Methods of three-dimensional deconvolution with a point-spread function as frequently employed in optical microscopy to reconstruct true three-dimensional distribution of objects are extended to holographic reconstructions. Two such schemes have been developed and are discussed: an instant deconvolution using the Wiener filter as well as an iterative deconvolution routine. The instant 3d-deconvolution can be applied to restore the positions of volume-spread objects such as small particles. The iterative deconvolution can be applied to restore the distribution of complex and extended objects. Simulated and experimental examples are presented and demonstrate artifact and noise free three-dimensional reconstructions from a single two-dimensional holographic record.
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http://dx.doi.org/10.1364/OE.18.022527 | DOI Listing |
Biosensors (Basel)
January 2025
Department of Electronic and Biomedical Engineering, Universitat de Barcelona, Martí i Franquès 1, 08028 Barcelona, Spain.
In recent years, the wine industry has been researching how to improve wine quality along the production value chain. In this scenario, we present here a new tool, MicroVi, a cost-effective chip-sized microscopy solution to detect and count yeast cells in wine samples. We demonstrate that this novel microscopy setup is able to measure the same type of samples as an optical microscopy system, but with smaller size equipment and with automated cell count configuration.
View Article and Find Full Text PDFSensors (Basel)
December 2024
Smart Computational Imaging Laboratory (SCILab), School of Electronic and Optical Engineering, Nanjing University of Science and Technology, Nanjing 210094, China.
Lens-free on-chip microscopy (LFOCM) is a powerful computational imaging technology that combines high-throughput capabilities with cost efficiency. However, in LFOCM, the phase recovered by iterative phase retrieval techniques is generally wrapped into the range of -π to π, necessitating phase unwrapping to recover absolute phase distributions. Moreover, this unwrapping process is prone to errors, particularly in areas with large phase gradients or low spatial sampling, due to the absence of reliable initial guesses.
View Article and Find Full Text PDFJ Biophotonics
January 2025
School of Optoelectronics, Zhejiang University, Hangzhou, China.
The article describes a technique for digital holographic reconstruction of complex amplitude fields in diffuse blood facies using laser polarization-interference phase scanning to isolate a single scattered component of the object field. This method serves as the basis for developing algorithms for Mueller-matrix reconstruction of linear and circular birefringence parameters in the polycrystalline architectonics of blood facies. Statistical (central moments of the 1st-4th orders) and multifractal analyses (fractal dimension spectra) are applied to study the optical anisotropy maps of polycrystalline networks during blood dehydration.
View Article and Find Full Text PDFSci Rep
January 2025
Faculty of Physics, Department of Optics and Optometry and Vision Sciences, Universitat de València, Burjassot, Spain.
A lensless compact arrangement based on digital in-line holography under Gabor's regime is proposed as a novel contactless method to assess the profile of multifocal intraocular lenses (MIOLs) which are conformed by several diffractive rings. Diffractive MIOLs are a widely adopted ophthalmologic option for the correction of presbyopia in patients undergoing cataract surgery. The MIOL optical design might introduce non-negligible optical performance differences between lenses as well as the introduction of undesirable photic phenomena (such as halos and glare) affecting the vision of users.
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.
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