[1] [1] Poh M Z, McDuff D J, Picard R W. Opt. Express, 2010, 18(10): 10762.

[2] [2] Monkaresi H, Calvo R A, Hong Y. IEEE Journal of Biomedical and Health Informatics, 2013, 18(4): 1153.

[3] [3] Poh M, McDuff D J, Picard R W. IEEE Transactions on Biomedical Engineering, 2011, 58(1): 7.

[4] [4] Balakrishnan G, Durand F, Guttag J. IEEE Conference on Computer Vision and Pattern Recognition, 2013, 6: 3430.

[5] [5] McDuff D, Gontarek S, Picard R W. IEEE Transactions on Biomedical Engineering, 2014, 61(10): 2593.

[6] [6] Rao Ruijian, Lai Xinquan, Li Yushan. Microelectronics, 2001(4): 272.

[7] [7] Liu Zhi, Chai Hua, Li Nana. Optics and Precision Engineering, 2009, (8): 2017.

[8] [8] Liu Dan, Liu Zhi, Sun Wei, et al. Journal of Jilin University, 2012, 30(6): 622.

[9] [9] Xiong Hui, Yang Xue, Zhou Mei, et al. Spectroscopy and Spectral Analysis, 2014, 34(4): 1130.

[10] [10] Wang Anmin, Chen liangfu. Application of Electronic Technique, 2006, 32(11): 118.

[11] [11] Wang Wenjin, Sander Stuijk, Gerard de Haan. IEEE TBME, 2015, 6: 415.