Scilab Wavelet Toolbox Function
Last update : Feburary 2006
wavedec2 - two dimensional multiple stride fast discrete wavelet transform
Calling Sequence
-
[c,s]=wavedec2(img,stride,wavename,[extension_method])
Parameters
-
sig
: Input Matrix
-
stride
: stride or level, how many times to decompose the
signal
-
wavename
: wavelet name
- 'haar': haar wavelet
- 'db1': daubechies 1 wavelet, same with haar
- 'db2': daubechies 2 wavelet
- 'db3': daubechies 3 wavelet
- 'db4': daubechies 4 wavelet
- 'db5': daubechies 5 wavelet
- 'db6': daubechies 6 wavelet
- 'db7': daubechies 7 wavelet
- 'db8': daubechies 8 wavelet
- 'db9': daubechies 9 wavelet
- 'db10': daubechies 10 wavelet
-
extension_method
: Signal Extension Method, default is 'symh'
- 'zpd': zero padding method
- 'ppd': period extension method
- 'asymh': half asymmetric extension method
- 'asymw': whold asymmetric extension method
- 'symh': half symmetric extension method
- 'symw': whole symmetric extension method
- 'sp0': border value constant extension method
- 'sp1': border value linear extension method
-
c
: Coefficient Bunch Vector
-
s
: Coefficient Size Matrix
Description
This function performs multiple stride two dimensional fast
discrete wavelet transform. The result come with a coefficient
vector which stores all the coefficients, and a size array holding
all size information corresponding to respective coefficient. Different
signal extension methods affect the decomposition result except
haar wavelet (haar) and daubechies wavelet (db1). Detail Alogrithm
is fully described in the userguide.
Examples
-->img=rand(64,64);
-->[c,s]=wavedec2(img,3,'db2','sp0');
-->s
s =
! 10. 10. !
! 18. 18. !
! 33. 33. !
! 64. 64. !
-->size(c)
ans =
! 1. 4639.
-->sig=rand(1,64);
-->[c,s]=wavedec2(sig,3,'db2','sp0');
Please input matrixes or use wavedec instead!
See Also
wavedec
,
waverec
,
waverec2