Results 211 to 220 of about 5,580 (232)
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Observation of abruptly autofocusing waves
Optics Letters, 2011We report on the experimental observation of abruptly autofocusing waves. This interesting family of wave packets has been realized by using a radially symmetric Airy intensity distribution. As demonstrated in our experiments, these waves can exhibit unusual features, such as the ability to autofocus by following a parabolic trajectory toward their ...
Papazoglou, Dimitrios G. +3 more
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Autofocusing in digital holography
SPIE Proceedings, 2013Digital holography allows the acquisition of 3D profiles of objects. Digitally captured holograms are reconstructed at the respective distances of the objects to reveal the phase and the intensity profiles. However, computing an object’s 3D profile with only a single reconstruction requires prior knowledge of the distance of the object from the ...
Hazar A. İlhan +2 more
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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.
Svetlana N, Khonina +2 more
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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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Autofocusing Accelerator Beams
A novel tuning approach, Model Coupled Accelerator Tuning (MCAT), has been applied to the separated function DTL at TRIUMF's Isotope Separator and Accelerator (ISAC). A digital twin of the rare-isotope postaccelerator is used for transverse and longitudinal tune optimizations, which are then loaded directly into the control system.Katrusiak,Alexander +4 more
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Separation of antibiotics by autofocusing
ELECTROPHORESIS, 1990AbstractThe autofocusing separation of nine antibiotics was investigated: tetracycline and chloramphenicol in large‐scale batches, and seven others in gram preparation amounts. All except one were found to be hetergeneous in autofocusing, and 2‐4 well‐characterized fractions emerged. These heterogeneities are described and the industrial utilization of
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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.
Ying, Zhang +3 more
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A survey on ISAR autofocusing techniques
2004 International Conference on Image Processing, 2004. ICIP '04., 2005Over many years of research, several ISAR autofocusing techniques have been proposed. Today, we can divide them into two main categories: parametric and non-parametric techniques. The prominent point processing and the phase gradient algorithm are two classical examples of non-parametric techniques, whereas the more recent image contrast and entropy ...
BERIZZI, FABRIZIO +4 more
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Abruptly Autofocusing Airy Pulses
Frontiers in Optics 2014, 2014We generated two counter-accelerating Airy pulses with a spatial light modulator pulse shaper and observed the autofocusing of such pulses in a dispersive medium. The same technique can be used to realize 3D autofocusing waves.
Chenchen Wan, Qian Cao, Andy Chong
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Autofocusing for tissue microscopy
Image and Vision Computing, 1993Abstract This paper describes the implementation of autofocusing for tissue microscopy. We first investigate the suitability of several criterion functions for the evaluation of image sharpness. Since tissue sections are invariably stained, we also discuss the selection of the colour component on which autofocusing will be performed.
Yeo, T. +3 more
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