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. Full Text: PDF References G. Hauesler, "A method to increase the depth of focus by two step image processing", Opt. Commun. 6, 38 (1972). CrossRef J. Ojeda-Casta?eda, R. Ramos, A. Noyola-Isgleas, "High focal depth by apodization and digital restoration", Appl. Opt. 27, 2583 (1988). CrossRef 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 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 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 J. Ojeda-Casta?eda, A. Díaz, "High focal depth by quasibifocus", Appl. Opt. 27, 4163 (1988). CrossRef 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 E.R. Dowski, T.W. Cathey, "Extended depth of field through wave-front coding", Appl. Opt. 34, 1859 (1995). CrossRef H. Wang, F. Gan, "High Focal Depth with a Pure-Phase Apodizer", Appl. Opt. 40, 5658 (2001). CrossRef N. George, W. Chi, "Extended depth of field using a logarithmic asphere", J. Opt. A: Pure Appl. Opt. 5, S157 (2003). CrossRef A. Castro, J. Ojeda-Casta?eda, "Asymmetric Phase Masks for Extended Depth of Field", Appl. Opt. 43(17), 1 (2004). CrossRef Á. Sauceda-Carvajal, J. Ojeda-Casta?eda, "High focal depth with fractional-power wave fronts", Opt. Lett. 29(6), 560 (2004). CrossRef 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 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 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 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 J. Ojeda-Casta?eda, E. Yépez-Vidal, E. García-Almanza, "Noncoherent imagery: a novel approach", Phot. Lett. Poland 2(4), 162 (2010). CrossRef H.H. Hopkins, Wave Theory of Aberrations (Oxford, 1950). 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