void
SVCandidateProcessor::
evaluateCandidates(
const EdgeInfo& edge,
const std::vector<SVMultiJunctionCandidate>& mjSVs,
const SVCandidateSetData& svData)
{
const bool isIsolatedEdge(testIsolatedEdge(_cset,edge));
bool isFindLargeInsertions(isIsolatedEdge);
if (isFindLargeInsertions)
{
for (const SVMultiJunctionCandidate& mjCandidateSV : mjSVs)
{
for (const SVCandidate& candidateSV : mjCandidateSV.junction)
{
if (! isComplexSV(candidateSV)) isFindLargeInsertions=false;
}
}
}
_svRefine.clearEdgeData();
for (const auto& cand : mjSVs)
{
evaluateCandidate(edge,cand,svData,isFindLargeInsertions);
}
}
GridFitter::candidate_set GridFitter::getInitialCandidates(const cv::Mat &binarizedROI, const cv::Mat& sobelXRoi, const cv::Mat& sobelYRoi, const Ellipse& ellipse_orig, const cv::Mat &roi)
{
static const auto initial_rotations = Util::linspace<double>(0, 2 * CV_PI - CV_PI / 32., 32);
static const auto initial_position_offsets = Util::linspace<int>(-3, 3, 7);
// initial search for gradient descent candidates in ellipse parameter space
// note that the position offsets have to be evaluated in the inner loop
// because shifting a known grid configuration is much faster than
// recalculating all coordinates.
candidate_set gridCandidates;
for (const double rotation : initial_rotations) {
// get the best candidates for the current rotation
candidate_set candidatesForRotation;
// estimate grid parameters from ellipse -> two possible candidates
const std::array<Util::gridconfig_t, 2> configCandidates =
Util::gridCandidatesFromEllipse(ellipse_orig, rotation);
for (Util::gridconfig_t const& config : configCandidates) {
PipelineGrid grid(config);
for (const int pos_x_offset : initial_position_offsets) {
for (const int pos_y_offset : initial_position_offsets) {
grid.setCenter({config.center.x + pos_x_offset, config.center.y + pos_y_offset});
const double error = evaluateCandidate(grid, roi, binarizedROI, sobelXRoi, sobelYRoi, _settings_cache);
candidatesForRotation.insert({error, grid.getConfig()});
}
}
// for each rotation and ellipse candidate, insert the best candiate into gridCandidates
gridCandidates.insert(*candidatesForRotation.begin());
}
}
return gridCandidates;
}
void GridFitter::GradientDescent::optimize()
{
const size_t num = std::min(_settings.gradient_num_initial, _initialCandidates.size());
candidate_set::iterator candidate_it = _initialCandidates.begin();
// iterate over the settings.numInitial best initial candidates
for (size_t idx = 0; idx < num; ++idx) {
candidate_t candidate = *candidate_it;
const Util::gridconfig_t& initial_config = candidate.config;
size_t iteration = 0;
PipelineGrid grid(initial_config);
Util::gridconfig_t config = initial_config;
double error = evaluateCandidate(grid, _roi, _binarizedRoi, _edgeRoiX, _edgeRoiY, _settings);
storeConfig(error, config);
candidate_set bestGridsForCandidate;
bestGridsForCandidate.insert(candidate);
std::array<StepParameter, 6> parameters { SCALE, POSX, POSY, ANGLE_X, ANGLE_Y, ANGLE_Z };
// gradient descent
size_t numWithoutImprovement = 0;
while ((error > _settings.gradient_error_threshold) && (iteration < _settings.gradient_max_iterations)) {
double const initerror = error;
// shuffle order of parameters
//std::shuffle(parameters.begin(), parameters.end(), _random_engine);
for (const StepParameter param : parameters) {
std::tie(error, config) = step(bestGridsForCandidate, config, error, param);
}
++iteration;
// abort gradient descent if error measurement did not improve by
// a significant amount during the last six steps
assert(!bestGridsForCandidate.empty());
if ((initerror - bestGridsForCandidate.begin()->error) < 0.0001) {
++numWithoutImprovement;
if (numWithoutImprovement >= 5) break;
} else {
numWithoutImprovement = 0;
}
// instead of continuing the next iteration with the result of the
// last step, use the best currently found config from now on.
error = bestGridsForCandidate.begin()->error;
config = bestGridsForCandidate.begin()->config;
}
assert(!bestGridsForCandidate.empty());
storeConfig(bestGridsForCandidate.begin()->error, bestGridsForCandidate.begin()->config);
++candidate_it;
}
}
std::pair<double, Util::gridconfig_t> GridFitter::GradientDescent::step(candidate_set &bestGrids, Util::gridconfig_t const& config, double error, const GridFitter::GradientDescent::StepParameter param)
{
// when adjusting one of the position parameters, we can not adjust the step
// size based on the difference between of the errors and the learning rate
// (because the coordinates are discrete values).
// instead, in each step we only change the position by either 1 or -1.
// furthermore, if the error does not improve after a position change,
// instead of just applying the reverse direction, we check if the error
// acutally improves when going in the reverse direction.
static const std::array<int, 2> directions {-1, 1};
const double alpha = _settings.alpha;
const double eps_scale = _settings.eps_scale;
const int eps_pos = _settings.eps_pos;
const double eps_angle = _settings.eps_angle;
for (int direction : directions) {
Util::gridconfig_t newConfig(config);
// adjust parameter
switch (param) {
case SCALE:
newConfig.radius = newConfig.radius + direction * eps_scale;
break;
case POSX:
newConfig.center = newConfig.center + cv::Point2i(direction * eps_pos, 0);
break;
case POSY:
newConfig.center = newConfig.center + cv::Point2i(0, direction * eps_pos);
break;
case ANGLE_X:
newConfig.angle_x = newConfig.angle_x + direction * eps_angle;
break;
case ANGLE_Y:
newConfig.angle_y = newConfig.angle_y + direction * eps_angle;
break;
case ANGLE_Z:
newConfig.angle_z = newConfig.angle_z + direction * eps_angle;
break;
default:
assert(false);
break;
}
// TODO: don't construct new Grid in each step
PipelineGrid newGrid(newConfig);
double newError = evaluateCandidate(newGrid, _roi, _binarizedRoi, _edgeRoiX, _edgeRoiY, _settings);
// adjust parameter based on learning rate and new error
if (param != POSX && param != POSY) {
switch (param) {
case SCALE:
newConfig.radius = config.radius + direction * alpha * (error - newError);
break;
case ANGLE_X:
newConfig.angle_x = config.angle_x + direction * alpha * (error - newError);
break;
case ANGLE_Y:
newConfig.angle_y = config.angle_y + direction * alpha * (error - newError);
break;
case ANGLE_Z:
newConfig.angle_z = config.angle_z + direction * alpha * (error - newError);
break;
default:
break;
}
PipelineGrid newGrid(newConfig);
newError = evaluateCandidate(newGrid, _roi, _binarizedRoi, _edgeRoiX, _edgeRoiY, _settings);
bestGrids.insert({newError, newConfig});
return {newError, newConfig};
} else if (newError < error) {
bestGrids.insert({newError, newConfig});
return {newError, newConfig};
}
}
return {error, config};
}
