org.jscience.mathematics.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, Signal, 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

double[] lowpass(double[] x)
lowpass filter

Parameters:
x - DOCUMENT ME!
Returns:
DOCUMENT ME!

highpass

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.

Parameters:
y - DOCUMENT ME!
Returns:
DOCUMENT ME!

lowpass

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

Parameters:
x - DOCUMENT ME!
param - a parameter for the filter
Returns:
DOCUMENT ME!

highpass

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:
y - DOCUMENT ME!
param - a parameter for the filter
Returns:
DOCUMENT ME!

previousDimension

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.

Parameters:
k - DOCUMENT ME!
Returns:
DOCUMENT ME!