Approach to 3-D ultrasound high resolution imaging for mechanically moving large-aperture transducer based upon Fourier transform

Abstract

A new three-dimensional (3-D) acoustic image formation technique is proposed that is based on the transmission of wide bandwidth pulse signals and the application of the 3-D fast Fourier transform. A solution to the Helmholz wave equation has been obtained using the Born approximation. The solution contains analytical expressions for the spatial spectra of the transmit and receive radiation patterns for transducers of various geometries with lenses of fixed focal distances. It has been shown that the proposed algorithms allow for radiation patterns with constant widths at depths both behind and in front of the focal point, starting practically from the plane of the transducer. The theoretical and experimental investigations and computer simulation for both spherical and rectangular transducer shapes have been performed. The results were used to estimate the beamwidths and the side lobe levels. A variant of the linear array has been studied for cylindrical lens of a fixed focal distance moving in a lateral direction. It has been shown that, in this case, a high resolution (of the order of a few wavelengths) can be achieved along all three Cartesian coordinates at a very high scanning velocity. The influence of the moving scatterers' velocity in inhomogeneous medium on the spatial radiation pattern characteristics has been estimated.

New radix-(2/spl times/2/spl times/2)/(4/spl times/4/spl times/4) and radix-(2/spl times/2/spl times/2)/(8/spl times/8/spl times/8) DIF FFT algorithms for 3-D DFT

“…We now give a brief scheme for the implementation of the proposed radix-FFT algorithm by considering the implementation of the butterfly given by (30) and (24). For a given combination of , by reading eight points from the off-chip memory according to (6) to compute the operation given by (5), we obtain the eight points given by (7). The first point of (7) is returned to the off-chip memory, whereas the other seven points are kept in the on-chip memory since they are used by the seven subbutterflies given by (24).…”

Ultrasound Sub-pixel Motion-tracking Method with Out-of-plane Motion Detection for Precise Vascular Imaging

“…Three-dimensional (3-D) tracking (Byram et al 2010) using volume data is a solution to measure the out-of-plane motion. Various groups have proposed matrix transducers (Benenson et al 2002;Karaman et al 2009;Bhuyan et al 2013) and developed novel methods of beamforming (Yang et al 2015;Burshtein et al 2016) to obtain high-quality volumetric images. Small-vascular imaging by the image-processing techniques using multiple frames, like PH or FA, requires the data sets with high-resolution, deeppenetration and high-frame-rate.…”

High-resolution and fast 3D ultrasonic imaging technique

“…After focusing by the algorithm based on the 3D Fourier transform [4], the resolution at far distances will be about 2 z L λ , i.e., 2 times higher than that in a conventional technique of dynamic focusing on receiving by a phased array.…”

“…The drawback of the 4-array probe is that the virtual array formed according to (4) has a hole at the center by the η coordinate of size 2a . This results in a high side lobe level.…”

“…for the virtual array data that cannot be obtained from other 4 sets of source signals.The signal processing algorithm consists of the following stages: fast Fourier transform by time of the received signals; forming subapertures from the original array elements (3); dividing the + ; forming the virtual array signals l S % (5); forming the signals S % ; implementing the focusing algorithm based upon 3D Fourier transforms[4]; visualization of the 3D image.…”