Apparatus for analyzing an audio signal with regard to rhythm information of the audio signal by using an autocorrelation function

US7012183B2 · kind B2 · utility

Assignee

• Fraunhofer-Gesellschaft zur förderung der angewandten Forschung e.V. · DE

Inventors

• Jürgen Herre · Buckenhof, DE
• Jan Rohden · Ilmenau, DE
• Christian Uhle · Nuremberg, DE
• Markus K. Cremer · Orinda, US

Key dates

• Filing date: Nov 14, 2003
• Grant date: Mar 14, 2006
• Expiry date: Feb 10, 2024

Classification

• Technology area (CPC G): Physics
• CPC primary: G10L25/90
• WIPO field: Computer technology
• WIPO sector: Electrical engineering

Abstract

An apparatus for analyzing an audio signal with regard to rhythm information of the audio signal by using an autocorrelation function comprises a filter bank for separating the audio signal into at least two sub-band signals. The sub-band signals are examined with regard to periodicities by an autocorrelation function, to obtain rhythm raw-information for the at least two sub-band signals. To reduce or eliminate the ambiguities of the autocorrelation function for periodical signals, the rhythm raw-information is postprocessed to obtain post-processed rhythm raw-information for the sub-band signal. The rhythm information of the audio signal is established based on the postprocessed rhythm raw-information. By the sub-band-wise ACF postprocessing, ACF ambiguities are already eliminated where they originate, and rhythm portions are added at double tempi, which an autocorrelation function processing does normally not provide, so that, as a result, a more robust determination of the rhythm information of the audio signal arises.