Scilab Wavelet Toolbox Function
Last update : Feburary 2006
dwt - one dimensional fast discrete wavelet transform
Calling Sequence
-
[a,d]=dwt(sig,wavename,[extension_method])
Parameters
-
sig
: Input 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
-
a
: Approximation Coefficient
-
d
: Detail Coefficient
Description
This function performs one dimensional fast discrete wavelet
transform and get two type of coefficient, approximation and detail.
Different signal extension methods affect the result except haar
('haar') or daubechies wavelet (db1). Detailed algorithm is
fully described in userguide.
Examples
-->sig=rand(1,64);
-->[a,d]=dwt(sig,'db2','zpd');
-->sig=rand(64,64);
-->[a,d]=dwt(sig,'db2','zpd');
Please use dwt2 instead!
-->[a,d]=dwt(3,'db2','symh');
Please use shorter wavelets!
See Also
idwt
,
dwt2
,
idwt2