1. Faculty of Computer Sciences, Multimedia and Telecommunication, Universitat Oberta de Catalunya, Barcelona, Spain
2. Institute of New Imaging Technologies, Universitat Jaume I, Castellón de la Plana, Spain
3. Institute of New Imaging Technologies and the Department of Industrial Engineering Systems and Design, Universitat Jaume I, Castelló de la Plana, Spain
4. Mathematics Department, Universitat Jaume I, Castellon de la Plana, Spain
5. Centro ALGORITMI, Universidade do Minho, Guimarães, Portugal