downsample: Downsample a Signal

In kuwisdelu/matter: Scientific computing for out-of-memory signals and images

Downsample a Signal

Description

Downsamples a signal for the purposes of visualization. A subset of the original samples are used to represent the signal. The downsampled signal is intended to resemble the original when visualized and should not typically be used for downstream processing.

Usage

downsample(x, n = length(x) / 10L, domain = NULL,
	method = c("lttb", "ltob", "dynamic"))

Arguments

x	A numeric vector.
n	The length of the downsampled signal.
domain	The domain variable of the signal.
method	The downsampling method to be used. Must be one of "lttb", "ltob", or "dynamic".

Details

This function implements the downsampling methods from Sveinn Steinarsson's 2013 MSc thesis Downsampling Time Series for Visual Representation, including largest-triangle-three-buckets (LTTB), largest-triangle-one-bucket (LTOB), and dynamic binning.

Value

A vector of length n, giving the downsampled signal.

Author(s)

Kylie A. Bemis

References

S. Steinarsson. “Downsampling Time Series for Visual Representation.” MSc, School of Engineering and Natural Sciences, University of Iceland, Reykjavik, Iceland, June 2013.

See Also

approx1

Examples

set.seed(1)
t <- seq(from=0, to=6 * pi, length.out=2000)
x <- sin(t) + 0.6 * sin(2.6 * t)
x <- x + runif(length(x))
xs <- downsample(x, n=200)
s <- attr(xs, "sample")

plot(x, type="l")
points(s, xs, col="red", type="b")

kuwisdelu/matter documentation built on May 1, 2024, 5:17 a.m.