fejerkorovkin

Fejér-Korovkin wavelet filters

Syntax

``Lo = fejerkorovkin(wname)``

Description

example

````Lo = fejerkorovkin(wname)` returns the Fejér-Korovkin scaling filter specified by `wname`. Valid entries for `wname` are `'fk4'`, `'fk6'`, `'fk8'`, `'fk14'`, `'fk18'`, and `'fk22'`. For information on the Fejér–Korovkin filters, see Nielson[1].```

Examples

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Construct and plot the Fejér-Korovkin (14) scaling function and wavelet.

Obtain the Fejér-Korovkin scaling filter and plot its 14 coefficients.

```Lo = fejerkorovkin("fk14"); stem(Lo) title("Scaling Filter Coefficients")```

Use the scaling filter to obtain the wavelet filter and plot its coefficients.

```Hi = qmf(Lo); stem(Hi) title("Wavelet Filter Coefficients")```

`wavefun` provides an efficient way to construct and plot the scaling function and wavelet.

```[phi,psi,xval] = wavefun("fk14"); tiledlayout(2,1) nexttile plot(xval,phi) title("Scaling Function") nexttile plot(xval,psi) title("Wavelet")```

Input Arguments

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Name of desired Fejér-Korovkin scaling filter. The numeric value in each name is the number of Fejér-Korovkin filter coefficients. For example, if `wname` is `'fk14'`, `Lo` has 14 coefficients.

Output Arguments

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Scaling filter, returned as a vector.

References

[1] Nielsen, M. "On the construction and frequency localization of finite orthogonal quadrature filters." Journal of Approximation Theory. Vol. 108, Number 1, 2001, pp. 36–52.

Version History

Introduced in R2015b