TY - GEN
T1 - A comparison between temporal and subband minimum variance adaptive beamforming
AU - Diamantis, Konstantinos
AU - Voxen, Iben H.
AU - Greenaway, Alan H.
AU - Anderson, Tom
AU - Jensen, Jørgen A.
AU - Sboros, Vassilis
PY - 2014/1/1
Y1 - 2014/1/1
N2 - 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 (0.14Î) 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.
AB - 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 (0.14Î) 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.
KW - adaptive beamforming
KW - covariance matrix
KW - medical ultrasound
KW - minimum variance
UR - http://www.scopus.com/inward/record.url?scp=84901813009&partnerID=8YFLogxK
U2 - 10.1117/12.2043602
DO - 10.1117/12.2043602
M3 - Conference contribution
AN - SCOPUS:84901813009
SN - 9780819498335
VL - 9040
BT - Medical Imaging 2014
PB - SPIE
ER -