| 摘要 |
PROBLEM TO BE SOLVED: To estimate the position of a sound source by precisely measuring an arriving time of sound generated from coils incorporated in an MRI system even under environment where the operating sound of a cooling machine is loud. SOLUTION: In a test before operating the MRI system, a transmission function of the sound of the cooling machine is calculated in advance from an acoustic signal measured by a sensor 11 for the sound of the cooling machine and an acoustic signal measured by sensors 12(1) to (n) for coil sound while the cooling machine 7 operates and the coils 5 and 6 are not exited. While the MRI equipment operates, the transmission function calculated in advance is multiplied to the sound of the cooling machine measured by the sensor 11 to estimate the noise of the cooling machine at the sensors 12(1) to (n) for measuring the coil sound, estimated noise is subtracted from the acoustic signal measured by sensors 12(1) to (n) for coil sound to clarify the sound generated at the coils, and thereafter the arriving time of the acoustic signal is measured precisely to estimate the position of the sound source. COPYRIGHT: (C)2007,JPO&INPIT
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