Scilab Wavelet Toolbox Function
Last update : Feburary 2006

appcoef2 - approximation coefficient extraction for two dimensional multiple stride fast discrete wavelet decompostion

Calling Sequence

ac=appcoef2(c,s,wavename,level,[extension_method])

Parameters

Description

This function extracts approximation coefficent from coefficent bunch vector. Almost all level approximation coefficients are obtained from inverse wavelet transform. So the wavelet name and extension method should be presented, consistently with those of the decomposition procedure. Only the highest decomposed approximation coefficent does not need inverse transform.

Examples


-->img=rand(64,64);                  
-->[c,s]=wavedec2(img,3,'db2','sp0');
-->a1=appcoef2(c,s,'db2',1,'sp0');
-->size(a1)
 ans  =
 
!   33.    33. !

-->a2=appcoef2(c,s,'db2',2,'sp0');
-->size(a2)                       
 ans  =
 
!   18.    18. !

-->a3=appcoef2(c,s,'db2',3,'sp0');
-->size(a3)                       
 ans  =
 
!   10.    10. !


  

See Also

appcoef ,   detcoef ,   wrcoef ,   detcoef2 ,   wrcoef2