Myopic aberrations: Simulation based comparison of curvature and Hartmann Shack wavefront sensors

Basavaraju, Roopashree M.; Akondi, Vyas; Weddell, Stephen J.; Budihal, Raghavendra Prasad

doi:10.1016/j.optcom.2013.09.004

Cited by 12 publications

(11 citation statements)

References 23 publications

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“…Then, the local wavefront slopes, S x and S y are estimated. Finally, the wavefronts are reconstructed using the singular value decomposition technique [13]. The reconstructed wavefronts are decomposed using the first four orders of Zernike polynomials and are shown in Fig.…”

Section: Resultsmentioning

confidence: 99%

“…From a linear combination of the intensities in the four pupils of the virtual PWS (I j , 1≤ j ≤ 4) in I pyr (x, y), the local 'x' and 'y' wavefront slopes, S x (x, y) and S y (x, y) can be evaluated [16]. The unwrapped phase, φ(x, y) is reconstructed from the estimated slope values using the slope geometry of Southwell [13,14,23]. The Zernike polynomials are used to decompose the reconstructed wavefront φ(x, y) using a least square fitting technique to eliminate the high spatial frequency components and artifacts arising from noise.…”

Section: Methodsmentioning

confidence: 99%

“…The wrapped phase was assumed to be incident on an array of simulated microlenses. The locations of the simulated HS focal spots were estimated using the intensity weighted centroiding algorithm [13] and the unwrapped phase was recovered from the calculated local wavefront slopes. It was shown that the accuracy of phase unwrapping primarily depends on sampling of the wrapped phase and diffraction-limited wavefront sensing can be achieved using an iterative estimation procedure in the presence of noise.…”

Section: Introductionmentioning

confidence: 99%

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Virtual pyramid wavefront sensor for phase unwrapping

2016

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Noise affects wavefront reconstruction from wrapped phase data. A novel method of phase unwrapping is proposed with the help of a virtual pyramid wavefront sensor. The method was tested on noisy wrapped phase images obtained experimentally with a digital phase-shifting point diffraction interferometer. The virtuality of the pyramid wavefront sensor allows easy tuning of pyramid apex angle and modulation amplitude. It is shown that an optimal modulation amplitude obtained by monitoring the Strehl ratio helps in achieving better accuracy. Through simulation studies and iterative estimation, it is shown that the virtual pyramid wavefront sensor is robust to random noise.

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Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Virtual pyramid wavefront sensor for phase unwrapping

2016

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“…A limiting factor of this approach, however, is that only a few hundred points can be measured accurately within the pupil, which in turn limits the spatial resolution of the measurement of LOAs. 4,21,76,77,78,79 However, an aberration map essentially describes the deviation between the measured and reference WFs. Usually, warmer colours in the map represent elevated or phase-advanced portions of the WF, and cooler colours represent the surface depressions or phase retardation for the WF measured.…”

Section: Adaptive Optics and The Measuring Apparatus Used For The Measurement Of Higher Order Aberrationsmentioning

confidence: 99%

Higher order aberrations of the eye: Part one

Oberholzer¹,

Gillan²,

Rubin³

2016

African Vision and Eye Health

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This article is the first in a series of two articles that provide a comprehensive literature review of higher order aberrations (HOAs) of the eye. The present article mainly explains the general principles of such HOAs as well as HOAs of importance, and the measuring apparatus used to measure HOAs of the eye. The second article in the series discusses factors contributing to variable results in measurements of HOAs of the eye.Keywords: Higher order aberrations; wavefront aberrations; aberrometer

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“…This combination was useful in determining individual wavefront aberrations for multisource operation, and to separate induced aberrations from distortions inherent in the optical system. A simulation-based comparison of both wavefront sensors for low-order myopic aberrations is given by Basavaraju et al [16].…”

Section: B Wavefront Sensingmentioning

confidence: 99%

Optical test-benches for multiple source wavefront propagation and spatiotemporal point-spread function emulation

Weddell

Lambert

2014

Appl. Opt.

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Precise measurement of aberrations within an optical system is essential to mitigate combined effects of user-generated aberrations for the study of anisoplanatic imaging using optical test benches. The optical system point spread function (PSF) is first defined, and methods to minimize the effects of the optical system are discussed. User-derived aberrations, in the form of low-order Zernike ensembles, are introduced using a liquid crystal spatial light modulator (LC-SLM), and dynamic phase maps are used to study the spatiotemporal PSF. A versatile optical test bench is described, where the Shack Hartmann and curvature wavefront sensors are used to emulate the effects of wavefront propagation over time from two independent sources.

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Myopic aberrations: Simulation based comparison of curvature and Hartmann Shack wavefront sensors

Cited by 12 publications

References 23 publications

Virtual pyramid wavefront sensor for phase unwrapping

Virtual pyramid wavefront sensor for phase unwrapping

Higher order aberrations of the eye: Part one

Optical test-benches for multiple source wavefront propagation and spatiotemporal point-spread function emulation

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