Wavelet Toolbox    

Extract 2-D approximation coefficients



appcoef2 is a two-dimensional wavelet analysis function.

appcoef2 computes the approximation coefficients of a two-dimensional signal.

A = appcoef2(C,S,'wname',N) computes the approximation coefficients at level N using the wavelet decomposition structure [C,S] (see wavedec2 for more information).

'wname' is a string containing the wavelet name. Level N must be an integer such that 0 N size(S,1)-2.

A = appcoef2(C,S,'wname') extracts the approximation coefficients at the last level: size(S,1)-2.

Instead of giving the wavelet name, you can give the filters.

For A = appcoef2(C,S,Lo_R,Hi_R) or A = appcoef2(C,S,Lo_R,Hi_R,N), Lo_R is the reconstruction low-pass filter and Hi_R is the reconstruction high-pass filter (see wfilters for more information).



The algorithm is built on the same principle as appcoef.

See Also
detcoef2, wavedec2

  appcoef bestlevt