation":[{"name":"Faculty of Resources and Environmental Science, Hubei University, Wuhan 430062, China"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2021,12,28]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"1190","DOI":"10.1080\/01904167.2016.1264596","article-title":"Nitrogen Nutrition Index and Leaf Chlorophyll Concentration and its relationship with Nitrogen Use Efficiency in Barley (Hordeum vulgare L.)","volume":"40","author":"Dordas","year":"2017","journal-title":"J. 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