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Active Noise Control for MRI inner cavity
Recently, MRI (Magnetic Resonance Imaging) devices are used in many medical institutions. The performance of MRI has been improved, that means higher resolution, faster scanning and so on. However, it also generates serious noises (max 130 dB), and could make the patient unpleasant, in addition, there is a possibility of causing a temporary hearing loss. The simplest form of hearing protection is the wearing of (passive) ear protection such as ear plugs or full ear defenders. The use of passive ear protection, however, is not a complete solution. In general, frequencies above 1000 Hz are adequately attenuated by around 30 dB by ear protection, but lower frequencies are attenuated by around 10 dB. Only part of the problem is solved. In this project, an overall method for MRI noise reduction by active noise control has been researched and developed.

Fig 1. Reducing MR noise around Target zone by generating anti-noise from outside speaker sources on the ground of prediction about target zone sound field by representative points.