Prof. Jørgen Arendt Jensen Profile

Prof. Jørgen Arendt Jensen

Professor at Technical Univ of Denmark

SPIE Involvement:

Conference Program Committee | Author | Instructor

Publications (62)

Proceedings Article | 4 April 2022 Presentation + Paper

Microbubble tracking with a forward-backward strategy

Iman Taghavi, Sofie Bech Andersen, Mikkel Schou, Michael Bachmann Nielsen, Charlotte Mehlin Sørensen, Matthias Bo Stuart, Jørgen Arendt Jensen

Proceedings Volume 12038, 120380C (2022) https://doi.org/10.1117/12.2610753

KEYWORDS: Ultrasonography, Kidney, Filtering (signal processing), In vivo imaging, Visualization, Super resolution, Super resolution microscopy, Detection and tracking algorithms

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Proceedings Article | 4 April 2022 Presentation + Paper

Fast super resolution ultrasound imaging by tracking of erythrocytes using different velocity constraints

Mostafa Amin-Naji, Iman Taghavi, Stinne Byrholdt Søgaard, Sofie Bech Andersen, Charlotte Mehlin Sørensen, Matthias Bo Stuart, Jørgen Arendt Jensen

Proceedings Volume 12038, 120380G (2022) https://doi.org/10.1117/12.2612355

KEYWORDS: Ultrasonography, Super resolution, Image fusion, Discrete wavelet transforms, Visualization, Target acquisition, Data acquisition, Particles, Image enhancement, Medical imaging, Biomedical ultrasonography, Ultrasound real time imaging, Ultrasonics, Medical image processing

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Proceedings Article | 4 April 2022 Presentation + Paper

Fast super resolution ultrasound imaging using the erythrocytes

Jørgen Arendt Jensen, Mikkel Schou, Sofie Bech Andersen, Stinne Byrholdt Søgaard, Charlotte Mehlin Sørensen, Michael Bachmann Nielsen, Carsten Gundlach, Hans Martin Kjer, Anders Bjorholm Dahl, Matthias Bo Stuart, Borislav Gueorguiev Tomov

Proceedings Volume 12038, 120380E (2022) https://doi.org/10.1117/12.2612245

KEYWORDS: Ultrasonography, Image resolution, Kidney, Super resolution, Tissues, Data acquisition, Scanners, Visualization, Point spread functions, Heart

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Proceedings Article | 15 March 2019 Presentation + Paper

Row-column beamforming with dynamic apodizations on a GPU

Matthias Bo Stuart, Mikkel Schou, Jørgen Arendt Jensen

Proceedings Volume 10955, 109550Q (2019) https://doi.org/10.1117/12.2512418

KEYWORDS: Apodization, Phased arrays, Point spread functions, MATLAB, Computer programming, Imaging systems, Ultrasonography, 3D image processing, Image quality, Transducers

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Proceedings Article | 13 March 2017 Paper

Automatic segmentation of vessels in in-vivo ultrasound scans

Philip Tamimi-Sarnikowski, Andreas Brink-Kjær, Ramin Moshavegh, Jørgen Arendt Jensen

Proceedings Volume 10137, 101371P (2017) https://doi.org/10.1117/12.2254101

KEYWORDS: Image segmentation, Ultrasonography, In vivo imaging, Vascular diseases, Arteries, Doppler effect, Scanners, Transducers, Image processing algorithms and systems

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Proceedings Article | 1 April 2016 Paper

High frame rate synthetic aperture vector flow imaging for transthoracic echocardiography

Carlos Villagómez-Hoyos, Matthias Stuart, Thor Bechsgaard, Michael Bachmann Nielsen, Jørgen Arendt Jensen

Proceedings Volume 9790, 979004 (2016) https://doi.org/10.1117/12.2216707

KEYWORDS: Ultrasonography, Cardiac imaging, Echocardiography, Heart, Tissues, In vivo imaging, Blood circulation, Blood, Scanners, Diagnostics, Transducers, Point spread functions, Synthetic aperture radar

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Proceedings Article | 1 April 2016 Paper

Optimization of synthetic aperture image quality

Ramin Moshavegh, Jonas Jensen, Carlos Villagomez-Hoyos, Matthias Stuart, Martin Christian Hemmsen, Jørgen Arendt Jensen

Proceedings Volume 9790, 97900Z (2016) https://doi.org/10.1117/12.2216506

KEYWORDS: Image quality, Image resolution, Objectives, Ultrasonography, Synthetic aperture radar, Image analysis, Synthetic aperture imaging, Ultrafast imaging, Transducers, Point spread functions, Computer simulations, Apodization

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Proceedings Article | 1 April 2016 Paper

Analog gradient beamformer for a wireless ultrasound scanner

Tommaso Di Ianni, Martin Christian Hemmsen, Jan Bagge, Henrik Jensen, Nitsan Vardi, Jørgen Arendt Jensen

Proceedings Volume 9790, 979010 (2016) https://doi.org/10.1117/12.2216238

KEYWORDS: Optical simulations, Ultrasonography, Analog electronics, Phased arrays, Scanners, Point spread functions, Image quality, Quantization, Point-of-care devices, Diagnostics, Transducers

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Proceedings Article | 1 April 2016 Paper

Blood flow velocity in the popliteal vein using transverse oscillation ultrasound

Thor Bechsgaard, Kristoffer Lindskov Hansen, Andreas Hjelm Brandt, Simon Holbek, Lars Lönn, Charlotte Strandberg, Niels Bækgaard, Michael Bachmann Nielsen, Jørgen Arendt Jensen

Proceedings Volume 9790, 979003 (2016) https://doi.org/10.1117/12.2216725

KEYWORDS: Veins, Ultrasonography, Doppler effect, Blood circulation, Velocity measurements, Scanners, Blood, Medicine, Biology, Image analysis, Visualization, Transducers, Doppler tomography

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Proceedings Article | 1 April 2016 Paper

3D vector flow using a row-column addressed CMUT array

Simon Holbek, Thomas Lehrmann Christiansen, Mathias Engholm, Anders Lei, Mathias Bo Stuart, Christopher Beers, Lars Nordahl Moesner, Jan Peter Bagge, Erik Vilain Thomsen, Jørgen Arendt Jensen

Proceedings Volume 9790, 979005 (2016) https://doi.org/10.1117/12.2216721

KEYWORDS: Ultrasonography, Ultrasonics, Transducers, 3D image processing, Electrodes, Prototyping, Apodization, Blood, Scanners, Motion estimation

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Proceedings Article | 1 April 2016 Paper

Preliminary investigation of an ultrasound method for estimating pressure changes in deep-positioned vessels

Jacob Bjerring Olesen, Carlos Armando Villagomez-Hoyos, Marie Sand Traberg, Adrian J. Chee, Billy Y. Yiu, Chung Kit Ho, Alfred C. Yu, Jørgen Arendt Jensen

Proceedings Volume 9790, 97900J (2016) https://doi.org/10.1117/12.2214974

KEYWORDS: Ultrasonography, Phased arrays, Transducers, 3D modeling, Scanners, Numerical simulations, Medicine, Biology, Ultrafast imaging, Heart, Data modeling, Signal to noise ratio, Synthetic aperture radar

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Proceedings Article | 1 April 2016 Paper

Volumetric synthetic aperture imaging with a piezoelectric 2D row-column probe

Hamed Bouzari, Mathias Engholm, Thomas Lehrmann Christiansen, Christopher Beers, Anders Lei, Matthias Bo Stuart, Svetoslav Ivanov Nikolov, Erik Vilain Thomsen, Jørgen Arendt Jensen

Proceedings Volume 9790, 97900Y (2016) https://doi.org/10.1117/12.2216074

KEYWORDS: Point spread functions, Transducers, Ultrasonography, Signal to noise ratio, Synthetic aperture imaging, 3D image processing, Spatial resolution, Prototyping, Scanners, Tissues, Apodization, Electrodes

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Proceedings Article | 1 April 2016 Paper

Novel automatic detection of pleura and B-lines (comet-tail artifacts) on in vivo lung ultrasound scans

Ramin Moshavegh, Kristoffer Lindskov Hansen, Hasse Møller Sørensen, Martin Christian Hemmsen, Caroline Ewertsen, Michael Bachmann Nielsen, Jørgen Arendt Jensen

Proceedings Volume 9790, 97900K (2016) https://doi.org/10.1117/12.2216499

KEYWORDS: Ultrasonography, Lung, Image segmentation, In vivo imaging, Visual analytics, Visualization, Medicine, Biology, Image analysis, Transducers, Detection and tracking algorithms, Binary data, Surgery, Signal attenuation, Scanners

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Proceedings Article | 17 March 2015 Paper

Automated hierarchical time gain compensation for in-vivo ultrasound imaging

Ramin Moshavegh, Martin Hemmsen, Bo Martins, Andreas Brandt, Kristoffer Hansen, Michael Nielsen, Jørgen Jensen

Proceedings Volume 9419, 941904 (2015) https://doi.org/10.1117/12.2081619

KEYWORDS: Signal attenuation, Signal to noise ratio, Tissues, Ultrasonography, Bladder, In vivo imaging, Interference (communication), Visualization, Image quality, Image segmentation

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Proceedings Article | 17 March 2015 Paper

In vivo real-time volumetric synthetic aperture ultrasound imaging

Hamed Bouzari, Morten Rasmussen, Andreas Brandt, Matthias Stuart, Svetoslav Nikolov, Jørgen Jensen

Proceedings Volume 9419, 94190I (2015) https://doi.org/10.1117/12.2081631

KEYWORDS: Ultrasonography, In vivo imaging, Transducers, Synthetic aperture radar, Scanners, Imaging systems, Tissues, Acoustics, Temporal resolution, Signal to noise ratio

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Proceedings Article | 17 March 2015 Paper

Surveillance of hemodialysis vascular access with ultrasound vector flow imaging

Andreas Brandt, Jacob Olesen, Kristoffer Hansen, Marianne Rix, Jørgen Jensen, Michael Nielsen

Proceedings Volume 9419, 94190U (2015) https://doi.org/10.1117/12.2081372

KEYWORDS: Ultrasonography, Surveillance, Scanners, Transducers, Blood circulation, Statistical analysis, Gold, Doppler effect, Blood, Nephrology

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Proceedings Article | 17 March 2015 Paper

Transverse oscillation vector flow imaging for transthoracic echocardiography

David Bradway, Kristoffer Hansen, Michael Nielsen, Jørgen Jensen

Proceedings Volume 9419, 941902 (2015) https://doi.org/10.1117/12.2081145

KEYWORDS: In vivo imaging, Ultrasonography, Scanners, Transducers, Doppler effect, Apodization, Acoustics, Velocity measurements, Point spread functions, Echocardiography

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Proceedings Article | 20 March 2014 Paper

Simulation study of real time 3D synthetic aperture sequential beamforming for ultrasound imaging

Martin Christian Hemmsen, Morten Fischer Rasmussen, Matthias Bo Stuart, Jørgen Arendt Jensen

Proceedings Volume 9040, 90401K (2014) https://doi.org/10.1117/12.2044017

KEYWORDS: Transducers, Phased arrays, Apodization, Ultrasonography, 3D image processing, Optical simulations, Computer simulations, Image resolution, Imaging systems, Image quality

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Proceedings Article | 20 March 2014 Paper

A comparison between temporal and subband minimum variance adaptive beamforming

Konstantinos Diamantis, Iben Holfort-Voxen, Alan Greenaway, Tom Anderson, Jørgen Jensen, Vassilis Sboros

Proceedings Volume 9040, 90400L (2014) https://doi.org/10.1117/12.2043602

KEYWORDS: Phased arrays, Apodization, Sensors, Ultrasonography, Transducers, Signal processing, Image resolution, Fourier transforms, Radar signal processing, Optical simulations

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This paper compares the performance between temporal and subband Minimum Variance (MV) beamformers for medical ultrasound imaging. Both adaptive methods provide an optimized set of apodization weights but are implemented in the time and frequency domains respectively. Their performance is evaluated with simulated synthetic aperture data obtained from Field II and is quantified by the Full-Width-Half-Maximum (FWHM), the Peak-Side-Lobe level (PSL) and the contrast level. From a point phantom, a full sequence of 128 emissions with one transducer element transmitting and all 128 elements receiving each time, provides a FWHM of 0.03 mm (0.14λ) for both implementations at a depth of 40 mm. This value is more than 20 times lower than the one achieved by conventional beamforming. The corresponding values of PSL are -58 dB and -63 dB for time and frequency domain MV beamformers, while a value no lower than -50 dB can be obtained from either Boxcar or Hanning weights. Interestingly, a single emission with central element #64 as the transmitting aperture provides results comparable to the full sequence. The values of FWHM are 0.04 mm and 0.03 mm and those of PSL are -42 dB and -46 dB for temporal and subband approaches. From a cyst phantom and for 128 emissions, the contrast level is calculated at -54 dB and -63 dB respectively at the same depth, with the initial shape of the cyst being preserved in contrast to conventional beamforming. The difference between the two adaptive beamformers is less significant in the case of a single emission, with the contrast level being estimated at -42 dB for the time domain and -43 dB for the frequency domain implementation. For the estimation of a single MV weight of a low resolution image formed by a single emission, 0.44 * 109 calculations per second are required for the temporal approach. The same numbers for the subband approach are 0.62 * 109 for the point and 1.33 * 109 for the cyst phantom. The comparison demonstrates similar resolution but slightly lower side-lobes and higher contrast for the subband approach at the expense of increased computation time.

Proceedings Article | 20 March 2014 Paper

Real-time GPU implementation of transverse oscillation vector velocity flow imaging

David Pierson Bradway, Michael Johannes Pihl, Andreas Krebs, Borislav Gueorguiev Tomov, Carsten Straso Kjær, Svetoslav Ivanov Nikolov, Jørgen Arendt Jensen

Proceedings Volume 9040, 90401Y (2014) https://doi.org/10.1117/12.2043582

KEYWORDS: Ultrasonography, Scanners, MATLAB, Visualization, Data acquisition, Signal processing, Data processing, Algorithm development, Quantization, Diagnostics

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Proceedings Article | 20 March 2014 Paper

Increasing the dynamic range of synthetic aperture vector flow imaging

Carlos Villagomez Hoyos, Matthias Bo Stuart, Jørgen Arendt Jensen

Proceedings Volume 9040, 904011 (2014) https://doi.org/10.1117/12.2043637

KEYWORDS: Transducers, Ultrasonography, Adaptive optics, Blood, Data acquisition, Scanners, Blood circulation, Beam analyzers, Apodization, Neon

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In current ultrasound systems the dynamic range of detectable velocities is susceptible to the selected pulse repetition frequency, thus limiting the dynamic range of flow mapping. To establish the feasibility of extending the range of detectable velocities towards low velocity vessels, results are presented using synthetic aperture which increases the frame-to-frame signal correlation of the scatterer displacement while providing continuous data. In this paper, recursive synthetic aperture acquisition, directional beamforming, and cross-correlation are used to produce B-mode and vector velocity images. The emissions for the two imaging modes are interleaved 1-to-1 ratio, providing a high frame rate equal to the effective pulse repetition frequency of each imaging mode. The direction of the flow is estimated, and the velocity is then determined in that direction. This method works for all angles, including fully axial and transverse flows. The method is investigated using Field II simulations and data from the experimental ultrasound scanner SARUS, acquired from a circulating flow rig with a parabolic flow. A 7 MHz linear array transducer is used, and several pulse repetition frequencies are synthesized in a simulated flow phantom with linearly increasing velocity and in a dual-vessel phantom with laminar flow with peak velocities of 0.05 m/s and 0.5 m/s. The experimental measurements are made with laminar flow as in the simulations. For the simulated and experimental vessel with peak velocity of 0.05 m/s and flow angle of 75°, the relative bias is -0.29% and -3.19%, and the relative standard deviations are 2.39% and 5.75% respectively. For the simulated and experimental vessel with peak velocity of 0.5 m/s and flow angle of -90°, the relative biases are -4.30% and -7.37%, and the relative standard deviations are 1.59% and 6.12%, respectively. The presented method can improve the estimates by synthesizing a lower pulse repetition frequency, thereby increasing the dynamic range of the vector velocity imaging.

Proceedings Article | 20 March 2014 Paper

Determining inter-fractional motion of the uterus using 3D ultrasound imaging during radiotherapy for cervical cancer

Mariwan Baker, Jørgen Jensen, Claus Behrens

Proceedings Volume 9040, 90400Y (2014) https://doi.org/10.1117/12.2043173

KEYWORDS: Bone, Uterus, Computed tomography, Radiotherapy, Tissues, Cervical cancer, Ultrasonography, Tumors, Bladder, Imaging systems

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Proceedings Article | 20 March 2014 Paper

Rapid measurements of intensities for safety assessment of advanced imaging sequences

Jørgen Arendt Jensen, Morten Fischer Rasmussen, Matthias Bo Stuart, Borislav Tomov

Proceedings Volume 9040, 90400Z (2014) https://doi.org/10.1117/12.2043688

KEYWORDS: Scanners, Transducers, Imaging systems, Calibration, Safety, Ultrasonography, Acoustics, Data storage, Multichannel imaging systems, Time metrology

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FDA requires that intensity and safety parameters are measured for all imaging schemes for clinical imaging. This is often cumbersome, since the scan sequence has to broken apart, measurements conducted for the individually emitted beams, and the final intensity levels calculated by combining the intensities from the individual beams. This paper suggests a fast measurement scheme using the multi-line sampling capability of modern scanners and research systems. The hydrophone is connected to one sampling channel in the research system, and the intensity is measured for all imaging lines in one emission sequence. This makes it possible to map out the pressure field and hence intensity level for all imaging lines in a single measurement. The approach has several advantages: the scanner does not have to be re-programmed and can use the scan sequence without modification. The measurements are orders of magnitude faster (minutes rather than hours) and the final intensity level calculation can be made generic and reused for any kind of scan sequence by just knowing the number of imaging lines and the pulse repetition time. The scheme has been implemented on the Acoustic Intensity Measurement System AIMS III (Onda, Sunnyvale, California, USA). The research scanner SARUS is used for the experiments, where one of the channels is used for the hydrophone signal. A 3 MHz BK 8820e (BK Medical, Herlev, Denmark) convex array with 192 elements is used along with an Onda HFL-0400 hydrophone connected to a AH-2010 pre-amplifier (Onda Corporation, Sunnyvale, USA). A single emission sequence is employed for testing and calibrating the approach. The measurements using the AIMS III and SARUS systems after calibration agree within a relative standard deviation of 0.24%. A duplex B-mode and flow sequence is also investigated. The complex intensity map is measured and the time averaged spatial peak intensity is found. A single point measurement takes 3.43 seconds and the whole sequence can be characterized on the acoustical axis in around 6 minutes.

Proceedings Article | 20 March 2014 Paper

Comparison of vector velocity imaging using directional beamforming and transverse oscillation for a convex array transducer

Jørgen Jensen

Proceedings Volume 9040, 904012 (2014) https://doi.org/10.1117/12.2043701

KEYWORDS: Ultrasonography, Scanners, Transducers, Data acquisition, Statistical analysis, Velocity measurements, Blood, Magnetism, Apodization, Correlation function

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Proceedings Article | 29 March 2013 Paper

Preliminary study of synthetic aperture tissue harmonic imaging on in-vivo data

Joachim Rasmussen, Martin Hemmsen, Signe Madsen, Peter Hansen, Michael Nielsen, Jørgen Jensen

Proceedings Volume 8675, 867512 (2013) https://doi.org/10.1117/12.2006363

KEYWORDS: Tissues, Apodization, Image quality, In vivo imaging, Video, Ultrasonography, Data acquisition, Image transmission, Scanners, Imaging systems

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Proceedings Article | 29 March 2013 Paper

Non-invasive measurement of pressure gradients using ultrasound

Jacob Olesen, Marie Traberg, Michael Pihl, Jørgen Jensen

Proceedings Volume 8675, 86750G (2013) https://doi.org/10.1117/12.2006732

KEYWORDS: Ultrasonography, Magnetic resonance imaging, Velocity measurements, Scanners, Data modeling, Transducers, Spatial resolution, Data acquisition, Arteries, Data analysis

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Proceedings Article | 29 March 2013 Paper

A delta-sigma beamformer with integrated apodization

Borislav Tomov, Matthias Stuart, Martin Hemmsen, Jørgen Jensen

Proceedings Volume 8675, 86750R (2013) https://doi.org/10.1117/12.2006731

KEYWORDS: Phased arrays, Apodization, Signal to noise ratio, Ultrasonography, Modulators, Analog electronics, Interference (communication), Scanners, Image filtering, Filtering (signal processing)

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Proceedings Article | 29 March 2013 Paper

Preliminary examples of 3D vector flow imaging

Michael Pihl, Matthias Stuart, Borislav Tomov, Jens Hansen, Morten Rasmussen, Jørgen Jensen

Proceedings Volume 8675, 86750H (2013) https://doi.org/10.1117/12.2006845

KEYWORDS: 3D image processing, 3D acquisition, Data acquisition, Visualization, 3D metrology, Ultrasonography, Transducers, Magnetic resonance imaging, Stereoscopy, Motion measurement

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This paper presents 3D vector flow images obtained using the 3D Transverse Oscillation (TO) method. The method employs a 2D transducer and estimates the three velocity components simultaneously, which is important for visualizing complex flow patterns. Data are acquired using the experimental ultrasound scanner SARUS on a flow-rig system with steady flow. The vessel of the flow-rig is centered at a depth of 30 mm, and the flow has an expected 2D circular-symmetric parabolic profile with a peak velocity of 1 m/s. Ten frames of 3D vector flow images are acquired in a cross-sectional plane orthogonal to the center axis of the vessel, which coincides with the y-axis and the flow direction. Hence, only out-of-plane motion is expected. This motion cannot be measured by typical commercial scanners employing 1D arrays. Each frame consists of 16 flow lines steered from -15 to 15 degrees in steps of 2 degrees in the ZX-plane. For the center line, 3200 M-mode lines are acquired yielding 100 velocity profiles. At the center of the vessel, the mean and standard deviation of the estimated velocity vectors are (v_x, v_y, v_z) = (-0.026, 95, 1.0)±(8.8, 6.2, 0.84) cm/s compared to the expected (0.0, 96, 0.0) cm/s. Relative to the velocity magnitude this yields standard deviations of (9.1, 6.4, 0.88) %, respectively. Volumetric flow rates were estimated for all ten frames yielding 57.9±2.0 mL/s in comparison with 56.2 mL/s measured by a commercial magnetic flow meter. One frame of the obtained 3D vector flow data is presented and visualized using three alternative approaches. Practically no in-plane motion (v_x and v_z) is measured, whereas the out-of-plane motion (v_y) and the velocity magnitude exhibit the expected 2D circular-symmetric parabolic shape. It shown that the ultrasound method is suitable for real-time data acquisition as opposed to magnetic resonance imaging (MRI). The results demonstrate that the 3D TO method is capable of performing 3D vector flow imaging.

Proceedings Article | 29 March 2013 Paper

3D ultrasound imaging performance of a row-column addressed 2D array transducer: a simulation study

Morten Rasmussen, Jørgen Jensen

Proceedings Volume 8675, 86750C (2013) https://doi.org/10.1117/12.2007083

KEYWORDS: Apodization, Point spread functions, Chemical elements, Transducers, Ultrasonography, Imaging arrays, 3D image processing, Wavefronts, Stereoscopy, Image resolution

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Proceedings Article | 29 March 2013 Open Access

New developments in vector velocity imaging using the transverse oscillation approach

Jørgen Jensen, Michael Pihl, Jacob Olesen, Peter Hansen, Kristoffer Hansen, Michael Nielsen

Proceedings Volume 8675, 86750F (2013) https://doi.org/10.1117/12.2013701

KEYWORDS: Ultrasonography, Arteries, Apodization, Phased arrays, Blood, Veins, Transducers, Heart, 3D image processing, Velocity measurements

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Proceedings Article | 25 February 2012 Paper

Clinical evaluation of synthetic aperture sequential beamforming

Peter Møller Hansen, Martin Christian Hemmsen, Theis Lange, Jens Munk Hansen, Michael Bachmann Nielsen, Jørgen Arendt Jensen

Proceedings Volume 8320, 83200K (2012) https://doi.org/10.1117/12.911135

KEYWORDS: Ultrasonography, Scanners, Image resolution, Transducers, Image quality, Kidney, Spatial resolution, Liver, Ions, Image processing

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Proceedings Article | 25 February 2012 Paper

Age and gender related differences in aortic blood flow

Marie Sand Enevoldsen, Mads Møller Pedersen, Martin Christian Hemmsen, Lars Lönn, Kaj-Åge Henneberg, Jørgen Arendt Jensen

Proceedings Volume 8320, 83200J (2012) https://doi.org/10.1117/12.910859

KEYWORDS: Blood circulation, Magnetic resonance imaging, Data acquisition, Image segmentation, Ultrasonography, Blood, Scanners, Arteries, Computational fluid dynamics, Medical research

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Proceedings Article | 25 February 2012 Paper

Preliminary comparison of 3D synthetic aperture imaging with Explososcan

Morten Fischer Rasmussen, Jens Munk Hansen, Guillaume Férin, Rémi Dufait, Jørgen Arendt Jensen

Proceedings Volume 8320, 83200F (2012) https://doi.org/10.1117/12.913925

KEYWORDS: Transducers, Point spread functions, 3D image processing, Synthetic aperture imaging, Ultrasonography, Phased arrays, Image resolution, Computer simulations, Medical imaging, Imaging systems

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Proceedings Article | 26 March 2011 Paper

Comparison of simulated and measured nonlinear ultrasound fields

Yigang Du, Henrik Jensen, Jørgen Arendt Jensen

Proceedings Volume 7968, 79680P (2011) https://doi.org/10.1117/12.877350

KEYWORDS: Transducers, Ultrasonography, Acoustics, Point spread functions, Fourier transforms, Signal attenuation, Wave propagation, Computer simulations, Oscilloscopes, Convolution

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Proceedings Article | 26 March 2011 Paper

Preliminary comparison between real-time in-vivo spectral and transverse oscillation velocity estimates

Mads Møller Pedersen, Michael Johannes Pihl, Per Haugaard, Jens Munk Hansen, Kristoffer Lindskov Hansen, Michael Bachmann Nielsen, Jørgen Arendt Jensen

Proceedings Volume 7968, 79680K (2011) https://doi.org/10.1117/12.877221

KEYWORDS: Picosecond phenomena, Arteries, Ultrasonography, Blood circulation, Blood, Data acquisition, Transducers, In vivo imaging, Scanners, Diagnostics

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Proceedings Article | 26 March 2011 Paper

An object-oriented multi-threaded software beamformation toolbox

Jens Munk Hansen, Martin Christian Hemmsen, Jørgen Arendt Jensen

Proceedings Volume 7968, 79680Y (2011) https://doi.org/10.1117/12.878178

KEYWORDS: Apodization, Ultrasonography, Transducers, Phased arrays, MATLAB, C++, Signal processing, Software development, Scanners, Optical simulations

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Proceedings Article | 16 March 2011 Paper

Simulation of ultrasound backscatter images from fish

An Hoai Pham, Bjarne Stage, Martin Christian Hemmsen, Bo Lundgren, Mads Møller Pedersen, Tina Bock Pedersen, Jørgen Arendt Jensen

Proceedings Volume 7961, 796152 (2011) https://doi.org/10.1117/12.878012

KEYWORDS: Computed tomography, Transducers, Acoustics, Ultrasonography, Scanners, Image segmentation, Backscatter, X-ray computed tomography, Tissues, Bone

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Proceedings Article | 12 March 2010 Paper

Ultrasound image quality assessment: a framework for evaluation of clinical image quality

Martin Christian Hemmsen, Mads Møller Petersen, Svetoslav Ivanov Nikolov, Michael Backmann Nielsen, Jørgen Arendt Jensen

Proceedings Volume 7629, 76290C (2010) https://doi.org/10.1117/12.840664

KEYWORDS: Scanners, Image quality, Ultrasonography, Data acquisition, Image quality standards, Image processing, Diagnostics, Statistical analysis, Transducers, MATLAB

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Proceedings Article | 13 March 2008 Paper

Simulation of microbubble response to ambient pressure changes

Klaus Scheldrup Andersen, Jørgen Arendt Jensen

Proceedings Volume 6920, 692016 (2008) https://doi.org/10.1117/12.773296

KEYWORDS: Acoustics, Ultrasonography, Blood pressure, Computer simulations, Liquids, Motion models, Rectangular pulse, Diagnostics, Arteries, In vivo imaging

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Proceedings Article | 12 March 2007 Paper

Coded ultrasound for blood flow estimation using subband processing

Fredrik Gran, Jesper Udesen, Michael Bachmann Nielsen, Jørgen Arendt Jensen

Proceedings Volume 6513, 651309 (2007) https://doi.org/10.1117/12.703345

KEYWORDS: Ultrasonography, Transducers, Signal to noise ratio, Amplifiers, Electronic filtering, Optical filters, Blood circulation, Blood, Signal processing, Spatial resolution

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Proceedings Article | 12 March 2007 Paper

In vivo examples of synthetic aperture vector flow imaging

Niels Oddershede, Kristoffer Lindskov Hansen, Michael Bachmann Nielsen, Jørgen Arendt Jensen

Proceedings Volume 6513, 65130A (2007) https://doi.org/10.1117/12.706467

KEYWORDS: Arteries, Transducers, Image resolution, In vivo imaging, Data acquisition, Ultrasonography, Veins, Optical filters, Scanners, Image processing

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Proceedings Article | 12 March 2007 Paper

Effective and versatile software beamformation toolbox

Jacob Kortbek, Svetoslav Nikolov, Jørgen Arendt Jensen

Proceedings Volume 6513, 651319 (2007) https://doi.org/10.1117/12.702996

KEYWORDS: Apodization, Phased arrays, Transducers, Ultrasonography, MATLAB, C++, Signal processing, Image processing, Image quality, Wave propagation

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Delay-and-sum array beamforming is an essential part of signal processing in ultrasound imaging. Although the principles are simple, there are many implementation details to consider for obtaining a reliable and computational efficient beamforming. Different methods for calculation of time-delays are used for different waveforms. Various inter-sample interpolation schemes such as FIR-filtering, polynomial, and spline interpolation can be chosen. Apodization can be any preferred window function of fixed size applied on the channel signals or it can be dynamic with an expanding and contracting aperture to obtain a preferred constant F-number. An effective and versatile software toolbox for off-line beamformation designed to address all of these issues has been developed. It is capable of exploiting parallelization of computations on a Linux cluster and is written in C++ with a MATLAB(MathWorks Inc.) interface. It is an aid to support simulations and experimental investigation of 3D imaging, synthetic aperture imaging, and directional flow estimation. A number of parameters are necessary to fully define the spatial beamforming and some parameters are optional. All spatial specifications are given in 3D space such as the physical positions of the transducer elements during transmit and receive and the positions of the points to beamform. The points of focus are defined as a collection of lines each having an origin, a direction, a distance between points and a length. The transducer, the points to beamform, and the apodization are defined as individual objects and a combination of these define the actual beamforming. Once the beamforming is defined, the time-delays and apodization values for every combination of transmit elements, receive elements and focus points can be calculated and stored in lookup-tables (LUT). Parametric beamforming can also be applied where calculations are done by demand, thus, reducing the storage demand dramatically. On a standard PC with a Pentium 4, 2.66 GHz processor running Linux the toolbox can beamform 100,000 points in lines of various directions in 20 seconds using a transducer of 128 elements, dynamic apodization and 3rd order polynomial interpolation. This is a decrease in computation time of at least a factor of 15 compared to an implementation directly in MATLAB of a similar beamformer.

Proceedings Article | 16 March 2006 Paper

Recursive delay calculation unit for parametric beamformer

Svetoslav Nikolov, Jørgen Jensen, Borislav Tomov

Proceedings Volume 6147, 61470D (2006) https://doi.org/10.1117/12.653573

KEYWORDS: Phased arrays, Field programmable gate arrays, Point spread functions, Transducers, Clocks, Imaging arrays, Synthetic aperture imaging, Error analysis, Image quality, Image transmission

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Proceedings Article | 16 March 2006 Paper

Plane wave fast color flow mode imaging: a parameter study

Ibrahim Bolic, Jesper Udesen, Fredrik Gran, Jørgen Jensen

Proceedings Volume 6147, 61470U (2006) https://doi.org/10.1117/12.653461

KEYWORDS: Ultrasonography, Transducers, Blood, Color imaging, Tissues, Blood circulation, Signal to noise ratio, Blood vessels, Image acquisition, Filtering (signal processing)

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Proceedings Article | 12 April 2005 Paper

Experimental investigation of synthetic aperture flow angle estimation

Niels Oddershede, Jorgen Jensen

Proceedings Volume 5750, (2005) https://doi.org/10.1117/12.592384

KEYWORDS: Transducers, Ultrasonography, Image resolution, Blood circulation, Virtual point source, Signal to noise ratio, Synthetic aperture imaging, Blood, Water, Velocity measurements

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Proceedings Article | 12 April 2005 Paper

Fast color flow mode imaging using plane wave excitation and temporal encoding

Jesper Udesen, Fredrik Gran, Jorgen Jensen

Proceedings Volume 5750, (2005) https://doi.org/10.1117/12.592394

KEYWORDS: Transducers, Ultrasonography, Signal to noise ratio, Scanners, Blood, Point spread functions, Apodization, Image transmission, Color imaging, Computer programming

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Proceedings Article | 12 April 2005 Paper

Spatio-temporal encoding using narrow-band linear frequency modulated signals in synthetic aperture ultrasound imaging

Fredrik Gran, Jorgen Jensen

Proceedings Volume 5750, (2005) https://doi.org/10.1117/12.592352

KEYWORDS: Transmitters, Signal to noise ratio, Computer programming, Optical filters, Ultrasonography, Transducers, Modulation, Point spread functions, Electronic filtering, Acoustics

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Proceedings Article | 28 April 2004 Paper

Preliminary in-vivo evaluation of convex array synthetic aperture imaging

Morten Pedersen, Kim Gammelmark, Jørgen Jensen

Proceedings Volume 5373, (2004) https://doi.org/10.1117/12.535084

KEYWORDS: Ultrasonography, Image quality, In vivo imaging, Image resolution, Medical imaging, Spherical lenses, Transducers, Imaging arrays, Synthetic aperture imaging, Image transmission

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Proceedings Article | 28 April 2004 Paper

Method for in-vivo synthetic aperture B-flow imaging

Jorgen Jensen

Proceedings Volume 5373, (2004) https://doi.org/10.1117/12.536394

KEYWORDS: Image resolution, Tissues, Blood, Linear filtering, Image filtering, Data acquisition, Electronic filtering, Arteries, In vivo imaging, Ultrasonography

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Proceedings Article | 28 April 2004 Paper

An in vitro investigation of transverse flow estimation

Jesper Udesen, Jorgen Jensen

Proceedings Volume 5373, (2004) https://doi.org/10.1117/12.535233

KEYWORDS: Ultrasonography, Blood, Arteries, Point spread functions, Scanners, Transducers, In vivo imaging, Data acquisition, Phased arrays, Apodization

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Proceedings Article | 28 April 2004 Paper

Compact implementation of dynamic receive apodization in ultrasound scanners

Borislav Tomov, Jørgen Jensen

Proceedings Volume 5373, (2004) https://doi.org/10.1117/12.532957

KEYWORDS: Apodization, Point spread functions, Phased arrays, Ultrasonography, Transducers, Logic, Scanners, Optical simulations, Field programmable gate arrays, Image quality

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Proceedings Article | 28 April 2004 Paper

A code division technique for multiple element synthetic aperture transmission

Fredrik Gran, Jorgen Jensen, Andreas Jakobsson

Proceedings Volume 5373, (2004) https://doi.org/10.1117/12.535222

KEYWORDS: Transmitters, Receivers, Image transmission, Ultrasonography, Signal to noise ratio, Point spread functions, Transducers, Image resolution, Systems modeling, Solids

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Proceedings Article | 23 May 2003 Paper

Delay generation methods with reduced memory requirements

Borislav Tomov, Jorgen Jensen

Proceedings Volume 5035, (2003) https://doi.org/10.1117/12.479957

KEYWORDS: Phased arrays, Ultrasonography, Transducers, Clocks, Algorithm development, Logic, Imaging arrays, Detection and tracking algorithms, Field programmable gate arrays, Surgery

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Proceedings Article | 11 April 2002 Paper

Modeling of higher harmonics formation in medical ultrasound systems

Louise Kold Taylor, Malene Schlaikjer, Joergen Jensen

Proceedings Volume 4687, (2002) https://doi.org/10.1117/12.462186

KEYWORDS: Transducers, Wave propagation, Ultrasonography, Signal attenuation, Diffraction, Chemical elements, Acoustics, Multi-element lenses, Systems modeling, Tissues

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Proceedings Article | 11 April 2002 Paper

Should compression of coded waveforms be done before or after focusing?

Rasmus Bjerngaard, Joergen Jensen

Proceedings Volume 4687, (2002) https://doi.org/10.1117/12.462176

KEYWORDS: Transducers, Convolution, Tissues, Chemical elements, Signal to noise ratio, Ultrasonography, In vivo imaging, Abdomen, Scanners, Fermium

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Proceedings Article | 11 April 2002 Paper

Virtual ultrasound sources in high-resolution ultrasound imaging

Svetoslav Nikolov, Joergen Jensen

Proceedings Volume 4687, (2002) https://doi.org/10.1117/12.462178

KEYWORDS: Transducers, Wavefronts, Point spread functions, Ultrasonography, Image resolution, Imaging arrays, Virtual reality, Spherical lenses, Signal to noise ratio, Wave propagation

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Proceedings Article | 11 April 2002 Paper

Multi-element synthetic transmit aperture imaging using temporal encoding

Kim Gammelmark, Joergen Jensen

Proceedings Volume 4687, (2002) https://doi.org/10.1117/12.462168

KEYWORDS: Imaging arrays, Signal to noise ratio, Fermium, Frequency modulation, Image resolution, Ultrasonography, Spatial resolution, Multi-element lenses, Transducers, Signal attenuation

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Proceedings Article | 11 April 2002 Paper

New coding concept for fast ultrasound imaging using pulse trains

Thanasis Misaridis, Joergen Jensen

Proceedings Volume 4687, (2002) https://doi.org/10.1117/12.462187

KEYWORDS: Ultrasonography, Frequency shift keying, Signal attenuation, Signal processing, Electronic filtering, Transducers, Image transmission, Modulation, Phase shift keying, Spherical lenses

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Proceedings Article | 11 April 2002 Paper

Comparison between different encoding schemes for synthetic aperture imaging

Svetoslav Nikolov, Joergen Jensen

Proceedings Volume 4687, (2002) https://doi.org/10.1117/12.462151

KEYWORDS: Computer programming, Signal to noise ratio, Ultrasonography, Image resolution, In vivo imaging, Fermium, Frequency modulation, Chemical elements, Image quality, Transducers

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Proceedings Article | 30 May 2001 Paper

Performance of velocity vector estimation using an improved dynamic beamforming setup

Peter Munk, Joergen Jensen

Proceedings Volume 4325, (2001) https://doi.org/10.1117/12.428199

KEYWORDS: Acoustics, Wave propagation, Phased arrays, Ultrasonography, Transducers, Apodization, Modulation, Arteries, Point spread functions

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Estimation of velocity vectors using transverse spatial modulation has previously been presented. Initially, the velocity estimation was improved using an approximated dynamic beamformer setup instead of a static combined with a new velocity estimation scheme. A new beamformer setup for dynamic control of the acoustic field, based on the Pulsed Plane Wave Decomposition (PPWD), is presented. The PPWD gives an unambiguous relation between a given acoustic field and the time functions needed on an array transducer for transmission. Applying this method for the receive beamformation results in a setup of the beamformer with different filters for each channel for each estimation depth. The method of the PPWD is illustrated by analytical expressions of the decomposed acoustic field and these results are used for simulation. Results of velocity estimates using the new setup are given on the basis of simulated and experimental data. The simulation setup is an attempt to approximate the situation present when performing a scanning of the carotid artery with a linear array. Measurement of the flow perpendicular to the emission direction is possible using the approach of transverse spatial modulation. This is most often the case in a scanning of the carotid artery, where the situation is handled by an angled Doppler setup in the present ultrasound scanners. The modulation period of 2 mm is controlled for a range of 20-40 mm which covers the typical range of the carotid artery. A 6 MHz array on a 128-channel system is simulated. The flow setup in the simulation is based on a vessel with a parabolic flow profile for a 60 and 90-degree flow angle. The experimental results are based on the backscattered signal from a sponge mounted in a stepping device. The bias and std. Dev. Of the velocity estimate are calculated for four different flow angles (50,60,75 and 90 degrees). The velocity vector is calculated using the improved 2D estimation approach at a range of depths.

Proceedings Article | 30 May 2001 Paper

Efficient focusing scheme for transverse velocity estimation using cross-correlation

Joergen Jensen

Proceedings Volume 4325, (2001) https://doi.org/10.1117/12.428200

KEYWORDS: Ultrasonography, Transducers, Signal to noise ratio, Apodization, Blood, Arteries, Correlation function, Interference (communication), Phased arrays, Medical imaging

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Proceedings Article | 1 May 1991 Paper

Sampling system for in vivo ultrasound images

Joergen Jensen, Jan Mathorne

Proceedings Volume 1444, (1991) https://doi.org/10.1117/12.45174

KEYWORDS: Transducers, Analog electronics, Ultrasonography, Signal processing, Scanners, Signal to noise ratio, In vivo imaging, Image processing, Amplifiers, Prototyping

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Showing 5 of 62 publications

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