1. Articles from Tim Bonin

    1-7 of 7
    1. Coronal in vivo forward-imaging of rat brain morphology with an ultra-small optical coherence tomography fiber probe

      Coronal in vivo forward-imaging of rat brain morphology with an ultra-small optical coherence tomography fiber probe

      A well-established navigation method is one of the key conditions for successful brain surgery: it should be accurate, safe and online operable. Recent research shows that optical coherence tomography (OCT) is a potential solution for this application by providing a high resolution and small probe dimension. In this study a fiber-based spectral-domain OCT system utilizing a super-luminescent-diode with the center wavelength of 840 nm providing 14.5 μm axial resolution was used. A composite 125 μm diameter detecting probe with a gradient index (GRIN) fiber fused to a single mode fiber was employed. Signals were reconstructed into grayscale images by ...

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    2. 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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    3. Holoscopy—holographic optical coherence tomography

      Holoscopy—holographic optical coherence tomography
      Scanning optical coherence tomography (OCT) is limited in sensitivity and resolution by the restricted focal depth of the confocal detection scheme. Holoscopy, a combination of holography and Fourier-domain full-field OCT, is proposed as a way to detect photons from all depths of a sample volume simultaneously with uniform sensitivity and lateral resolution, even at high NAs. By using the scalar diffraction theory, as frequently applied in digital holographic imaging, we fully reconstruct the object field with depth-invariant imaging quality. In vivo imaging of human skin is demonstrated with an image quality comparable to conventionally scanned OCT.
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    4. Comparison of fast swept source full-field OCT with conventional scanning OCT

      Comparison of fast swept source full-field OCT with conventional scanning OCT
      Recently, in-vivo full eld (FF) optical coherence tomography (OCT) with an ultra-high speed camera has been presented for fast in vivo retinal imaging. By parallel A-scans acquisition, imaging with 1,5 million A-scans/s was shown with an extended illumination of the retina. In this paper, the image quality of FF-OCT images will be compared to conventional scanning OCT systems. The eect of the absence of a confocal aperture leading to crosstalk between adjacent image points will be shown and an experimental analysis of the systems lateral point spread function (PSF) in dependence of depth will be given and discussed.
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    5. 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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    6. Towards Multi-Directional OCT for Speckle Noise Reduction

      Multi-directional optical coherence tomography (MD-OCT) applies and extends the concept of angular compounding for speckle noise reduction to the area of OCT imaging. OCT images are acquired from a wide range of angles of view. Averaging of the rotated images therefore requires compensation of the parallax which is achieved by simple image registration for image reconstruction. Test measurements of a sample structure in a low and highly scattering environment show that the method improves the signal-to-noise ratio by a factor of 4 and hence reduces speckle noise significantly. Experimental results also show that the proposed averaging increases the performance of ...
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    1-7 of 7
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  2. Topics in the News

    1. (6 articles) University of Lübeck
    2. (4 articles) Thorlabs
    3. (1 articles) University of Freiburg
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    In vivo Fourier-domain full-field OCT of the human retina with 1.5 million A-lines/s Comparison of fast swept source full-field OCT with conventional scanning OCT Holoscopy: holographic optical coherence tomography Holoscopy—holographic optical coherence tomography Common approach for compensation of axial motion artifacts in swept-source OCT and dispersion in Fourier-domain OCT Coronal in vivo forward-imaging of rat brain morphology with an ultra-small optical coherence tomography fiber probe 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 OCT signal processing device and recording medium Application of optical coherence tomography angiography to assess systemic severity in patients with hereditary transthyretin amyloidosis