Depth-filtered digital holography

Koukourakis, Nektarios; Jaedicke, Volker; Adinda-Ougba, Adamou; Goebel, Sebastian; Wiethoff, Helge; Höpfner, Henning; Gerhardt, Nils C.; Hofmann, Martin R.

doi:10.1364/oe.20.022636

Cited by 14 publications

(3 citation statements)

References 32 publications

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“…The precise quantitative phase imaging performance can be hardly achieved using other endoscopes illuminated by incoherent light sources due to the wide spectrum of the light source. Digital holography is a common method for quantitative phase imaging 49 , 50 , however, digital holographic imaging with long MCFs requires complex optical systems and tedious optical alignment 44 , 51 . Our proposed FAST reconstruction method does not require digital holography, the precise amplitude and phase images of the sample can be recovered from an intensity-only speckle.…”

Section: Discussionmentioning

confidence: 99%

Quantitative phase imaging through an ultra-thin lensless fiber endoscope

Sun

et al. 2022

Light Sci Appl

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Quantitative phase imaging (QPI) is a label-free technique providing both morphology and quantitative biophysical information in biomedicine. However, applying such a powerful technique to in vivo pathological diagnosis remains challenging. Multi-core fiber bundles (MCFs) enable ultra-thin probes for in vivo imaging, but current MCF imaging techniques are limited to amplitude imaging modalities. We demonstrate a computational lensless microendoscope that uses an ultra-thin bare MCF to perform quantitative phase imaging with microscale lateral resolution and nanoscale axial sensitivity of the optical path length. The incident complex light field at the measurement side is precisely reconstructed from the far-field speckle pattern at the detection side, enabling digital refocusing in a multi-layer sample without any mechanical movement. The accuracy of the quantitative phase reconstruction is validated by imaging the phase target and hydrogel beads through the MCF. With the proposed imaging modality, three-dimensional imaging of human cancer cells is achieved through the ultra-thin fiber endoscope, promising widespread clinical applications.

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Section: Discussionmentioning

confidence: 99%

Quantitative phase imaging through an ultra-thin lensless fiber endoscope

Sun

et al. 2022

Light Sci Appl

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“…Combining high sensitivity and flexibility, this method is attractive to be used for research. Moreover, the digital acquisition of data allows for data processing and numerical propagation of the wavefield to any plane of interest [4]. The direct phase retrieval and its differential nature, make digital holographic interferometry an attractive tool for the study of heat transfer phenomena [5].…”

Section: Introductionmentioning

confidence: 99%

Digital Holographic Interferometry for the Measurement of Symmetrical Temperature Fields in Liquids

et al. 2021

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In this paper, we present a method of quantitatively measuring in real-time the dynamic temperature field change and visualization of volumetric temperature fields generated by a 2D axial-symmetric heated fluid from a pulsatile jet in a water tank through off-axis digital holographic interferometry. A Mach-Zehnder interferometer on portable platform was built for the experimental investigation. The pulsatile jet was submerged in a water tank and fed with water with higher temperature. Tomographic approach was used to reconstruct the temperature fields through the Abel Transform and the filtered back-projection. Averaged results, tomographic view, standard deviation and errors are presented. The presented results reveal digital holographic interferometry as a powerful technique to visualize temperature fields in flowing liquids and gases.

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“…for detecting pre-cancerous cells [4] [5] or measuring the depth resolved blood oxygenation [6]. Aside from that, high resolution phase images can be obtained from the same data when depth resolved spectra are used to synthesize holograms [7] on which holographic reconstruction methods can be applied. Typically, the spectroscopic data is calculated by time-frequency distributions like the short time Fourier transform (STFT) from the standard OCT data set.…”

Section: Introductionmentioning

confidence: 99%

Spectroscopic optical coherence tomography with graphics processing unit based analysis of three dimensional data sets

et al. 2013

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Spectroscopic optical coherence tomography (OCT) is an extension of the standard backscattering intensity analysis of OCT. It enables depth resolved monitoring of molecular and structural differences of tissue. One drawback of most methods to calculate the spectroscopic data is the long processing time. Also systematic and stochastic errors make the interpretation of the results challenging. Our approach combines modern signal processing tools with powerful graphics processing unit (GPU) programming. The processing speed for the spectroscopic analysis is nearly 3 mega voxel per second. This allows us to analyze multiple B-Scans in a few seconds and to display the results as a three dimensional data set. Our algorithm contains the following steps in addition to the conventional processing for frequency domain OCT: a quality map to exclude noisy parts of the data, spectral analysis by short time Fourier transform, feature reduction by Principal Component Analysis, unsupervised pattern recognition with K-means and rendering of the gray scale backscattering OCT data which is superimposed with a color map that is based on the results of the pattern recognition algorithm. Our set up provides a spectral range from 650-950nm and is optimized to suppress chromatic errors. In a proof-of-principle attempt, we already achieved additional spectroscopic contrast in phantom samples including scattering microspheres of different sizes and ex vivo biological tissue. This is an important step towards a system for real time spectral analysis of OCT data, which would be a powerful diagnosis tool for many diseases e.g. cancer detection at an early stage.

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Depth-filtered digital holography

Cited by 14 publications

References 32 publications

Quantitative phase imaging through an ultra-thin lensless fiber endoscope

Quantitative phase imaging through an ultra-thin lensless fiber endoscope

Digital Holographic Interferometry for the Measurement of Symmetrical Temperature Fields in Liquids

Spectroscopic optical coherence tomography with graphics processing unit based analysis of three dimensional data sets

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