Quaternion DISC-harmonic moments based on healpix sampling for fast 2D colour shape retrieval

摘要

In this paper, we present an efficient improvement of our colour shape descriptor, QDHMs, which is based on harmonics defined on the unit disc. A new sampling of the unit disc, using the Healpix (hierarchical equal area isolatitude pixelation) tool, is established. The use of Healpix is justified by its geometric properties that insure a fast analysis of big amounts of data. Healpix was initially developed to deal with needs in terms of treatment and analysis of data of the new research missions related to the Cosmic Microwave Background (CMB). The previously proposed version of the QDHMs outperforms its competitors in terms of retrieval performance using COIL-100 and ALOI-VIEW databases. The improvement we propose is more about accelerating the computation time of the moments. The QDHMs version proposed in this paper could be a useful descriptor in real-time content-based colour image retrieval systems.