fft2rm.c

用c语言实现了图像二维快速傅里叶变换

/* fft2rm.c: fast Fourier transform of 2 dimensional complex array,
 direct and inverse,
 thise program is comtributed by Jiang Youg, 2003. 6 */
#define N1 8
#define N2 8
#include "rowco2r.c"
/*void functf( double A[2][N1][N2] );*/
void main( void )
{
unsigned int i,j;
 double A[2][N1][N2];
double t=0;
FILE *fp;
fp=fopen("t.txt","r");
/*system("cls");
functf( A );*/
for(i=0;i<N1;i++)
{ for(j=0;j<N2;j++)
{A[0][i][j]=(i+1)+(j+1);
printf("%f\n",A[0][i][j]);
}
}
/*fscanf(fp,%3d,A[0][i][j]);*/
printf("The original data, Ak:\n");
fprintf(fp,"The original data, Ak:\n");
/*for(i=0;i<N1;i++)
{ for(j=0;j<N2;j++)
    fprintf(fp,"%4u,%4u: %15.9f,%16.8e\n",i,j,A[0][i][j],A[1][i][j]); }*/
/*A[0][N1][N2]={{1,4,5,4,4,6,4,31},{4,52,4,4,64,4,31,4},{5,41,4,6,14,31,4,5},{14,4,6,64,3,4,4,6}};*/
rowcolumnr( A, 1 );
printf("FFT, direct transform ( A -> x ), x:\n");
fprintf(fp,"FFT, direct transform ( A -> x ), x:\n");
for(i=0;i<N1;i++)
{ 
	for(j=0;j<N2;j++)
{
	/*fprintf(fp,"%4u,%4u: %15.9f,%16.8e\n",i,j,A[0][i][j],A[1][i][j]); */
    
    t=t+A[0][i][j]*A[0][i][j]+A[1][i][j]*A[1][i][j];
	printf("%f\n",t);
}

rowcolumnr( A, -1 );
printf("IFFT, inverse transform ( x -> A ), A:\n");
fprintf(fp,"IFFT, inverse transform ( x -> A ), A:\n");
for(i=0;i<N1;i++)
{ for(j=0;j<N2;j++)
    fprintf(fp,"%4u,%4u: %15.9f,%16.8e\n",i,j,A[0][i][j],A[1][i][j]);  }
fclose(fp);
printf("OK!\n");
}
/*******************************************************************/
/*void functf( double A[2][N1][N2] )
{
unsigned int i,j;
double tti,ttj,dti,dtj,A0i,A1i,A0j,A1j;
dti=0.1;  dtj=dti;
A0i=exp(-N1*dti);  A0j=exp(-N2*dtj);
for(i=0;i<N1;i++)
  { tti=(double)i*dti; A1i=exp(-tti);
    for(j=0;j<N2;j++)
      { ttj=(double)j*dtj; A1j=exp(-ttj);
        A[0][i][j]=(A1i+A0i/A1i)*dti*(A1j+A0j/A1j)*dtj;
        A[1][i][j]=0.0; } }
}*/
}