scales
CWT filter bank scales
Description
Examples
CWT Filter Bank Scales
Create a CWT filter bank with a sampling period of 0.001 seconds. By default, the filter bank uses the analytic Morse (3,60) wavelet and 10 voices per octave.
fb = cwtfilterbank(SamplingPeriod=seconds(0.001));
Obtain the raw and normalized scales used in creating the wavelet bandpass filters.
[rs,cs] = scales(fb);
Confirm the scales increase by a factor of approximately , where is the number of voices per octave.
nv = 10; scaleRatios = rs(2:end)./rs(1:end-1); [2^(1/nv) min(scaleRatios) max(scaleRatios)]
ans = 1×3
1.0718 1.0718 1.0718
Confirm the normalized scales are equivalent to the wavelet center periods divided by the sampling period. Plot the normalized wavelet center periods as a function of the raw scale.
P = centerPeriods(fb); Pnormalized = P/seconds(0.001); plot(rs,[cs(:) Pnormalized(:)]) ylabel("Center Periods (Samples)") xlabel("Unitless Scale (Dilation Factor)") title("Normalized Center Period by Dilation Factor") grid on
Input Arguments
fb
— Continuous wavelet transform filter bank
cwtfilterbank
object
Continuous wavelet transform (CWT) filter bank, specified as a cwtfilterbank
object.
Output Arguments
rs
— Raw scales
vector
Raw scales used in creating the wavelet bandpass filters, returned as a real-valued vector of length Ns, where Ns is the number of wavelet bandpass frequencies. Scales are ordered from finest scale to coarsest scale.
Data Types: double
cs
— Normalized scales
vector
Normalized scales,
returned as a real-valued vector of length Ns, where
Ns is the number of wavelet bandpass
frequencies. The scales are expressed
as the normalized period of the wavelet corresponding to the scale in
samples. Equivalently, cs
contains the wavelet center
periods divided by the sampling period. The elements of
cs
are ordered from the smallest normalized period
to the largest normalized
period.
Data Types: double
Extended Capabilities
C/C++ Code Generation
Generate C and C++ code using MATLAB® Coder™.
Version History
Introduced in R2018a
MATLAB Command
You clicked a link that corresponds to this MATLAB command:
Run the command by entering it in the MATLAB Command Window. Web browsers do not support MATLAB commands.
Select a Web Site
Choose a web site to get translated content where available and see local events and offers. Based on your location, we recommend that you select: .
You can also select a web site from the following list:
How to Get Best Site Performance
Select the China site (in Chinese or English) for best site performance. Other MathWorks country sites are not optimized for visits from your location.
Americas
- América Latina (Español)
- Canada (English)
- United States (English)
Europe
- Belgium (English)
- Denmark (English)
- Deutschland (Deutsch)
- España (Español)
- Finland (English)
- France (Français)
- Ireland (English)
- Italia (Italiano)
- Luxembourg (English)
- Netherlands (English)
- Norway (English)
- Österreich (Deutsch)
- Portugal (English)
- Sweden (English)
- Switzerland
- United Kingdom (English)