gtsam/gtsam_unstable/examples/SmartProjectionFactorExampl...

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4.1 KiB
C++

/* ----------------------------------------------------------------------------
* 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 SmartProjectionFactorExample.cpp
* @brief A stereo visual odometry example
* @date May 30, 2014
* @author Stephen Camp
* @author Chris Beall
*/
/**
* A smart projection factor example based on stereo data, throwing away the
* measurement from the right camera
* -robot starts at origin
* -moves forward, taking periodic stereo measurements
* -makes monocular observations of many landmarks
*/
#include <gtsam/slam/SmartProjectionPoseFactor.h>
#include <gtsam/slam/dataset.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 <string>
#include <fstream>
#include <iostream>
using namespace std;
using namespace gtsam;
int main(int argc, char** argv){
typedef SmartProjectionPoseFactor<Cal3_S2> SmartFactor;
Values initial_estimate;
NonlinearFactorGraph graph;
const noiseModel::Isotropic::shared_ptr model = noiseModel::Isotropic::Sigma(2,1);
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
cout << "Reading calibration info" << endl;
ifstream calibration_file(calibration_loc.c_str());
double fx, fy, s, u0, v0, b;
calibration_file >> fx >> fy >> s >> u0 >> v0 >> b;
const Cal3_S2::shared_ptr K(new Cal3_S2(fx, fy, s, u0, v0));
cout << "Reading camera poses" << endl;
ifstream pose_file(pose_loc.c_str());
int pose_index;
MatrixRowMajor m(4,4);
//read camera pose parameters and use to make initial estimates of camera poses
while (pose_file >> pose_index) {
for (int i = 0; i < 16; i++)
pose_file >> m.data()[i];
initial_estimate.insert(pose_index, Pose3(m));
}
// landmark keys
size_t landmark_key;
// 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 measurements and construct smart factors
SmartFactor::shared_ptr factor(new SmartFactor(model, K));
size_t current_l = 3; // hardcoded landmark ID from first measurement
while (factor_file >> pose_index >> landmark_key >> uL >> uR >> v >> X >> Y >> Z) {
if(current_l != landmark_key) {
graph.push_back(factor);
factor = SmartFactor::shared_ptr(new SmartFactor(model, K));
current_l = landmark_key;
}
factor->add(Point2(uL,v), pose_index);
}
Pose3 firstPose = initial_estimate.at<Pose3>(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> >(1,firstPose);
LevenbergMarquardtParams params;
params.verbosityLM = LevenbergMarquardtParams::TRYLAMBDA;
params.verbosity = NonlinearOptimizerParams::ERROR;
cout << "Optimizing" << endl;
//create Levenberg-Marquardt optimizer to optimize the factor graph
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;
}