//! Interpolate scale-space extrema to subpixel accuracy to form an image feature.
void interpolateExtremum(int r, int c, ResponseLayer *t, ResponseLayer *m, ResponseLayer *b, FastHessian *fh)
{
double xi = 0, xr = 0, xc = 0;
// get the step distance between filters
// check the middle filter is mid way between top and bottom
int filterStep = (m->filter - b->filter);
assert(filterStep > 0 && t->filter - m->filter == m->filter - b->filter);
// Get the offsets to the actual location of the extremum
interpolateStep(r, c, t, m, b, &xi, &xr, &xc );
if( fabs( xi ) < 0.5f && fabs( xr ) < 0.5f && fabs( xc ) < 0.5f )
{
Ipoint ipt;
ipt.x = (float)((c + xc) * t->step);
ipt.y = (float)((r + xr) * t->step);
ipt.scale = (float)((0.1333f) * (m->filter + xi * filterStep));
ipt.laplacian = (int)(getLaplacian(r,c,t,m));
fh->ipts[count] = ipt;
count++;
}
}
//! Interpolate scale-space extrema to subpixel accuracy to form an image feature.
void FastHessian::interpolateExtremum(int r, int c, ResponseLayer *t, ResponseLayer *m, ResponseLayer *b)
{
// get the step distance between filters
// check the middle filter is mid way between top and bottom
int filterStep = (m->filter - b->filter);
assert(filterStep > 0 && t->filter - m->filter == m->filter - b->filter);
// Get the offsets to the actual location of the extremum
double xi = 0, xr = 0, xc = 0;
interpolateStep(r, c, t, m, b, &xi, &xr, &xc );
// If point is sufficiently close to the actual extremum
if( fabs( xi ) < 0.5f && fabs( xr ) < 0.5f && fabs( xc ) < 0.5f )
{
sim::alg::SurfLandmark ipt;
ipt.x = static_cast<float>((c + xc) * t->step);
ipt.y = static_cast<float>((r + xr) * t->step);
ipt.scale = static_cast<float>((0.1333f) * (m->filter + xi * filterStep));
ipt.laplacian_sign = static_cast<int>(m->getLaplacian(r,c,t));
ipts.push_back(ipt);
}
}
