The Experts below are selected from a list of 43437 Experts worldwide ranked by ideXlab platform
Christoph K Hitzenberger - One of the best experts on this subject based on the ideXlab platform.
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in vitro and in vivo three dimensional Velocity Vector measurement by three beam spectral domain doppler optical coherence tomography
Journal of Biomedical Optics, 2013Co-Authors: Wolfgang Trasischker, Rene M Werkmeister, Stefan Zotter, Bernhard Baumann, Teresa Torzicky, Michael Pircher, Christoph K HitzenbergerAbstract:We developed a three-beam Doppler optical coherence tomography (OCT) system that enables measurement of the Velocity Vector of moving particles in three-dimensions (3-D). The spatial orientation as well as the magnitude of motion can be determined without prior knowledge of the geometry of motion. The system combines three spectral-domain OCT interferometers whose sample beams are focused at the sample by a common focusing lens at three different angles. This provides three spatially independent Velocity components simultaneously from which the Velocity Vector can be reconstructed. We demonstrate the system in a simple test object (rotating disc), a flow phantom, and for blood flow measurements in the retina of a healthy human subject. Measurements of blood flow at a venous bifurcation achieve a good agreement between in- and outflow and demonstrate the reliability of the method.
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in vitro and in vivo three dimensional Velocity Vector measurement by three beam spectral domain doppler optical coherence tomography
Journal of Biomedical Optics, 2013Co-Authors: Wolfgang Trasischker, Rene M Werkmeister, Stefan Zotter, Bernhard Baumann, Teresa Torzicky, Michael Pircher, Christoph K HitzenbergerAbstract:Abstract. We developed a three-beam Doppler optical coherence tomography (OCT) system that enables meas-urement of the Velocity Vector of moving particles in three-dimensions (3-D). The spatial orientation as well as themagnitude of motion can be determined without prior knowledge of the geometry of motion. The system combinesthree spectral-domain OCT interferometers whose sample beams are focused at the sample by a common focusinglens at three different angles. This provides three spatially independent Velocity components simultaneously fromwhich the Velocity Vector can be reconstructed. We demonstrate the system in a simple test object (rotating disc), aflow phantom, and for blood flow measurements in the retina of a healthy human subject. Measurements of bloodflow at a venous bifurcation achieve a good agreement between in- and outflow and demonstrate the reliability ofthe method. ©The Authors.PublishedbySPIE under aCreative Commons Attribution 3.0Unported License. Distributionorreproduction ofthisworkinwhole or in part requires full attribution of the original publication, including its DOI. [DOI: 10.1117/1.JBO.18.11.116010]
Rene M Werkmeister - One of the best experts on this subject based on the ideXlab platform.
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blood flow Velocity Vector field reconstruction from dual beam bidirectional doppler oct measurements in retinal veins
Biomedical Optics Express, 2015Co-Authors: Gerold C Aschinger, Leopold Schmetterer, Veronika Doblhoffdier, Rainer A Leitgeb, Gerhard Garhofer, Martin Groschl, Rene M WerkmeisterAbstract:In this paper, we demonstrate the possibility to reconstruct the actual blood flow Velocity Vector field in retinal microvessels from dual-beam bidirectional Doppler optical coherence tomography measurements. First, for a better understanding of measured phase patterns, several flow situations were simulated on the basis of the known dual beam measurement geometry. We were able to extract the Vector field parameters that determine the measured phase pattern, allowing for the development of an algorithm to reconstruct the Velocity Vector field from measured phase data. In a next step, measurements were performed at a straight vessel section and at a venous convergence; the obtained phase data were evaluated by means of the new approach. For the straight vessel section, the reconstructed flow Velocity Vector field yielded a parabolic flow. For the venous convergence, however, the reconstructed Vector field deviated from a parabolic profile, but was in very good accordance with the simulated Vector field for the given vessel geometry. The proposed algorithm allows predictions of the Velocity Vector field. Moreover, the algorithm is also sensitive to directional changes of the flow Velocity as small as <1°, thereby offering insight in the flow characteristics of the non-Newtonian fluid blood in microvessels.
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in vitro and in vivo three dimensional Velocity Vector measurement by three beam spectral domain doppler optical coherence tomography
Journal of Biomedical Optics, 2013Co-Authors: Wolfgang Trasischker, Rene M Werkmeister, Stefan Zotter, Bernhard Baumann, Teresa Torzicky, Michael Pircher, Christoph K HitzenbergerAbstract:We developed a three-beam Doppler optical coherence tomography (OCT) system that enables measurement of the Velocity Vector of moving particles in three-dimensions (3-D). The spatial orientation as well as the magnitude of motion can be determined without prior knowledge of the geometry of motion. The system combines three spectral-domain OCT interferometers whose sample beams are focused at the sample by a common focusing lens at three different angles. This provides three spatially independent Velocity components simultaneously from which the Velocity Vector can be reconstructed. We demonstrate the system in a simple test object (rotating disc), a flow phantom, and for blood flow measurements in the retina of a healthy human subject. Measurements of blood flow at a venous bifurcation achieve a good agreement between in- and outflow and demonstrate the reliability of the method.
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in vitro and in vivo three dimensional Velocity Vector measurement by three beam spectral domain doppler optical coherence tomography
Journal of Biomedical Optics, 2013Co-Authors: Wolfgang Trasischker, Rene M Werkmeister, Stefan Zotter, Bernhard Baumann, Teresa Torzicky, Michael Pircher, Christoph K HitzenbergerAbstract:Abstract. We developed a three-beam Doppler optical coherence tomography (OCT) system that enables meas-urement of the Velocity Vector of moving particles in three-dimensions (3-D). The spatial orientation as well as themagnitude of motion can be determined without prior knowledge of the geometry of motion. The system combinesthree spectral-domain OCT interferometers whose sample beams are focused at the sample by a common focusinglens at three different angles. This provides three spatially independent Velocity components simultaneously fromwhich the Velocity Vector can be reconstructed. We demonstrate the system in a simple test object (rotating disc), aflow phantom, and for blood flow measurements in the retina of a healthy human subject. Measurements of bloodflow at a venous bifurcation achieve a good agreement between in- and outflow and demonstrate the reliability ofthe method. ©The Authors.PublishedbySPIE under aCreative Commons Attribution 3.0Unported License. Distributionorreproduction ofthisworkinwhole or in part requires full attribution of the original publication, including its DOI. [DOI: 10.1117/1.JBO.18.11.116010]
Zhongping Chen - One of the best experts on this subject based on the ideXlab platform.
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quantification of a three dimensional Velocity Vector using spectral domain doppler optical coherence tomography
Optics Letters, 2007Co-Authors: Yehchan Ahn, Woonggyu Jung, Zhongping ChenAbstract:Multiangle, fiber-based, spectral-domain Doppler optical coherence tomography with a phase-resolved algorithm is presented to measure three components of an arbitrary Velocity Vector. A beam divider that divides a probe beam to have five independent viewpoints and path length delays was designed. The divider was inserted into the sampling arm of a Doppler optical coherence tomography system between the collimator and the first galvo mirror of a two-axis galvo scanner. The divider produced five independent D k's (the average difference between the wave Vectors of incoming and outgoing beams) after passing through the focusing lens while keeping two-axis scanning capability. After calibration, an unknown Velocity Vector field inside a microtube was quantified by solving a three-dimensional minimization problem.
Wolfgang Trasischker - One of the best experts on this subject based on the ideXlab platform.
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in vitro and in vivo three dimensional Velocity Vector measurement by three beam spectral domain doppler optical coherence tomography
Journal of Biomedical Optics, 2013Co-Authors: Wolfgang Trasischker, Rene M Werkmeister, Stefan Zotter, Bernhard Baumann, Teresa Torzicky, Michael Pircher, Christoph K HitzenbergerAbstract:We developed a three-beam Doppler optical coherence tomography (OCT) system that enables measurement of the Velocity Vector of moving particles in three-dimensions (3-D). The spatial orientation as well as the magnitude of motion can be determined without prior knowledge of the geometry of motion. The system combines three spectral-domain OCT interferometers whose sample beams are focused at the sample by a common focusing lens at three different angles. This provides three spatially independent Velocity components simultaneously from which the Velocity Vector can be reconstructed. We demonstrate the system in a simple test object (rotating disc), a flow phantom, and for blood flow measurements in the retina of a healthy human subject. Measurements of blood flow at a venous bifurcation achieve a good agreement between in- and outflow and demonstrate the reliability of the method.
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in vitro and in vivo three dimensional Velocity Vector measurement by three beam spectral domain doppler optical coherence tomography
Journal of Biomedical Optics, 2013Co-Authors: Wolfgang Trasischker, Rene M Werkmeister, Stefan Zotter, Bernhard Baumann, Teresa Torzicky, Michael Pircher, Christoph K HitzenbergerAbstract:Abstract. We developed a three-beam Doppler optical coherence tomography (OCT) system that enables meas-urement of the Velocity Vector of moving particles in three-dimensions (3-D). The spatial orientation as well as themagnitude of motion can be determined without prior knowledge of the geometry of motion. The system combinesthree spectral-domain OCT interferometers whose sample beams are focused at the sample by a common focusinglens at three different angles. This provides three spatially independent Velocity components simultaneously fromwhich the Velocity Vector can be reconstructed. We demonstrate the system in a simple test object (rotating disc), aflow phantom, and for blood flow measurements in the retina of a healthy human subject. Measurements of bloodflow at a venous bifurcation achieve a good agreement between in- and outflow and demonstrate the reliability ofthe method. ©The Authors.PublishedbySPIE under aCreative Commons Attribution 3.0Unported License. Distributionorreproduction ofthisworkinwhole or in part requires full attribution of the original publication, including its DOI. [DOI: 10.1117/1.JBO.18.11.116010]
Yehchan Ahn - One of the best experts on this subject based on the ideXlab platform.
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quantification of a three dimensional Velocity Vector using spectral domain doppler optical coherence tomography
Optics Letters, 2007Co-Authors: Yehchan Ahn, Woonggyu Jung, Zhongping ChenAbstract:Multiangle, fiber-based, spectral-domain Doppler optical coherence tomography with a phase-resolved algorithm is presented to measure three components of an arbitrary Velocity Vector. A beam divider that divides a probe beam to have five independent viewpoints and path length delays was designed. The divider was inserted into the sampling arm of a Doppler optical coherence tomography system between the collimator and the first galvo mirror of a two-axis galvo scanner. The divider produced five independent D k's (the average difference between the wave Vectors of incoming and outgoing beams) after passing through the focusing lens while keeping two-axis scanning capability. After calibration, an unknown Velocity Vector field inside a microtube was quantified by solving a three-dimensional minimization problem.
