Measuring 3D velocity vectors using the Transverse Oscillation method

Abstract

Abstract-Experimentally obtained estimates of threedimensional (3D) velocity vectors using the 3D Transverse Oscillation (TO) method are presented. The method employs a 2D transducer and synthesizes two double-oscillating fields in receive to obtain the axial, transverse, and elevation velocity components simultaneously. Experimental data are acquired using the ultrasound research scanner SARUS. The double-oscillating TO fields are investigated in an experimental scanning tank setup. The results demonstrate that the created fields only oscillate in the axial plus either the transverse or the elevation direction. Velocity measurements are conducted in an experimental flow-rig with steady flow in two different directions (mainly in x or y direction). Velocity estimates are obtained along the z axis. All three velocity components (vx, vy, vz) are measured with relative biases and standard deviations (normalized to expected value) below 5% and 12%, respectively. For an expected velocity magnitude of 25.2 cm/s, the method estimates 24.4±3.1 cm/s and 25.1±1.9 cm/s for the two directions. Under similar conditions, Field II simulations yield 25.1±1.5 cm/s and 25.4±1.6 cm/s. The experimental results validate the results obtained through simulations and verify that the 3D TO method estimates the full 3D velocity vectors simultaneously as well as the correct velocity magnitudes.

A transverse oscillation approach for estimation of three-dimensional velocity vectors, Part II: experimental validation

“…The measured fields exhibit the expected trends, and a comparison with simulated results [31] using the same parameter settings shows comparable results.…”

Non-invasive measurement of pressure gradients using ultrasound

“…This makes the estimator vulnerable in complex flow environments that has vector velocity components in all three spatial direction. However, Pihl and Jensen 28,29 recently presented a novel technique for measuring the out-of-plane velocity using an ultrasound system. Exploiting this technique, would yield three-dimensional vector velocity fields that could easily be included in the suggested pressure gradient estimator, leaving no-need for assuming that v y is zero.…”

New developments in vector velocity imaging using the transverse oscillation approach

“…This can be accomplished by using a 32 x 32 elements phased array matrix probe and sending out a weakly focused field. 37,38 Five lines are then beamformed in parallel during receive processing to generate signals for finding the axial velocity component v z , the lateral velocity component v x , and the elevation component v y . For the last two components the TO approach is used, and in-phase and quadrature beams are focused in the lateral direction for finding v x together with the in-phase and quadrature beams in the elevation direction for finding v y .…”

“…40 A weakly focused ultrasound field is emitted and the RF signals from all 1024 elements are stored in memory and then beamformed off-line. 38 Data has been acquired from stationary parabolic flow in a flow rig, and the resulting profiles are shown in Fig. 12 for all three velocity components for simulated data (left columns) and measured data (right columns).…”