Phase unwrapping with a virtual Hartmann-Shack wavefront sensor

Akondi, Vyas; Falldorf, Claas; Marcos, Susana; Vohnsen, Brian

doi:10.1364/oe.23.025425

Cited by 12 publications

(19 citation statements)

References 34 publications

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“…Here, the interferograms (I 1−3 ) in a digital PS PDI are obtained as described earlier [4,17]. Root-mean-square (RMS) of the residual wavefront is used to evaluate the quality of reconstruction [4].…”

Section: Methodsmentioning

confidence: 99%

“…Root-mean-square (RMS) of the residual wavefront is used to evaluate the quality of reconstruction [4]. Alternately, the Strehl ratio of the residual wavefront is evaluated by assuming that the pupil plane has aberrations equal to the difference of the induced aberration and the reconstructed wavefront.…”

Section: Methodsmentioning

confidence: 99%

“…The effects of noise become crucial when the number of pixels per interference fringe is not sufficiently large and the signal to noise ratio is low. In such situations, conventional phase unwrapping methods are not consistent [4]. Most phase unwrapping methods are application dependent and demand an optimization of multiple parameters.…”

Section: Introductionmentioning

confidence: 99%

“…Recently, a virtual Hartmann-Shack (HS) method was proposed for phase unwrapping [4]. The wrapped phase was assumed to be incident on an array of simulated microlenses.…”

Section: Introductionmentioning

confidence: 99%

“…Modulation plays an important role in controlling the dynamic range and sensitivity of the PWS [16] and its role in phase unwrapping is studied. The method is tested on noisy interferograms recorded experimentally with a CCD camera in a digital phase-shifting (PS) point diffraction interferometer (PDI) [4,17] by using a spatial light modulator to avoid mechanically moving components. The light used was a 632.8 nm He-Ne laser.…”

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: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

“…Recently, a virtual Hartmann-Shack (HS) method was proposed for phase unwrapping [4]. The wrapped phase was assumed to be incident on an array of simulated microlenses.…”

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Virtual pyramid wavefront sensor for phase unwrapping

2016

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Accounting for Polychromatic Light in Virtual Shack-Hartmann Wavefront Sensing

et al. 2023

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Virtual Shack-Hartmann wavefront sensing (vSHWS) has some significant advantages and is promising for aberration measurement in the field of biomedical optical imaging. The illumination sources used in vSHWS are almost broadband, but are treated as monochromatic sources (only using center wavelength) in current data processing, which may cause errors. This work proposed a data processing method to take into account the multiple wavelengths of the broadband spectrum, named multiple-wavelength centroid-weighting method. Its feasibility was demonstrated through a series of simulations. A wavefront generated with a set of statistical human ocular aberrations was used as the target wavefront to evaluate the performance of the proposed and current methods. The results showed that their performance was very close when used for the symmetrical, but the wavefront error of the proposed method was much smaller than that of the current method when used for the asymmetrical spectrum, especially for the broader spectrum. These results were also validated by using 20 sets of clinical human ocular aberrations including normal and diseased eyes. The proposed method and the obtained conclusions have important implications for the application of vSHWS.

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Fast and robust estimation of ophthalmic wavefront aberrations

Dillon

2016

J. Biomed. Opt

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Rapidly rising levels of myopia, particularly in the developing world, have led to an increased need for inexpensive and automated approaches to optometry. A simple and robust technique is provided for estimating major ophthalmic aberrations using a gradient-based wavefront sensor. The approach is based on the use of numerical calculations to produce diverse combinations of phase components, followed by Fourier transforms to calculate the coefficients. The approach does not utilize phase unwrapping nor iterative solution of inverse problems. This makes the method very fast and tolerant to image artifacts, which do not need to be detected and masked or interpolated as is needed in other techniques. These features make it a promising algorithm on which to base low-cost devices for applications that may have limited access to expert maintenance and operation.

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Phase unwrapping with a virtual Hartmann-Shack wavefront sensor

Cited by 12 publications

References 34 publications

Virtual pyramid wavefront sensor for phase unwrapping

Virtual pyramid wavefront sensor for phase unwrapping

Accounting for Polychromatic Light in Virtual Shack-Hartmann Wavefront Sensing

Fast and robust estimation of ophthalmic wavefront aberrations

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