Phenological analysis of a Mediterranean maquis vegetation based on data processing routines of digital images

Near-surface remote sensing techniques are used to quantify, at high temporal resolution, and with a certain degree of spatial integration, the seasonal variations of the surface optical and radiometric properties. These data provide information on vegetation phenological and ecophysiological responses (Richardson et al 2009; Sonnentag 2011). The ECO-SCALE (Integrated High Resolution Monitoring of Mediterranean vegetation) project is aimed to the development and validation of new technologies and methodologies for the identification of functional responses of natural vegetation in a Mediterranean area to environmental and climatic changes. In particular, the project aims to develop an integrated system for environmental monitoring based on digital photography, hyperspectral radiometry, and micrometeorological techniques. The analyses of integrated data obtained from different methods and techniques would improve our knowledge of the mechanisms underlying the development processes of Mediterranean species. In this paper results of the specific work package of the project aimed to implement a methodology based on digital images for the automated phenological vegetation monitoring are presented, with particular regards to those related to the analysis of a phenological behavior based on digital image. To the end of retrieve phenological information from digital images, a routine of commands to process the digital image file using the program MATLAB (R2014b, The MathWorks, Natick, Mass.) was specifically created. The color channel information was extracted and the RGB value was correlated with the pattern of phenological development. Results showed that the use of digital images is well-suited to identify phenological pattern of shrubland Mediterranean species.