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Edge-Preserving Autofocusing in Digital Holography
Digital Holography and Three-Dimensional Imaging, 2016In digital holography, it is essential to know the axial position of the recorded object for reconstruction. Here we propose an autofocusing algorithm using structure tensor to determine the focal distance and to extract the edge information.
Ren, Z, Lam, EYM
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Adaptive Optics for Autofocusing Eyeglasses
Imaging and Applied Optics 2017 (3D, AIO, COSI, IS, MATH, pcAOP), 2017Over 1 billion people worldwide including more than 100 million people in the United States of America alone suffer from an age-related eye condition known as presbyopia. Presbyopia is caused by a loss of focal accommodation of the crystalline lens inside the eye as the lens stiffens with age.
Nazmul Hasan +5 more
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Role of chirped factor on the focusing and imaging properties of the autofocusing beam
Physica Scripta, 2023The focusing and imaging properties of the beam have attracted considerable attention recently. In this work, we generated an autofocusing beam termed a chirped autofocusing beam (CAFB) by using the phase of multiple chirped two-dimensional Airy beams ...
Danping Lin, Shaohua Tao
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Aberration laser beams with autofocusing properties
Applied Optics, 2018We investigate theoretically, numerically, and experimentally a novel type of laser beam-an aberration laser beam (ALB). To generate the ALB, a diffractive optical element with a phase transmission function having an arbitrary radial dependence of power q and a periodic angular dependence of sin(mϕ) or cos(mϕ) form can be used.
Alexey P. Porfirev +2 more
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2008
Publisher Summary Fast, accurate, and reliable autofocusing is crucial to high-throughput scanning microscopy applications, where large numbers of specimens must be imaged and analyzed routinely. The objective of autofocusing is to locate the z-axis position of best image focus.
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Publisher Summary Fast, accurate, and reliable autofocusing is crucial to high-throughput scanning microscopy applications, where large numbers of specimens must be imaged and analyzed routinely. The objective of autofocusing is to locate the z-axis position of best image focus.
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Autofocusing in digital holographic microscopy
3D Research, 2011Many applications in non-destructive testing at a microscopic level and in live cell imaging require automated focusing due to unstable environmental conditions, moving specimen or the limited depth of field of the applied optical imaging systems.
Björn Kemper +2 more
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Adaptive autofocusing: a closed-loop perspective
Journal of the Optical Society of America A, 2005We present an adaptive autofocusing scheme. In this scheme, the focus measure is updated with focus tuning. To achieve this, we construct the focus measure by using image moments and develop an adaptive focus-tuning strategy to estimate the measure in closed loop.
Aik Meng Fong +3 more
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Autofocusing optical-resolution photoacoustic endoscopy
Optics Letters, 2018Photoacoustic (PA) endoscopy has the potential to diagnose early diseases in the gastrointestinal tract. For the first time, to our knowledge, we developed an autofocusing PA endoscope (AF-PAE) for the usually irregular gastrointestinal tract imaging to solve the deterioration of transverse resolution caused by the defocus scanning of the probe.
Xiaowan Li +3 more
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Algorithms for compressed ISAR autofocusing
Proceedings of 2011 IEEE CIE International Conference on Radar, 2011This paper is reporting some experimental results of compressed inverse synthetic aperture radar (ISAR) imaging. Autofocusing is applied on the sparse echoes, which consists of range alignment and phase correction as in conventional ISAR processing. Range alignment is implemented through minimizing the entropy of the average range profile, while phase ...
Daiyin Zhu, Xiang Yu, Zhaoda Zhu
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Autofocusing system for a photothermal microscope
Review of Scientific Instruments, 2003Photoreflectance and interferometric microscopy are rather new methods used for thermal and thermoelastic characterizations of materials at a microscopic scale. These methods make use of an intensity modulated laser beam (pump) to produce a thermal wave which is at the origin of thermal diffusion and elastic deformations.
N. N. Hoang +3 more
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