snake {Rwave}

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.