Zero-crossing rate

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The zero-crossing rate is the rate of sign-changes along a signal, i.e., the rate at which the signal changes from positive to negative or back. This feature has been used heavily in both speech recognition and music information retrieval and is defined formally as

zcr = \frac{1}{T} \sum_{t=0}^{T-1} {{\mathbb I}\left\{{s_t s_{t-1} < 0}\right\}}

where s is a signal of length T and the indicator function {{\mathbb I}\left\{{A}\right\}} is 1 if its argument A is true and 0 otherwise.

For monophonic tonal signals, the zero-crossing rate can be used as a primitive pitch detection algorithm.

[edit] See also

[edit] References

  • Chen, C. H. (1988). Signal processing handbook. New York: Dekker, 531. ISBN 0-8247-7956-8. 
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