JSci.maths.wavelet
Interface Filter

All Known Implementing Classes:

CDF2_4, CDF3_5, Daubechies2, Daubechies3, Daubechies4, Daubechies5, Daubechies6, Daubechies7, Daubechies8, LinearSpline, MultiSpline2_4, MultiSpline3_5, MultiSplineHaar, PiecewiseConstant, QuadraticSpline, SumOfDiracs

public interface Filter

This interface is used to define wavelet filters. It is fairly general to accomodate just about any filter (except complex ones). Since changing an interface is painful, it must be as general as possible to start with. Therefore it doesn't assume that you are using dyadic wavelets (for example) and so, some object will implement somewhat redundant method that builds on the dyadic grid (for simplicity).

Method Summary

double[]	highpass(double[] y) Highpass filters are normalized in order to get L2 orthonormality of the resulting wavelets (when it applies).
double[]	highpass(double[] y, double[] param) Highpass filters are normalized in order to get L2 orthonormality of the resulting wavelets (when it applies).
double[]	lowpass(double[] x) lowpass filter
double[]	lowpass(double[] x, double[] param) lowpass filter
int	previousDimension(int k) This method return the number of "scaling" functions at the previous scale given a number of scaling functions.

Method Detail

lowpass

public double[] lowpass(double[] x)

lowpass filter

highpass

public double[] highpass(double[] y)

Highpass filters are normalized in order to get L2 orthonormality of the resulting wavelets (when it applies). See the class DiscreteHilbertSpace for an implementation of the L2 integration.

lowpass

public double[] lowpass(double[] x,
                        double[] param)

lowpass filter

Parameters:

param - a parameter for the filter

highpass

public double[] highpass(double[] y,
                         double[] param)

Highpass filters are normalized in order to get L2 orthonormality of the resulting wavelets (when it applies). See the class DiscreteHilbertSpace for an implementation of the L2 integration.

Parameters:

param - a parameter for the filter

previousDimension

public int previousDimension(int k)

This method return the number of "scaling" functions at the previous scale given a number of scaling functions. The answer is always smaller than the provided value (about half since this is a dyadic implementation). This relates to the same idea as the "filter type". However this method is used in the context of signal processing for performance reasons.