Kelly, D.P. and Hennelly, Bryan M. and McElhinney, Conor P. and Naughton, Thomas J. (2008) A Practical Guide to Digital Holography and Generalized Sampling. Proceedings of SPIE, 7072. 707215.1-707215.11. ISSN 0277-786X

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Abstract

The theorems of Nyquist, Shannon and Whittaker have long held true for sampling optical signals. They showed that a signal (with finite bandwidth) should be sampled at a rate at least as fast as twice the maximum spatial frequency of the signal. They proceeded to show how the continuous signal could be reconstructed perfectly from its well sampled counterpart by convolving a Sinc function with the sampled signal. Recent years have seen the emergence of a new generalized sampling theorem of which Nyquist Shannon is a special case. This new theorem suggests that it is possible to sample and reconstruct certain signals at rates much slower than those predicted by Nyquist-Shannon. One application in which this new theorem is of considerable interest is Fresnel Holography. A number of papers have recently suggested that the sampling rate for the digital recording of Fresnel holograms can be relaxed considerably. This may allow the positioning of the object closer to the camera allowing for a greater numerical aperture and thus an improved range of 3D perspective. In this paper we: (i) Review generalized sampling for Fresnel propagated signals, (ii) Investigate the effect of the twin image, always present in recording, on the generalized sampling theorem and (iii) Discuss the effect of finite pixel size for the first time.

Item Type:	Article
Keywords:	Digital holography; phase shifting interferometry; generalized sampling; Nyquist-Shannon; Fresnel; Fourier Transform;
Academic Unit:	Faculty of Science and Engineering > Computer Science
Item ID:	2358
Depositing User:	Thomas Naughton
Date Deposited:	18 Jan 2011 11:52
Journal or Publication Title:	Proceedings of SPIE
Publisher:	SPIE
Refereed:	Yes
URI:
Use Licence:	This item is available under a Creative Commons Attribution Non Commercial Share Alike Licence (CC BY-NC-SA). Details of this licence are available here

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