About the Authors

Lingyun Zhao

Affiliation Department of Biomedical Engineering, School of Medicine, Tsinghua University, Beijing, P.R. China

Li Zhaoping

z.li@ucl.ac.uk

Affiliation Department of Computer Science, University College London, London, United Kingdom

Competing Interests

The authors have declared that no competing interests exist.

Author Contributions

Conceived and designed the experiments: L. Zhao, L. Zhaoping. Performed the experiments: L. Zhao, L. Zhaoping. Analyzed the data: L. Zhao, L. Zhaoping. Wrote the paper: L. Zhao, L. Zhaoping. Began the project as a course project: L. Zhao. Supervised and completed the project: L. Zhaoping.