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Merge pull request #1534 from borglab/lost-underconstrained 

LOST Triangulation Underconstrained
release/4.3a0
Frank Dellaert 2023-06-12 17:15:07 -07:00 committed by GitHub
parent adc4389220 1e6f1b757c
commit 8bd690cd26
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GPG Key ID: 4AEE18F83AFDEB23
2 changed files with 42 additions and 12 deletions
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44
gtsam/geometry/triangulation.cpp
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@ -85,7 +85,8 @@ Vector4 triangulateHomogeneousDLT(
Point3 triangulateLOST(const std::vector<Pose3>& poses,
const Point3Vector& calibratedMeasurements,
const SharedIsotropic& measurementNoise) {
const SharedIsotropic& measurementNoise,
double rank_tol) {
size_t m = calibratedMeasurements.size();
assert(m == poses.size());
@ -96,17 +97,38 @@ Point3 triangulateLOST(const std::vector<Pose3>& poses,
for (size_t i = 0; i < m; i++) {
const Pose3& wTi = poses[i];
// TODO(akshay-krishnan): are there better ways to select j?
const int j = (i + 1) % m;
int j = (i + 1) % m;
const Pose3& wTj = poses[j];
const Point3 d_ij = wTj.translation() - wTi.translation();
Point3 d_ij = wTj.translation() - wTi.translation();
Point3 wZi = wTi.rotation().rotate(calibratedMeasurements[i]);
Point3 wZj = wTj.rotation().rotate(calibratedMeasurements[j]);
double num_i = wZi.cross(wZj).norm();
double den_i = d_ij.cross(wZj).norm();
const Point3 wZi = wTi.rotation().rotate(calibratedMeasurements[i]);
const Point3 wZj = wTj.rotation().rotate(calibratedMeasurements[j]);
// Handle q_i = 0 (or NaN), which arises if the measurement vectors, wZi and
// wZj, coincide (or the baseline vector coincides with the jth measurement
// vector).
if (num_i == 0 || den_i == 0) {
bool success = false;
for (size_t k = 2; k < m; k++) {
j = (i + k) % m;
const Pose3& wTj = poses[j];
d_ij = wTj.translation() - wTi.translation();
wZj = wTj.rotation().rotate(calibratedMeasurements[j]);
num_i = wZi.cross(wZj).norm();
den_i = d_ij.cross(wZj).norm();
if (num_i > 0 && den_i > 0) {
success = true;
break;
}
}
if (!success) throw(TriangulationUnderconstrainedException());
}
// Note: Setting q_i = 1.0 gives same results as DLT.
const double q_i = wZi.cross(wZj).norm() /
(measurementNoise->sigma() * d_ij.cross(wZj).norm());
const double q_i = num_i / (measurementNoise->sigma() * den_i);
const Matrix23 coefficientMat =
q_i * skewSymmetric(calibratedMeasurements[i]).topLeftCorner(2, 3) *
@ -115,7 +137,13 @@ Point3 triangulateLOST(const std::vector<Pose3>& poses,
A.block<2, 3>(2 * i, 0) << coefficientMat;
b.block<2, 1>(2 * i, 0) << coefficientMat * wTi.translation();
}
return A.colPivHouseholderQr().solve(b);
Eigen::ColPivHouseholderQR<Matrix> A_Qr = A.colPivHouseholderQr();
A_Qr.setThreshold(rank_tol);
if (A_Qr.rank() < 3) throw(TriangulationUnderconstrainedException());
return A_Qr.solve(b);
}
Point3 triangulateDLT(

10
gtsam/geometry/triangulation.h
View File

@ -110,7 +110,8 @@ GTSAM_EXPORT Point3 triangulateDLT(
*/
GTSAM_EXPORT Point3 triangulateLOST(const std::vector<Pose3>& poses,
const Point3Vector& calibratedMeasurements,
const SharedIsotropic& measurementNoise);
const SharedIsotropic& measurementNoise,
double rank_tol = 1e-9);
/**
* Create a factor graph with projection factors from poses and one calibration
@ -439,7 +440,8 @@ Point3 triangulatePoint3(const std::vector<Pose3>& poses,
auto calibratedMeasurements =
calibrateMeasurementsShared<CALIBRATION>(*sharedCal, measurements);
point = triangulateLOST(poses, calibratedMeasurements, measurementNoise);
point = triangulateLOST(poses, calibratedMeasurements, measurementNoise,
rank_tol);
} else {
// construct projection matrices from poses & calibration
auto projection_matrices = projectionMatricesFromPoses(poses, sharedCal);
@ -512,7 +514,8 @@ Point3 triangulatePoint3(const CameraSet<CAMERA>& cameras,
auto calibratedMeasurements =
calibrateMeasurements<CAMERA>(cameras, measurements);
point = triangulateLOST(poses, calibratedMeasurements, measurementNoise);
point = triangulateLOST(poses, calibratedMeasurements, measurementNoise,
rank_tol);
} else {
// construct projection matrices from poses & calibration
auto projection_matrices = projectionMatricesFromCameras(cameras);
@ -750,4 +753,3 @@ using CameraSetCal3Fisheye = CameraSet<PinholeCamera<Cal3Fisheye>>;
using CameraSetCal3Unified = CameraSet<PinholeCamera<Cal3Unified>>;
using CameraSetSpherical = CameraSet<SphericalCamera>;
} // \namespace gtsam