Wavelet filter implementation

Discussion in 'Programmer's Corner' started by Birdie, Aug 26, 2011.

  1. Birdie

    Thread Starter New Member

    Feb 7, 2011
    2
    0
    Dear all,

    I would like to implement a Koren-Laine wavelet into my project, but I am a little bit confused of one thing. The proposed FIR filter bank looks like this:

    g(-1,1)=[2 -2]
    h(-2,-1,0,1)=[0.125,0.375,0.375,0.125]
    k(-2,-1,0,1,2,3)=[-0.0078125 -0.0546875 -0.171875 0.171875 0.0546875 0.0078125]

    My question is - is it possible to implement this filter bank as:
    g=[2 -2 0 0 0 0]
    h=[0.125 0.375 0.375 0.125 0 0]
    k=[-0.0078125 -0.0546875 -0.171875 0.171875 0.0546875 0.0078125]?

    Or do I have to shift g to look like this:
    g=[0 2 -2 0 0 0].

    What could g(-1,1) and h(-2,-1,0,1) mean anyway? Because adding zeros in front of filter causes only a change in delay. And this shift needs to be compensated in convolution to keep detail coefficients on the right place and achieve perfect reconstruction. Isn`t this right?

    Anyone any idea?

    Thanks for any advice.
     
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