||Hidetsugu UCHIDA, Kohei WAKAMIYA, Kaburagi Tokihiko, Improvement of measurement accuracy for the three-dimensional electromagnetic articulograph by optimizing the alignment of the transmitter coils, Acoustical Science and Technology, 37, 3, 106-114, 2016.05, The alignment of transmitter coils for the three-dimensional electromagnetic articulograph (3D-EMA), an instrument used to measure articulatory movements, was studied. Receiver coils of the 3D-EMA are used as position markers and are placed in alternating magnetic field produced by multiple transmitter coils. The estimation of the state (the position and orientation) of each receiver coil is based on the minimization of the signal error between the measured and predicted receiver signals using a model of the magnetic field. Previous studies report a noticeable increase in the position estimation error irrespective of small signal error at a specific portion of the measurement region. The existence of the non-uniqueness problem in the position estimation is hypothesized to be the cause of this problem. To resolve the problem, we optimized the alignment of the transmitter coils by maximizing the difference between the receiver signals for any pair of states in the measurement region and evaluated the alignment by performing computer simulations and actual measurement. As a result, a measurement accuracy of approximately 0.4 mm was obtained..
||Tokihiko KABURAGI, Kohei WAKAMIYA, Masaaki HONDA, Three-dimensional electromagnetic articulgoraphy: A measurement principle, J. Acoust. Soc. Am., 10.1121/1.1928707, 118, 1, 428-443, vol. 118(1), pp.428-443, 2005.07.
||Kohei WAKAMIYA, Takuya TSUJI and Tokihiko KABURAGI, Estimation of the vocal tract spectrum from the articulatory movement usnig phneme-dependent neural networks, Proceedings of International Conference of Spoken Language Processing 2004, TuB603-15, 2004.10.
||Kohei WAKAMIYA, Tokihiko KABURAGI and Masaaki HONDA, An investigation of the measurement accuracy on the three-dimensional electromagnetic articulography, Proceedings of the 6th International Seminar on Speech Production, 301-307, 2003.12.
||Tokihiko KABURAGI, Kohei WAKAMIYA and Masaaki HONDA, Three-dimensional electromagnetic articulograph based on a nonparametric representation of the magnetic field, Prec. International Conference on Spoken Language Processing, 2297-2300, 2002.09.
||Terumitsu TANAKA, Kohei WAKAMIYA and Toshiyuki SUZUKI, Read/Write Track Fringe Effect of Thin Film and MR Head with Different Pole Shapes, IEICE Transactions on Electronics, E82-C/12, 2165-2170, 1999.12.
||``Error Rate Performance of Viterbi Detection with Path-feedback in Digital Magnetic Recording,'' Yoshihiro OKAMOTO, Yusuke INAI, Kohei WAKAMIYA, Hidetoshi SAITO and Hisashi OSAWA, Memoirs of the Faculty of Engineering, Ehime University.