System and method for automatic audio content analysis for word spotting, indexing, classification and retrieval

A computer-implemented method for analyzing an audio signal, comprising:

• detecting audio events in one or more intervals of the audio signal, each interval including a temporal sequence of one or more segments;
• analyzing the audio events to identify speech boundaries with associated speech confidence levels;
• indexing the audio signal based on the speech boundaries and confidence levels using heuristically determined rules to improve precision;
• indexing alternatives to at least one recognized word in the audio signal along with an associated weight to improve recall;
• and
• undertaking one or more of:
• word spotting, summarizing, and skimming, the audio signal using the indexing thereof.

A computer including a data storage device including a computer usable medium having computer usable code means for classifying and indexing at least one audio signal representing an audio event, the computer usable code means having:

• logic means for rendering the audio signal into intervals, each interval including one or more segments;
• logic means for determining whether the segments of an interval exhibit one or more predetermined audio features, each audio feature being representative of at least one respective audio event;
• logic means for classifying the intervals by associating the intervals with respective audio events in response to the means for determining;
• logic means for determining whether at least one group of intervals matches a meta pattern in a predefined set of meta patterns;
• logic means for associating the group of intervals with a meta pattern classification when it is determined that the group of intervals matches a meta pattern;
• and
• logic means for indexing the audio signal based on interval classifications and meta pattern classifications.

A computer program product comprising:

• a computer program storage device readable by a digital processing apparatus;
• and
• a program means on the program storage device and including program code elements embodying instructions executable by the digital processing apparatus for performing method steps for indexing at least one audio signal, the method steps comprising:
• rendering the audio signal into intervals, each interval including one or more segments;
• determining whether the segments of an interval exhibit one or more predetermined audio features selected from a set of features including zero crossing rate of at least a portion of the audio signal, energy of at least a portion of the audio signal, frequency of at least a portion of the audio signal, and spectral energy concentration of at least a portion of the audio signal, each audio feature being representative of at least one respective audio event including at least music and speech;
• classifying the intervals by associating the intervals with respective audio events in response to the determining step;
• and
• indexing the audio signal based at least in part on the interval classification.