Results 41 to 50 of about 26,873 (277)

Wavefront Restoration Technology of Dynamic Non-Uniform Intensity Distribution Based on Extreme Learning Machine

open access: yesSensors, 2021
Non-uniform intensity distribution of laser near-field beam results in the irregular shape of the spot in the wavefront sensor. The intensity of some sub-aperture spots may be too weak to be detected, and the accuracy of wavefront restoration is ...
Haiqi Lin   +3 more
doaj   +1 more source

Experimental Demonstration of Sequential Operation Approach for a Three-Sided Pyramid Wavefront Sensor

open access: yesIEEE Photonics Journal, 2016
We describe a sequential operation approach for a three-sided pyramid wavefront sensor (PWFS) based on a micromirror array with hexagonal geometry. The geometrical optics analysis and numerical simulations show that a linear relationship exists between ...
Lu Chen   +6 more
doaj   +1 more source

Deep Learning-Based Prediction Algorithm on Atmospheric Turbulence-Induced Wavefront for Adaptive Optics

open access: yesIEEE Photonics Journal, 2022
Correction performance of an adaptive optics (AO) system is severely limited by its system latency under high temporal frequency distortions. Wavefront prediction methods has been proven to be an effective way to compensate system delay.
Ning Wang   +8 more
doaj   +1 more source

Centroid-Predicted Deep Neural Network in Shack-Hartmann Sensors

open access: yesIEEE Photonics Journal, 2022
The Shack-Hartmann wavefront sensor produces incorrect wavefront measurements when some sub-spots are weak and missing. In this paper, a method is proposed to predict the centroids of these sub-spots for the Shack-Hartmann wavefront sensor based on the ...
Mengmeng Zhao   +6 more
doaj   +1 more source

Fast minimum variance wavefront reconstruction for extremely large telescopes [PDF]

open access: yes, 2010
We present a new algorithm, FRiM (FRactal Iterative Method), aiming at the reconstruction of the optical wavefront from measurements provided by a wavefront sensor.
Béchet   +25 more
core   +1 more source

Measuring Ocular Aberrations Sequentially Using a Digital Micromirror Device

open access: yesMicromachines, 2019
The Hartmann⁻Shack wavefront sensor is widely used to measure aberrations in both astronomy and ophthalmology. Yet, the dynamic range of the sensor is limited by cross-talk between adjacent lenslets.
Alessandra Carmichael Martins   +1 more
doaj   +1 more source

Optical detection of values of separate aberrations using a multi-channel filter matched with phase Zernike functions

open access: yesКомпьютерная оптика, 2021
The use of a multichannel wavefront sensor matched with phase Zernike functions to determine the type and magnitude of aberration in the analyzed wavefront is investigated.
P.A. Khorin   +2 more
doaj   +1 more source

A Local Threshold Checkerboard Algorithm for Adaptive Optics System With a Plenoptic Sensor

open access: yesIEEE Photonics Journal, 2022
Adaptive optics systems will encounter challenges under strong atmospheric turbulence conditions. Recently, a modified approach based on plenoptic sensor has attracted considerable attention.
Zhichong Wang   +5 more
doaj   +1 more source

Shack-Hartmann Wavefront Sensing of Ultrashort Optical Vortices

open access: yesSensors, 2021
Light beams carrying Orbital Angular Momentum (OAM), also known as optical vortices (OV), have led to fascinating new developments in fields ranging from quantum communication to novel light–matter interaction aspects. Even though several techniques have
Alok Kumar Pandey   +4 more
doaj   +1 more source

A new low-cost, compact, auto-phoropter for refractive assessment in developing countries

open access: yesScientific Reports, 2017
Using a phoropter to measure the refractive error is one of the most commonly used methods by ophthalmologists and optometrists. Here, we demonstrate design and fabrication of a portable automatic phoropter with no need for patient’s feedback. The system
Babak Amirsolaimani   +4 more
doaj   +1 more source

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