Phase aberration correction for medical ultrasound systems has attracted a great deal of attention. Since phased array techniques are now widely employed for industrial non-destructive testing （NDT） applications in ...Phase aberration correction for medical ultrasound systems has attracted a great deal of attention. Since phased array techniques are now widely employed for industrial non-destructive testing （NDT） applications in various fields, the problem of phase aberrations in the process of NDT testing is considered. The technique of cross-covariance for phase aberration correction is presented. The performance of the technique for phase aberration correction is tested by means of echo signals obtained in practical non-destructive testing experiment. The results show that the technique has the better accuracy of phase correction.展开更多
A coherence-based correction method was proposed in order to improve the lateral resolution and enhance the contrast of medical ultrasound imaging in the presence of phase aberration. The averaged coherence factor was...A coherence-based correction method was proposed in order to improve the lateral resolution and enhance the contrast of medical ultrasound imaging in the presence of phase aberration. The averaged coherence factor was proposed at first and used as a metric to evaluate phase aberration correction. By maximizing the averaged coherence factor, the time delay parameter of each channel was adjusted. A new set of coherence factors was calculated and the corrected data was optimized to form the final B-mode image. The simulations on point targets and a cyst phantom showed that the proposed method outperformed the nearest neighboring cross correlation method and conventional coherence-weighting method, and the lateral resolution and contrast ratio was improved by approximately 0.24mm and 18dB respectively. The proposed method combined the advantages of phase error correction and coherence-weighting, which could improve imaging qualities effectively in medical ultrasound.展开更多
This article theoretically studies the influence of inhomogeneous abdominal walls on focused therapeutic ultrasound based on the phase screen model. An inhomogeneous tissue is considered as a combination of a homogene...This article theoretically studies the influence of inhomogeneous abdominal walls on focused therapeutic ultrasound based on the phase screen model. An inhomogeneous tissue is considered as a combination of a homogeneous medium and a phase aberration screen. Variations of acoustic parameters such as peak positive pressure, peak negative pressure, and acoustic intensity are discussed with respect to the phase screen statistics of human abdominal walls. Results indicate that the abdominal wall can result in energy loss of the sound in the focal plane. For a typical human abdominal wall with correlation length of 7.9 mm and variance of 0.36, the peak acoustic intensity radiated from a 1MHz transmitter with a radius of 30 mm can be reduced by about 14% at the focal plane.展开更多
基金National Natural Science Foundation of China(No.61201412)Ntural Science Foundation of Shanxi Province(No.2012021011-5)
文摘Phase aberration correction for medical ultrasound systems has attracted a great deal of attention. Since phased array techniques are now widely employed for industrial non-destructive testing （NDT） applications in various fields, the problem of phase aberrations in the process of NDT testing is considered. The technique of cross-covariance for phase aberration correction is presented. The performance of the technique for phase aberration correction is tested by means of echo signals obtained in practical non-destructive testing experiment. The results show that the technique has the better accuracy of phase correction.
基金supported by the National Natural Science Foundation of China(11204346)
文摘A coherence-based correction method was proposed in order to improve the lateral resolution and enhance the contrast of medical ultrasound imaging in the presence of phase aberration. The averaged coherence factor was proposed at first and used as a metric to evaluate phase aberration correction. By maximizing the averaged coherence factor, the time delay parameter of each channel was adjusted. A new set of coherence factors was calculated and the corrected data was optimized to form the final B-mode image. The simulations on point targets and a cyst phantom showed that the proposed method outperformed the nearest neighboring cross correlation method and conventional coherence-weighting method, and the lateral resolution and contrast ratio was improved by approximately 0.24mm and 18dB respectively. The proposed method combined the advantages of phase error correction and coherence-weighting, which could improve imaging qualities effectively in medical ultrasound.
基金Project supported by the Program for New Century Excellent Talents in University of China (Grant No 06-0450)the National Natural Science Foundation of China (Grant No 10774071)the Natural Science Foundation of Jiangsu Province, China (Grant No BK2007518)
文摘This article theoretically studies the influence of inhomogeneous abdominal walls on focused therapeutic ultrasound based on the phase screen model. An inhomogeneous tissue is considered as a combination of a homogeneous medium and a phase aberration screen. Variations of acoustic parameters such as peak positive pressure, peak negative pressure, and acoustic intensity are discussed with respect to the phase screen statistics of human abdominal walls. Results indicate that the abdominal wall can result in energy loss of the sound in the focal plane. For a typical human abdominal wall with correlation length of 7.9 mm and variance of 0.36, the peak acoustic intensity radiated from a 1MHz transmitter with a radius of 30 mm can be reduced by about 14% at the focal plane.
