时间：2025年12月21日 上午09点
地点：北区杨咏曼楼515室
报告内容简介：
Conventional velocity estimation techniques, such as the autocorrelation estimator, are designed to measure the mean motion velocity of scatterers. However, these traditional approaches are inherently limited, as they can only evaluate velocity components along the direction of ultrasound propagation, namely the axial direction. To overcome this drawback, many researchers have explored the development of angle-independent velocity estimation methods. Among them, the vector Doppler technique has gained significant attention. It reconstructs flow velocity vectors by combining axial velocity measurements obtained from multiple insonification directions. The autocorrelation method is widely utilized in this framework to determine axial velocities. In the vector Doppler approach, it is essential to know both the axial velocities and the corresponding insonification angles. Typically, the steering angles used in the beamforming process serve as these insonification angles. However, such angles can fluctuate owing to echo interference. In this study, we present an enhanced autocorrelation-based estimator within the vector Doppler framework. The proposed approach not only determines the center frequency along the axial direction but also estimates the insonification angle through multidimensional wavevector analysis using the autocorrelation principle. By accurately estimating the insonification angle, our method enables precise velocity vector estimation even when the insonification angle range is as narrow as 10 degrees.
主讲人：
Hideyuki Hasegawa (Member, IEEE) received the B.E. degree in electrical engineering and the M.E. and Ph.D. degrees in electronic engineering from Tohoku University, Sendai, Japan, in 1996, 1998, and 2001, respectively. From 2001 to 2002, he was a Postdoctoral Researcher at Tohoku University under the Research Fellowship for Young Scientists (PD) of the Japan Society for the Promotion of Science. He joined the Graduate School of Engineering, Tohoku University, as an Assistant Professor in 2002 and became an Associate Professor in 2007. In 2008, he also held a concurrent appointment with the Graduate School of Biomedical Engineering, Tohoku University. Since 2015, he has been a Full Professor with the Faculty of Engineering, University of Toyama, Toyama, Japan. His research interests include ultrasound beamforming and functional ultrasound imaging.
