Assessment of RGB Vegetation Indices to Estimate Chlorophyll Content in Sugar Beet Leaves in the Final Cultivation Stage
Estimation of chlorophyll content with portable meters is an easy way to quantify crop nitrogen status in sugar beet leaves. In this work, an alternative for chlorophyll content estimation using RGB-only vegetation indices has been explored. In a first step, pictures of spring-sown ‘Fernan...
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| Format: | Article |
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MDPI AG
2020-03-01
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| Series: | AgriEngineering |
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| Online Access: | https://www.mdpi.com/2624-7402/2/1/9 |
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| author | Luis Fernando Sánchez-Sastre Nuno M. S. Alte da Veiga Norlan Miguel Ruiz-Potosme Paula Carrión-Prieto José Luis Marcos-Robles Luis Manuel Navas-Gracia Pablo Martín-Ramos |
| author_facet | Luis Fernando Sánchez-Sastre Nuno M. S. Alte da Veiga Norlan Miguel Ruiz-Potosme Paula Carrión-Prieto José Luis Marcos-Robles Luis Manuel Navas-Gracia Pablo Martín-Ramos |
| author_sort | Luis Fernando Sánchez-Sastre |
| collection | DOAJ |
| description | Estimation of chlorophyll content with portable meters is an easy way to quantify crop nitrogen status in sugar beet leaves. In this work, an alternative for chlorophyll content estimation using RGB-only vegetation indices has been explored. In a first step, pictures of spring-sown ‘Fernanda KWS’ variety sugar beet leaves taken with a commercial camera were used to calculate 25 RGB indices reported in the literature and to obtain 9 new indices through principal component analysis (PCA) and stepwise linear regression (SLR) techniques. The performance of the 34 indices was examined in order to evaluate their ability to estimate chlorophyll content and chlorophyll degradation in the leaves under different natural light conditions along 4 days of the canopy senescence period. Two of the new proposed RGB indices were found to improve the already good performance of the indices reported in the literature, particularly for leaves featuring low chlorophyll contents. The 4 best indices were finally tested in field conditions, using unmanned aerial vehicle (UAV)-taken photographs of a sugar beet plot, finding a reasonably good agreement with chlorophyll-meter data for all indices, in particular for <i>I</i><sub>2</sub> and (<i>R−B</i>)/(<i>R+G+B</i>). Consequently, the suggested RGB indices may hold promise for inexpensive chlorophyll estimation in sugar beet leaves during the harvest time, although a direct relationship with nitrogen status still needs to be validated. |
| first_indexed | 2024-12-19T17:00:38Z |
| format | Article |
| id | doaj.art-7c805f575b2f43d293b5e24f5b6af01b |
| institution | Directory Open Access Journal |
| issn | 2624-7402 |
| language | English |
| last_indexed | 2024-12-19T17:00:38Z |
| publishDate | 2020-03-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | AgriEngineering |
| spelling | doaj.art-7c805f575b2f43d293b5e24f5b6af01b2022-12-21T20:13:18ZengMDPI AGAgriEngineering2624-74022020-03-012112814910.3390/agriengineering2010009agriengineering2010009Assessment of RGB Vegetation Indices to Estimate Chlorophyll Content in Sugar Beet Leaves in the Final Cultivation StageLuis Fernando Sánchez-Sastre0Nuno M. S. Alte da Veiga1Norlan Miguel Ruiz-Potosme2Paula Carrión-Prieto3José Luis Marcos-Robles4Luis Manuel Navas-Gracia5Pablo Martín-Ramos6Department of Agricultural and Forestry Engineering, ETSIIAA, Universidad de Valladolid, 34004 Palencia, SpainDepartamento de Ciências da Terra, Universidade de Coimbra, 3030-790 Coimbra, PortugalDepartment of Technical Education. European University Miguel de Cervantes, 47012 Valladolid, SpainDepartment of Agricultural and Forestry Engineering, ETSIIAA, Universidad de Valladolid, 34004 Palencia, SpainDepartment of Agricultural and Forestry Engineering, ETSIIAA, Universidad de Valladolid, 34004 Palencia, SpainDepartment of Agricultural and Forestry Engineering, ETSIIAA, Universidad de Valladolid, 34004 Palencia, SpainInstituto Universitario de Investigación en Ciencias Ambientales de Aragón (IUCA), EPS, Universidad de Zaragoza, 22001 Huesca, SpainEstimation of chlorophyll content with portable meters is an easy way to quantify crop nitrogen status in sugar beet leaves. In this work, an alternative for chlorophyll content estimation using RGB-only vegetation indices has been explored. In a first step, pictures of spring-sown ‘Fernanda KWS’ variety sugar beet leaves taken with a commercial camera were used to calculate 25 RGB indices reported in the literature and to obtain 9 new indices through principal component analysis (PCA) and stepwise linear regression (SLR) techniques. The performance of the 34 indices was examined in order to evaluate their ability to estimate chlorophyll content and chlorophyll degradation in the leaves under different natural light conditions along 4 days of the canopy senescence period. Two of the new proposed RGB indices were found to improve the already good performance of the indices reported in the literature, particularly for leaves featuring low chlorophyll contents. The 4 best indices were finally tested in field conditions, using unmanned aerial vehicle (UAV)-taken photographs of a sugar beet plot, finding a reasonably good agreement with chlorophyll-meter data for all indices, in particular for <i>I</i><sub>2</sub> and (<i>R−B</i>)/(<i>R+G+B</i>). Consequently, the suggested RGB indices may hold promise for inexpensive chlorophyll estimation in sugar beet leaves during the harvest time, although a direct relationship with nitrogen status still needs to be validated.https://www.mdpi.com/2624-7402/2/1/9<i>beta vulgaris</i>camerachlorophyllvegetation indicessugar beetunmanned aerial vehicle |
| spellingShingle | Luis Fernando Sánchez-Sastre Nuno M. S. Alte da Veiga Norlan Miguel Ruiz-Potosme Paula Carrión-Prieto José Luis Marcos-Robles Luis Manuel Navas-Gracia Pablo Martín-Ramos Assessment of RGB Vegetation Indices to Estimate Chlorophyll Content in Sugar Beet Leaves in the Final Cultivation Stage AgriEngineering <i>beta vulgaris</i> camera chlorophyll vegetation indices sugar beet unmanned aerial vehicle |
| title | Assessment of RGB Vegetation Indices to Estimate Chlorophyll Content in Sugar Beet Leaves in the Final Cultivation Stage |
| title_full | Assessment of RGB Vegetation Indices to Estimate Chlorophyll Content in Sugar Beet Leaves in the Final Cultivation Stage |
| title_fullStr | Assessment of RGB Vegetation Indices to Estimate Chlorophyll Content in Sugar Beet Leaves in the Final Cultivation Stage |
| title_full_unstemmed | Assessment of RGB Vegetation Indices to Estimate Chlorophyll Content in Sugar Beet Leaves in the Final Cultivation Stage |
| title_short | Assessment of RGB Vegetation Indices to Estimate Chlorophyll Content in Sugar Beet Leaves in the Final Cultivation Stage |
| title_sort | assessment of rgb vegetation indices to estimate chlorophyll content in sugar beet leaves in the final cultivation stage |
| topic | <i>beta vulgaris</i> camera chlorophyll vegetation indices sugar beet unmanned aerial vehicle |
| url | https://www.mdpi.com/2624-7402/2/1/9 |
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