314 lines
10 KiB
C++
314 lines
10 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 TranslationFactor.h
|
|
* @author Frank Dellaert
|
|
* @date March 2020
|
|
* @brief Binary factor for a relative translation direction measurement.
|
|
*/
|
|
|
|
#include <gtsam/geometry/Point3.h>
|
|
#include <gtsam/geometry/Unit3.h>
|
|
#include <gtsam/linear/NoiseModel.h>
|
|
#include <gtsam/nonlinear/NonlinearFactor.h>
|
|
|
|
namespace gtsam {
|
|
|
|
/**
|
|
* Binary factor for a relative translation direction measurement
|
|
* w_aZb. The measurement equation is
|
|
* w_aZb = Unit3(Tb - Ta)
|
|
* i.e., w_aZb is the translation direction from frame A to B, in world
|
|
* coordinates. Although Unit3 instances live on a manifold, following
|
|
* Wilson14eccv_1DSfM.pdf error we compute the *chordal distance* in the
|
|
* ambient world coordinate frame:
|
|
* normalized(Tb - Ta) - w_aZb.point3()
|
|
*
|
|
* @addtogroup SAM
|
|
*/
|
|
class TranslationFactor : public NoiseModelFactor2<Point3, Point3> {
|
|
private:
|
|
typedef NoiseModelFactor2<Point3, Point3> Base;
|
|
Point3 measured_w_aZb_;
|
|
|
|
public:
|
|
/// default constructor
|
|
TranslationFactor() {}
|
|
|
|
TranslationFactor(Key a, Key b, const Unit3& w_aZb,
|
|
const SharedNoiseModel& noiseModel)
|
|
: Base(noiseModel, a, b), measured_w_aZb_(w_aZb.point3()) {}
|
|
|
|
/**
|
|
* @brief Caclulate error norm(p1-p2) - measured
|
|
*
|
|
* @param Ta translation for key a
|
|
* @param Tb translation for key b
|
|
* @param H1 optional jacobian in Ta
|
|
* @param H2 optional jacobian in Tb
|
|
* @return * Vector
|
|
*/
|
|
Vector evaluateError(
|
|
const Point3& Ta, const Point3& Tb,
|
|
boost::optional<Matrix&> H1 = boost::none,
|
|
boost::optional<Matrix&> H2 = boost::none) const override {
|
|
const Point3 dir = Tb - Ta;
|
|
Matrix33 H_predicted_dir;
|
|
const Point3 predicted =
|
|
dir.normalized(H1 || H2 ? &H_predicted_dir : nullptr);
|
|
if (H1) *H1 = H_predicted_dir;
|
|
if (H2) *H2 = -H_predicted_dir;
|
|
return predicted - measured_w_aZb_;
|
|
}
|
|
|
|
private:
|
|
friend class boost::serialization::access;
|
|
template <class ARCHIVE>
|
|
void serialize(ARCHIVE& ar, const unsigned int /*version*/) {
|
|
ar& boost::serialization::make_nvp(
|
|
"Base", boost::serialization::base_object<Base>(*this));
|
|
}
|
|
}; // \ TranslationFactor
|
|
} // namespace gtsam
|
|
|
|
/* ----------------------------------------------------------------------------
|
|
|
|
* 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 TranslationRecovery.h
|
|
* @author Frank Dellaert
|
|
* @date March 2020
|
|
* @brief test recovering translations when rotations are given.
|
|
*/
|
|
|
|
// #include <gtsam/sam/TranslationFactor.h>
|
|
#include <gtsam/geometry/Point3.h>
|
|
#include <gtsam/geometry/Pose3.h>
|
|
#include <gtsam/geometry/Unit3.h>
|
|
#include <gtsam/inference/Symbol.h>
|
|
#include <gtsam/linear/NoiseModel.h>
|
|
#include <gtsam/nonlinear/LevenbergMarquardtOptimizer.h>
|
|
#include <gtsam/nonlinear/NonlinearFactor.h>
|
|
#include <gtsam/nonlinear/NonlinearFactorGraph.h>
|
|
#include <gtsam/nonlinear/Values.h>
|
|
|
|
namespace gtsam {
|
|
|
|
// Set up an optimization problem for the unknown translations Ti in the world
|
|
// coordinate frame, given the known camera attitudes wRi with respect to the
|
|
// world frame, and a set of (noisy) translation directions of type Unit3,
|
|
// w_aZb. The measurement equation is
|
|
// w_aZb = Unit3(Tb - Ta) (1)
|
|
// i.e., w_aZb is the translation direction from frame A to B, in world
|
|
// coordinates. Although Unit3 instances live on a manifold, following
|
|
// Wilson14eccv_1DSfM.pdf error we compute the *chordal distance* in the
|
|
// ambient world coordinate frame.
|
|
//
|
|
// It is clear that we cannot recover the scale, nor the absolute position,
|
|
// so the gauge freedom in this case is 3 + 1 = 4. We fix these by taking fixing
|
|
// the translations Ta and Tb associated with the first measurement w_aZb,
|
|
// clamping them to their initial values as given to this method. If no initial
|
|
// values are given, we use the origin for Tb and set Tb to make (1) come
|
|
// through, i.e.,
|
|
// Tb = s * wRa * Point3(w_aZb) (2)
|
|
// where s is an arbitrary scale that can be supplied, default 1.0. Hence, two
|
|
// versions are supplied below corresponding to whether we have initial values
|
|
// or not. Because the latter one is called from the first one, this is prime.
|
|
|
|
class TranslationRecovery {
|
|
public:
|
|
using KeyPair = std::pair<Key, Key>;
|
|
using TranslationEdges = std::map<KeyPair, Unit3>;
|
|
|
|
private:
|
|
TranslationEdges relativeTranslations_;
|
|
|
|
public:
|
|
/**
|
|
* @brief Construct a new Translation Recovery object
|
|
*
|
|
* @param relativeTranslations the relative translations, in world coordinate
|
|
* frames, indexed in a map by a pair of Pose keys.
|
|
*/
|
|
TranslationRecovery(const TranslationEdges& relativeTranslations)
|
|
: relativeTranslations_(relativeTranslations) {}
|
|
|
|
/**
|
|
* @brief Build the factor graph to do the optimization.
|
|
*
|
|
* @return NonlinearFactorGraph
|
|
*/
|
|
NonlinearFactorGraph buildGraph() const {
|
|
auto noiseModel = noiseModel::Isotropic::Sigma(3, 0.01);
|
|
NonlinearFactorGraph graph;
|
|
for (auto edge : relativeTranslations_) {
|
|
Key a, b;
|
|
std::tie(a, b) = edge.first;
|
|
const Unit3 w_aZb = edge.second;
|
|
graph.emplace_shared<TranslationFactor>(a, b, w_aZb, noiseModel);
|
|
}
|
|
return graph;
|
|
}
|
|
|
|
/**
|
|
* @brief Create random initial translations.
|
|
*
|
|
* @return Values
|
|
*/
|
|
Values initalizeRandomly() const {
|
|
Values initial;
|
|
auto insert = [&initial](Key j) {
|
|
if (!initial.exists(j)) {
|
|
initial.insert<Point3>(j, Vector3::Random());
|
|
}
|
|
};
|
|
|
|
// Loop over measurements and add a random translation
|
|
for (auto edge : relativeTranslations_) {
|
|
Key a, b;
|
|
std::tie(a, b) = edge.first;
|
|
insert(a);
|
|
insert(b);
|
|
}
|
|
return initial;
|
|
}
|
|
|
|
/**
|
|
* @brief Build and optimize factor graph.
|
|
*
|
|
* @param scale scale for first relative translation which fixes gauge.
|
|
* @return Values
|
|
*/
|
|
Values run(const double scale = 1.0) const {
|
|
const auto graph = buildGraph();
|
|
const Values initial = initalizeRandomly();
|
|
|
|
LevenbergMarquardtParams params;
|
|
params.setVerbosityLM("Summary");
|
|
LevenbergMarquardtOptimizer lm(graph, initial, params);
|
|
Values result = lm.optimize();
|
|
|
|
return result;
|
|
}
|
|
|
|
/**
|
|
* @brief Simulate translation direction measurements
|
|
*
|
|
* @param poses SE(3) ground truth poses stored as Values
|
|
* @param edges pairs (a,b) for which a measurement w_aZb will be generated.
|
|
*/
|
|
static TranslationEdges SimulateMeasurements(
|
|
const Values& poses, const std::vector<KeyPair>& edges) {
|
|
TranslationEdges relativeTranslations;
|
|
for (auto edge : edges) {
|
|
Key a, b;
|
|
std::tie(a, b) = edge;
|
|
const Pose3 wTa = poses.at<Pose3>(a), wTb = poses.at<Pose3>(b);
|
|
const Point3 Ta = wTa.translation(), Tb = wTb.translation();
|
|
const Unit3 w_aZb(Tb - Ta);
|
|
relativeTranslations[edge] = w_aZb;
|
|
}
|
|
return relativeTranslations;
|
|
}
|
|
};
|
|
} // namespace gtsam
|
|
|
|
/* ----------------------------------------------------------------------------
|
|
|
|
* 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 testTranslationRecovery.cpp
|
|
* @author Frank Dellaert
|
|
* @date March 2020
|
|
* @brief test recovering translations when rotations are given.
|
|
*/
|
|
|
|
#include <CppUnitLite/TestHarness.h>
|
|
#include <gtsam/slam/dataset.h>
|
|
|
|
using namespace std;
|
|
using namespace gtsam;
|
|
|
|
/* ************************************************************************* */
|
|
// We read the BAL file, which has 3 cameras in it, with poses. We then assume
|
|
// the rotations are correct, but translations have to be estimated from
|
|
// translation directions only. Since we have 3 cameras, A, B, and C, we can at
|
|
// most create three relative measurements, let's call them w_aZb, w_aZc, and
|
|
// bZc. These will be of type Unit3. We then call `recoverTranslations` which
|
|
// sets up an optimization problem for the three unknown translations.
|
|
TEST(TranslationRecovery, BAL) {
|
|
const string filename = findExampleDataFile("dubrovnik-3-7-pre");
|
|
SfM_data db;
|
|
bool success = readBAL(filename, db);
|
|
if (!success) throw runtime_error("Could not access file!");
|
|
|
|
// Get camera poses, as Values
|
|
size_t j = 0;
|
|
Values poses;
|
|
for (auto camera : db.cameras) {
|
|
poses.insert(j++, camera.pose());
|
|
}
|
|
|
|
// Simulate measurements
|
|
const auto relativeTranslations = TranslationRecovery::SimulateMeasurements(
|
|
poses, {{0, 1}, {0, 2}, {1, 2}});
|
|
|
|
// Check
|
|
const Pose3 wTa = poses.at<Pose3>(0), wTb = poses.at<Pose3>(1),
|
|
wTc = poses.at<Pose3>(2);
|
|
const Point3 Ta = wTa.translation(), Tb = wTb.translation(),
|
|
Tc = wTc.translation();
|
|
const Rot3 aRw = wTa.rotation().inverse();
|
|
const Unit3 w_aZb = relativeTranslations.at({0, 1});
|
|
EXPECT(assert_equal(Unit3(Tb - Ta), w_aZb));
|
|
const Unit3 w_aZc = relativeTranslations.at({0, 2});
|
|
EXPECT(assert_equal(Unit3(Tc - Ta), w_aZc));
|
|
|
|
TranslationRecovery algorithm(relativeTranslations);
|
|
const auto graph = algorithm.buildGraph();
|
|
EXPECT_LONGS_EQUAL(3, graph.size());
|
|
|
|
// Translation recovery, version 1
|
|
const auto result = algorithm.run(2);
|
|
|
|
// Check result
|
|
EXPECT(assert_equal(Point3(0, 0, 0), result.at<Point3>(0)));
|
|
EXPECT(assert_equal(Point3(2 * w_aZb.point3()), result.at<Point3>(1)));
|
|
EXPECT(assert_equal(Point3(0, 0, 0), result.at<Point3>(2)));
|
|
|
|
// TODO(frank): how to get stats back
|
|
// EXPECT_DOUBLES_EQUAL(0.0199833, actualError, 1e-5);
|
|
}
|
|
|
|
/* ************************************************************************* */
|
|
int main() {
|
|
TestResult tr;
|
|
return TestRegistry::runAllTests(tr);
|
|
}
|
|
/* ************************************************************************* */
|