Shape-Based Image Retrieval By Alignment

Abstract

Among the existing Content Based Image Retrieval (CBIR) techniques for still images based on different perceptual features (e. g., colour, texture, etc.), shape-based methods are particularly challenging due to the intrinsic difficulties in dealing with shape localization and recognition problems. Nevertheless, there is no doubt that shape is one of the most important perceptual feature and successful shape-based techniques would significantly improve the spreading of general-purpose image retrieval systems. In this chapter we present a shape-based image retrieval approach able to efficiently deal with domain independent images with possible cluttered backgrounds and partially occluded objects. It is based on an alignment approach proved to be robust in rigid object recognition which we have modified in order to deal with inexact matching between the stylized shape input by the user as query and the real shapes represented in the system’s database. Results with a database composed of difficult real-life images are shown.