| Group: | Mathematical Functions |
| Topic: | Fourier and Wavelet transforms |
| See also: | invdwt fwt invfwt fwtin fwtinshift fwt2 |
| Function: | dwt | |
| Description: | dwt computes the Discrete Wavelet Transformation of a vector. |
| Usage: | y = dwt (x, l, h) | |
| Input: | ||
| x | n x 1 vector, input data where n has to be a power of 2 | |
| l | integer, number of father wavelet coefficients, l has to be a power of 2 | |
| h | m x 1 vector, wavelet basis | |
| Output: | ||
| y | n x 1 vector, wavelet coefficients | |
To get vectors of the wavelet basis, the library wavelet has to be loaded: h can be either daubechies2,4,6,8,10,12,14,16,18,20, symmlet4 to 10 or coiflet1 to 5.
library("wavelet")
x =(0:1023)/1023
d = dwt(x, 4, daubechies4)
d
Contents of d [ 1,] 2.5285 [ 2,] 6.5324 [ 3,] 10.795 [ 4,] 12.144 [ 5,] -3.6494 [ 6,] -7.0777e-16 ... [1019,] -8.3267e-17 [1020,] -1.6653e-16 [1021,] -1.3878e-16 [1022,] -1.3878e-16 [1023,] -1.1102e-16 [1024,] -8.3267e-17