Accessible Requires Authentication Published by De Gruyter October 10, 2012

Development and evaluation of an automated digital image analysis software for obtaining seagrass leaf metrics

Alexis Ramfos, Andreas Gazis and George Katselis
From the journal Botanica Marina

Abstract

We developed a simple and inexpensive digital image analysis method for measuring leaf area and the length of strapped-shaped seagrass leaves. The method uses specialized software that permits automatic leaf and scale recognition in digital images along with batch image processing. The leaf biometrics of 80 Posidonia oceanica and Cymodocea nodosa leaves were used for the evaluation of the method for accuracy, precision, and speed in comparison to manual measurements. Each leaf was measured 90 times under different combinations of several factors that might affect software estimation. The factors examined included leaf shape, leaf orientation in the image, scale dimensions, image resize, and binary conversion. Estimates of leaf length and leaf area were highly correlated between the new image analysis procedure and manual measurements. Relative error values between the two methods were <10% in 99% of leaf length measures and in 75% of leaf area measures. The factors examined explained <10% of the relative error variance; the remaining variance was mostly attributed to technical issues concerning leaf size and image illumination. The digital method proved to be approximately 2.5 times faster than the manual one.


Corresponding author: Alexis Ramfos, Department of Aquaculture and Fisheries Management, Technological Educational Institute of Messolonghi, New Buildings TEI, 30200 Mesolonghi, Greece

Received: 2012-3-22
Accepted: 2012-9-12
Published Online: 2012-10-10
Published in Print: 2012-12-01

©2012 by Walter de Gruyter Berlin Boston