1. Articles from M. Pircher

    1-7 of 7
    1. Polarisation-sensitive optical coherence tomography for material

      Polarisation-sensitive optical coherence tomography for material

      Optical Coherence Tomography (OCT) is an emerging technology for high-resolution non-contact imaging of semi-transparent structures. Originally developed for medical diagnostics, we extend the OCT-technique to problems posed in material testing and characterisation. Layer thickness and refractive indices as well as internal structures of polymer parts have been determined within this study. An extension of OCT, namely polarisation-sensitive OCT (PS-OCT) has been used to identify regions of increased anisotropy within injection-moulded plastic parts and to determine quantitatively internal strain within translucent materials in a non-destructive way.

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    2. Three-beam Doppler optical coherence tomography using a facet prism telescope and MEMS mirror for improved transversal resolution

      Three-beam Doppler optical coherence tomography using a facet prism telescope and MEMS mirror for improved transversal resolution

      An improved three-beam Doppler optical coherence tomography system was developed. It utilizes a custom-made three-facet prism telescope to improve the transversal resolution at the sample. Furthermore, a two-axis gimbal-less MEMS mirror is used to minimize off-pivot beam movement at the pupil of the eye, enabling circular scanning for in vivo retinal measurements. We demonstrate the system’s abilities for in vitro circular scanning to measure absolute flow and to reconstruct the full velocity vector on a bifurcation flow phantom. Moreover, in vivo retinal measurements using circular scanning around vessel bifurcations of healthy human volunteers were performed. Measurements of the absolute ...

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    3. Spatially resolved stress measurements in materials with polarization-sensitive optical coherence tomography: image acquisition and processing aspects.

      Spatially resolved stress measurements in materials with polarization-sensitive optical coherence tomography: image acquisition and processing aspects.
      We demonstrate that polarization-sensitive optical coherence tomography (PS-OCT) is suitable to map the stress distribution within materials in a contactless and non-destructive way. In contrast to transmission photoelasticity measurements the samples do not have to be transparent but can be of scattering nature. Denoising and analysis of fringe patterns in single PS-OCT retardation images are demonstrated to deliver the basis for a quantitative whole-field evaluation of the internal stress state of samples under investigation.
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    4. Performance of Automated Drusen Detection by Polarization-sensitive Optical Coherence Tomography

      Performance of Automated Drusen Detection by Polarization-sensitive Optical Coherence Tomography
      Purpose: To estimate the potential of polarization-sensitive optical coherence tomography (PS-OCT) for quantitative assessment of drusen in patients with early age-related macular degeneration (AMD). Methods: Fifteen eyes of thirteen patients presenting drusen consistent with AREDS 2 and 3 classification were examined ophthalmoscopically, followed by fundus photography, autofluorescence imaging and three-dimensional scanning using a PS-OCT. For the automated evaluation of drusen location, area and volume, a novel segmentation algorithm was developed based on the polarization scrambling characteristics of the retinal pigment epithelium (RPE) and applied to each complete dataset. Subsequently, the drusen in each individual B-scan were identified by two independent ...
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    5. Temporal changes of human cone photoreceptors observed in vivo with SLO/OCT

      Temporal changes of human cone photoreceptors observed in vivo with SLO/OCT
      In this study we use our previously introduced scanning laser ophthalmoscope (SLO) / transverse scanning optical coherence tomography (TS-OCT) instrument to investigate long term changes in cone photoreceptors. The instrument is capable to provide 3D information of the human cone photoreceptors with negligible eye motion artifacts due to an implemented 3D motion correction on a cellular level. This allows for an in vivo investigation of exactly the same location on the retina with cellular resolution over several days. Temporal changes in the backscattered intensity are observed and quantified within the junction between inner and outer segments of cone photoreceptors, the cone ...
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    6. Spatially Resolved Stress Measurements in Materials With Polarisation-Sensitive Optical Coherence Tomography: Image Acquisition and Processing Aspects

      Spatially Resolved Stress Measurements in Materials With Polarisation-Sensitive Optical Coherence Tomography: Image Acquisition and Processing Aspects
      We demonstrate that polarisation-sensitive optical coherence tomography (PS-OCT) is suitable for mapping the stress distribution within materials in a contact-free and non-destructive way. In contrast to transmission photoelasticity measurements, the samples do not have to be transparent but can be of scattering nature. Denoising and analysis of fringe patterns in single PS-OCT retardation images are demonstrated to be the bases for a quantitative whole-field evaluation of the internal stress state of samples under investigation.
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    7. Investigation of polymer and polymer/fibre composite materials with optical coherence tomography

      Optical coherence tomography (OCT), a technique originally proposed for applications in the field of biomedical diagnostics, is shown to be an efficient measurement technique for a multitude of problems posed in technical engineering and material research. Especially advanced OCT modifications, involving ultrahigh-resolution (UHR) imaging and fast Fourier-domain (FD) techniques, show promising potential, as successfully demonstrated in this paper by a variety of applications from the field of polymer materials. Thin polymer films and multilayer structures as well as polymer blends and fibre-reinforced polymer composites are successfully evaluated by means of UHR-OCT and FD-OCT performed at different wavelengths. In addition, comparative ...
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    1-7 of 7
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    1. (7 articles) Medical University of Vienna
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    Temporal changes of human cone photoreceptors observed in vivo with SLO/OCT Performance of Automated Drusen Detection by Polarization-sensitive Optical Coherence Tomography Spatially resolved stress measurements in materials with polarization-sensitive optical coherence tomography: image acquisition and processing aspects. Spatially Resolved Stress Measurements in Materials With Polarisation-Sensitive Optical Coherence Tomography: Image Acquisition and Processing Aspects Three-beam Doppler optical coherence tomography using a facet prism telescope and MEMS mirror for improved transversal resolution Polarisation-sensitive optical coherence tomography for material Normative data and associations of Optical Coherence Tomography Angiography measurements of the macula: The Singapore Malay Eye Study Automatic Segmentation and Measurement of Choroid Layer in High Myopia for OCT Imaging Using Deep Learning In-process monitoring in laser grooving with line-shaped femtosecond pulses using optical coherence tomography Three-dimensional opto-thermo-mechanical model for predicting photo-thermal optical coherence tomography responses in multilayer geometries The role of optical coherence tomography angiography in moderate and advanced primary open-angle glaucoma OCT-angiography follow-up of choroidal neovascularization treated with treat- and- extend aflibercept regimen to avoid over-treatment