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/* ----------------------------------------------------------------------------
* GTSAM Copyright 2010, Georgia Tech Research Corporation,
* Atlanta, Georgia 30332-0415
* All Rights Reserved
* Authors: Frank Dellaert, et al. (see THANKS for the full author list)
* See LICENSE for the license information
* -------------------------------------------------------------------------- */
/**
* @file StereoVOExample_large.cpp
* @brief A stereo visual odometry example
* @date May 25, 2014
* @author Stephen Camp
*/
/**
* A 3D stereo visual odometry example
* - robot starts at origin
* -moves forward, taking periodic stereo measurements
* -takes stereo readings of many landmarks
*/
#include <gtsam/geometry/Pose3.h>
#include <gtsam/geometry/Cal3_S2Stereo.h>
#include <gtsam/nonlinear/Values.h>
#include <gtsam/nonlinear/utilities.h>
#include <gtsam/nonlinear/NonlinearEquality.h>
#include <gtsam/nonlinear/NonlinearFactorGraph.h>
#include <gtsam/nonlinear/LevenbergMarquardtOptimizer.h>
#include <gtsam/inference/Symbol.h>
#include <gtsam/slam/StereoFactor.h>
#include <gtsam/slam/dataset.h>
#include <string>
#include <fstream>
#include <iostream>
using namespace std;
using namespace gtsam;
int main(int argc, char** argv) {
Values initial_estimate;
NonlinearFactorGraph graph;
const auto model = noiseModel::Isotropic::Sigma(3, 1);
string calibration_loc = findExampleDataFile("VO_calibration.txt");
string pose_loc = findExampleDataFile("VO_camera_poses_large.txt");
string factor_loc = findExampleDataFile("VO_stereo_factors_large.txt");
// read camera calibration info from file
// focal lengths fx, fy, skew s, principal point u0, v0, baseline b
double fx, fy, s, u0, v0, b;
ifstream calibration_file(calibration_loc.c_str());
cout << "Reading calibration info" << endl;
calibration_file >> fx >> fy >> s >> u0 >> v0 >> b;
// create stereo camera calibration object
const Cal3_S2Stereo::shared_ptr K(new Cal3_S2Stereo(fx, fy, s, u0, v0, b));
ifstream pose_file(pose_loc.c_str());
cout << "Reading camera poses" << endl;
int pose_id;
MatrixRowMajor m(4, 4);
// read camera pose parameters and use to make initial estimates of camera
// poses
while (pose_file >> pose_id) {
for (int i = 0; i < 16; i++) {
pose_file >> m.data()[i];
}
initial_estimate.insert(Symbol('x', pose_id), Pose3(m));
}
// camera and landmark keys
size_t x, l;
// pixel coordinates uL, uR, v (same for left/right images due to
// rectification) landmark coordinates X, Y, Z in camera frame, resulting from
// triangulation
double uL, uR, v, X, Y, Z;
ifstream factor_file(factor_loc.c_str());
cout << "Reading stereo factors" << endl;
// read stereo measurement details from file and use to create and add
// GenericStereoFactor objects to the graph representation
while (factor_file >> x >> l >> uL >> uR >> v >> X >> Y >> Z) {
graph.emplace_shared<GenericStereoFactor<Pose3, Point3> >(
StereoPoint2(uL, uR, v), model, Symbol('x', x), Symbol('l', l), K);
// if the landmark variable included in this factor has not yet been added
// to the initial variable value estimate, add it
if (!initial_estimate.exists(Symbol('l', l))) {
Pose3 camPose = initial_estimate.at<Pose3>(Symbol('x', x));
// transformFrom() transforms the input Point3 from the camera pose space,
// camPose, to the global space
Point3 worldPoint = camPose.transformFrom(Point3(X, Y, Z));
initial_estimate.insert(Symbol('l', l), worldPoint);
}
}
Pose3 first_pose = initial_estimate.at<Pose3>(Symbol('x', 1));
// constrain the first pose such that it cannot change from its original value
// during optimization
// NOTE: NonlinearEquality forces the optimizer to use QR rather than Cholesky
// QR is much slower than Cholesky, but numerically more stable
graph.emplace_shared<NonlinearEquality<Pose3> >(Symbol('x', 1), first_pose);
cout << "Optimizing" << endl;
// create Levenberg-Marquardt optimizer to optimize the factor graph
LevenbergMarquardtParams params;
params.orderingType = Ordering::METIS;
LevenbergMarquardtOptimizer optimizer(graph, initial_estimate, params);
Values result = optimizer.optimize();
cout << "Final result sample:" << endl;
Values pose_values = utilities::allPose3s(result);
pose_values.print("Final camera poses:\n");
return 0;
}
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