1. Institute for Infocomm Research (I2R), Agency for Science, Technology and Research (A*STAR), Singapore 138632, Singapore
2. Department of Experimental and Clinical Biomedical Sciences, University of Florence—Azienda Ospedaliero-Universitaria Careggi, 50134 Florence, Italy
3. School of Computer Science and Engineering, Nanyang Technological University, Singapore 639798, Singapore