fix triangulatePoint3 for calibrations with distortion
Prior implementation only used the K() portion of all Cal3 calibrations for the linear triangulation of points with triangulatePoint3. - Added tests for triangulation with non-Cal3_S2 calibrations. - Added skew to the test Cal3_S2 calibration. - Added an undistortMeasurements step to triangulatePoint3 so that linear triangulation works for calibrations with distortion coefficients.release/4.3a0
Thomas Sayre-McCord
parent
a0d64a9448
commit
ba32a0de85
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@ -19,6 +19,7 @@
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#include <CppUnitLite/TestHarness.h>
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#include <gtsam/geometry/Cal3Bundler.h>
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#include <gtsam/geometry/Cal3DS2.h>
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#include <gtsam/geometry/CameraSet.h>
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#include <gtsam/geometry/PinholeCamera.h>
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#include <gtsam/geometry/SphericalCamera.h>
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@ -38,7 +39,7 @@ using namespace boost::assign;
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// Some common constants
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static const boost::shared_ptr<Cal3_S2> sharedCal = //
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boost::make_shared<Cal3_S2>(1500, 1200, 0, 640, 480);
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boost::make_shared<Cal3_S2>(1500, 1200, 0.1, 640, 480);
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// Looking along X-axis, 1 meter above ground plane (x-y)
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static const Rot3 upright = Rot3::Ypr(-M_PI / 2, 0., -M_PI / 2);
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@ -95,11 +96,113 @@ TEST(triangulation, twoPoses) {
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EXPECT(assert_equal(Point3(4.995, 0.499167, 1.19814), *actual4, 1e-4));
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}
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//******************************************************************************
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// Simple test with a well-behaved two camera situation with Cal3S2 calibration.
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TEST(triangulation, twoPosesCal3S2) {
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static const boost::shared_ptr<Cal3DS2> sharedDistortedCal = //
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boost::make_shared<Cal3DS2>(1500, 1200, 0, 640, 480, -.3, 0.1, 0.0001, -0.0003);
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PinholeCamera<Cal3DS2> camera1Distorted(pose1, *sharedDistortedCal);
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PinholeCamera<Cal3DS2> camera2Distorted(pose2, *sharedDistortedCal);
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// 1. Project two landmarks into two cameras and triangulate
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Point2 z1Distorted = camera1Distorted.project(landmark);
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Point2 z2Distorted = camera2Distorted.project(landmark);
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vector<Pose3> poses;
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Point2Vector measurements;
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poses += pose1, pose2;
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measurements += z1Distorted, z2Distorted;
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double rank_tol = 1e-9;
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// 1. Test simple DLT, perfect in no noise situation
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bool optimize = false;
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boost::optional<Point3> actual1 = //
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triangulatePoint3<Cal3DS2>(poses, sharedDistortedCal, measurements, rank_tol, optimize);
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EXPECT(assert_equal(landmark, *actual1, 1e-7));
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// 2. test with optimization on, same answer
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optimize = true;
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boost::optional<Point3> actual2 = //
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triangulatePoint3<Cal3DS2>(poses, sharedDistortedCal, measurements, rank_tol, optimize);
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EXPECT(assert_equal(landmark, *actual2, 1e-7));
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// 3. Add some noise and try again: result should be ~ (4.995,
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// 0.499167, 1.19814)
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measurements.at(0) += Point2(0.1, 0.5);
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measurements.at(1) += Point2(-0.2, 0.3);
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optimize = false;
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boost::optional<Point3> actual3 = //
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triangulatePoint3<Cal3DS2>(poses, sharedDistortedCal, measurements, rank_tol, optimize);
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EXPECT(assert_equal(Point3(4.995, 0.499167, 1.19814), *actual3, 1e-3));
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// 4. Now with optimization on
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optimize = true;
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boost::optional<Point3> actual4 = //
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triangulatePoint3<Cal3DS2>(poses, sharedDistortedCal, measurements, rank_tol, optimize);
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EXPECT(assert_equal(Point3(4.995, 0.499167, 1.19814), *actual4, 1e-3));
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}
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//******************************************************************************
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// Simple test with a well-behaved two camera situation with Fisheye calibration.
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TEST(triangulation, twoPosesFisheye) {
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using Calibration = Cal3Fisheye;
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static const boost::shared_ptr<Calibration> sharedDistortedCal = //
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boost::make_shared<Calibration>(1500, 1200, .1, 640, 480, -.3, 0.1, 0.0001, -0.0003);
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PinholeCamera<Calibration> camera1Distorted(pose1, *sharedDistortedCal);
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PinholeCamera<Calibration> camera2Distorted(pose2, *sharedDistortedCal);
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// 1. Project two landmarks into two cameras and triangulate
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Point2 z1Distorted = camera1Distorted.project(landmark);
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Point2 z2Distorted = camera2Distorted.project(landmark);
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vector<Pose3> poses;
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Point2Vector measurements;
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poses += pose1, pose2;
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measurements += z1Distorted, z2Distorted;
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double rank_tol = 1e-9;
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// 1. Test simple DLT, perfect in no noise situation
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bool optimize = false;
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boost::optional<Point3> actual1 = //
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triangulatePoint3<Calibration>(poses, sharedDistortedCal, measurements, rank_tol, optimize);
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EXPECT(assert_equal(landmark, *actual1, 1e-7));
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// 2. test with optimization on, same answer
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optimize = true;
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boost::optional<Point3> actual2 = //
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triangulatePoint3<Calibration>(poses, sharedDistortedCal, measurements, rank_tol, optimize);
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EXPECT(assert_equal(landmark, *actual2, 1e-7));
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// 3. Add some noise and try again: result should be ~ (4.995,
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// 0.499167, 1.19814)
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measurements.at(0) += Point2(0.1, 0.5);
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measurements.at(1) += Point2(-0.2, 0.3);
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optimize = false;
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boost::optional<Point3> actual3 = //
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triangulatePoint3<Calibration>(poses, sharedDistortedCal, measurements, rank_tol, optimize);
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EXPECT(assert_equal(Point3(4.995, 0.499167, 1.19814), *actual3, 1e-3));
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// 4. Now with optimization on
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optimize = true;
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boost::optional<Point3> actual4 = //
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triangulatePoint3<Calibration>(poses, sharedDistortedCal, measurements, rank_tol, optimize);
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EXPECT(assert_equal(Point3(4.995, 0.499167, 1.19814), *actual4, 1e-3));
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}
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//******************************************************************************
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// Similar, but now with Bundler calibration
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TEST(triangulation, twoPosesBundler) {
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boost::shared_ptr<Cal3Bundler> bundlerCal = //
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boost::make_shared<Cal3Bundler>(1500, 0, 0, 640, 480);
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boost::make_shared<Cal3Bundler>(1500, 0.1, 0.2, 640, 480);
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PinholeCamera<Cal3Bundler> camera1(pose1, *bundlerCal);
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PinholeCamera<Cal3Bundler> camera2(pose2, *bundlerCal);
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@ -126,7 +229,7 @@ TEST(triangulation, twoPosesBundler) {
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boost::optional<Point3> actual2 = //
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triangulatePoint3<Cal3Bundler>(poses, bundlerCal, measurements, rank_tol, optimize);
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EXPECT(assert_equal(Point3(4.995, 0.499167, 1.19847), *actual2, 1e-4));
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EXPECT(assert_equal(Point3(4.995, 0.499167, 1.19847), *actual2, 1e-3));
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}
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//******************************************************************************
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@ -227,6 +227,35 @@ std::vector<Matrix34, Eigen::aligned_allocator<Matrix34>> projectionMatricesFrom
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return projection_matrices;
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}
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/** Remove distortion for measurements so as if the measurements came from a pinhole camera.
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*
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* Removes distortion but maintains the K matrix of the initial sharedCal. Operates by calibrating using
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* full calibration and uncalibrating with only the pinhole component of the calibration.
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* @tparam CALIBRATION Calibration type to use.
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* @param sharedCal Calibration with which measurements were taken.
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* @param measurements Vector of measurements to undistort.
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* @return measurements with the effect of the distortion of sharedCal removed.
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*/
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template <class CALIBRATION>
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Point2Vector undistortMeasurements(boost::shared_ptr<CALIBRATION> sharedCal, const Point2Vector& measurements) {
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const auto& K = sharedCal->K();
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Cal3_S2 pinholeCalibration(K(0,0), K(1,1), K(0,1), K(0,2), K(1,2));
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Point2Vector undistortedMeasurements;
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// Calibrate with sharedCal and uncalibrate with pinhole version of sharedCal so that measurements are undistorted.
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std::transform(measurements.begin(), measurements.end(), std::back_inserter(undistortedMeasurements), [&sharedCal, &pinholeCalibration](auto& measurement) {
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return pinholeCalibration.uncalibrate(sharedCal->calibrate(measurement));
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});
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return undistortedMeasurements;
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}
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/** Specialization for Cal3_S2 as it doesn't need to be undistorted. */
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template <>
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Point2Vector undistortMeasurements(boost::shared_ptr<Cal3_S2> sharedCal, const Point2Vector& measurements) {
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return measurements;
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}
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/**
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* Function to triangulate 3D landmark point from an arbitrary number
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* of poses (at least 2) using the DLT. The function checks that the
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@ -253,8 +282,11 @@ Point3 triangulatePoint3(const std::vector<Pose3>& poses,
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// construct projection matrices from poses & calibration
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auto projection_matrices = projectionMatricesFromPoses(poses, sharedCal);
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// Undistort the measurements, leaving only the pinhole elements in effect.
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auto undistortedMeasurements = undistortMeasurements<CALIBRATION>(sharedCal, measurements);
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// Triangulate linearly
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Point3 point = triangulateDLT(projection_matrices, measurements, rank_tol);
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Point3 point = triangulateDLT(projection_matrices, undistortedMeasurements, rank_tol);
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// Then refine using non-linear optimization
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if (optimize)
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