title: Analysis of superimposed ultrasonic guided waves in long bones by the joint approximate diagonalization of eigen-matrices algorithm.
abstract: The parameters of ultrasonic guided waves (GWs) are very sensitive to mechanical and structural changes in long cortical bones. However, it is a challenge to obtain the group velocity and other parameters of GWs because of the presence of mixed multiple modes. This paper proposes a blind identification algorithm using the joint approximate diagonalization of eigen-matrices (JADE) and applies it to the separation of superimposed GWs in long bones. For the simulation case, the velocity of the single mode was calculated after separation. A strong agreement was obtained between the estimated velocity and the theoretical expectation. For the experiments in bovine long bones, by using the calculated velocity and a theoretical model, the cortical thickness (CTh) was obtained. For comparison with the JADE approach, an adaptive Gaussian chirplet time-frequency (ACGTF) method was also used to estimate the CTh. The results showed that the mean error of the CTh acquired by the JADE approach was 4.3%, which was smaller than that of the ACGTF method (13.6%). This suggested that the JADE algorithm may be used to separate the superimposed GWs and that the JADE algorithm could potentially be used to evaluate long bones.
authors.affiliation: Department of Electronic Engineering, Fudan University, Shanghai, China.
authors.forename: Xiaojun
authors.initials: X
authors.lastname: Song
authors.forename: Dean
authors.initials: D
authors.lastname: Ta
authors.forename: Weiqi
authors.initials: W
authors.lastname: Wang
mesh_terms: D000465:Algorithms; D000818:Animals; D001842:Bone and Bones / Q000000981:diagnostic imaging; D002417:Cattle; D012815:Signal Processing, Computer-Assisted; D059629:Signal-To-Noise Ratio; D013977:Tibia / Q000000981:diagnostic imaging*; D014463:Ultrasonography