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Visualizing Audio for Anomaly Detection. Mark Hasegawa-Johnson, Camille Goudeseune, Hank Kaczmarski, Thomas Huang, David Cohen, Xiaodan Zhuang, Xi Zhou, and Kyung-Tae Kim. Research Goals. Problem: Microphones are cheap, yet they are rarely used in security installations.
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Visualizing Audio for Anomaly Detection • Mark Hasegawa-Johnson, Camille Goudeseune, Hank Kaczmarski, Thomas Huang, David Cohen, Xiaodan Zhuang, Xi Zhou, and Kyung-Tae Kim
Research Goals • Problem: Microphones are cheap, yet they are rarely used in security installations. • Interactive browsing is difficult: Audio is hard to browse much faster than real-time • Automatic acoustic event detection (AED) is nearly useless: many false alarms Proposal: Best of both worlds • Use probabilistic features (AED) to color-code audio segments, guiding analysts to pieces worth closer study
Dataset #1: Meeting Room Audio 30 annotators, 24 hours of data, 14 acoustic events
Dataset #2: Willard Airport • 24 hours of audio, `labeled' by commercial airplane takeoff & landing records (inadequate!)
Data Representations #1: Multiscale FFT • Problem: Short-time Fourier transforms with sizes N1, N2, N3, … require O{T(log2N1+log2N2+log2N3+...)}, T=audio filesize, N=FFT size • Solution: XN(2k) = XN/2,1(k)+XN/2,2(k)
Data Representations #2: Bayesian Feature Selection • Problem: Best features for nonspeech acoustic event detection are unknown (different from speech), different for different classes of acoustic events • Solution: Select the best features from a big pile, according to a minimum-Bayes-risk selection criterion
Testbed #1: Portable Multi-Day Audio Timeliner • Dramatis Personae: Emergency first responders (EFRs) • Analysis Object: One microphone, one month • Act 1, Scene 1: EFRs arrive on scene, download surveillance audio to a handheld • Objective: Event diagnosis, prognosis, & management
Testbed #2: 1000 Microphones = One Milliphone • Dramatis Personae: Command center data analysts • Analysis Object: 1000 microphones, 24 hours • Act 2, Scene 1: Analyst in a Virtual Reality Theater (the Beckman CUBE) seeks anomalies in a large dataset • Objective: Find the anomalies
Conclusions: Current Status of this Research, August 18 2009 • Results so far • Meeting room audio: transcription nearly complete. Airport audio: no transcriptions. • Data representations, Testbeds: separate prototypes exist • Ongoing research • Insert (Data Representations) into (Testbeds) • Create new data representations in order to improve testbed visualization • Formal human subject tests