Tunable Gaussian mask for extending the depth of field

Abstract

We present the use of two asymmetrical amplitude masks, for generating a tunable Gaussian filter. The two masks work as a pair. By introducing a lateral displacement, between the members of the pair, one can tune the width of the Gaussian filter. This tunable mask is useful for controlling unwanted oscillations in the MTFs, which are associated to the use of phase filters extending the depth of field.

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References

1. G. Hauesler, "A method to increase the depth of focus by two step image processing", Opt. Commun. 6, 38 (1972).CrossRef
2. J. Ojeda-Casta?eda, R. Ramos, A. Noyola-Isgleas, "High focal depth by apodization and digital restoration", Appl. Opt. 27, 2583 (1988).CrossRef
3. M. Mino, Y. Okano, "Improvement in the OTF of a Defocused Optical System Through the Use of Shaded Apertures", Appl. Opt. 10, 2219 (1971).CrossRef
4. J. Ojeda-Casta?eda, L.R. Berriel Valdos, E. L. Montes, "Line-spread function relatively insensitive to defocus", Opt. Lett. 8(8), 458 (1983).CrossRef
5. J. Ojeda-Casta?eda, L.R. Berriel-Valdos, E. Montes, "Spatial filter for increasing the depth of focus", Opt. Lett. 10(11), 520 (1985).CrossRef
6. J. Ojeda-Casta?eda, A. Díaz, "High focal depth by quasibifocus", Appl. Opt. 27, 4163 (1988).CrossRef
7. J. Ojeda-Casta?eda, L.R Berriel-Valdos, E. Montes, "Ambiguity function as a design tool for high focal depth", Appl. Opt. 27(4), 790 (1988).CrossRef
8. E.R. Dowski, T.W. Cathey, "Extended depth of field through wave-front coding", Appl. Opt. 34, 1859 (1995).CrossRef
9. H. Wang, F. Gan, "High Focal Depth with a Pure-Phase Apodizer", Appl. Opt. 40, 5658 (2001).CrossRef
10. N. George, W. Chi, "Extended depth of field using a logarithmic asphere", J. Opt. A: Pure Appl. Opt. 5, S157 (2003).CrossRef
11. A. Castro, J. Ojeda-Casta?eda, "Asymmetric Phase Masks for Extended Depth of Field", Appl. Opt. 43(17), 1 (2004).CrossRef
12. Á. Sauceda-Carvajal, J. Ojeda-Casta?eda, "High focal depth with fractional-power wave fronts", Opt. Lett. 29(6), 560 (2004).CrossRef
13. G. Mikula, Z. Jaroszewicz, A. Kolodziejczyk, K. Petelczyc, M. Sypek, "Imaging with extended focal depth by means of lenses with radial and angular modulation", Opt. Exp. 15, 9184 (2007).CrossRef
14. J. Ojeda-Castaneda, J.E.A. Landgrave, C.M. Gómez-Sarabia, "Conjugate phase plate use in analysis of the frequency response of imaging systems designed for extended depth of field", Appl. Opt. 47, E99 ? E105 (2008).CrossRef
15. J. Ares García, S. Bará, M. Gomez García, Z. Jaroszewicz, A. Kolodziejczyk, K. Petelczyc, "Imaging with extended focal depth by means of the refractive light sword optical element", Opt. Exp. 16, 18371 (2008).CrossRef
16. G. Muyo, A. Singh, M. Andersson, D. Huckridge, A. Wood, A.R. Harvey, "Infrared imaging with a wavefront-coded singlet lens", Opt. Exp. 17(23), 21118 (2009).CrossRef
17. J. Ojeda-Casta?eda, E. Yépez-Vidal, E. García-Almanza, "Noncoherent imagery: a novel approach", Phot. Lett. Poland 2(4), 162 (2010).CrossRef
18. H.H. Hopkins, Wave Theory of Aberrations (Oxford, 1950).
19. K.-H. Brenner, A.W. Lohmann, J. Ojeda-Castaneda, "The ambiguity function as a polar display of the OTF", Opt. Comm. 77, 89 (1982).CrossRef