float getFFTCorrelation(complexFloat *igram,int sizeX,int sizeY)
{
int line, samp;
int fftpowr;
float ampTmp=0;
float maxAmp=0;
complexFloat *fftBuf;
complexFloat *fftTemp;
complexFloat *fft;
/* fftBuf=(complexFloat *)MALLOC(sizeof(complexFloat)*sizeX);*/
fft=(complexFloat *)MALLOC(sizeof(complexFloat)*sizeX*sizeX);
fftTemp=(complexFloat *)MALLOC(sizeof(complexFloat)*sizeX*sizeX);
fftpowr=(log(sizeX)/log(2));
fftInit(fftpowr);
/* Compute the 2d complex FFT since no libraries exist to do this */
/* First do the FFT of each line*/
for(line=0;line<sizeX;line++)
{
fftBuf=&igram[line*sizeX];
ffts((float *)fftBuf,fftpowr,1);
for(samp=0;samp<sizeX;samp++)
{
fftTemp[line*sizeX+samp].real=fftBuf[samp].real;
fftTemp[line*sizeX+samp].imag=fftBuf[samp].imag;
}
}
/* Now do the FFT of the columns of the FFT'd lines */
for(samp=0;samp<sizeX;samp++)
{
/* Fill up the FFT buffer */
for(line=0;line<sizeX;line++)
{
fftBuf[line].real=fftTemp[line*sizeX+samp].real;
fftBuf[line].imag=fftTemp[line*sizeX+samp].imag;
}
/* Do the FFT */
ffts((float *)fftBuf,fftpowr,1);
for(line=0;line<sizeX;line++)
{
fft[line*sizeX+samp].real=fftBuf[line].real;
fft[line*sizeX+samp].imag=fftBuf[line].imag;
}
}
free(fftTemp);
fftFree();
/* Now we have a two dimension FFT that we can search to find the max value */
for(line=0;line<sizeX;line++)
{
for(samp=0;samp<sizeX;samp++)
{
ampTmp=sqrt(fft[line*sizeX+samp].real*fft[line*sizeX+samp].real+fft[line*sizeX+samp].imag*fft[line*sizeX+samp].imag);
if(ampTmp>maxAmp)
maxAmp=ampTmp;
}
}
free(fft);
return maxAmp;
}
void main(){
const long N2 = 2; /* the number ffts to test */
long N = 2048; /* size of FFTs, must be power of 2 */
long kernSize = 1003; /* kernal size must be less than N */
long dataSize = N-kernSize+1; /* data size */
float *a;
float *b;
long i1;
long i2;
long TheErr;
long M;
FILE *fdataout; /* output file */
unsigned int randseed = 777;
int rannum;
#if macintosh
UnsignedWide TheTime1;
Microseconds(&TheTime1);
randseed = TheTime1.lo;
#endif
printf(" %6d Byte Floats \n", sizeof(a[0]));
printf(" randseed = %10u\n", randseed);
srand(randseed);
M = roundtol(LOG2(N));
N = POW2(M);
printf("fft size = %6d, ", N);
if (dataSize <= 0) TheErr = 22;
else TheErr = 0;
if(!TheErr){
TheErr = fftInit(M);
}
a = (float *) calloc(N2*N,sizeof(float) ); // calloc to zero pad data to fill N
if (a == 0) TheErr = 2;
if(!TheErr){
b = (float *) calloc(N2*N,sizeof(float) ); // calloc to zero pad data to fill N
if (b == 0) TheErr = 2;
}
if(!TheErr){
fdataout = fopen("convdat.cnv", "wb");
if (fdataout == NULL) TheErr = -50;
}
if(!TheErr){
/* write sizes to fdataout */
fwrite(&dataSize, sizeof(dataSize), 1, fdataout);
fwrite(&kernSize, sizeof(kernSize), 1, fdataout);
fwrite(&N2, sizeof(N2), 1, fdataout);
/* set up a simple test case and write to fdataout */
for (i2=0; i2<N2; i2++){
for (i1=0; i1<dataSize; i1++){
rannum = rand();
a[i2*N+i1] = BIPRAND(rannum);
}
fwrite(&a[i2*N], dataSize*sizeof(float), 1, fdataout);
}
for (i2=0; i2<N2; i2++){
for (i1=0; i1<kernSize; i1++){
rannum = rand();
b[i2*N+i1] = BIPRAND(rannum);
}
fwrite(&b[i2*N], kernSize*sizeof(float), 1, fdataout);
}
/* fast convolution of zero padded sequences */
rffts(a, M, N2);
rffts(b, M, N2);
for (i2=0; i2<N2*N; i2+=N){
rspectprod(&a[i2], &b[i2], &a[i2], N);
}
riffts(a, M, N2);
/* write out answer */
fwrite(a, N2*N*sizeof(float), 1, fdataout);
fclose(fdataout);
free(b);
free(a);
fftFree();
}
else{
if(TheErr==2) printf(" out of memory \n");
else printf(" error \n");
fftFree();
}
printf(" Done. \n");
return;
}