[1] [1] S. Hu and L. V. Wang, J. Biomed. Opt. 15, 011101 (2010).

[2] [2] H. F. Zhang, K. Maslov, G. Stoica, and L. V. Wang, Nat. Biotechnol. 24, 848 (2006).

[3] [3] L. V. Wang, IEEE J. Sel. Top. Quantum Electron. 14, 171 (2008).

[4] [4] K. Maslov, H. F. Zhang, S. Hu, and L. V. Wang, Opt. Lett. 33, 929 (2008).

[5] [5] J. D. Briers, Opt. Applicata XXXVII, 139 (2007).

[6] [6] H. Cheng, Q. Luo, Q. Liu, H. Gong, and S. Zeng, Phys. Med. Biol. 49, 1347 (2004).

[7] [7] J. D. Briers, G. Richards, and X. W. Xiao, J. Biomed. Opt. 4, 164 (1999).

[8] [8] A. K. Dunn, H. Bolay, M. A. Moskowitz, and D. A. Boas, J. Cerebr. Blood F. Met. 21, 195 (2001).

[9] [9] A. K. Dunn, A. Devor, H. Bolay, M. L. Andermann, M. A. Moskowitz, A. M. Dale, and D. A. Boas, Opt. Lett. 28, 28 (2003).

[10] [10] A. Devor, A. K. Dunn, M. L. Andermann, I. Ulbert, D. A. Boas, and A. M. Dale, Neuron 39, 353 (2003).

[11] [11] J. B. A. Maintz and M. A .Viergever, Med. Image Anal. 2, 1 (1997).

[12] [12] B. Zitova and J. Flusser, Image Vision Comput. 21, 977 (2003).

[13] [13] F. Maes, A. Collignon, D. Vandermeulen, G. Marchal, and P. Suetens, IEEE Trans. Med. Imag. 16, 187 (1997).

[14] [14] N. Otsu, IEEE Trans. Syst. Man. Cy. 9, 62 (1979).

[15] [15] X. Yang, X. Cai, K. Maslov, L. Wang, and Q. Luo, Chin. Opt. Lett. 8, 609 (2010).

[16] [16] J. Qiu, P. Li, W. Luo, J. Wang, H. Zhang, and Q. Luo, J. Biomed. Opt. 15, 016003 (2010).

[17] [17] J. P. W. Pluim, J. B. A. Maintz, and M. A. Viergever, IEEE Trans. Med. Imag. 19, 1 (2000).

[18] [18] C. Pohl and J. L. Van Genderen, Int. J. Remote Sensing 19, 823 (1988).

[19] [19] P. Xu and D. Yao, Comput. Biol. Med. 37, 320 (2007).