An object-oriented multi-threaded software beamformation toolbox

Hansen, Jens Munk; Hemmsen, Martin Christian; Jensen, Jørgen Arendt

doi:10.1117/12.878178

Cited by 51 publications

(37 citation statements)

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“…Using the simulation software Field II [5], [6] data were acquired for five steering angles (0, ±2, ±4 degrees) using a cyst phantom containing echoic and anechoic cysts of different sizes at depths of 40, 50, 60, 70, and 80 mm. The beamformation is carried out using the Beamformation Toolbox III [7]. CNR and SNR are calculated for B-mode images with 60 dB dynamic range.…”

Section: Methodsmentioning

confidence: 99%

Compound imaging using Synthetic Aperture Sequential Beamformation

Jensen

Hemmsen

et al. 2011

2011 IEEE International Ultrasonics Symposium

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Abstract-Synthetic Aperture Sequential Beamforming (SASB) is a technique with low complexity and the ability to yield a more uniform lateral resolution with range. However, the presence of speckle artifacts in ultrasound images degrades the contrast. In conventional imaging speckle is reduced by using spatial compounding at the cost of a reduced frame rate. The objective is to apply spatial compounding to SASB and evaluate if the images have a reduced speckle appearance and thereby an improved image quality in terms of contrast compared to ordinary SASB. Using the simulation software Field II, RF data are acquired for a phantom with cysts at different sizes and scattering levels. 192 scanlines are recorded for five steering angles (0, ±2, ±4 degrees) using a 192 element linear array transducer. SASB is performed for each angle using a rectangular grid in the second stage beamformation. After envelope detection the five second stage images are added to form the compounded image. Using a ProFocus scanner and the 8804 linear array transducer (BK Medical, Herlev, Denmark) measurements of a phantom containing water filled cysts are obtained to validate the simulation results. The setup is the same as in the simulations and SASB second stage beamformation data are processed offline for each of the five angles. Contrast-to-noise ratio (CNR) and speckle-to-noise ratio (SNR) are extracted for the compounded image and the reference image (ordinary SASB). CNR was calculated for the simulated cysts at depths of 40, 50, 60, 70 and 80 mm. On average the CNR was improved by 33.2% compared to the values obtained from the reference image. For regions of increasing depth SNR was on average increased by 9.3%. Results from the simulation were confirmed by calculations on the measured data. CNR of cysts at depths from 18 to 78 mm with a separation of 10 mm was on average improved by 45.9%. On average an improvement of 16.6% in SNR was obtained. The calculations along with visual inspection revealed larger improvements in deeper regions, and the compounded image for the measured phantom showed a 3 mm diameter cyst not detectable in the reference image. Compounding applied to SASB improves CNR and SNR results in images with a reduced speckle appearance. This was shown for simulations and confirmed on measured data.

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Section: Methodsmentioning

confidence: 99%

Compound imaging using Synthetic Aperture Sequential Beamformation

Jensen

Hemmsen

et al. 2011

2011 IEEE International Ultrasonics Symposium

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“…Received signals from all elements were stored for each emission and beamformation were performed using the BFT3 toolbox. 12 The beamformed low-resolution images were subsequently combined to high-resolution images. Several high-resolution images were generated by varying maximum beam steered angle (α max ) and the number of emissions (N ).…”

Section: Simulationsmentioning

confidence: 99%

Optimization of synthetic aperture image quality

et al. 2016

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Synthetic Aperture (SA) imaging produces high-quality images and velocity estimates of both slow and fast flow at high frame rates. However, grating lobe artifacts can appear both in transmission and reception. These affect the image quality and the frame rate. Therefore optimization of parameters effecting the image quality of SA is of great importance, and this paper proposes an advanced procedure for optimizing the parameters essential for acquiring an optimal image quality, while generating high resolution SA images. Optimization of the image quality is mainly performed based on measures such as F-number, number of emissions and the aperture size. They are considered to be the most contributing acquisition factors in the quality of the high resolution images in SA. Therefore, the performance of image quality is quantified in terms of full-width at half maximum (FWHM) and the cystic resolution (CTR). The results of the study showed that SA imaging with only 32 emissions and maximum sweep angle of 22 degrees yields a very good image quality compared with using 256 emissions and the full aperture size. Therefore the number of emissions and the maximum sweep angle in the SA can be optimized to reach a reasonably good performance, and to increase the frame rate by lowering the required number of emissions. All the measurements are performed using the experimental SARUS scanner connected to a λ/2-pitch transducer. A wire phantom and a tissue mimicking phantom containing anechoic cysts are scanned using the optimized parameters for the transducer. Measurements coincide with simulations.

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“…The data were processed using the BFT3 toolbox [10] in Matlab, and the velocity vector was found using the estimator from [11]. Echo canceling was performed by averaging across all emissions and then subtracting this from the signals.…”

Section: Measurement Setup and Processingmentioning

confidence: 99%

In-vivo convex array vector flow imaging

Jensen

Brandt

Nielsen

2014

2014 IEEE International Ultrasonics Symposium

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Abstract-In-vivo VFI scans obtained from the abdomen of a human volunteer using a convex array transducers and transverse oscillation vector flow imaging (VFI) are presented. A 3 MHz BK Medical 8820e (Herlev, Denmark) 192-element convex array probe is used with the SARUS experimental ultrasound scanner. A sequence with a 129-line B-mode image is followed by a VFI sequence in 17 directions with 32 emissions in each direction. The pulse repetition frequency was set to 5 kHz, and the intensity and MI were measured with the Acoustic Intensity Measurement System AIMS III (Onda, Sunnyvale, California, USA). The derated I spta.3 was 79.7 mW/m 2 and MI was 1.32, which are within FDA limits for abdominal scans. The right liver lobe of a 28-year healthy volunteer was scanned with a view of the main portal vein and vena cava inferior at a frame rate of 7.4 Hz. Thirty frames were acquired, giving 4 seconds of data. For this volunteer the duration corresponded to roughly 3 heartbeats. The velocities were found at a beam-to-flow angle of 72 ± 21 • , where a conventional CFM scan would yield poor results. Three VF images from the same position in the cardiac cycle were investigated and the mean lateral velocities were -0.079, -0.081 and -0.080 m/s showing the consistence of the in-vivo results.

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An object-oriented multi-threaded software beamformation toolbox

Cited by 51 publications

References 0 publications

Compound imaging using Synthetic Aperture Sequential Beamformation

Compound imaging using Synthetic Aperture Sequential Beamformation

Optimization of synthetic aperture image quality

In-vivo convex array vector flow imaging

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