1. School of Computer Science and Informatics, De Montfort University, Leicester, U.K.
2. School of Computer Science, University of Nottingham, Nottingham, U.K.
3. Artificial Intelligence Department, XAI Group, Fraunhofer Heinrich Hertz Institute, Berlin, Germany
4. CIBERCV, Hospital Universitario Virgen de la Victoria, Málaga, Spain
5. Department of Computer Languages and Computer Science, University of Málaga, Málaga, Spain