About the Authors

Xunqiang Tao

Contributed equally to this work with: Xunqiang Tao, Xinjian Chen

Affiliation Center for Biometrics and Security Research, Institute of Automation, Chinese Academy of Sciences, Beijing, China

Xinjian Chen

Contributed equally to this work with: Xunqiang Tao, Xinjian Chen

Affiliation Department of Electrical and Computer Engineering, University of Iowa, Iowa City, Iowa, United States of America

Xin Yang

Affiliation Center for Biometrics and Security Research, Institute of Automation, Chinese Academy of Sciences, Beijing, China

Jie Tian

tian@ieee.org

Affiliations Center for Biometrics and Security Research, Institute of Automation, Chinese Academy of Sciences, Beijing, China, Life Science Research Center, School of Electronic Engineering, Xidian University, Xi'an, Shaanxi, China

Competing Interests

The authors have declared that no competing interests exist.

Author Contributions

Conceived and designed the experiments: XT XY JT. Performed the experiments: XT XY. Contributed reagents/materials/analysis tools: XY XC. Wrote the paper: XT XC.