snake: Ridge Estimation by Snake Method

In Rwave: Time-Frequency Analysis of 1-D Signals

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.

Rwave documentation built on Oct. 22, 2022, 1:05 a.m.