Share Email Print
cover

Proceedings Paper

Improving the resolution in phase-shifting Gabor holography by CCD shift
Format Member Price Non-Member Price
PDF $14.40 $18.00

Paper Abstract

Holography dates back to the year when Dennis Gabor reported on a method to avoid spherical aberration and to improve image quality in electron microscopy. Gabor’s two-step holographic method was pioneer but suffered from three major drawbacks: the reconstructed image is affected by coherent noise, the twin image problem of holography that also affects the final image quality, and a restricted sample range (weak diffraction assumption) for preserving the holographic behavior of the method. Nowadays, most of those drawbacks have been overcome and new capabilities have been added due to the replacement of the classical recording media (photographic plate) by digital sensors (CCD and CMOS cameras). But in the Gabor’ regime, holography is restricted to weak diffraction assumptions because otherwise, diffraction prevents an accurate recovery of the object's complex wavefront. In this contribution, we present an experimental approach to overcome such limitation and improve final image resolution. We use the phase-shifting Gabor configuration while the CCD camera is shifted to different off-axis positions in order to capture a bigger portion of the diffracted wavefront. Thus, once the whole image set is recorded and digitally processed for each camera's position, we merge the resulting band-pass images into one image by assembling a synthetic aperture. Finally, a superresolved image is recovered by Fourier transformation of the information contained in the generated synthetic aperture. Experimental results are provided using a USAF resolution test target and validating our concepts for a gain in resolution of close to 2.

Paper Details

Date Published: 22 June 2015
PDF: 10 pages
Proc. SPIE 9525, Optical Measurement Systems for Industrial Inspection IX, 95253U (22 June 2015); doi: 10.1117/12.2184779
Show Author Affiliations
L. Granero, Univ. de València (Spain)
V. Micó, Univ. de València (Spain)
Z. Zalevsky, Bar-Ilan Univ. (Israel)
J. García, Univ. de València (Spain)
B. Javidi, Univ. of Connecticut (United States)


Published in SPIE Proceedings Vol. 9525:
Optical Measurement Systems for Industrial Inspection IX
Peter Lehmann; Wolfgang Osten; Armando Albertazzi Gonçalves, Editor(s)

© SPIE. Terms of Use
Back to Top