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represents the Symlet wavelet of order 4.

represents the Symlet wavelet of order n.

Details

  • SymletWavelet, also known as "least asymmetric" wavelet, defines a family of orthogonal wavelets.
  • SymletWavelet[n] is defined for any positive integer n.
  • The scaling function () and wavelet function () have compact support length of 2n. The scaling function has n vanishing moments.
  • SymletWavelet can be used with such functions as DiscreteWaveletTransform and WaveletPhi, etc.

Examples

open allclose all

Basic Examples  (3)Summary of the most common use cases

Scaling function:

Out[1]=1
Out[2]=2

Wavelet function:

Out[1]=1
Out[2]=2

Filter coefficients:

Out[1]=1

Scope  (14)Survey of the scope of standard use cases

Basic Uses  (8)

Compute primal lowpass filter coefficients:

Out[1]=1

Primal highpass filter coefficients:

Out[1]=1

Lifting filter coefficients:

Out[1]=1
Out[2]=2

Generate a function to compute lifting wavelet transform:

Out[1]=1
Out[2]=2
Out[3]=3

Symlet scaling function of order 4:

Out[1]=1

SymletWavelet of order 10:

Out[2]=2

Plot scaling function using different levels of recursion:

Out[1]=1

Symlet wavelet function of order 4:

Out[1]=1

SymletWavelet of order 10:

Out[2]=2

Plot scaling function using different levels of recursion:

Out[1]=1

Wavelet Transforms  (5)

Compute a DiscreteWaveletTransform:

Out[2]=2
Out[3]=3

View the tree of wavelet coefficients:

Out[4]=4

Get the dimensions of wavelet coefficients:

Out[5]=5

Plot the wavelet coefficients:

Out[6]=6

Compute a DiscreteWaveletPacketTransform:

Out[2]=2

View the tree of wavelet coefficients:

Out[3]=3

Get the dimensions of wavelet coefficients:

Out[4]=4

Plot the wavelet coefficients:

Out[5]=5

Compute a StationaryWaveletTransform:

View the tree of wavelet coefficients:

Out[3]=3

Get the dimensions of wavelet coefficients:

Out[4]=4

Plot the wavelet coefficients:

Out[5]=5

Compute a StationaryWaveletPacketTransform:

View the tree of wavelet coefficients:

Out[3]=3

Get the dimensions of wavelet coefficients:

Out[4]=4

Plot the wavelet coefficients:

Out[5]=5

Compute a LiftingWaveletTransform:

View the tree of wavelet coefficients:

Out[3]=3

Get the dimensions of wavelet coefficients:

Out[4]=4

Plot the wavelet coefficients:

Out[5]=5

Higher Dimensions  (1)

Multivariate scaling and wavelet functions are products of univariate ones:

Out[2]=2
Out[3]=3
Out[4]=4
Out[5]=5

Applications  (3)Sample problems that can be solved with this function

Approximate a function using Haar wavelet coefficients:

Perform a LiftingWaveletTransform:

Approximate original data by keeping n largest coefficients and thresholding everything else:

Compare the different approximations:

Out[4]=4

Compute the multiresolution representation of a signal containing an impulse:

Out[2]=2
Out[3]=3
Out[4]=4

Compare the cumulative energy in a signal and its wavelet coefficients:

Out[2]=2

Compute the ordered cumulative energy in the signal:

Out[4]=4

The energy in the signal is captured by relatively few wavelet coefficients:

Out[7]=7

Properties & Relations  (12)Properties of the function, and connections to other functions

Order 1 SymletWavelet is equivalent to HaarWavelet:

Out[1]=1

Lowpass filter coefficients sum to unity; :

Out[1]=1

Highpass filter coefficients sum to zero; :

Out[2]=2

Scaling function integrates to unity; :

Out[2]=2

In particular, :

Out[3]=3

Wavelet function integrates to zero; :

Out[1]=1

Wavelet function is orthogonal to the scaling function at the same scale; :

Out[1]=1

The lowpass and highpass filter coefficients are orthogonal; :

Out[2]=2

Order n of SymletWavelet indicates n vanishing moments; :

Out[1]=1

This means linear signals are fully represented in the scaling functions part ({0}):

Out[3]=3

Quadratic or higher-order signals are not:

Out[4]=4
Out[5]=5

satisfies the recursion equation :

Plot the components and the sum of the recursion:

Out[4]=4

satisfies the recursion equation :

Plot the components and the sum of the recursion:

Out[4]=4

Frequency response for is given by :

The filter is a lowpass filter:

Out[2]=2

The higher the order n, the flatter the response function at the ends:

Out[3]=3

Fourier transform of is given by :

Out[3]=3

Frequency response for is given by :

The filter is a highpass filter:

Out[2]=2

The higher the order n, the flatter the response function at the ends:

Out[3]=3

Fourier transform of is given by :

Out[4]=4

Possible Issues  (1)Common pitfalls and unexpected behavior

SymletWavelet is restricted to n less than 20:

Out[1]=1

SymletWavelet is not defined when n is not a positive machine integer:

Out[2]=2

Neat Examples  (2)Surprising or curious use cases

Plot translates and dilations of scaling function:

Out[2]=2
Out[3]=3

Plot translates and dilations of wavelet function:

Out[2]=2
Out[3]=3
Wolfram Research (2010), SymletWavelet, Wolfram Language function, https://reference.wolfram.com/language/ref/SymletWavelet.html.
Wolfram Research (2010), SymletWavelet, Wolfram Language function, https://reference.wolfram.com/language/ref/SymletWavelet.html.

Text

Wolfram Research (2010), SymletWavelet, Wolfram Language function, https://reference.wolfram.com/language/ref/SymletWavelet.html.

Wolfram Research (2010), SymletWavelet, Wolfram Language function, https://reference.wolfram.com/language/ref/SymletWavelet.html.

CMS

Wolfram Language. 2010. "SymletWavelet." Wolfram Language & System Documentation Center. Wolfram Research. https://reference.wolfram.com/language/ref/SymletWavelet.html.

Wolfram Language. 2010. "SymletWavelet." Wolfram Language & System Documentation Center. Wolfram Research. https://reference.wolfram.com/language/ref/SymletWavelet.html.

APA

Wolfram Language. (2010). SymletWavelet. Wolfram Language & System Documentation Center. Retrieved from https://reference.wolfram.com/language/ref/SymletWavelet.html

Wolfram Language. (2010). SymletWavelet. Wolfram Language & System Documentation Center. Retrieved from https://reference.wolfram.com/language/ref/SymletWavelet.html

BibTeX

@misc{reference.wolfram_2025_symletwavelet, author="Wolfram Research", title="{SymletWavelet}", year="2010", howpublished="\url{https://reference.wolfram.com/language/ref/SymletWavelet.html}", note=[Accessed: 29-April-2025 ]}

@misc{reference.wolfram_2025_symletwavelet, author="Wolfram Research", title="{SymletWavelet}", year="2010", howpublished="\url{https://reference.wolfram.com/language/ref/SymletWavelet.html}", note=[Accessed: 29-April-2025 ]}

BibLaTeX

@online{reference.wolfram_2025_symletwavelet, organization={Wolfram Research}, title={SymletWavelet}, year={2010}, url={https://reference.wolfram.com/language/ref/SymletWavelet.html}, note=[Accessed: 29-April-2025 ]}

@online{reference.wolfram_2025_symletwavelet, organization={Wolfram Research}, title={SymletWavelet}, year={2010}, url={https://reference.wolfram.com/language/ref/SymletWavelet.html}, note=[Accessed: 29-April-2025 ]}