Extending the depth of field with chromatic aberration for dual-wavelength iris imaging

Fitzgerald, Niamh; Dainty, Christopher; Goncharov, Alexander V.

doi:10.1364/oe.25.031696

Cited by 4 publications

(1 citation statement)

References 21 publications

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“…A single calibration with the laser in CW mode was sufficient to determine the TM needed to generate an chromatic extended depth of field for femtosecond pulses. Indeed, dispersion in the step-index MMF axially distributed the broader spectral content of pulses compared to the CW light around the calibration plane, effectively generating an axially elongated chromatic focus [23,24]. The use of a CW laser for the calibration had the added benefit of allowing a design employing removable distal optics, an im- portant advantage for biological imaging applications.…”

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confidence: 99%

Volumetric two-photon fluorescence imaging of live neurons using a multimode optical fiber

Turcotte

Schmidt

Booth

et al. 2020

Preprint

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11An ability to optically visualize neurons and their subcellular components across brain regions is 12 integral to our understanding of neuronal function 1 . Multimode optical fibers (MMFs), combined 13 with wavefront control methods, have achieved minimally-invasive in vivo imaging of neurons in 14 deep-brain regions with diffraction-limited spatial resolution 2-5 . To date MMF systems have been 15 based on linear fluorescence and are therefore only able to perform two-dimensional imaging due to 16 an absence of confocal filtering 6 . Here we report a method to achieve optical sectioning in live brain 17 tissue by taking advantage of the nonlinearity of two-photon excited fluorescence (TPEF). In 18 addition, we provide a new approach for the determination of transmission matrix for TPEF, a 19 necessary step for the light shaping requirement of MMF imaging. Central to these advances is the 20 use of a laser source able to generate both continuous wave (CW) light and femtosecond pulses. This 21 configuration allows the system to be compact with minimal distal optics, enhancing suitability for 22 neuroscience applications. With our system we demonstrate TPEF imaging of neurons and their 23 dendrites in live brain slices through a single 60 μm-core MMF with a numerical aperture of 0.37. 24 Taken together these developments represent an important step towards three-dimensional (3D) deep-25 brain imaging in vivo. 26 27 132 RT, CCS, MJB and NE acknowledge support from the Biotechnology and Biological Sciences 133

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confidence: 99%

Volumetric two-photon fluorescence imaging of live neurons using a multimode optical fiber

Turcotte

Schmidt

Booth

et al. 2020

Preprint

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Telecentricity based measurement error compensation in the bilateral telecentric system

Liu

et al. 2019

Measurement

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Depth-of-field extension method for iris recognition based on multi-wavelength illumination and dispersion principle

Wang,

Wei,

et al. 2024

Opt. Eng.

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This article describes the design of an optical system using multi-wavelength illumination and dispersion principle to achieve iris recognition imaging with a large depth of field in noncooperative environments. Through the use of optical design software, the iris acquisition imaging system was designed with the modulation transfer function (MTF) curve serving as the evaluation criteria for this system. It was found that at different object distances, the MTF value at a spatial frequency of 100 lp/mm is greater than 0.33, indicating that the iris acquisition imaging system has a significant depth of field. To further validate the performance of the system, we set up an actual optical platform based on the parameters designed by the optical design software for the iris acquisition imaging system and conducted iris image acquisition experiments at different object distances, obtaining iris images of three different individuals. We performed algorithm verification on the iris recognition of the three sets of iris images and found that the average interclass matching result was 0.44, while the average intraclass matching result was 0.30, demonstrating a high level of accuracy in iris recognition. This indicates that the iris images obtained by the system have a high resolution, thereby confirming the feasibility of depth extension using multi-wavelength illumination and lens chromatic aberration imaging principle. It is worth mentioning that this method is not only applicable to iris recognition but also holds reference value in other biometric recognition fields.

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Extending the depth of field with chromatic aberration for dual-wavelength iris imaging

Cited by 4 publications

References 21 publications

Volumetric two-photon fluorescence imaging of live neurons using a multimode optical fiber

Volumetric two-photon fluorescence imaging of live neurons using a multimode optical fiber

Telecentricity based measurement error compensation in the bilateral telecentric system

Depth-of-field extension method for iris recognition based on multi-wavelength illumination and dispersion principle

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