Optimization on the Essential manifold !

release/4.3a0
Frank Dellaert 2013-12-17 05:54:29 +00:00
parent f8d2c93303
commit 8b9d6b78dc
5 changed files with 221 additions and 167 deletions

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@ -904,6 +904,14 @@
<useDefaultCommand>true</useDefaultCommand> <useDefaultCommand>true</useDefaultCommand>
<runAllBuilders>true</runAllBuilders> <runAllBuilders>true</runAllBuilders>
</target> </target>
<target name="testEssentialMatrixFactor.run" path="build/gtsam/slam" targetID="org.eclipse.cdt.build.MakeTargetBuilder">
<buildCommand>make</buildCommand>
<buildArguments>-j5</buildArguments>
<buildTarget>testEssentialMatrixFactor.run</buildTarget>
<stopOnError>true</stopOnError>
<useDefaultCommand>true</useDefaultCommand>
<runAllBuilders>true</runAllBuilders>
</target>
<target name="all" path="build_wrap" targetID="org.eclipse.cdt.build.MakeTargetBuilder"> <target name="all" path="build_wrap" targetID="org.eclipse.cdt.build.MakeTargetBuilder">
<buildCommand>make</buildCommand> <buildCommand>make</buildCommand>
<buildArguments>-j2</buildArguments> <buildArguments>-j2</buildArguments>

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@ -10,6 +10,7 @@
#include <gtsam/geometry/Rot3.h> #include <gtsam/geometry/Rot3.h>
#include <gtsam/geometry/Sphere2.h> #include <gtsam/geometry/Sphere2.h>
#include <gtsam/geometry/Point2.h> #include <gtsam/geometry/Point2.h>
#include <iostream>
namespace gtsam { namespace gtsam {

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@ -8,115 +8,21 @@
#include <gtsam/geometry/EssentialMatrix.h> #include <gtsam/geometry/EssentialMatrix.h>
#include <gtsam/geometry/CalibratedCamera.h> #include <gtsam/geometry/CalibratedCamera.h>
#include <gtsam/base/Testable.h> #include <gtsam/base/Testable.h>
#include <gtsam/nonlinear/NonlinearFactorGraph.h>
#include <gtsam/nonlinear/LevenbergMarquardtOptimizer.h>
#include <gtsam/base/numericalDerivative.h>
#include <CppUnitLite/TestHarness.h> #include <CppUnitLite/TestHarness.h>
#include <boost/bind.hpp>
#include <boost/assign/std/vector.hpp>
#include <vector>
using namespace std; using namespace std;
using namespace boost::assign;
using namespace gtsam; using namespace gtsam;
/**
* Factor that evaluates epipolar error p'Ep for given essential matrix
*/
class EssentialMatrixFactor: public NoiseModelFactor1<EssentialMatrix> {
Point2 pA_, pB_; ///< Measurements in image A and B
Vector vA_, vB_; ///< Homogeneous versions
typedef NoiseModelFactor1<EssentialMatrix> Base;
public:
/// Constructor
EssentialMatrixFactor(Key key, const Point2& pA, const Point2& pB,
const SharedNoiseModel& model) :
Base(model, key), pA_(pA), pB_(pB), //
vA_(EssentialMatrix::Homogeneous(pA)), //
vB_(EssentialMatrix::Homogeneous(pB)) {
}
/// print
virtual void print(const std::string& s, const KeyFormatter& keyFormatter =
DefaultKeyFormatter) const {
Base::print(s);
std::cout << " EssentialMatrixFactor with measurements\n ("
<< pA_.vector().transpose() << ")' and (" << pB_.vector().transpose()
<< ")'" << endl;
}
/// vector of errors returns 1D vector
Vector evaluateError(const EssentialMatrix& E, boost::optional<Matrix&> H =
boost::none) const {
return (Vector(1) << E.error(vA_, vB_, H));
}
};
//************************************************************************* //*************************************************************************
// Create two cameras and corresponding essential matrix E // Create two cameras and corresponding essential matrix E
Rot3 aRb = Rot3::yaw(M_PI_2); Rot3 aRb = Rot3::yaw(M_PI_2);
Point3 aTb(0.1, 0, 0); Point3 aTb(0.1, 0, 0);
Pose3 identity, aPb(aRb, aTb);
typedef CalibratedCamera Cam;
Cam cameraA(identity), cameraB(aPb);
Matrix aEb_matrix = skewSymmetric(aTb.x(), aTb.y(), aTb.z()) * aRb.matrix();
// Create test data, we need at least 5 points
Point3 P[5] = { Point3(0, 0, 1), Point3(-0.1, 0, 1), Point3(0.1, 0, 1), //
Point3(0, 0.5, 0.5), Point3(0, -0.5, 0.5) };
// Project points in both cameras
vector<Point2> pA(5), pB(5);
vector<Point2>::iterator //
it1 = std::transform(P, P + 5, pA.begin(),
boost::bind(&Cam::project, &cameraA, _1, boost::none, boost::none)), //
it2 = std::transform(P, P + 5, pB.begin(),
boost::bind(&Cam::project, &cameraB, _1, boost::none, boost::none));
// Converto to homogenous coordinates
vector<Vector> vA(5), vB(5);
vector<Vector>::iterator //
it3 = std::transform(pA.begin(), pA.end(), vA.begin(),
&EssentialMatrix::Homogeneous), //
it4 = std::transform(pB.begin(), pB.end(), vB.begin(),
&EssentialMatrix::Homogeneous);
//*************************************************************************
TEST (EssentialMatrix, testData) {
// Check E matrix
Matrix expected(3, 3);
expected << 0, 0, 0, 0, 0, -0.1, 0.1, 0, 0;
EXPECT(assert_equal(expected, aEb_matrix));
// Check some projections
EXPECT(assert_equal(Point2(0,0),pA[0]));
EXPECT(assert_equal(Point2(0,0.1),pB[0]));
EXPECT(assert_equal(Point2(0,-1),pA[4]));
EXPECT(assert_equal(Point2(-1,0.2),pB[4]));
// Check homogeneous version
EXPECT(assert_equal((Vector(3) << -1,0.2,1),vB[4]));
// Check epipolar constraint
for (size_t i = 0; i < 5; i++)
EXPECT_DOUBLES_EQUAL(0, vA[i].transpose() * aEb_matrix * vB[i], 1e-8);
// Check epipolar constraint
EssentialMatrix trueE(aRb, aTb);
for (size_t i = 0; i < 5; i++)
EXPECT_DOUBLES_EQUAL(0, trueE.error(vA[i],vB[i]), 1e-8);
}
//************************************************************************* //*************************************************************************
TEST (EssentialMatrix, equality) { TEST (EssentialMatrix, equality) {
// EssentialMatrix actual, expected; EssentialMatrix actual(aRb, aTb), expected(aRb, aTb);
// EXPECT(assert_equal(expected, actual)); EXPECT(assert_equal(expected, actual));
} }
//************************************************************************* //*************************************************************************
@ -135,76 +41,6 @@ TEST (EssentialMatrix, retract2) {
EXPECT(assert_equal(expected, actual)); EXPECT(assert_equal(expected, actual));
} }
//*************************************************************************
TEST (EssentialMatrix, factor) {
EssentialMatrix trueE(aRb, aTb);
noiseModel::Unit::shared_ptr model = noiseModel::Unit::Create(1);
for (size_t i = 0; i < 5; i++) {
EssentialMatrixFactor factor(1, pA[i], pB[i], model);
// Check evaluation
Vector expected(1);
expected << 0;
Matrix HActual;
Vector actual = factor.evaluateError(trueE, HActual);
EXPECT(assert_equal(expected, actual, 1e-8));
// Use numerical derivatives to calculate the expected Jacobian
Matrix HExpected;
HExpected = numericalDerivative11<EssentialMatrix>(
boost::bind(&EssentialMatrixFactor::evaluateError, &factor, _1,
boost::none), trueE);
// Verify the Jacobian is correct
CHECK(assert_equal(HExpected, HActual, 1e-9));
}
}
//*************************************************************************
TEST (EssentialMatrix, fromConstraints) {
// Here we want to optimize directly on essential matrix constraints
// Yi Ma's algorithm (Ma01ijcv) is a bit cumbersome to implement,
// but GTSAM does the equivalent anyway, provided we give the right
// factors. In this case, the factors are the constraints.
// We start with a factor graph and add constraints to it
// Noise sigma is 1cm, assuming metric measurements
NonlinearFactorGraph graph;
noiseModel::Isotropic::shared_ptr model = noiseModel::Isotropic::Sigma(1,0.01);
for (size_t i = 0; i < 5; i++)
graph.add(EssentialMatrixFactor(1, pA[i], pB[i], model));
// Check error at ground truth
Values truth;
EssentialMatrix trueE(aRb, aTb);
truth.insert(1, trueE);
EXPECT_DOUBLES_EQUAL(0, graph.error(truth), 1e-8);
// Check error at initial estimate
Values initial;
EssentialMatrix initialE = trueE.retract((Vector(5) << 0.1, -0.1, 0.1, 0.1, -0.1));
initial.insert(1, initialE);
EXPECT_DOUBLES_EQUAL(640, graph.error(initial), 1e-2);
// Optimize
LevenbergMarquardtParams parameters;
LevenbergMarquardtOptimizer optimizer(graph, initial, parameters);
Values result = optimizer.optimize();
// Check result
EssentialMatrix actual = result.at<EssentialMatrix>(1);
EXPECT(assert_equal(trueE, actual,1e-1));
// Check error at result
EXPECT_DOUBLES_EQUAL(0, graph.error(result), 1e-4);
// Check errors individually
for (size_t i = 0; i < 5; i++)
EXPECT_DOUBLES_EQUAL(0, actual.error(vA[i],vB[i]), 1e-6);
}
/* ************************************************************************* */ /* ************************************************************************* */
int main() { int main() {
TestResult tr; TestResult tr;

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/*
* @file EssentialMatrixFactor.cpp
* @brief EssentialMatrixFactor class
* @author Frank Dellaert
* @date December 17, 2013
*/
#pragma once
#include <gtsam/nonlinear/NonlinearFactor.h>
#include <gtsam/geometry/EssentialMatrix.h>
#include <iostream>
namespace gtsam {
/**
* Factor that evaluates epipolar error p'Ep for given essential matrix
*/
class EssentialMatrixFactor: public NoiseModelFactor1<EssentialMatrix> {
Point2 pA_, pB_; ///< Measurements in image A and B
Vector vA_, vB_; ///< Homogeneous versions
typedef NoiseModelFactor1<EssentialMatrix> Base;
public:
/// Constructor
EssentialMatrixFactor(Key key, const Point2& pA, const Point2& pB,
const SharedNoiseModel& model) :
Base(model, key), pA_(pA), pB_(pB), //
vA_(EssentialMatrix::Homogeneous(pA)), //
vB_(EssentialMatrix::Homogeneous(pB)) {
}
/// print
virtual void print(const std::string& s, const KeyFormatter& keyFormatter =
DefaultKeyFormatter) const {
Base::print(s);
std::cout << " EssentialMatrixFactor with measurements\n ("
<< pA_.vector().transpose() << ")' and (" << pB_.vector().transpose()
<< ")'" << std::endl;
}
/// vector of errors returns 1D vector
Vector evaluateError(const EssentialMatrix& E, boost::optional<Matrix&> H =
boost::none) const {
return (Vector(1) << E.error(vA_, vB_, H));
}
};
} // gtsam

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/*
* @file testEssentialMatrixFactor.cpp
* @brief Test EssentialMatrixFactor class
* @author Frank Dellaert
* @date December 17, 2013
*/
#include <gtsam/slam/EssentialMatrixFactor.h>
#include <gtsam/geometry/CalibratedCamera.h>
#include <gtsam/base/Testable.h>
#include <gtsam/nonlinear/NonlinearFactorGraph.h>
#include <gtsam/nonlinear/LevenbergMarquardtOptimizer.h>
#include <gtsam/base/numericalDerivative.h>
#include <CppUnitLite/TestHarness.h>
#include <boost/bind.hpp>
#include <boost/assign/std/vector.hpp>
#include <vector>
using namespace std;
using namespace boost::assign;
using namespace gtsam;
//*************************************************************************
// Create two cameras and corresponding essential matrix E
Rot3 aRb = Rot3::yaw(M_PI_2);
Point3 aTb(0.1, 0, 0);
Pose3 identity, aPb(aRb, aTb);
typedef CalibratedCamera Cam;
Cam cameraA(identity), cameraB(aPb);
Matrix aEb_matrix = skewSymmetric(aTb.x(), aTb.y(), aTb.z()) * aRb.matrix();
// Create test data, we need at least 5 points
Point3 P[5] = { Point3(0, 0, 1), Point3(-0.1, 0, 1), Point3(0.1, 0, 1), //
Point3(0, 0.5, 0.5), Point3(0, -0.5, 0.5) };
// Project points in both cameras
vector<Point2> pA(5), pB(5);
vector<Point2>::iterator //
it1 = std::transform(P, P + 5, pA.begin(),
boost::bind(&Cam::project, &cameraA, _1, boost::none, boost::none)), //
it2 = std::transform(P, P + 5, pB.begin(),
boost::bind(&Cam::project, &cameraB, _1, boost::none, boost::none));
// Converto to homogenous coordinates
vector<Vector> vA(5), vB(5);
vector<Vector>::iterator //
it3 = std::transform(pA.begin(), pA.end(), vA.begin(),
&EssentialMatrix::Homogeneous), //
it4 = std::transform(pB.begin(), pB.end(), vB.begin(),
&EssentialMatrix::Homogeneous);
//*************************************************************************
TEST (EssentialMatrix, testData) {
// Check E matrix
Matrix expected(3, 3);
expected << 0, 0, 0, 0, 0, -0.1, 0.1, 0, 0;
EXPECT(assert_equal(expected, aEb_matrix));
// Check some projections
EXPECT(assert_equal(Point2(0,0),pA[0]));
EXPECT(assert_equal(Point2(0,0.1),pB[0]));
EXPECT(assert_equal(Point2(0,-1),pA[4]));
EXPECT(assert_equal(Point2(-1,0.2),pB[4]));
// Check homogeneous version
EXPECT(assert_equal((Vector(3) << -1,0.2,1),vB[4]));
// Check epipolar constraint
for (size_t i = 0; i < 5; i++)
EXPECT_DOUBLES_EQUAL(0, vA[i].transpose() * aEb_matrix * vB[i], 1e-8);
// Check epipolar constraint
EssentialMatrix trueE(aRb, aTb);
for (size_t i = 0; i < 5; i++)
EXPECT_DOUBLES_EQUAL(0, trueE.error(vA[i],vB[i]), 1e-8);
}
//*************************************************************************
TEST (EssentialMatrix, factor) {
EssentialMatrix trueE(aRb, aTb);
noiseModel::Unit::shared_ptr model = noiseModel::Unit::Create(1);
for (size_t i = 0; i < 5; i++) {
EssentialMatrixFactor factor(1, pA[i], pB[i], model);
// Check evaluation
Vector expected(1);
expected << 0;
Matrix HActual;
Vector actual = factor.evaluateError(trueE, HActual);
EXPECT(assert_equal(expected, actual, 1e-8));
// Use numerical derivatives to calculate the expected Jacobian
Matrix HExpected;
HExpected = numericalDerivative11<EssentialMatrix>(
boost::bind(&EssentialMatrixFactor::evaluateError, &factor, _1,
boost::none), trueE);
// Verify the Jacobian is correct
CHECK(assert_equal(HExpected, HActual, 1e-9));
}
}
//*************************************************************************
TEST (EssentialMatrix, fromConstraints) {
// Here we want to optimize directly on essential matrix constraints
// Yi Ma's algorithm (Ma01ijcv) is a bit cumbersome to implement,
// but GTSAM does the equivalent anyway, provided we give the right
// factors. In this case, the factors are the constraints.
// We start with a factor graph and add constraints to it
// Noise sigma is 1cm, assuming metric measurements
NonlinearFactorGraph graph;
noiseModel::Isotropic::shared_ptr model = noiseModel::Isotropic::Sigma(1,0.01);
for (size_t i = 0; i < 5; i++)
graph.add(EssentialMatrixFactor(1, pA[i], pB[i], model));
// Check error at ground truth
Values truth;
EssentialMatrix trueE(aRb, aTb);
truth.insert(1, trueE);
EXPECT_DOUBLES_EQUAL(0, graph.error(truth), 1e-8);
// Check error at initial estimate
Values initial;
EssentialMatrix initialE = trueE.retract((Vector(5) << 0.1, -0.1, 0.1, 0.1, -0.1));
initial.insert(1, initialE);
EXPECT_DOUBLES_EQUAL(640, graph.error(initial), 1e-2);
// Optimize
LevenbergMarquardtParams parameters;
LevenbergMarquardtOptimizer optimizer(graph, initial, parameters);
Values result = optimizer.optimize();
// Check result
EssentialMatrix actual = result.at<EssentialMatrix>(1);
EXPECT(assert_equal(trueE, actual,1e-1));
// Check error at result
EXPECT_DOUBLES_EQUAL(0, graph.error(result), 1e-4);
// Check errors individually
for (size_t i = 0; i < 5; i++)
EXPECT_DOUBLES_EQUAL(0, actual.error(vA[i],vB[i]), 1e-6);
}
/* ************************************************************************* */
int main() {
TestResult tr;
return TestRegistry::runAllTests(tr);
}
/* ************************************************************************* */