Reassignment method: Difference between revisions

Revision as of 19:48, 27 November 2012

Revision as of 13:11, 5 December 2012

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This mapping to reassigned time-frequency coordinates is

very precise for signals that are separable in time and

frequency with respect to the analysis window.

== Introduction ==

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[[Image:Reassigned spectrogral surface of bass pluck.png|thumb|400px|

Reassigned spectral surface for the onset of an acoustic bass tone

having a sharp pluck and a fundamental frequency of approximately 73.4  Hz.

Sharp spectral ridges representing the harmonics are evident, as is the

abrupt onset of the tone.

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<ref name = "improving">

{{cite journal |author=F. Auger and P. Flandrin |year=1995 | month=May |title=Improving the readability of time-frequency and

time-scale representations by the reassignment method |journal=IEEE Transactions on Signal Processing |volume=43 |issue=5 |pages=1068-10891068–1089 |publisher= |doi=10.1109/78.382394 |url= |accessdate= }}

</ref>

.<ref>P. Flandrin, F. Auger, and E. Chassande-Mottin,

''Time-frequency reassignment: From principles to algorithms'',

in Applications in Time-Frequency Signal Processing

(A. Papandreou-Suppappola, ed.), ch. 5, pp. 179 – 203, CRC Press, 2003.</ref>.

In the case of the reassigned

spectrogram, the short-time phase spectrum is used to

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name of ''Modified Moving Window Method''

<ref>

{{cite journal |author=K. Kodera, R. Gendrin, and C. de Villedary |year=1978 |title=Analysis of time-varying signals with small BT values |journal=IEEE Transactions on Acoustics, Speech and Signal Processing |volume=26 |issue=1 |pages=64 – 7664–76 |month=Feb | publisher= |doi=10.1109/TASSP.1978.1163047 |url= |accessdate= }}

</ref>

Their technique enhances the resolution in time and

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spectrum.

<ref name = "crossspectral">

{{cite journal |author=D. J. Nelson |year=2001 |month=Nov |title=Cross-spectral methods for processing speech |journal=Journal of the Acoustical Society of America |volume=110 |issue=5 |pages=2575 – 25922575–2592 |publisher= |doi=10.1121/1.1402616 |url= |accessdate= }}

</ref>

It is easily shown that Nelson's

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== Further reading ==

*S. A. Fulop and K. Fitz, ''A spectrogram for the twenty-first century'', Acoustics Today, vol. 2, no. 3, pp. &nbsp;26–33, 2006.

*S. A. Fulop and K. Fitz, ''Algorithms for computing the time-corrected instantaneous frequency (reassigned) spectrogram, with applications'', Journal of the Acoustical Society of America, vol. 119, pp. &nbsp;360 – 371, Jan 2006.

== External links ==