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Off-axis digital holography plays a crucial role in high-precision three-dimensional imaging. However, high-resolution phase images are often affected by the limited pixel size of the sensor. To address this issue, this study proposes, for the first time, to the best of our knowledge, the application of Real-ESRGAN for the super-resolution reconstruction of off-axis digital holography images. By directly applying super-resolution processing to the hologram, the limitations of the sensor's pixel size are overcome, followed by phase reconstruction to obtain high-resolution phase images. The Real-ESRGAN model enhances the texture information of the hologram through a deep network with multiple residual-in-residual dense blocks (RRDBs), restoring a clearer hologram. A U-Net architecture with spectral normalization, offering stronger discriminative capability, is used to provide detailed per-pixel feedback for the generator. The experimental results demonstrate that this method can be applied to multi-scale holograms, outperforming comparison networks in both visual quality and quantitative metrics, thus providing an innovative solution for the super-resolution reconstruction of off-axis digital holography.
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http://dx.doi.org/10.1364/AO.545914 | DOI Listing |
Optical scattering limits the ability to focus light deep inside scattering media, posing a long-standing challenge in biomedical applications such as deep-tissue imaging and photodynamic therapy. Digital optical phase conjugation (DOPC), combined with ultrasonic guide stars-an approach named as time-reversed ultrasonically encoded (TRUE) optical focusing-has shown promise in overcoming this limitation. However, practical applications, such as imaging in living tissues, require TRUE systems to operate at high speeds to compensate for dynamic scattering caused by physiological motion.
View Article and Find Full Text PDFWe present a compact and portable setup for digital holographic microscopy that works in a slightly off-axis configuration. It has a monolithic structure and a minimal number of elements, a feature that makes it insensitive to vibrations. The design uses an LED as an illuminating source and a single cube beam splitter interferometer to avoid parasitic interferences and coherent noise reduction.
View Article and Find Full Text PDFOff-axis digital holography plays a crucial role in high-precision three-dimensional imaging. However, high-resolution phase images are often affected by the limited pixel size of the sensor. To address this issue, this study proposes, for the first time, to the best of our knowledge, the application of Real-ESRGAN for the super-resolution reconstruction of off-axis digital holography images.
View Article and Find Full Text PDFCubeSats are becoming increasingly popular in scientific missions due to lower costs, but installing a long-focus unobscured reflective optical system within such a small volume is not easy. This paper proposes two methods to increase the focal length of optical systems in cube satellites. One method breaks the planar symmetry of the traditional off-axis three-mirror system, modifying the system structure to be off-axis in two directions, and simultaneously uses a fifth-order polynomial freeform surface to correct the higher-order aberrations caused by the off-axis configuration.
View Article and Find Full Text PDFDual-path off-axis digital holographic microscopy (DHM) has been effectively used for quantitative phase imaging applications. However, challenges are involved in its development because of complex and bulky optical systems, phase aberrations, and low temporal stability. In this work, a common-path off-axis DHM is proposed based on the lateral shearing of object-scattered wavefronts.
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