title: Towards undistorted and noise-free speech in an MRI scanner: correlation subtraction followed by spectral noise gating.
abstract: Noise cancellation in an MRI environment is difficult due to the high noise levels that are in the spectral range of human speech. This paper describes a two-step method to cancel MRI noise that combines operations in both the time domain (correlation subtraction) and the frequency domain (spectral noise gating). The resulting filtered recording has a noise power suppression of over 100 dB, a significant improvement over previously described techniques on MRI noise cancellation. The distortion is lower and the noise suppression higher than using spectral noise gating in isolation. Implementation of this method will aid in detailed studies of speech in relation to vocal tract and velopharyngeal function.
authors.affiliation: Department of Biomedical Engineering, University of Virginia, Charlottesville, Virginia 22902.
authors.forename: Joshua M
authors.initials: JM
authors.lastname: Inouye
authors.affiliation: Department of Biomedical Engineering, University of Virginia, Charlottesville, Virginia 22902.
authors.forename: Silvia S
authors.initials: SS
authors.lastname: Blemker
authors.affiliation: Department of Computer Science, University of Texas at Austin, Austin, Texas 78712.
authors.forename: David I
authors.initials: DI
authors.lastname: Inouye
mesh_terms: D000162:Acoustics; D000465:Algorithms; D016477:Artifacts; D004867:Equipment Design; D006801:Humans; D007830:Larynx / Q000033:anatomy & histology / Q000502:physiology*; D008279:Magnetic Resonance Imaging / Q000295:instrumentation*; D009622:Noise / Q000009:adverse effects / Q000517:prevention & control*; D010470:Perceptual Masking; D012815:Signal Processing, Computer-Assisted; D012984:Software; D013018:Sound Spectrography; D013061:Speech Acoustics; D013065:Speech Intelligibility; D013067:Speech Perception; D013068:Speech Production Measurement