snake {Rwave}R Documentation

Ridge Estimation by Snake Method

Description

Estimate a ridge from a time-frequency representation, using the snake method.

Usage

snake(tfrep, guessA, guessB, snakesize=length(guessB),
tfspec=numeric(dim(modulus)[2]), subrate=1, temprate=3, muA=1,
muB=muA, lambdaB=2 * muB, lambdaA=2 * muA, iteration=1000000,
seed=-7, costsub=1, stagnant=20000, plot=TRUE)

Arguments

tfrep Time-Frequency representation (real valued).
guessA Initial guess for the algorithm (frequency variable).
guessB Initial guess for the algorithm (time variable).
snakesize the length of the initial guess of time variable.
tfspec Estimate for the contribution of the noise to modulus.
subrate Subsampling rate for ridge estimation.
temprate Initial value of temperature parameter.
muA Coefficient of the ridge's derivative in cost function (frequency component).
muB Coefficient of the ridge's derivative in cost function (time component).
lambdaB Coefficient of the ridge's second derivative in cost function (time component).
lambdaA Coefficient of the ridge's second derivative in cost function (frequency component).
iteration Maximal number of moves.
seed Initialization of random number generator.
costsub Subsampling of cost function in output.
stagnant maximum number of steps without move (for the stopping criterion)
plot when set (by default), certain results will be displayed

Value

Returns a structure containing:
ridge 1D array (of same length as the signal) containing the ridge.
cost 1D array containing the cost function.

References

See discussions in the text of “Practical Time-Frequency Analysis”.

See Also

corona, coronoid, icm, snakoid.


[Package Rwave version 1.24-2 Index]