Selection of Relevant Nodes from Component-Trees in Linear Time

Component-trees associate to a discrete grey-level image a descriptive data structure induced by the inclusion relation between the binary components obtained at successive level-sets. In this work we propose a method to extract a subset of the component-tree of an image enabling to fit at best a given binary target selected beforehand in the image. A proof of the algorithmic efficiency of this method is proposed. Application examples related to the extraction of drop caps from ancient documents emphasise the usefulness of this technique in the context of assisted segmentation. Component-tree • A component-tree associates to a (discrete) grey-level image a descriptive data structure induced by the inclusion relation between the binary components obtained at successive level-sets. • A threshold set of an image I : E → V at level v is defined as: Xv(I) = {p ∈ E | I(p) ≥ v}. • A node of the component-tree is a connected component of Xv(F ). • A node N1 is an ancestor of N2 if N2 ⊂ N1. • The root of the component-tree is the set E. A