-/*
+ /*
Copyright (C) 2012 Simon A. Eugster (Granjow) <simon.eu@gmail.com>
This file is part of kdenlive. See www.kdenlive.org.
// The correlation vector will have entries up to N (number of entries
// of the vector), so converting to integers will not lose that much
// of precision.
- for (int i = 0; i < leftSize+rightSize+1; i++) {
+ for (int i = 0; i < leftSize+rightSize+1; ++i) {
out_correlated[i] = correlatedFloat[i];
}
}
// Dividing by the max value is maybe not the best solution, but the
// maximum value after correlation should not be larger than the longest
// vector since each value should be at most 1
- int64_t maxLeft = 0;
- int64_t maxRight = 0;
- for (int i = 0; i < leftSize; i++) {
+ int64_t maxLeft = 1;
+ int64_t maxRight = 1;
+ for (int i = 0; i < leftSize; ++i) {
if (labs(left[i]) > maxLeft) {
maxLeft = labs(left[i]);
}
}
- for (int i = 0; i < rightSize; i++) {
+ for (int i = 0; i < rightSize; ++i) {
if (labs(right[i]) > maxRight) {
maxRight = labs(right[i]);
}
// One side needs to be reverted, since multiplication in frequency domain (fourier space)
// calculates the convolution: \sum l[x]r[N-x] and not the correlation: \sum l[x]r[x]
- for (int i = 0; i < leftSize; i++) {
+ for (int i = 0; i < leftSize; ++i) {
leftF[i] = double(left[i])/maxLeft;
}
- for (int i = 0; i < rightSize; i++) {
+ for (int i = 0; i < rightSize; ++i) {
rightF[rightSize-1 - i] = double(right[i])/maxRight;
}
// Now we can convolve to get the correlation
- convolute(leftF, leftSize, rightF, rightSize, out_correlated);
+ convolve(leftF, leftSize, rightF, rightSize, out_correlated);
std::cout << "Correlation (FFT based) computed in " << t.elapsed() << " ms." << std::endl;
}
-void FFTCorrelation::convolute(const float *left, const int leftSize,
+void FFTCorrelation::convolve(const float *left, const int leftSize,
const float *right, const int rightSize,
float *out_convolved)
{
kiss_fftr(fftConfig, rightData, rightFFT);
// Convolution in spacial domain is a multiplication in fourier domain. O(n).
- for (int i = 0; i < size/2; i++) {
+ for (int i = 0; i < size/2; ++i) {
correlatedFFT[i].r = leftFFT[i].r*rightFFT[i].r - leftFFT[i].i*rightFFT[i].i;
correlatedFFT[i].i = leftFFT[i].r*rightFFT[i].i + leftFFT[i].i*rightFFT[i].r;
}