1 / 13

Digital Audio Restoration

Digital Audio Restoration. Simon Godsill Signal Processing Group University of Cambridge www-sigproc.eng.cam.ac.uk/~sjg. Overview. Audio Restoration - motivation Audio Restoration in Cambridge 1984-2003 Review of core technologies Audio restoration - principles Advanced topics

Download Presentation

Digital Audio Restoration

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. Digital Audio Restoration Simon Godsill Signal Processing Group University of Cambridge www-sigproc.eng.cam.ac.uk/~sjg

  2. Overview • Audio Restoration - motivation • Audio Restoration in Cambridge 1984-2003 • Review of core technologies • Audio restoration - principles • Advanced topics • Emerging techniques

  3. Audio Restoration - motivation • Requirement to enhance material from • Sound Archives: • Historical disk remastering: • `Recent’ Magnetic Tape recordings: • Forensic recordings, …

  4. Audio Restoration in Cambridge • 1984-88 - British Library fundsresearch into restoration of archived gramophone recordings at Signal Processing Group with Prof. Peter Rayner. • 1988 Cambridge company spun-out: CEDAR Audio. First real-time de-hiss and de-click in 1990, using DSP hardware on a PC platform. • 1990 -- Research into advanced audio processing at Cambridge University - Godsill, Rayner, Wolfe, Fong, …

  5. Core Technologies • De-click, de-crackle • De-hiss • Resonant noise pulse removal

  6. De-click/de-crackle

  7. De-click/de-crackle • Time domain models for clicks and audio • Optimal detection and estimation of corrupted samples • Use fully Bayesian methods where time permits

  8. De-hiss * * • Frequency-domain methods predominate • Non-linear processing of spectral information to incorporate local temporal and frequency dependence • Time-domain model-based methods also developed (joint click/hiss removal) * Courtesy Patrick Wolfe – see www-sigproc.eng.cam.ac.uk/~pjw47

  9. Resonant noise pulses • Tone-arm resonance in the presence of breakages or other severe damage to gramophone disk grooves • Simplest methods subtract an averaged template for the transient • More sophisticated methods apply a stochastic model for the resonant system

  10. Low frequency noise pulse removal, contd.

  11. Advanced Topics • Bayesian statistical models • De-clipping/de-quantizing • Pitch variation defects (Wow)

  12. Future Directions

  13. Resources • `Digital Audio Restoration - a statistical model-based approach’ by Simon Godsill and Peter Rayner, Springer-Verlag 1998 • See www-sigproc.eng.cam.ac.uk/~sjg for extracts, publications and sound examples

More Related