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Java > Open Source Codes > JSci > maths > wavelet > symmlet8 > FastSymmlet8


1 package JSci.maths.wavelet.symmlet8;
2
3 import JSci.maths.wavelet.FWT;
4
5 /************************
6 * This is a very fast implementation of the
7 * Fast Wavelet Transform. It uses in-place computations
8 * for less memory usage. Data length should be
9 * a power of 2 a be at least of length 8.
10 * Handles boundaries by assuming periodicity.
11 * Ideal for image processing or processing large
12 * amount of data. Uses floats for more performance.
13 * Safety is minimal, so be careful!
14 * @author Daniel Lemire
15 *************************/
16 public final class FastSymmlet8 extends FWT {
17
18   public FastSymmlet8() {
19   }
20
21   static final float[] scale = {0.0322231006040782f,
22                                 -0.0126039672622638f,
23                                 -0.0992195435769564f,
24                                 0.297857795605605f,
25                                 0.803738751805386f,
26                                 0.497618667632563f,
27                                 -0.0296355276459604f,
28                                 -0.0757657147893567f};
29   static final float[] wavelet = {-scale[7],scale[6],-scale[5],scale[4],-scale[3],scale[2],-scale[1],scale[0]};
30
31   public static void transform (float[] v,int last) {
32     float[] ans=new float[last];
33     final int half=last/2;
34     try {
35       for(int k=0;/*k<half*/;k++) {
36           ans[k+half]=v[(2*k+0)]*wavelet[0]+v[(2*k+1)]*wavelet[1]+v[(2*k+2)]*wavelet[2]+v[(2*k+3)]*wavelet[3]+v[(2*k+4)]*wavelet[4]+v[(2*k+5)]*wavelet[5]+v[(2*k+6)]*wavelet[6]+v[(2*k+7)]*wavelet[7];
37           ans[k]=v[(2*k+0)]*scale[0]+v[(2*k+1)]*scale[1]+v[(2*k+2)]*scale[2]+v[(2*k+3)]*scale[3]+v[(2*k+4)]*scale[4]+v[(2*k+5)]*scale[5]+v[(2*k+6)]*scale[6]+v[(2*k+7)]*scale[7];
38       }
39     } catch (IndexOutOfBoundsException JavaDoc e) {}
40     ans[last-3]=v[last-6]*wavelet[0]+v[last-5]*wavelet[1]+v[last-4]*wavelet[2]+v[last-3]*wavelet[3]+v[last-2]*wavelet[4]+v[last-1]*wavelet[5]+v[0]*wavelet[6]+v[1]*wavelet[7];
41     ans[half-3]=v[last-6]*scale[0]+v[last-5]*scale[1]+v[last-4]*scale[2]+v[last-3]*scale[3]+v[last-2]*scale[4]+v[last-1]*scale[5]+v[0]*scale[6]+v[1]*scale[7];
42     ans[last-2]=v[last-4]*wavelet[0]+v[last-3]*wavelet[1]+v[last-2]*wavelet[2]+v[last-1]*wavelet[3]+v[0]*wavelet[4]+v[1]*wavelet[5]+v[2]*wavelet[6]+v[3]*wavelet[7];
43     ans[half-2]=v[last-4]*scale[0]+v[last-3]*scale[1]+v[last-2]*scale[2]+v[last-1]*scale[3]+v[0]*scale[4]+v[1]*scale[5]+v[2]*scale[6]+v[3]*scale[7];
44     ans[last-1]=v[last-2]*wavelet[0]+v[last-1]*wavelet[1]+v[0]*wavelet[2]+v[1]*wavelet[3]+v[2]*wavelet[4]+v[3]*wavelet[5]+v[4]*wavelet[6]+v[5]*wavelet[7];
45     ans[half-1]=v[last-2]*scale[0]+v[last-1]*scale[1]+v[0]*scale[2]+v[1]*scale[3]+v[2]*scale[4]+v[3]*scale[5]+v[4]*scale[6]+v[5]*scale[7];
46     System.arraycopy(ans,0,v,0,last);
47   }
48
49   public void transform (float[] v) {
50     int last;
51     for (last=v.length;last>8;last/=2) {
52       transform(v,last);
53     }
54     if(last!=8)
55       System.err.println("Careful! this should be a power of 2 : "+v.length);
56   }
57
58   public void invTransform(float[] v) {
59     int last;
60     for (last=8;2*last<=v.length;last*=2) {
61       invTransform(v,last);
62     }
63     if(last!=v.length)
64       System.err.println("Careful! this should be a power of 2 : "+v.length);
65   }
66
67   public static void invTransform (float[] v, int last) {
68     final int ResultingLength=2*last;
69     float[] ans=new float[ResultingLength];
70     try {
71       for(int k=0;/*k<last*/;k++) {
72           ans[(2*k+7)]+=scale[7]*v[k]+wavelet[7]*v[k+last] ;
73           ans[(2*k+6)]+=scale[6]*v[k]+wavelet[6]*v[k+last] ;
74           ans[(2*k+5)]+=scale[5]*v[k]+wavelet[5]*v[k+last] ;
75           ans[(2*k+4)]+=scale[4]*v[k]+wavelet[4]*v[k+last] ;
76           ans[(2*k+3)]+=scale[3]*v[k]+wavelet[3]*v[k+last] ;
77           ans[(2*k+2)]+=scale[2]*v[k]+wavelet[2]*v[k+last] ;
78           ans[(2*k+1)]+=scale[1]*v[k]+wavelet[1]*v[k+last] ;
79           ans[(2*k+0)]+=scale[0]*v[k]+wavelet[0]*v[k+last] ;
80       }
81     } catch (IndexOutOfBoundsException JavaDoc e) {}
82     ans[ResultingLength-6]+=scale[0]*v[last-3]+wavelet[0]*v[ResultingLength-3] ;
83     ans[ResultingLength-5]+=scale[1]*v[last-3]+wavelet[1]*v[ResultingLength-3] ;
84     ans[ResultingLength-4]+=scale[2]*v[last-3]+wavelet[2]*v[ResultingLength-3] ;
85     ans[ResultingLength-3]+=scale[3]*v[last-3]+wavelet[3]*v[ResultingLength-3] ;
86     ans[ResultingLength-2]+=scale[4]*v[last-3]+wavelet[4]*v[ResultingLength-3] ;
87     ans[ResultingLength-1]+=scale[5]*v[last-3]+wavelet[5]*v[ResultingLength-3] ;
88     ans[0]+=scale[6]*v[last-3]+wavelet[6]*v[ResultingLength-3] ;
89     ans[1]+=scale[7]*v[last-3]+wavelet[7]*v[ResultingLength-3] ;
90     ans[ResultingLength-4]+=scale[0]*v[last-2]+wavelet[0]*v[ResultingLength-2] ;
91     ans[ResultingLength-3]+=scale[1]*v[last-2]+wavelet[1]*v[ResultingLength-2] ;
92     ans[ResultingLength-2]+=scale[2]*v[last-2]+wavelet[2]*v[ResultingLength-2] ;
93     ans[ResultingLength-1]+=scale[3]*v[last-2]+wavelet[3]*v[ResultingLength-2] ;
94     ans[0]+=scale[4]*v[last-2]+wavelet[4]*v[ResultingLength-2] ;
95     ans[1]+=scale[5]*v[last-2]+wavelet[5]*v[ResultingLength-2] ;
96     ans[2]+=scale[6]*v[last-2]+wavelet[6]*v[ResultingLength-2] ;
97     ans[3]+=scale[7]*v[last-2]+wavelet[7]*v[ResultingLength-2] ;
98     ans[ResultingLength-2]+=scale[0]*v[last-1]+wavelet[0]*v[ResultingLength-1] ;
99     ans[ResultingLength-1]+=scale[1]*v[last-1]+wavelet[1]*v[ResultingLength-1] ;
100     ans[0]+=scale[2]*v[last-1]+wavelet[2]*v[ResultingLength-1] ;
101     ans[1]+=scale[3]*v[last-1]+wavelet[3]*v[ResultingLength-1] ;
102     ans[2]+=scale[4]*v[last-1]+wavelet[4]*v[ResultingLength-1] ;
103     ans[3]+=scale[5]*v[last-1]+wavelet[5]*v[ResultingLength-1] ;
104     ans[4]+=scale[6]*v[last-1]+wavelet[6]*v[ResultingLength-1] ;
105     ans[5]+=scale[7]*v[last-1]+wavelet[7]*v[ResultingLength-1] ;
106     System.arraycopy(ans,0,v,0,ans.length);
107   }
108 }
109
110
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