title: Perceptual effects of noise reduction by time-frequency masking of noisy speech.
abstract: Time-frequency masking is a method for noise reduction that is based on the time-frequency representation of a speech in noise signal. Depending on the estimated signal-to-noise ratio (SNR), each time-frequency unit is either attenuated or not. A special type of a time-frequency mask is the ideal binary mask (IBM), which has access to the real SNR (ideal). The IBM either retains or removes each time-frequency unit (binary mask). The IBM provides large improvements in speech intelligibility and is a valuable tool for investigating how different factors influence intelligibility. This study extends the standard outcome measure (speech intelligibility) with additional perceptual measures relevant for noise reduction: listening effort, noise annoyance, speech naturalness, and overall preference. Four types of time-frequency masking were evaluated: the original IBM, a tempered version of the IBM (called ITM) which applies limited and non-binary attenuation, and non-ideal masking (also tempered) with two different types of noise-estimation algorithms. The results from ideal masking imply that there is a trade-off between intelligibility and sound quality, which depends on the attenuation strength. Additionally, the results for non-ideal masking suggest that subjective measures can show effects of noise reduction even if noise reduction does not lead to differences in intelligibility.
authors.affiliation: Academic Medical Center, Clinical and Experimental Audiology, Meibergdreef 9, 1105 AZ, Amsterdam, The Netherlands. i.brons@amc.uva.nl
authors.forename: Inge
authors.initials: I
authors.lastname: Brons
authors.forename: Rolph
authors.initials: R
authors.lastname: Houben
authors.forename: Wouter A
authors.initials: WA
authors.lastname: Dreschler
mesh_terms: D000161:Acoustic Stimulation; D000465:Algorithms; D001302:Audiometry, Speech; D001309:Auditory Threshold; D003463:Cues; D005583:Fourier Analysis; D006801:Humans; D016014:Linear Models; D016015:Logistic Models; D009622:Noise / Q000009:adverse effects / Q000517:prevention & control*; D010470:Perceptual Masking; D012815:Signal Processing, Computer-Assisted; D013018:Sound Spectrography; D013061:Speech Acoustics; D013065:Speech Intelligibility; D013067:Speech Perception; D013997:Time Factors; D055815:Young Adult