bool
vpHomography::degenerateConfiguration(const std::vector<double> &xb, const std::vector<double> &yb,
const std::vector<double> &xa, const std::vector<double> &ya)
{
unsigned int n = (unsigned int)xb.size();
if (n < 4)
throw(vpException(vpException::fatalError, "There must be at least 4 matched points"));
std::vector<vpColVector> pa(n), pb(n);
for (unsigned i=0; i<n;i++) {
pa[i].resize(3);
pa[i][0] = xa[i];
pa[i][1] = ya[i];
pa[i][2] = 1;
pb[i].resize(3);
pb[i][0] = xb[i];
pb[i][1] = yb[i];
pb[i][2] = 1;
}
for (unsigned int i = 0; i < n-2; i++) {
for (unsigned int j = i+1; j < n-1; j++) {
for (unsigned int k = j+1; k < n ; k++)
{
if (isColinear(pa[i], pa[j], pa[k])) {
return true;
}
if (isColinear(pb[i], pb[j], pb[k])){
return true;
}
}
}
}
return false;
}
static void stripColinear(gdPointPtr tpts, int *num_pts){
int total = 0;
int i;
gdPointPtr npts, first, second;
if (*num_pts <= 2){
return;
}
npts = (gdPointPtr)umalloc(sizeof(gdPoint) * *num_pts);
assert(npts);
first = tpts;
second = tpts+1;
for (i=2; i < *num_pts; ++i){
gdPointPtr third = &tpts[i];
if (isColinear(first, second, third)){
second = third;
} else {
npts[total].x = first->x;
npts[total].y = first->y;
++total;
first = second;
second = third;
}
}
npts[total].x = first->x;
npts[total].y = first->y;
++total;
npts[total].x = second->x;
npts[total].y = second->y;
++total;
memcpy(tpts, npts, sizeof(gdPoint)*total);
free(npts);
*num_pts = total;
#ifdef DEBUG
printf("--------------------------------------\n");
for (i=0; i < total; ++i){
printf("strip: (%d, %d)\n", tpts[i].x, tpts[i].y);
}
#endif
}