High topographical accuracy by optical shot noise reduction in digital holographic microscopy

León-Rodríguez, Miguel; Rodrı́guez-Vera, Ramón; Rayas, J. A.; Calixto, Sergio

doi:10.1364/josaa.29.000498

Cited by 22 publications

(24 citation statements)

References 23 publications

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“…The shutter camera enables us to reduce the exposure time down to 40 μs, with a variable gain from 0 to 17 dB in 14 increments. We do not reach a camera's full well capacity with a LED source in the setup presented, even with the maximum integration time and no electrical gain of camera parameters [21]. The optical power of the intensity was measured with a photo detector.…”

Section: Numerical and Experimental Resultsmentioning

confidence: 94%

“…We have noncorrelation among phase images reconstructed at different distances [21]. These images were obtained of the recorded experimental holograms from Eq.…”

Section: Numerical and Experimental Resultsmentioning

confidence: 99%

“…These reconstructed images are uncorrelated with each other at specific reconstruction distances, and computed from the same complex amplitude [21].…”

Section: Focus Depth and Averaging Methodsmentioning

confidence: 99%

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Microtopography and Thickness Measurement with Digital Holographic Microscopy Highlighting and Its Tomographic Capacity

León-Rodríguez¹,

Rayas-Alvarez²,

García³

et al. 2017

Holographic Materials and Optical Systems

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The refocusing capacity is a unique feature of digital holography. In this chapter, we show the capability of reconstructing digital holograms at different planes for different purposes. One of such purposes is to increase the focus depth of the microscope system. First, we show experimental results of the feasibility to perform digital holographic microscopy (DHM) using a Mirau interferometric objective. A profile phase comparison of a 4.2 μm high microlens using interferometry and DHM, extending the depth of focus of the microscope objective as proof of the proposal, is presented. Second, it is also useful in reducing shot noise when using an LED as a light source. In order to attain the reduction noise, we performed an averaging process of phase and amplitude images reconstructed at different reconstruction distances. This reconstruction range is performed within the focus depth of the optical system. We get a reduction of 50% shot noise. Finally, we show a strategy based on this tomographic capability of reducing a ringing effect by using an ideal filter in off-axis digital holography.

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Section: Numerical and Experimental Resultsmentioning

confidence: 94%

“…We have noncorrelation among phase images reconstructed at different distances [21]. These images were obtained of the recorded experimental holograms from Eq.…”

Section: Numerical and Experimental Resultsmentioning

confidence: 99%

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Microtopography and Thickness Measurement with Digital Holographic Microscopy Highlighting and Its Tomographic Capacity

León-Rodríguez¹,

Rayas-Alvarez²,

García³

et al. 2017

Holographic Materials and Optical Systems

Self Cite

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“…2, the primary sources of noise in the DHM are shot noise, which is related to the intrinsic variability in photons incident on the CCD camera, and Gaussian noise, which is the combined effects from numerous intrinsic and extrinsic sources [23][24][25][26][27][28][29]. Given that the findings in this study evaluated the global uncertainty in measurements, it is not possible to reliably state which source (or sources) of noise is the primary cause of the quantified uncertainty.…”

Section: Sources Of Noisementioning

confidence: 94%

“…1e), with sub-nanometer vertical accuracy being reported [22]. However, one complication of the technique is the presence of inherent (intrinsic and extrinsic) noise [23][24][25][26][27][28][29], which has not undergone a rigorous analysis to relate it to uncertainty in the measured phase (and therefore height) data. Furthermore, recent studies have utilized reflection DHM 1 to track in situ surface topography changes of dissolving mineral phases in static and flowing water [13,14], but it is inconclusive from those studies how the presence of water (or any solution) or the use of flowing water conditions affects the noise and uncertainty in the measurement.…”

Section: Introductionmentioning

confidence: 99%

Phase Uncertainty in Digital Holographic Microscopy Measurements in the Presence of Solution Flow Conditions

Brand¹

2017

J. RES. NATL. INST. STAN.

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Digital holographic microscopy (DHM) is a surface topography measurement technique with reported sub-nanometer vertical resolution. Although it has been made commercially available recently, few studies have evaluated the uncertainty or noise in the phase measurement by the DHM. As current research is using the DHM to monitor surface topography changes of dissolving materials under flowing water conditions, it is necessary to evaluate the effect of water and flow rate on the uncertainty in the measurement. Uncertainty in this study was concerned with the temporal standard deviation per pixel of the reconstructed phase. Considering the effects of solution flow rate, magnification, objective lens type (air or immersion), and experimental configuration, measurements under static conditions in air and in water with an immersion lens yielded the smallest amount of uncertainty (mean of ≤ 0.5 nm up to 40× magnification). Increasing the water flow rate resulted in an increase in mean uncertainty to ≤ 0.6 nm up to 40× with an immersion lens. Observations of a sample through a glass window at 20× magnification in flowing water also yielded increasing uncertainty, with mean values of ≤ 0.5 nm, ≤ 0.8 nm, and ≤ 1.1 nm for flow rates of 0 mL min ) did not significantly impact the uncertainty in the phase. Collecting holograms in single-wavelength versus dual-wavelength modes did impact the uncertainty, with the mean uncertainty at 10× magnification for the same wavelength being ≤ 0.5 nm from the single-wavelength mode compared to ≤ 1.5 nm from the dualwavelength mode. When the quantified uncertainty was applied to simulated dissolution data, lower limits of measured dissolution rates were found below which the measured data may not be distinguishable from the uncertainty in the measurement. The limiting surface-normal dissolution velocity is −10 −11.7 m s ) flowing water conditions in experiments with a glass window, respectively. The data presented by this study will allow for better experimental design and methodology for future dissolution or precipitation studies using DHM and will provide confidence in the data produced in postprocessing.

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Noise Reduction in Off-Axis Digital Holography Reconstruction from Two Reconstruction Distances Based on Talbot Effect

León-Rodríguez

Cordero

Rayas

et al. 2016

Emerging Challenges for Experimental Mechanics in Energy and Environmental Applications, Proceedings of the 5th International S

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High topographical accuracy by optical shot noise reduction in digital holographic microscopy

Cited by 22 publications

References 23 publications

Microtopography and Thickness Measurement with Digital Holographic Microscopy Highlighting and Its Tomographic Capacity

Microtopography and Thickness Measurement with Digital Holographic Microscopy Highlighting and Its Tomographic Capacity

Phase Uncertainty in Digital Holographic Microscopy Measurements in the Presence of Solution Flow Conditions

Noise Reduction in Off-Axis Digital Holography Reconstruction from Two Reconstruction Distances Based on Talbot Effect

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