Howtosignalprocessing
- What is Daubechies wavelet transform?
- What is scaling function and wavelet function?
- What is db1 in wavelet transform?
- What are vanishing moments in wavelets?
What is Daubechies wavelet transform?
A wavelet transform (WT) is the decomposition of a signal into a set of basis functions consisting of contractions, expansions, and translations of a mother function ψ(t), called the wavelet (Daubechies, 1991). The are the coefficients of a discrete biorthogonal wavelet transform of x(t).
What is scaling function and wavelet function?
Wavelets are defined by the wavelet function ψ(t) (i.e. the mother wavelet) and scaling function φ(t) (also called father wavelet) in the time domain. The wavelet function is in effect a band-pass filter and scaling that for each level halves its bandwidth.
What is db1 in wavelet transform?
The names of the Daubechies family wavelets are written dbN , where N is the order, and db the “surname” of the wavelet. The db1 wavelet, as mentioned above, is the same as Haar wavelet.
What are vanishing moments in wavelets?
Each wavelet has a number of zero moments or vanishing moments equal to half the number of coefficients. For example, D2 has one vanishing moment, D4 has two, etc. A vanishing moment limits the wavelets ability to represent polynomial behaviour or information in a signal.
