Registration and reconstruction of high-quality digital holograms with a large view angle are intensive computer tasks since they require the space-bandwidth product (SBP) of the order of tens of gigapixels or more. This massive use of SBP severely affects the storing and manipulation of digital holograms. In order to reduce the computer burden, this work focuses on the generation and reconstruction of very large horizontal parallax only digital holograms (HPO-DHs). It is shown that these types of holograms can preserve high quality and large view angle in x direction while keeping a low use of SBP. This work first proposes a numerical technique that allows calculating very large HPO-DHs with large pixel size by merging the Fourier holography and phase added stereogram algorithm. The generated Fourier HPO-DHs enable accurate storing of holographic data from 3D objects. To decode the information contained in these Fourier HPO-DHs (FHPO-DHs), a novel angular spectrum (AS) technique that provides an efficient use of the SBP for reconstruction is proposed. Our reconstruction technique, which is called compact space bandwidth AS (CSW-AS), makes use of cylindrical parabolic waves that solve sampling issues of FHPO-DHs and AS. Moreover, the CSW-AS allows for implementing zero-padding for accurate wavefield reconstructions. Hence, suppression of aliased components and high spatial resolution is possible. Notably, the imaging chain of Fourier HPO-DH enables efficient calculation, reconstruction and storing of HPO holograms of large size. Finally, the accuracy and utility of the developed technique is proved by both numerical and optical reconstructions.
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http://dx.doi.org/10.1364/OE.421186 | DOI Listing |
Chirurgie (Heidelb)
January 2025
Pius-Hospital Oldenburg, Universitätsklinik für Viszeralchirurgie, Universitätsmedizin Oldenburg, Georgstr. 12, 26121, Oldenburg, Deutschland.
Digital technologies, such as virtual and augmented reality (VR and AR) are mainly used in the preclinical and clinical phases in neurosurgery and orthopedics. In contrast, they are used less frequently in visceral surgery as the intraoperative deformation is challenging for the clinical use. The application of VR is used successfully particularly in education and training.
View Article and Find Full Text PDFIn order to address the issue of low effective bandwidth ratio in off-axis digital holography, which is caused by the impact of zeroth- and first-order terms on the first-order term, an improved digital holographic reconstruction algorithm by zeroth-order term elimination based on the Riesz transform is proposed in this paper. First, an off-axis hologram is convolved with the Riesz kernels. Then, in the spectrum, the zeroth-order term is effectively eliminated by a singularity at the origin of the Riesz kernels, which can improve the effective bandwidth ratio and make the best use of the bandwidth.
View Article and Find Full Text PDFNanophotonics
December 2023
School of Physics and Astronomy, Faculty of Science, Monash University, Melbourne, Victoria 3800, Australia.
Nanophotonics
March 2024
Department of Materials Science and Engineering, City University of Hong Kong, Kowloon, Hong Kong, China.
Gels
November 2024
Department of Philosophy, al-Farabi Kazakh National University, Almaty 050040, Kazakhstan.
The current state of affairs in the field of using polymer hydrogels for the creation of innovative systems for signal and image processing, of which computing is a special case, is analyzed. Both of these specific examples of systems capable of forming an alternative to the existing semiconductor-based computing technology, but assuming preservation of the used algorithmic basis, and non-trivial signal converters, the nature of which requires transition to fundamentally different algorithms of data processing, are considered. It is shown that the variability of currently developed information processing systems based on the use of polymers, including polymer hydrogels, leads to the need to search for complementary algorithms.
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