Seminar - Ultrasonic Guided Dispersion Extraction and Its Application In the Long Bone evaluation by Dr. Kailiang XU
Date: 20 October 2015 (Tuesday)
Time: 11:00 am – 12:00 pm
Venue: EF305, The Hong Kong Polytechnic University
Recently, ultrasonic guided waves have been used to characterize long bones. The pilot system Azaleé has been design in the Laboratoire d’ Imagerie Biomedicine Paris 06. One of the most difficulties is to well extract the ultrasonic guided dispersion towards the real clinical application. A variety of processing techniques have been described to transform the data from the time-distance (t, x) space to the frequency¬wavenumber (f, k) space, leading to the velocity dispersion curves of guided waves. In order to enhance the extraction of the dispersion curves of low amplitude guided modes, a SVD-based de-noising method together with the multi-emitter and multi-receiver system has been proposed to improve the limits of the 2-D spatio¬temporal Fourier transform. However, whereas the relatively long duration of the recorded time signals ensures a high frequency resolution, the limited number of positions where these signals are recorded (a few tenths of points at best) still results in a much lower resolution on the k-axis. Recently, a signal processing techniques named as sparse inversion SVD (SI-SVD) method has been proposed to enhance the energy contrast for the accurate dispersion curves extraction. Some preliminary investigation of the in vivo measurement of the human radii will be illustrated to demonstrate the feasibility of the ultrasonic guided waves based long bone evaluation. Some other ongoing interesting works of the ultrasound bone measurement will also be briefly introduced.
Kailiang Xu was born in Zhejiang, China, in 1985. He received the PhD degree in biomedical engineering from Fudan University in 2012. He continued two years postdoctoral study there. Supported by the China Postdoctoral International Exchange Scholarship and EU Marie Skłodowska-Curie International Incoming Fellowship, he joined the Laboratoire d’Imagerie Biomedicale UPMC Univ Paris 06 as a joint post-doctor between the Fudan and Paris 06 since 2014. His research mainly focuses on ultrasound in biomedicine (mainly ultrasonic characterization of cortical bone) and NDT&E application, including the ultrasonic guided waves, resonant ultrasound spectroscopy and also the inverse problem involved in the ultrasound bio-marker extraction.