Digital Signal Processing Reference
In-Depth Information
Table 13.2 Typical Wavelet Filter Coefficients
h 0 ðkÞ
Haar
Daubechies 4
Daubechies 6
Daubechies 8
0.707106781186548
0.707106781186548
0.482962913144534
0.836516303737808
0.224143868042013
0.332670552950083
0.806891509311093
0.459877502118492
0.230377813308896
0.714846570552915
0.630880767929859
0.129409522551260
0.135011020010255
0.027983769416859
0.085441273882027
0.035226291885710
0.187034811719093
0.030841381835561
0.032883011666885
0.010597401785069
Figure 13.33 shows each component at resolution j ¼ 1 and the constructed scaling function fðtÞ .
The original scaling function fðtÞ is also included as shown in the last plot for comparison.
With the given coefficients h 0 ðkÞ
and applying Equation (13.45) , we can obtain the wavelet
coefficients h 1 ðkÞ as
h 1 ð 0 Þ¼ 0 : 1294 ; h 1 ð 1 Þ¼ 0 : 2241 ; h 1 ð 2 Þ¼ 0 : 8365 ;
and
h 1 ð 2 Þ¼ 0 : 4830
1
2
0.5
1
0
0
-0.5
-1
0
1
2
3
0
1
2
3
0.5
0.5
0
0
-0.5
-0.5
0
1
2
3
0
1
2
3
2
2
1
1
0
0
-1
-1
0
1
2
3
0
1
2
3
Time (s ec . )
Time (s ec . )
FIGURE 13.33
Constructed 4-tap Daubechies father wavelet.
 
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