Near-Orthogonal Linear Phase Wavelet Filters

S.-W. Park and G. Godinez (USA)


FIR filter design, subband coding,wavelet transform.


The differences between the orthogonal and symmetric biorthogonal wavelet filters are described and design of near-orthogonal symmetric wavelet filters using windows is presented. Symmetric wavelet filters have advantage over orthogonal wavelet filters: it does not result in coefficient expansion when symmetric extension is used. Symmetric extension is preferred to periodic extension, as the former does not introduce discontinuity that makes highpass filter output coefficients unduly large. It is shown that the near-orthogonal filter performs as good as the popular biorthogonal wavelet filter that gives linear phase in the case of random signals. Because the new filter is very close to orthogonal, it has advantage over biorthogonal filters: energy preserving.

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