Main Content

fejerkorovkin

Fejér-Korovkin wavelet filters

collapse all in page

Syntax

Lo = fejerkorovkin(wname)

Description

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].

example

Examples

collapse all

Open Live Script

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")

Figure contains an axes object. The axes object with title Scaling Filter Coefficients contains an object of type stem.

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

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

Figure contains an axes object. The axes object with title Wavelet Filter Coefficients contains an object of type stem.

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")

Figure contains 2 axes objects. Axes object 1 with title Scaling Function contains an object of type line. Axes object 2 with title Wavelet contains an object of type line.

Input Arguments

collapse all

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

collapse all

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

See Also

| |