point random_sample(point p, bool (*inside)(const point), int niter) {
point cur_point(p.n), next_point(p.n), delta(p.n);
cur_point = p;
real eps = 0.1;
for(int iter = 0; iter < niter; iter++) {
next_point = cur_point;
random_unit_ball(&delta);
delta *= eps;
next_point += delta;
if(inside(next_point)) {
cur_point = next_point;
}
}
return cur_point;
}
void TractCluster::add_tract(const float* points,unsigned int count)
{
unsigned int tract_index = tract_labels.size();
tract_labels.push_back(0);
tract_length.push_back(count);
// get the passed region and the regoin with error
std::vector<unsigned short> passed_points;
std::vector<unsigned short> ranged_points;
const float* points_end = points + count;
for (;points_end != points;points += 3)
{
image::vector<3,float> cur_point(points);
cur_point /= error_distance;
cur_point += 0.5;
cur_point.floor();
if(!dim.is_valid(cur_point))
continue;
image::pixel_index<3> center(cur_point[0],cur_point[1],cur_point[2],dim);
passed_points.push_back(center.index() & 0xFFFF);
std::vector<image::pixel_index<3> > iterations;
image::get_neighbors(center,dim,iterations);
for(unsigned int index = 0;index < iterations.size();++index)
if (dim.is_valid(iterations[index]))
ranged_points.push_back(iterations[index].index() & 0xFFFF);
}
// delete repeated points
{
std::set<unsigned short> unique_passed_points(passed_points.begin(),passed_points.end());
passed_points = std::vector<unsigned short>(unique_passed_points.begin(),unique_passed_points.end());
std::set<unsigned short> unique_ranged_points(ranged_points.begin(),ranged_points.end());
ranged_points = std::vector<unsigned short>(unique_ranged_points.begin(),unique_ranged_points.end());
}
// get the eligible fibers for merging, and also register the ending points
std::vector<unsigned int> passing_tracts;
if(passed_points.empty() || ranged_points.empty())
goto end;
{
const std::vector<unsigned int>* connection_set = add_connection(passed_points.front(),tract_index);
passing_tracts.insert(passing_tracts.end(),connection_set->begin(),connection_set->end());
connection_set = add_connection(passed_points.back(),tract_index);
passing_tracts.insert(passing_tracts.end(),connection_set->begin(),connection_set->end());
passing_tracts.erase(std::remove(passing_tracts.begin(),passing_tracts.end(),tract_index),passing_tracts.end());
std::set<unsigned int> unique_tracts(passing_tracts.begin(),passing_tracts.end());
passing_tracts = std::vector<unsigned int>(unique_tracts.begin(),unique_tracts.end());
}
// check each tract to see if anyone is included in the error range
{
std::vector<unsigned int>::const_iterator iter = passing_tracts.begin();
std::vector<unsigned int>::const_iterator end = passing_tracts.end();
for (;iter !=end;++iter)
{
unsigned int cur_index = *iter;
Cluster* label1 = tract_labels.back();
Cluster* label2 = tract_labels[cur_index];
if (label1 != 0 && label1 == label2)
continue;
unsigned int cur_count = tract_length[cur_index];
float dif = cur_count;
dif -= (float) count;
dif /= (float)std::max(cur_count,count);
if (std::abs(dif) > 0.2)
continue;
if (std::includes(ranged_points.begin(),ranged_points.end(),
tract_passed_voxels[cur_index].begin(),tract_passed_voxels[cur_index].end()) &&
std::includes(tract_ranged_voxels[cur_index].begin(),tract_ranged_voxels[cur_index].end(),
passed_points.begin(),passed_points.end()))
merge_tract(tract_index,cur_index);
}
}
end:
tract_passed_voxels.push_back(std::vector<unsigned short>());
tract_passed_voxels.back().swap(passed_points);
tract_ranged_voxels.push_back(std::vector<unsigned short>());
tract_ranged_voxels.back().swap(ranged_points);
}