title: Grapevine yield and leaf area estimation using supervised classification methodology on RGB images taken under field conditions.
abstract: The aim of this research was to implement a methodology through the generation of a supervised classifier based on the Mahalanobis distance to characterize the grapevine canopy and assess leaf area and yield using RGB images. The method automatically processes sets of images, and calculates the areas (number of pixels) corresponding to seven different classes (Grapes, Wood, Background, and four classes of Leaf, of increasing leaf age). Each one is initialized by the user, who selects a set of representative pixels for every class in order to induce the clustering around them. The proposed methodology was evaluated with 70 grapevine (V. vinifera L. cv. Tempranillo) images, acquired in a commercial vineyard located in La Rioja (Spain), after several defoliation and de-fruiting events on 10 vines, with a conventional RGB camera and no artificial illumination. The segmentation results showed a performance of 92% for leaves and 98% for clusters, and allowed to assess the grapevine's leaf area and yield with R2 values of 0.81 (p < 0.001) and 0.73 (p = 0.002), respectively. This methodology, which operates with a simple image acquisition setup and guarantees the right number and kind of pixel classes, has shown to be suitable and robust enough to provide valuable information for vineyard management.
authors.affiliation: Instituto de Ciencias de la Vid y del Vino (CSIC, University of La Rioja, La Rioja Government) Madre de Dios, 51, 26006 Logroño, Spain. mpaz.diago.santamaria@gmail.com
authors.forename: Maria-Paz
authors.initials: MP
authors.lastname: Diago
authors.forename: Christian
authors.initials: C
authors.lastname: Correa
authors.forename: Borja
authors.initials: B
authors.lastname: Millán
authors.forename: Pilar
authors.initials: P
authors.lastname: Barreiro
authors.forename: Constantino
authors.initials: C
authors.lastname: Valero
authors.forename: Javier
authors.initials: J
authors.lastname: Tardaguila
mesh_terms: D005638:Fruit; D018515:Plant Leaves; D013030:Spain; D027843:Vitis