Difference between revisions of "File:Fafo2test2.png"
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+ | Filtering of the real array $A$ shown in [[File:Fafo2test0.png|128px]]. |
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− | Importing image file |
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+ | |||
+ | The [[Fourier-2 transform]] $B$ of the function $A$ is determines with |
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+ | |||
+ | : $\displaystyle B(p,q)=\frac{1}{2\pi} \int \int \mathrm d x \mathrm d y \exp(-ipx-iqy) A(x,y)$ |
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+ | |||
+ | |||
+ | The modulus of array $B$ is shown in figure [[File:Fafo2test1.png|128px]]. |
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+ | |||
+ | The filtered function $\tilde A$ is determined with |
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+ | |||
+ | : $\displaystyle \tilde A(x,y)=\frac{1}{2\pi} \int \int \mathrm d x \mathrm d y \exp(ipx+iqy) |
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+ | \exp(-0.04 (p^2+q^2)) |
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+ | B(p,q)$ |
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+ | |||
+ | The generator is copypasted below. |
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+ | |||
+ | ==[[C++]] generator== |
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+ | // Files [[ado.cin]] and [[fafo.cin]] should be in the working directory for the compillation of the code below: |
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+ | |||
+ | #include<math.h> |
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+ | #include<stdio.h> |
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+ | #include <stdlib.h> |
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+ | #include <complex> |
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+ | using namespace std; |
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+ | #define z_type complex<double> |
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+ | #define DB double |
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+ | |||
+ | #include "fafo.cin" |
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+ | #include "ado.cin" |
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+ | #define DO(x,y) for(x=0;x<y;x++) |
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+ | |||
+ | main(){ int m,M=64, n,N=64; DB x,y, dx,dy, u,v, s,t; |
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+ | z_type c,z; |
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+ | FILE *o; |
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+ | o=fopen("fafo2test2.eps","w"); ado(o, 10*M+2, 10*N+2); |
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+ | fprintf(o,"1 1 translate\n"); |
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+ | fprintf(o,"10 10 scale\n"); |
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+ | z_type *A; A=(z_type *)malloc((size_t)((M*N)*sizeof(z_type))); |
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+ | z_type *b; b=(z_type *)malloc((size_t)((M)*sizeof(z_type))); |
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+ | |||
+ | // Assuming M >= N |
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+ | dx=sqrt(2.*M_PI/M); |
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+ | dy=sqrt(2.*M_PI/N); |
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+ | DO(m,M){ x=dx*(m-M/2.); |
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+ | DO(n,N){ y=dy*(n-N/2.); if(.3*x*x+.2*y*y >2.1) A[n*M+m]=0.; else A[n*M+m]=1.; |
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+ | if(fabs(x)<.8 && fabs(y+1.7)<.3 ) A[n*M+m]-=1.; |
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+ | if( (fabs(x-1.)<.3 || fabs(x+1.)<.3 ) && fabs(y-.8)<.2 ) A[n*M+m]-=1.; |
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+ | }} |
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+ | |||
+ | // Fourier: |
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+ | DO(m,M){ DO(n,N) b[n]=A[n*M+m]; fafo(b,N,1); DO(n,N) A[n*M+m]=b[n]; } |
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+ | DO(n,N){ DO(m,M) b[m]=A[n*M+m]; fafo(b,M,1); DO(m,M) A[n*M+m]=b[m]; } |
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+ | |||
+ | DO(m,M){ x=dx*(m-M/2.); |
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+ | DO(n,N){ y=dy*(n-N/2.); s=x*x+y*y; A[n*M+m]*=exp(-.04*s); }} |
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+ | |||
+ | DO(m,M){ DO(n,N) b[n]=A[n*M+m]; fafo(b,N,-1); DO(n,N) A[n*M+m]=b[n]; } |
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+ | DO(n,N){ DO(m,M) b[m]=A[n*M+m]; fafo(b,M,-1); DO(m,M) A[n*M+m]=b[m]; } |
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+ | |||
+ | fprintf(o,"gsave\n"); |
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+ | fprintf(o,"%2d %2d scale\n",M,N); |
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+ | fprintf(o,"%2d %2d 4 [%2d 0 0 %2d 0 %2d]\n<", M,N,M,-N,N); |
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+ | |||
+ | s=0; DO(m,M) DO(n,N){ t=abs(A[n*M+m]); if(t>s) s=t; } |
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+ | s=15./s; |
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+ | |||
+ | for(n=N-1;n>=0;n--) { fprintf(o,"\n"); |
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+ | DO(m,M){ fprintf(o,"%1x",int(s*abs(A[n*M+m])+.6) ); |
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+ | }} |
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+ | fprintf(o,"\n>\n"); |
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+ | fprintf(o,"image\n"); |
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+ | free(A); |
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+ | fprintf(o,"grestore\n"); |
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+ | #define M(x,y) fprintf(o,"%6.3f %6.3f M\n",0.+x,0.+y); |
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+ | #define L(x,y) fprintf(o,"%6.3f %6.3f L\n",0.+x,0.+y); |
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+ | M(M/2.+.5,-1); L(M/2+.5,N+1); |
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+ | M(-1,N/2.+.5); L(M+1,N/2.+.5); |
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+ | fprintf(o,"1 0 0 RGB .1 W S\n"); |
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+ | fprintf(o,"showpage\n%c%cTrailer\n",'%','%'); fclose(o); |
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+ | system("epstopdf fafo2test2.eps"); |
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+ | system( "convert fafo2test2.eps fafo2test2.gif"); |
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+ | system( "convert fafo2test2.eps fafo2test2.png"); |
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+ | system( "open fafo2test2.png"); |
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+ | } |
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+ | |||
+ | ==Resulting EPS== |
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+ | |||
+ | %!PS-Adobe-2.0 EPSF-2.0 |
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+ | |||
+ | %%BoundingBox: 0 0 642 642 |
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+ | |||
+ | /M {moveto} bind def |
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+ | /L {lineto} bind def |
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+ | /S {stroke} bind def |
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+ | /s {show newpath} bind def |
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+ | /C {closepath} bind def |
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+ | /F {fill} bind def |
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+ | /o {.1 0 360 arc C S} bind def |
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+ | /times-Roman findfont 20 scalefont setfont |
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+ | /W {setlinewidth} bind def |
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+ | /RGB {setrgbcolor} bind def |
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+ | 1 1 translate |
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+ | 10 10 scale |
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+ | gsave |
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+ | 64 64 scale |
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+ | 64 64 4 [64 0 0 -64 0 64] |
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+ | < |
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+ | 0000000000000000000000000000000000000000000000000000000000000000 |
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+ | 0000000000000000000000000000000000000000000000000000000000000000 |
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+ | 0000000000000000000000000000000000000000000000000000000000000000 |
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+ | 0000000000000000000000000000000000000000000000000000000000000000 |
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+ | 0000000000000000000000000000000000000000000000000000000000000000 |
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+ | 0000000000000000000000000000000000000000000000000000000000000000 |
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+ | 0000000000000000000000000000000000000000000000000000000000000000 |
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+ | 0000000000000000000000000000000000000000000000000000000000000000 |
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+ | 0000000000000000000000000000000000000000000000000000000000000000 |
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+ | 0000000000000000000000000000000000000000000000000000000000000000 |
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+ | 0000000000000000000000000000000000000000000000000000000000000000 |
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+ | 0000000000000000000000000000000000000000000000000000000000000000 |
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+ | 0000000000000000000000000000000000000000000000000000000000000000 |
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+ | 0000000000000000000000000000000000000000000000000000000000000000 |
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+ | 0000000000000000000000000000000000000000000000000000000000000000 |
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+ | 0000000000000000000000000000000000000000000000000000000000000000 |
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+ | 0000000000000000000000000000000000000000000000000000000000000000 |
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+ | 0000000000000000000000000000000000000000000000000000000000000000 |
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+ | 0000000000000000000000000000000000000000000000000000000000000000 |
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+ | 0000000000000000000000000000001111100000000000000000000000000000 |
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+ | 0000000000000000000000000000123444321000000000000000000000000000 |
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+ | 0000000000000000000000000002469bbb964200000000000000000000000000 |
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+ | 00000000000000000000000000259cdeeedc9520000000000000000000000000 |
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+ | 000000000000000000000000025adfffffffda52000000000000000000000000 |
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+ | 000000000000000000000000149dfffffffffd94100000000000000000000000 |
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+ | 00000000000000000000000026cefffffffffec6200000000000000000000000 |
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+ | 00000000000000000000000149dfffffffffffd9410000000000000000000000 |
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+ | 0000000000000000000000026ceeccefffecceec620000000000000000000000 |
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+ | 0000000000000000000000139dec88cfffc88ced931000000000000000000000 |
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+ | 000000000000000000000014befc88cfffc88cfeb41000000000000000000000 |
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+ | 000000000000000000000014befeccefffeccefeb41000000000000000000000 |
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+ | 000000000000000000000014bfffffffffffffffb41000000000000000000000 |
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+ | 000000000000000000000014befffffffffffffeb41000000000000000000000 |
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+ | 000000000000000000000014befffffffffffffeb41000000000000000000000 |
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+ | 0000000000000000000000139dfffffffffffffd931000000000000000000000 |
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+ | 0000000000000000000000026cfffecbbbcefffc620000000000000000000000 |
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+ | 00000000000000000000000149effc85558cffe9410000000000000000000000 |
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+ | 00000000000000000000000026cefc85558cfec6200000000000000000000000 |
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+ | 000000000000000000000000149dfecbbbcefd94100000000000000000000000 |
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+ | 000000000000000000000000025adeeeeeeeda52000000000000000000000000 |
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+ | 00000000000000000000000000259cdeeedc9520000000000000000000000000 |
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+ | 0000000000000000000000000002469bbb964200000000000000000000000000 |
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+ | 0000000000000000000000000000123444321000000000000000000000000000 |
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+ | 0000000000000000000000000000001111100000000000000000000000000000 |
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+ | 0000000000000000000000000000000000000000000000000000000000000000 |
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+ | 0000000000000000000000000000000000000000000000000000000000000000 |
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+ | 0000000000000000000000000000000000000000000000000000000000000000 |
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+ | 0000000000000000000000000000000000000000000000000000000000000000 |
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+ | 0000000000000000000000000000000000000000000000000000000000000000 |
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+ | 0000000000000000000000000000000000000000000000000000000000000000 |
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+ | 0000000000000000000000000000000000000000000000000000000000000000 |
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+ | 0000000000000000000000000000000000000000000000000000000000000000 |
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+ | 0000000000000000000000000000000000000000000000000000000000000000 |
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+ | 0000000000000000000000000000000000000000000000000000000000000000 |
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+ | 0000000000000000000000000000000000000000000000000000000000000000 |
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+ | 0000000000000000000000000000000000000000000000000000000000000000 |
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+ | 0000000000000000000000000000000000000000000000000000000000000000 |
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+ | 0000000000000000000000000000000000000000000000000000000000000000 |
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+ | 0000000000000000000000000000000000000000000000000000000000000000 |
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+ | 0000000000000000000000000000000000000000000000000000000000000000 |
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+ | 0000000000000000000000000000000000000000000000000000000000000000 |
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+ | 0000000000000000000000000000000000000000000000000000000000000000 |
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+ | 0000000000000000000000000000000000000000000000000000000000000000 |
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+ | 0000000000000000000000000000000000000000000000000000000000000000 |
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+ | > |
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+ | image |
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+ | grestore |
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+ | 32.500 -1.000 M |
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+ | 32.500 65.000 L |
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+ | -1.000 32.500 M |
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+ | 65.000 32.500 L |
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+ | 1 0 0 RGB .1 W S |
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+ | showpage |
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+ | %%Trailer |
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+ | ==Keywords== |
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+ | |||
+ | ==References== |
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+ | |||
+ | [[Category:Fourier-2 transform]] |
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+ | [[Category:Filtering of images]] |
Latest revision as of 09:39, 21 June 2013
Filtering of the real array $A$ shown in .
The Fourier-2 transform $B$ of the function $A$ is determines with
- $\displaystyle B(p,q)=\frac{1}{2\pi} \int \int \mathrm d x \mathrm d y \exp(-ipx-iqy) A(x,y)$
The modulus of array $B$ is shown in figure .
The filtered function $\tilde A$ is determined with
- $\displaystyle \tilde A(x,y)=\frac{1}{2\pi} \int \int \mathrm d x \mathrm d y \exp(ipx+iqy)
\exp(-0.04 (p^2+q^2)) B(p,q)$
The generator is copypasted below.
C++ generator
// Files ado.cin and fafo.cin should be in the working directory for the compillation of the code below:
#include<math.h> #include<stdio.h> #include <stdlib.h> #include <complex> using namespace std; #define z_type complex<double> #define DB double
#include "fafo.cin" #include "ado.cin" #define DO(x,y) for(x=0;x<y;x++)
main(){ int m,M=64, n,N=64; DB x,y, dx,dy, u,v, s,t; z_type c,z; FILE *o; o=fopen("fafo2test2.eps","w"); ado(o, 10*M+2, 10*N+2); fprintf(o,"1 1 translate\n"); fprintf(o,"10 10 scale\n"); z_type *A; A=(z_type *)malloc((size_t)((M*N)*sizeof(z_type))); z_type *b; b=(z_type *)malloc((size_t)((M)*sizeof(z_type)));
// Assuming M >= N dx=sqrt(2.*M_PI/M); dy=sqrt(2.*M_PI/N); DO(m,M){ x=dx*(m-M/2.); DO(n,N){ y=dy*(n-N/2.); if(.3*x*x+.2*y*y >2.1) A[n*M+m]=0.; else A[n*M+m]=1.; if(fabs(x)<.8 && fabs(y+1.7)<.3 ) A[n*M+m]-=1.; if( (fabs(x-1.)<.3 || fabs(x+1.)<.3 ) && fabs(y-.8)<.2 ) A[n*M+m]-=1.; }}
// Fourier: DO(m,M){ DO(n,N) b[n]=A[n*M+m]; fafo(b,N,1); DO(n,N) A[n*M+m]=b[n]; } DO(n,N){ DO(m,M) b[m]=A[n*M+m]; fafo(b,M,1); DO(m,M) A[n*M+m]=b[m]; }
DO(m,M){ x=dx*(m-M/2.); DO(n,N){ y=dy*(n-N/2.); s=x*x+y*y; A[n*M+m]*=exp(-.04*s); }}
DO(m,M){ DO(n,N) b[n]=A[n*M+m]; fafo(b,N,-1); DO(n,N) A[n*M+m]=b[n]; } DO(n,N){ DO(m,M) b[m]=A[n*M+m]; fafo(b,M,-1); DO(m,M) A[n*M+m]=b[m]; }
fprintf(o,"gsave\n"); fprintf(o,"%2d %2d scale\n",M,N); fprintf(o,"%2d %2d 4 [%2d 0 0 %2d 0 %2d]\n<", M,N,M,-N,N);
s=0; DO(m,M) DO(n,N){ t=abs(A[n*M+m]); if(t>s) s=t; } s=15./s;
for(n=N-1;n>=0;n--) { fprintf(o,"\n"); DO(m,M){ fprintf(o,"%1x",int(s*abs(A[n*M+m])+.6) ); }} fprintf(o,"\n>\n"); fprintf(o,"image\n"); free(A); fprintf(o,"grestore\n"); #define M(x,y) fprintf(o,"%6.3f %6.3f M\n",0.+x,0.+y); #define L(x,y) fprintf(o,"%6.3f %6.3f L\n",0.+x,0.+y); M(M/2.+.5,-1); L(M/2+.5,N+1); M(-1,N/2.+.5); L(M+1,N/2.+.5); fprintf(o,"1 0 0 RGB .1 W S\n"); fprintf(o,"showpage\n%c%cTrailer\n",'%','%'); fclose(o); system("epstopdf fafo2test2.eps"); system( "convert fafo2test2.eps fafo2test2.gif"); system( "convert fafo2test2.eps fafo2test2.png"); system( "open fafo2test2.png"); }
Resulting EPS
%!PS-Adobe-2.0 EPSF-2.0
%%BoundingBox: 0 0 642 642
/M {moveto} bind def /L {lineto} bind def /S {stroke} bind def /s {show newpath} bind def /C {closepath} bind def /F {fill} bind def /o {.1 0 360 arc C S} bind def /times-Roman findfont 20 scalefont setfont /W {setlinewidth} bind def /RGB {setrgbcolor} bind def 1 1 translate 10 10 scale gsave 64 64 scale 64 64 4 [64 0 0 -64 0 64] < 0000000000000000000000000000000000000000000000000000000000000000 0000000000000000000000000000000000000000000000000000000000000000 0000000000000000000000000000000000000000000000000000000000000000 0000000000000000000000000000000000000000000000000000000000000000 0000000000000000000000000000000000000000000000000000000000000000 0000000000000000000000000000000000000000000000000000000000000000 0000000000000000000000000000000000000000000000000000000000000000 0000000000000000000000000000000000000000000000000000000000000000 0000000000000000000000000000000000000000000000000000000000000000 0000000000000000000000000000000000000000000000000000000000000000 0000000000000000000000000000000000000000000000000000000000000000 0000000000000000000000000000000000000000000000000000000000000000 0000000000000000000000000000000000000000000000000000000000000000 0000000000000000000000000000000000000000000000000000000000000000 0000000000000000000000000000000000000000000000000000000000000000 0000000000000000000000000000000000000000000000000000000000000000 0000000000000000000000000000000000000000000000000000000000000000 0000000000000000000000000000000000000000000000000000000000000000 0000000000000000000000000000000000000000000000000000000000000000 0000000000000000000000000000001111100000000000000000000000000000 0000000000000000000000000000123444321000000000000000000000000000 0000000000000000000000000002469bbb964200000000000000000000000000 00000000000000000000000000259cdeeedc9520000000000000000000000000 000000000000000000000000025adfffffffda52000000000000000000000000 000000000000000000000000149dfffffffffd94100000000000000000000000 00000000000000000000000026cefffffffffec6200000000000000000000000 00000000000000000000000149dfffffffffffd9410000000000000000000000 0000000000000000000000026ceeccefffecceec620000000000000000000000 0000000000000000000000139dec88cfffc88ced931000000000000000000000 000000000000000000000014befc88cfffc88cfeb41000000000000000000000 000000000000000000000014befeccefffeccefeb41000000000000000000000 000000000000000000000014bfffffffffffffffb41000000000000000000000 000000000000000000000014befffffffffffffeb41000000000000000000000 000000000000000000000014befffffffffffffeb41000000000000000000000 0000000000000000000000139dfffffffffffffd931000000000000000000000 0000000000000000000000026cfffecbbbcefffc620000000000000000000000 00000000000000000000000149effc85558cffe9410000000000000000000000 00000000000000000000000026cefc85558cfec6200000000000000000000000 000000000000000000000000149dfecbbbcefd94100000000000000000000000 000000000000000000000000025adeeeeeeeda52000000000000000000000000 00000000000000000000000000259cdeeedc9520000000000000000000000000 0000000000000000000000000002469bbb964200000000000000000000000000 0000000000000000000000000000123444321000000000000000000000000000 0000000000000000000000000000001111100000000000000000000000000000 0000000000000000000000000000000000000000000000000000000000000000 0000000000000000000000000000000000000000000000000000000000000000 0000000000000000000000000000000000000000000000000000000000000000 0000000000000000000000000000000000000000000000000000000000000000 0000000000000000000000000000000000000000000000000000000000000000 0000000000000000000000000000000000000000000000000000000000000000 0000000000000000000000000000000000000000000000000000000000000000 0000000000000000000000000000000000000000000000000000000000000000 0000000000000000000000000000000000000000000000000000000000000000 0000000000000000000000000000000000000000000000000000000000000000 0000000000000000000000000000000000000000000000000000000000000000 0000000000000000000000000000000000000000000000000000000000000000 0000000000000000000000000000000000000000000000000000000000000000 0000000000000000000000000000000000000000000000000000000000000000 0000000000000000000000000000000000000000000000000000000000000000 0000000000000000000000000000000000000000000000000000000000000000 0000000000000000000000000000000000000000000000000000000000000000 0000000000000000000000000000000000000000000000000000000000000000 0000000000000000000000000000000000000000000000000000000000000000 0000000000000000000000000000000000000000000000000000000000000000 > image grestore 32.500 -1.000 M 32.500 65.000 L -1.000 32.500 M 65.000 32.500 L 1 0 0 RGB .1 W S showpage
%%Trailer
Keywords
References
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