Estimation of Leaf Area Index in vineyards by analysing projected shadows using UAV imagery
A few decades ago, farmers could precisely monitor their croplands just by walking over the fields, but this task becomes more difficult as farm size increases. Precision viticulture can help better understand the vineyard and measure some key structural parameters, such as the Leaf Area Index (LAI)...
| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
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International Viticulture and Enology Society
2021-11-01
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| Series: | OENO One |
| Subjects: | |
| Online Access: | https://oeno-one.eu/article/view/4639 |
| _version_ | 1818407490876866560 |
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| author | Sergio Vélez Carlos Poblete-Echeverría José Antonio Rubio Rubén vacas Enrique Barajas |
| author_facet | Sergio Vélez Carlos Poblete-Echeverría José Antonio Rubio Rubén vacas Enrique Barajas |
| author_sort | Sergio Vélez |
| collection | DOAJ |
| description | A few decades ago, farmers could precisely monitor their croplands just by walking over the fields, but this task becomes more difficult as farm size increases. Precision viticulture can help better understand the vineyard and measure some key structural parameters, such as the Leaf Area Index (LAI). Remote Sensing is a typical approach to monitoring vegetation which measures the spectral information directly emitted and reflected from vegetation. This study explores a new method for estimating LAI which measures the projected shadows of plants using UAV (unmanned aerial vehicle) imagery. A flight mission over a vineyard was scheduled in the afternoon (15:30 to 16:00 solar time), which is the optimal time for the projection of vine shadows on the ground. Real LAI was measured destructively by removing all the vegetation from the area. Then, the projected shadows in the image were detected using machine learning methods (k-means and random forest) and analysed at pixel level using a customised R code. A strong linear relationship (R² = 0.76, RMSE = 0.160 m² m-2 and MAE = 0.139 m² m-2) was found between the shaded area and the LAI per vine. This is a quick and simple method, which is non-destructive and gives accurate results; moreover, flights can be scheduled during other periods of the day than solar noon, such as in the morning or afternoon, thus enabling pilots to extend their working day. Therefore, it may be a viable option for determining LAI in vineyards trained on Vertical Shoot Positioned (VSP) systems. |
| first_indexed | 2024-12-14T09:28:40Z |
| format | Article |
| id | doaj.art-771aaf7ab26946399ca3d5092cd370b7 |
| institution | Directory Open Access Journal |
| issn | 2494-1271 |
| language | English |
| last_indexed | 2024-12-14T09:28:40Z |
| publishDate | 2021-11-01 |
| publisher | International Viticulture and Enology Society |
| record_format | Article |
| series | OENO One |
| spelling | doaj.art-771aaf7ab26946399ca3d5092cd370b72022-12-21T23:08:07ZengInternational Viticulture and Enology SocietyOENO One2494-12712021-11-0155410.20870/oeno-one.2021.55.4.4639Estimation of Leaf Area Index in vineyards by analysing projected shadows using UAV imagerySergio Vélez0Carlos Poblete-Echeverría1José Antonio Rubio2Rubén vacas3Enrique Barajas4Instituto Tecnológico Agrario de Castilla y León (ITACyL), Unidad de Cultivos Leñosos y Hortícolas. ValladolidSouth African Grape and Wine Research Institute (SAGWRI), Department of Viticulture and Oenology, Faculty of AgriSciences, Stellenbosch University, Private Bag X1, Matieland 7602Instituto Tecnológico Agrario de Castilla y León (ITACyL), Unidad de Cultivos Leñosos y Hortícolas. ValladolidInstituto Tecnológico Agrario de Castilla y León (ITACyL), Unidad de Cultivos Leñosos y Hortícolas. ValladolidInstituto Tecnológico Agrario de Castilla y León (ITACyL), Unidad de Cultivos Leñosos y Hortícolas. ValladolidA few decades ago, farmers could precisely monitor their croplands just by walking over the fields, but this task becomes more difficult as farm size increases. Precision viticulture can help better understand the vineyard and measure some key structural parameters, such as the Leaf Area Index (LAI). Remote Sensing is a typical approach to monitoring vegetation which measures the spectral information directly emitted and reflected from vegetation. This study explores a new method for estimating LAI which measures the projected shadows of plants using UAV (unmanned aerial vehicle) imagery. A flight mission over a vineyard was scheduled in the afternoon (15:30 to 16:00 solar time), which is the optimal time for the projection of vine shadows on the ground. Real LAI was measured destructively by removing all the vegetation from the area. Then, the projected shadows in the image were detected using machine learning methods (k-means and random forest) and analysed at pixel level using a customised R code. A strong linear relationship (R² = 0.76, RMSE = 0.160 m² m-2 and MAE = 0.139 m² m-2) was found between the shaded area and the LAI per vine. This is a quick and simple method, which is non-destructive and gives accurate results; moreover, flights can be scheduled during other periods of the day than solar noon, such as in the morning or afternoon, thus enabling pilots to extend their working day. Therefore, it may be a viable option for determining LAI in vineyards trained on Vertical Shoot Positioned (VSP) systems.https://oeno-one.eu/article/view/4639leaf area indexshadow detectionimage analysisprecision agriculturemachine learningspatial variability |
| spellingShingle | Sergio Vélez Carlos Poblete-Echeverría José Antonio Rubio Rubén vacas Enrique Barajas Estimation of Leaf Area Index in vineyards by analysing projected shadows using UAV imagery OENO One leaf area index shadow detection image analysis precision agriculture machine learning spatial variability |
| title | Estimation of Leaf Area Index in vineyards by analysing projected shadows using UAV imagery |
| title_full | Estimation of Leaf Area Index in vineyards by analysing projected shadows using UAV imagery |
| title_fullStr | Estimation of Leaf Area Index in vineyards by analysing projected shadows using UAV imagery |
| title_full_unstemmed | Estimation of Leaf Area Index in vineyards by analysing projected shadows using UAV imagery |
| title_short | Estimation of Leaf Area Index in vineyards by analysing projected shadows using UAV imagery |
| title_sort | estimation of leaf area index in vineyards by analysing projected shadows using uav imagery |
| topic | leaf area index shadow detection image analysis precision agriculture machine learning spatial variability |
| url | https://oeno-one.eu/article/view/4639 |
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