Make Signals and Images

DESCRIPTION:

Creates signals, signal with Gaussian noise and images.

USAGE:

make.signal(name, n=1024, snr=Inf) 
make.image(name, nrow=128, ncol=nrow) 

REQUIRED ARGUMENTS:

name
a character string giving signal/image name, e.g., "doppler". See details below for all available signal and image names.

OPTIONAL ARGUMENTS:

n
a number greater than 0 giving the signal length. The default is 1024.
nrow,ncol
a natural number giving the size of the image. The default is 128 rows and an equal number of columns.
snr
signal-to-noise ratio, the default produces noiseless signal. If `0 < snr < Inf', Gaussian white noise is added to the signal.

VALUE:

make.signal returns a regular time series (class "rts") with frequency n and length trunc(n). make.image returns a matrix with dimensions nrow by ncol.

DETAILS:

Available signals are: (signals are defined for x=k/n, k=0, 1, ..., n-1)

"dirac"

an approximated Dirac function with a shift at around 0.37.

"kronecker"
the Kronecker function with a shift at around 0.37.
"heavisine"
a sine with jumps at 0.3 and 0.72.
"bumps"
a series of sharp peaks.

"blocks"
a piecewise-constant function.

"doppler"
a sinusoid with changing amplitude and frequency.
"ramp"
a signal with Lipschitz exponent 0.
"cusp"
a signal with Lipschitz exponent 0.5.
"crease"
a signal with Lipschitz exponent 1.
"sing"
a signal with Lipschitz exponent -1 (singularity).
"hisine"
a high-frequency sinusoid.
"midsine"
a mid-frequency sinusoid.
"losine"
a low-frequency sinusoid.
"linchirp"
a linear chirp.
"twochirp
two linear chirps.
"quadchirp"
a quadratic chirp.
"mishmash1"
a combination of linear chirp, quadratic chirp, and high-frequency sinusoid.
"mishmash2"
a signal with components: a high-frequency sine, a linear chirp, a quadratic chirp, and the bumps signal.
"mishmash3"
a signal with components: a low-frequency sine, a mid-frequency sine, a linear chirp, a quadratic chirp, and a singularity.
"gauss"
Normal density with mean 0.3 and standard deviation 0.025.
"jumpsine"
a sine with jumps at 0.625 and 0.875.
"levelshift"
a constant signal with offsetting level shifts (a square wave)
"patches"
signal is a series of outlier patches (square waves) of increasing dyadic length
"linear"
a linear function with mean zero.
"quadratic"
a quadratic polynomial with end values zero.
"cubic"
a cubic polynomial with mean zero, and end values zero.

Available images are:
"circle"

creates an image of a circle.

"diamond"
creates an image of an equal sided diamond.

"xbox"
creates an image of a square with both diagonals.