1. Articles from Gesa Franke

    1-8 of 8
    1. Reduction of frame rate in full-field swept-source optical coherence tomography by numerical motion correction [Invited]

      Reduction of frame rate in full-field swept-source optical coherence tomography by numerical motion correction [Invited]

      Full-field swept-source optical coherence tomography (FF-SS-OCT) was recently shown to allow new and exciting applications for imaging the human eye that were previously not possible using current scanning OCT systems. However, especially when using cameras that do not acquire data with hundreds of kHz frame rate, uncorrected phase errors due to axial motion of the eye lead to a drastic loss in image quality of the reconstructed volumes. Here we first give a short overview of recent advances in techniques and applications of parallelized OCT and finally present an iterative and statistical algorithm that estimates and corrects motion-induced phase errors ...

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    2. In-vivo retinal imaging with off-axis full-field time-domain optical coherence tomography

      In-vivo retinal imaging with off-axis full-field time-domain optical coherence tomography

      With a simple setup, mainly composed of a low coherence light source and a camera, full-field optical coherence tomography (FF-OCT) allows volumetric tissue imaging. However, fringe washout constrains its use in retinal imaging. Here, we present a novel motion-insensitive approach to FF-OCT, which introduces path-length differences between the reference and the sample light in neighboring pixels using an off-axis reference beam. The temporal carrier frequency in scanned time-domain OCT is replaced by a spatial carrier frequency. Volumetric in-vivo FF-OCT measurements of the human retina were acquired in only 1.3 s, comparable to the acquisition times of current clinically used ...

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    3. Feature Of The Week 10/25/2015: Imaging Pulse Wave Propagation in Human Retina using Full-Field Swept-Source OCT

      Feature Of The Week 10/25/2015: Imaging Pulse Wave Propagation in Human Retina using Full-Field Swept-Source OCT

      We demonstrate a new noninvasive method to assess biomechanical properties of the retinal vascular system. Phase-sensitive full-field swept-source optical coherence tomography (PhS-FF-SS-OCT) is used to investigate retinal vascular dynamics at unprecedented temporal resolution. The motion of retinal tissue that is induced by expansion of the vessels therein is measured with an accuracy of about 10 nm. The pulse shapes of arterial and venous pulsations, their temporal delays, as well as the frequency-dependent pulse propagation through the capillary bed, are determined. For the first time, imaging speed and motion sensitivity are sufficient for a direct measurement of pulse waves propagating with ...

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    4. Imaging pulse wave propagation in human retinal vessels using full-field swept-source optical coherence tomography

      Imaging pulse wave propagation in human retinal vessels using full-field swept-source optical coherence tomography

      We demonstrate a new noninvasive method to assess biomechanical properties of the retinal vascular system. Phase-sensitive full-field swept-source optical coherence tomography (PhS-FF-SS-OCT) is used to investigate retinal vascular dynamics at unprecedented temporal resolution. The motion of retinal tissue that is induced by expansion of the vessels therein is measured with an accuracy of about 10 nm. The pulse shapes of arterial and venous pulsations, their temporal delays, as well as the frequency-dependent pulse propagation through the capillary bed, are determined. For the first time, imaging speed and motion sensitivity are sufficient for a direct measurement of pulse waves propagating with ...

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    5. Efficient holoscopy image reconstruction

      Efficient holoscopy image reconstruction

      Holoscopy is a tomographic imaging technique that combines digital holography and Fourier-domain optical coherence tomography (OCT) to gain tomograms with diffraction limited resolution and uniform sensitivity over several Rayleigh lengths. The lateral image information is calculated from the spatial interference pattern formed by light scattered from the sample and a reference beam. The depth information is obtained from the spectral dependence of the recorded digital holograms. Numerous digital holograms are acquired at different wavelengths and then reconstructed for a common plane in the sample. Afterwards standard Fourier-domain OCT signal processing achieves depth discrimination. Here we describe and demonstrate an optimized ...

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      Mentions: Thorlabs
    6. Common approach for compensation of axial motion artifacts in swept-source OCT and dispersion in Fourier-domain OCT

      Common approach for compensation of axial motion artifacts in swept-source OCT and dispersion in Fourier-domain OCT

      Swept-source optical coherence tomography (SS-OCT) is sensitive to sample motion during the wavelength sweep, which leads to image blurring and image artifacts. In line-field and full-field SS-OCT parallelization is achieved by using a line or area detector, respectively. Thus, approximately 1000 lines or images at different wavenumbers are acquired. The sweep duration is identically with the acquisition time of a complete B-scan or volume, rendering parallel SS-OCT more sensitive to motion artifacts than scanning OCT. The effect of axial motion on the measured spectra is similar to the effect of non-balanced group velocity dispersion (GVD) in the interferometer arms. It ...

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    7. In vivo Fourier-domain full-field OCT of the human retina with 1.5 million A-lines/s

      In vivo Fourier-domain full-field OCT of the human retina with 1.5 million A-lines/s
      In vivo full-field (FF) optical coherence tomography (OCT) images of human retina are presented by using a rapidly tunable laser source in combination with an ultra-high-speed camera. Fourier-domain FF-OCT provided a way to increase the speed of retinal imaging by parallel acquisition of A-scans. Reduced contrast caused by cross talk was observed only below the retinal pigment epithelium. With a 100Hz sweep rate, FF-OCT was fast enough to acquire OCT images with acceptable motion artifacts. FF-OCT allows ultrafast retinal imaging, boosting image speed by a lack of moving parts and a considerably higher irradiation power.
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    1-8 of 8
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    1. (7 articles) University of Lübeck
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    In vivo Fourier-domain full-field OCT of the human retina with 1.5 million A-lines/s Common approach for compensation of axial motion artifacts in swept-source OCT and dispersion in Fourier-domain OCT 3D OPTICAL IMAGING: Holoscopy makes ultrafast lensless imaging of scattering tissues possible Efficient holoscopy image reconstruction Imaging pulse wave propagation in human retinal vessels using full-field swept-source optical coherence tomography Feature Of The Week 10/25/2015: Imaging Pulse Wave Propagation in Human Retina using Full-Field Swept-Source OCT In-vivo retinal imaging with off-axis full-field time-domain optical coherence tomography Reduction of frame rate in full-field swept-source optical coherence tomography by numerical motion correction [Invited] Editorial – Optical Coherence Tomography Angiography: Considerations Regarding Diagnostic Parameters Imaging of the optic nerve: technological advances and future prospects Optical coherence tomography assessment of pulmonary vascular remodeling in advanced heart failure. The OCTOPUS-CHF study Systems and methods for automated widefield optical coherence tomography angiography