Assessment of vineyard canopy porosity using machine vision

Canopy porosity is an important viticultural factor because canopy gaps favor fruit exposure and air circulation, both of which benefit fruit quality and health. Point quadrat analysis (PQA) is standard for assessing canopy gaps but has limited utility because the method is laborious and time consuming. A new, objective, noninvasive, image-based method was developed and compared with PQA to assess the percent canopy gaps in vineyards with diverse viticultural conditions and grape varieties in New Zealand, Croatia, and Spain. The determination coefficient (R) of the regressions between the percent gaps using both methods exceeded 0.90 (p < 0.05) at each site, and R of the global regression was 0.93 (p < 0.05). The time of day and side of the canopy photographed did not significantly affect the performance of the algorithm. With this new image-based assessment method, canopy management may be optimized to configure a desired amount of canopy gaps and thereby improve fruit quality and health.The authors thank the Agencia de Desarrollo Económico de La Rioja ( ADER-2012-I-IDD-0009) for financial support.Peer Reviewe