title: Assessment of cluster yield components by image analysis.
abstract: BACKGROUND
  Berry weight, berry number and cluster weight are key parameters for yield estimation for wine and tablegrape industry. Current yield prediction methods are destructive, labour-demanding and time-consuming. In this work, a new methodology, based on image analysis was developed to determine cluster yield components in a fast and inexpensive way.
  
  
  RESULTS
  Clusters of seven different red varieties of grapevine (Vitis vinifera L.) were photographed under laboratory conditions and their cluster yield components manually determined after image acquisition. Two algorithms based on the Canny and the logarithmic image processing approaches were tested to find the contours of the berries in the images prior to berry detection performed by means of the Hough Transform. Results were obtained in two ways: by analysing either a single image of the cluster or using four images per cluster from different orientations. The best results (R(2) between 69% and 95% in berry detection and between 65% and 97% in cluster weight estimation) were achieved using four images and the Canny algorithm. The model's capability based on image analysis to predict berry weight was 84%.
  
  
  CONCLUSIONS
  The new and low-cost methodology presented here enabled the assessment of cluster yield components, saving time and providing inexpensive information in comparison with current manual methods.
authors.affiliation: Instituto de Ciencias de la Vid y del Vino, University of La Rioja, CSIC, Gobierno de La Rioja, 26006, Logroño, Spain.
authors.forename: Maria P
authors.initials: MP
authors.lastname: Diago
authors.forename: Javier
authors.initials: J
authors.lastname: Tardaguila
authors.forename: Nuria
authors.initials: N
authors.lastname: Aleixos
authors.forename: Borja
authors.initials: B
authors.lastname: Millan
authors.forename: Jose M
authors.initials: JM
authors.lastname: Prats-Montalban
authors.forename: Sergio
authors.initials: S
authors.lastname: Cubero
authors.forename: Jose
authors.initials: J
authors.lastname: Blasco
mesh_terms: D000465:Algorithms; D018533:Biomass; D016000:Cluster Analysis; D005638:Fruit / Q000254:growth & development*; D006801:Humans; D008954:Models, Biological; D027843:Vitis / Q000254:growth & development*; D014920:Wine
keywords: Hough Transform; LIP-Canny; Vitis vinifera L; berry number per cluster; berry weight; cluster weight