Results 161 to 170 of about 5,505 (209)

Scanning Shack-Hartmann wavefront sensor

SPIE Proceedings, 2004
Criss-crossing of focal images is the cause of a narrow dynamic range in Shack-Hartmann sensors. Practically, aberration range wider than ±3 diopters can not be measured. A method has been proposed for ophthalmologic applications using a rarefied lenslet array through which a wave front is projected with the successive step-by-step changing of the ...
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Educational Shack–Hartmann wavefront sensor

American Journal of Physics
The Shack–Hartmann wavefront sensor (SHWFS) is a standard detector used in the measurement of a light wave's wavefront shape. However, its relatively high price restricts its use as an educational tool in instructional optics laboratories. In this work, we show how a low-cost educational SHWFS can be assembled using spare parts and also provide the ...
Khosrow Hassani, Veyana Khajehhassanirabori   +1 more
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Reconfigurable Shack-Hartmann wavefront sensor

Optical Engineering, 2004
The conventional Shack-Hartmann wavefront sensor (SH-WFS) has a fixed subaperture area that is determined by consideration of several parameters such as the average atmospheric coherence diameter r 0 at the telescope site. Its SNR can be severely degraded due to low-light conditions caused by increasing turbulence, strong atmospheric scintillation ...
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Shack-Hartmann wavefront sensor and its problems

SPIE Proceedings, 2011
Shack-Hartman wavefront sensors are widely used in scientific investigations of wavefronts and also, as a component of the closed-loop adaptive optical system, intended to correct for laser beam aberrations. This paper presents successful application of such type sensors in the laser systems investigations to obtain high quality laser radiation ...
Alexis Kudryashov, Valentina Zavalova, Alexey Rukosuev, Alexander Alexandrov, Julia Sheldakova, Vadim Samarkin   +5 more
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Coded Shack-Hartmann Wavefront Sensor

2016
Wavefront sensing is an old yet fundamental problem in adaptive optics. Traditional wavefront sensors are limited to time-consuming measurements, complicated and expensive setup, or low theoretically achievable resolution. In this thesis, we introduce an optically encoded and computationally decodable novel approach to the wavefront sensing problem ...
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Shack-Hartmann wavefront sensor for optical metrology

SPIE Proceedings, 2003
Abstract: A new type of Shack-Hartmann wavefront sensor (SHWS) for optical metrology usingdigital still camera and a personal computer is designed. There has not expensive image-grabberhardware in this system. We can control image format of storing with this method.
Bo Qi, Hongbin Chen
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Deep learning assisted Shack–Hartmann wavefront sensor for direct wavefront detection

Optics Letters, 2020
The conventional Shack–Hartmann wavefront sensor (SHWS) requires wavefront slope measurements of every micro-lens for wavefront reconstruction. In this Letter, we applied deep learning on the SHWS to directly predict the wavefront distributions without wavefront slope measurements. The results show that our method could provide a lower root mean square
Lejia, Hu, Shuwen, Hu, Wei, Gong, Ke, Si
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Shack–Hartmann versus reverse Hartmann wavefront sensors: experimental results

Optics Letters, 2020
With respect to the classical Shack–Hartmann (SH) wavefront sensor (WFS), the recently proposed reverse Hartmann (RH) sensor inverts the locations of the filtering and observation planes and forms a direct image of the pupil on a detector array. The slopes of the wavefront error (WFE) are then reconstructed by using a double Fourier transform algorithm.
Cyril, Pannetier, François, Hénault
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Optical testing using Shack-Hartmann wavefront sensors

SPIE Proceedings, 2001
The basic problem associated with aspheric testing without the use of null optics is to obtain increased measurement range while maintaining the required measurement accuracy. Typically, the introduction of a custom-designed and fabricated null corrector has allowed the problem of aspheric testing to be reduced to that of spherical testing.
John E. Greivenkamp, Daniel G. Smith, Robert O. Gappinger, Gregory A. Williby   +3 more
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Using photodetectors in Shack-Hartmann wavefront sensors

Optoelectronics, Instrumentation and Data Processing, 2012
High-resolution cameras are used as photodetectors in the image recording plane of a Shack-Hartmann wavefront sensor to record centroid coordinates which provide basic information for wavefront reconstruction. A comparative analysis is made of the accuracy of determining the centroid coordinates for CCD and CMOS cameras.
L. V. Antoshkin, V. V. Lavrinov, L. N. Lavrinova, V. P. Lukin   +3 more
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