How to determine the level of decomposition in discete wavelet trransform?
Answers
Answer:
The maximum number of levels Jmax with which a signal can be decomposed, can be determined using the following equation :
Jmax= fix(log2[(N/Nw)-1])
N is the length of the signal, Nw gives the length of the decomposition filter associated with the chosen mother wavelet and fix is to round the value in the brackets to its nearest integer.
For example, sampling frequency of a given signal is 1024 samples/sec, you will get 5 levels, the frequency band corresponding to this sampling frequency is from -512 to 512. Let's as usual neglect the negative part for real signals. The first level trend contains 0..256, the detail 512..256. The second level trend then contains the frequencies 0..128, the second level details 256..128. Etc.
Good luck
I hope it would help you.