Distinguishing characteristics in underwater images of Northern and Eurasian watermilfoils

摘要

Abstract: This paper describes a simple scheme for distinguishing between two very similar watermilfoils, Eurasian or Myriophyllum spicatum L. and Northern or Myriophyllum exalbescens. Leaf images were isolated from underwater images of the plants. Characteristic features consisting of the ratio of black to white pixels within the convex hull of an edge-mapped leaf, the eccentricity of the ellipse surrounding the leaf and a spatial-dependency analysis, measuring the frequency of change of pixel intensity of an edge-mapped leaf were combined to provide a measure which could be used to determine whether a leaf was Northern or Eurasian. !14