1. School of Intelligent Engineering, Shandong Management University, Jinan 250357, China
2. School of Information Science and Engineering, Shandong University, Qingdao 266237, China
3. Key Laboratory of Optical Engineering, Xi’an Research Institute of High Technology, Xi’an 710025, China
4. Department of Information Engineering, University of Pisa, 56122 Pisa, Italy
5. Department of Electronics and Industrial Informatics, National Institute for Applied Sciences of Rennes, F-35000 Rennes, France