82 lines
2.4 KiB
C++
82 lines
2.4 KiB
C++
/* ----------------------------------------------------------------------------
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* GTSAM Copyright 2010, Georgia Tech Research Corporation,
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* Atlanta, Georgia 30332-0415
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* All Rights Reserved
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* Authors: Frank Dellaert, et al. (see THANKS for the full author list)
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* See LICENSE for the license information
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* -------------------------------------------------------------------------- */
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/**
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* @file triangulation.cpp
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* @brief Functions for triangulation
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* @author Chris Beall
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*/
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#include <gtsam_unstable/geometry/triangulation.h>
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#include <gtsam/geometry/SimpleCamera.h>
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#include <boost/foreach.hpp>
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#include <boost/assign.hpp>
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#include <boost/assign/std/vector.hpp>
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using namespace std;
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using namespace boost::assign;
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namespace gtsam {
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/* ************************************************************************* */
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// See Hartley and Zisserman, 2nd Ed., page 312
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Point3 triangulateDLT(const vector<Matrix>& projection_matrices,
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const vector<Point2>& measurements) {
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Matrix A = Matrix_(projection_matrices.size() *2, 4);
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for(size_t i=0; i< projection_matrices.size(); i++) {
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size_t row = i*2;
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const Matrix& projection = projection_matrices.at(i);
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const Point2& p = measurements.at(i);
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// build system of equations
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A.row(row) = p.x() * projection.row(2) - projection.row(0);
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A.row(row+1) = p.y() * projection.row(2) - projection.row(1);
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}
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int rank;
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double error;
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Vector v;
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boost::tie(rank, error, v) = DLT(A);
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return Point3(sub( (v / v(3)),0,3));
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}
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/* ************************************************************************* */
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boost::optional<Point3> triangulatePoint3(const vector<Pose3>& poses,
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const vector<Point2>& measurements, const Cal3_S2& K) {
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assert(poses.size() == measurements.size());
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if(poses.size() < 2)
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return boost::none;
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vector<Matrix> projection_matrices;
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// construct projection matrices from poses & calibration
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BOOST_FOREACH(const Pose3& pose, poses)
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projection_matrices += K.matrix() * sub(pose.inverse().matrix(),0,3,0,4);
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Point3 triangulated_point = triangulateDLT(projection_matrices, measurements);
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// verify that the triangulated point lies infront of all cameras
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BOOST_FOREACH(const Pose3& pose, poses) {
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const Point3& p_local = pose.transform_to(triangulated_point);
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if(p_local.z() <= 0)
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return boost::none;
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}
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return triangulated_point;
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}
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/* ************************************************************************* */
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} // namespace gtsam
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