//! Populate IpPairVec with matched ipts
void getMatches(IpVec &ipts1, IpVec &ipts2, IpPairVec &matches) {
float dist, d1, d2;
Ipoint *match;
matches.clear();
for (unsigned int i = 0; i < ipts1.size(); i++) {
d1 = d2 = 1000;
for (unsigned int j = 0; j < ipts2.size(); j++) {
dist = ipts1[i] - ipts2[j];
if (dist < d1) // if this feature matches better than current best
{
d2 = d1;
d1 = dist;
match = &ipts2[j];
} else if (dist < d2) // this feature matches better than second best
{
d2 = dist;
}
}
// If match has a d1:d2 ratio < 0.65 ipoints are a match
if (d1 / d2 < 0.65) {
// Store the change in position
ipts1[i].dx = match->x - ipts1[i].x;
ipts1[i].dy = match->y - ipts1[i].y;
match->dx = ipts1[i].x -match->x;
match->dy = ipts1[i].y -match->y;
matches.push_back(std::make_pair(ipts1[i], *match));
}
}
}
//! Populate IpPairVec with matched ipts using nearest neighbour and RANSAC
Score getMatchesRANSAC(IpVec &ipts1, IpVec &ipts2, IpPairVec &matches)
{
#if RUNSWIFT
#else
timespec matchings, matchinge, verifys, verifye;
clock_gettime(CLOCK_PROCESS_CPUTIME_ID, &matchings);
#endif
float dist, d1, d2;
Ipoint *match;
float matching_score = 0;
matches.clear();
for(unsigned int i = 0; i < ipts1.size(); i++)
{
ipts1[i].x = ipts1[i].x;
d1 = d2 = FLT_MAX;
match = &ipts2[0]; // to avoid unitialized warning
for(unsigned int j = 0; j < ipts2.size(); j++)
{
ipts2[j].x = ipts2[j].x;
dist = ipts1[i] - ipts2[j];
if(dist<d1) // if this feature matches better than current best
{
d2 = d1;
d1 = dist;
match = &ipts2[j];
}
else if(dist<d2) // this feature matches better than second best
{
d2 = dist;
}
}
// If match has a d1:d2 ratio < 0.75 ipoints are a match
if(d1/d2 < 0.75)
{
// Store the match
matches.push_back(std::make_pair(ipts1[i], *match));
//Increment the matching score
matching_score += 1/d1;
}
}
float best_score = matching_score;
float best_b = -1;
float best_m = -1;
#if RUNSWIFT
#else
Ipoint::totalNumMatches = matches.size();
//At this point we have the total matches before the final number of matches
clock_gettime(CLOCK_PROCESS_CPUTIME_ID, &verifys);
#endif
if(matches.size()>1){
best_score = 0;
for(int i=0; i<ITERATIONS; i++){
//Choose random matches
int pos1 = rand() % (int)matches.size();
int pos2 = rand() % (int)matches.size();
while(pos1 == pos2) {
//Make sure that both matches are different
pos2 = rand() % (int)matches.size();
}
//Should generate a positive value
float m = (matches.at(pos2).second.x - matches.at(pos1).second.x)/(matches.at(pos2).first.x - matches.at(pos1).first.x);
//If a gradient is discarded
if (m <= 0){
continue;
}
//Calculate the translation component
float b = matches.at(pos2).second.x - m*matches.at(pos2).first.x;
float score = 0;
for(int j=0; j<(int)matches.size(); j++){
//Calculate the function x_stored,i = b_s * x_test,i + b_d
if( fabs(matches.at(j).second.x - (m*matches.at(j).first.x + b)) < PIXEL_ERROR_MARGIN)
score += 1/fabs(matches.at(j).first - matches.at(j).second);
}
if (score > best_score){
best_score = score;
best_b = b;
best_m = m;
}
}
}
// Now remove all matches who are not within this pixel error margin
//if(best_m > 0){
for(int j=0; j<(int)matches.size(); j++){
if( fabs(matches.at(j).second.x - (best_m*matches.at(j).first.x + best_b)) >= PIXEL_ERROR_MARGIN) {
matches.erase(matches.begin() + j);
j--;
}
}
//}
Score score = {best_score, best_m, best_b};
#if RUNSWIFT
#else
Ipoint::numValidMatches = matches.size();
clock_gettime(CLOCK_PROCESS_CPUTIME_ID, &verifye);
Ipoint::verificationTime = Ipoint::diffSurf(verifys,verifye).tv_nsec/1000000.0f;
clock_gettime(CLOCK_PROCESS_CPUTIME_ID, &matchinge);
Ipoint::matchingTime = Ipoint::diffSurf(matchings,matchinge).tv_nsec/1000000.0f;
#endif
return score;
}