TY - JOUR
T1 - Precise Time-of-Flight Calculation For 3-D Synthetic Aperture Focusing
AU - Andresen, Henrik
AU - Nikolov, Svetoslav
AU - Jensen, Jørgen Arendt
N1 - Copyright: 2009 IEEE. Personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution to servers or lists, or to reuse any copyrighted component of this work in other works must be obtained from the IEEE
PY - 2009
Y1 - 2009
N2 - Conventional linear arrays can be used for 3D ultrasound imaging, by moving the array in the elevation direction and stacking the planes in a volume. The point spread function (PSF) is larger in the elevation plane, as the aperture is smaller and has a fixed elevation focus. Resolution improvements in elevation can be achieved by applying synthetic aperture (SA) focusing to the beamformed in-plane RF-data. The proposed method uses a virtual source (VS) placed at the elevation focus for postbeamforming. This has previously been done in two steps, in plane focusing followed by SA post-focusing in elevation, because of a lack of a simple expression for the exact time of flight (ToF).
This paper presents a new method for calculating the ToF for a 3D case in a single step using a linear array. This method is more flexible than the previously proposed method and is able to beamform a fewer number of points much more efficiently.
The method is evaluated using both simulated data and phantom measurements using the RASMUS experimental scanner. Computational cost for the method is higher than the 2-step method for a full volume beamforming, but allows for a reduction by an order of magnitude if three planes are used for real-time visualization. In addition, the need for a temporary storage of beamformed data is removed.
AB - Conventional linear arrays can be used for 3D ultrasound imaging, by moving the array in the elevation direction and stacking the planes in a volume. The point spread function (PSF) is larger in the elevation plane, as the aperture is smaller and has a fixed elevation focus. Resolution improvements in elevation can be achieved by applying synthetic aperture (SA) focusing to the beamformed in-plane RF-data. The proposed method uses a virtual source (VS) placed at the elevation focus for postbeamforming. This has previously been done in two steps, in plane focusing followed by SA post-focusing in elevation, because of a lack of a simple expression for the exact time of flight (ToF).
This paper presents a new method for calculating the ToF for a 3D case in a single step using a linear array. This method is more flexible than the previously proposed method and is able to beamform a fewer number of points much more efficiently.
The method is evaluated using both simulated data and phantom measurements using the RASMUS experimental scanner. Computational cost for the method is higher than the 2-step method for a full volume beamforming, but allows for a reduction by an order of magnitude if three planes are used for real-time visualization. In addition, the need for a temporary storage of beamformed data is removed.
U2 - 10.1109/TUFFC.2009.1264
DO - 10.1109/TUFFC.2009.1264
M3 - Journal article
C2 - 19811991
SN - 0885-3010
VL - 56
SP - 1880
EP - 1887
JO - I E E E Transactions on Ultrasonics, Ferroelectrics and Frequency Control
JF - I E E E Transactions on Ultrasonics, Ferroelectrics and Frequency Control
IS - 9
ER -