[1] Welford W T. Use of annular apertures to increase focal depth[J]. Journal of the Optical Society of America, 50, 749-753(1960).

[2] Mino M, Okano Y. Improvement in the OTF of a defocused optical system through the use of shaded apertures[J]. Applied Optics, 10, 2219-2225(1971).

[3] Kuthirummal S, Nagahara H, Zhou C Y et al. Flexible depth of field photography[J]. IEEE Transactions on Pattern Analysis and Machine Intelligence, 33, 58-71(2011).

[4] Forster B, van de Ville D, Berent J et al. Complex wavelets for extended depth-of-field: a new method for the fusion of multichannel microscopy images[J]. Microscopy Research and Technique, 65, 33-42(2004).

[5] Li H, Manjunath B S, Mitra S K. Multisensor image fusion using the wavelet transform[J]. Graphical Models and Image Processing, 57, 235-245(1995).

[6] Forster B, Van De Ville D, Berent J et al. Extended depth-of-focus for multi-channel microscopy images: a complex wavelet approach[C], 660-663(2005).

[7] Li X S, Zhou F, Tan H et al. Multi-focus image fusion based on nonsubsampled contourlet transform and residual removal[J]. Signal Processing, 184, 108062(2021).

[8] Selvaraj A, Ganesan P. Infra-red and visible image fusion using multi-scale NSCT and rolling-guidance filter[J]. IET Image Processing, 14, 4210-4219(2020).

[9] Wang Y, Li X, Zhu R et al. A multi-focus image fusion framework based on multi-scale sparse representation in the gradient domain[J]. Signal Processing, 189, 108254(2021).

[10] Tan J, Zhang T, Zhao L et al. Multi-focus image fusion with Geometrical Sparse Representation[J]. Signal Processing: Image Communication, 92, 116130(2021).

[11] Bai Y C, Chen X, Ma J et al. Transient property of liquid crystal lens and its application in extended depth of field imaging[J]. Optics Communications, 473, 125974(2020).

[12] Wang B, Ye M, Sato S. Liquid crystal lens with a focal length variable from negative to positive values[J]. IEEE Photonics Technology Letters, 18, 79-81(2006).

[13] Sato S. Liquid-crystal lens-cells with variable focal length[J]. Japanese Journal of Applied Physics, 18, 1679-1684(1979).

[14] Wang B, Ye M, Honma M et al. Liquid crystal lens with spherical electrode[J]. Japanese Journal of Applied Physics, 41, L1232-L1233(2002).

[15] Ye M, Sato S. Optical properties of liquid crystal lens of any size[J]. Japanese Journal of Applied Physics, 41, L571-L573(2002).

[16] Ye M, Wang B, Sato S. Liquid-crystal lens with a focal length that is variable in a wide range[J]. Applied Optics, 43, 6407-6412(2004).

[17] Liu Z Q, Hu Y Y, Ye M. Liquid crystal axicon[J]. Acta Optica Sinica, 42, 0823001(2022).

[18] Ye M, Wang B, Uchida M et al. Focus tuning by liquid crystal lens in imaging system[J]. Applied Optics, 51, 7630-7635(2012).

[19] Ye M, Noguchi M, Wang B et al. Zoom lens system without moving elements realised using liquid crystal lenses[J]. Electronics Letters, 45, 646(2009).

[20] Hu Y Y, Liu Z Q, Sun T et al. The local zoom imaging system using liquid crystal lens[J]. Acta Optica Sinica, 42, 2311001(2022).

[21] Li P W, Chen X C, Chen X X et al. Liquid crystal lens imaging method using 90° twisted nematic liquid crystal cell instead of polariser[J]. Acta Optica Sinica, 42, 0711004(2022).

[22] Schrag J F, Sanderson A C, Neuman C P et al. The implementation of automatic focussing algorithms for a computer vision system with camera control[EB/OL]. https://www.ri.cmu.edu/pub_files/pub3/schlag_john_f_1983_1/schlag_john_f_1983_1.pdf

[23] Chen X, Li G Y, Li P W et al. Driving method for liquid crystal lens to increase focus range[J]. Electronics Letters, 55, 336-337(2019).

[24] Lina J M, Mayrand M. Complex daubechies wavelets[J]. Applied and Computational Harmonic Analysis, 2, 219-229(1995).