An automatic method for assembling a large synthetic aperture digital hologram

• Published in: Optics express Vol. 20; no. 5; pp. 4830 - 4839
• Main Authors: Pelagotti, A, Paturzo, M, Locatelli, M, Geltrude, A, Meucci, R, Finizio, A, Ferraro, P
• Format: Journal Article
• Language: English
• Published: United States 27.02.2012
• Subjects: Algorithms; Artificial Intelligence; Holography - methods; Image Enhancement - methods; Image Interpretation, Computer-Assisted - methods; Imaging, Three-Dimensional - methods; Pattern Recognition, Automated - methods; Reproducibility of Results; Sensitivity and Specificity; Signal Processing, Computer-Assisted; Subtraction Technique
• ISSN: 1094-4087; 1094-4087
• DOI: 10.1364/OE.20.004830

A major issue so far for digital holography is the low spatial resolution generally achieved. The numerical aperture is limited by the area of currently available detectors, such as CCD sensors, which is significantly lower than that of a holographic plate. This is an even more severe constraint when IR sensors such as microbolometers are taken into account. In order to increase the numerical aperture of such systems, we developed an automatic technique which is capable of recording several holograms and of stitching them together, obtaining a digital hologram with a synthetic but larger numerical aperture. In this way we show that more detail can be resolved and a wider parallax angle can be achieved. The method is demonstrated for visible as well IR digital holography, recording and displaying large size objects.