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create a helper function to remove repeat code.

release/4.3a0
alexma3312 2020-08-21 20:53:52 -04:00
parent 9a07a61779
commit e00fa5605a
2 changed files with 25 additions and 32 deletions
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52
gtsam_unstable/geometry/Similarity3.cpp
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@ -95,6 +95,22 @@ Point3 Similarity3::operator*(const Point3& p) const {
return transformFrom(p);
}
// Refer to: http://www5.informatik.uni-erlangen.de/Forschung/Publikationen/2005/Zinsser05-PSR.pdf Chapter 3
Similarity3 Similarity3::GetSim3(const std::vector<Point3Pair>& abPointPairs, const Point3 aCentroid, const Point3 bCentroid, const Rot3 aRb) {
double x = 0;
double y = 0;
for (const Point3Pair& abPair : abPointPairs) {
Point3 da = abPair.first - aCentroid;
Point3 db = abPair.second - bCentroid;
Vector3 Rdb = aRb * db;
y += da.transpose() * Rdb;
x += Rdb.transpose() * Rdb;
}
double s = y / x;
Point3 aTb = (aCentroid - s * (aRb * bCentroid)) / s;
return Similarity3(aRb, aTb, s);
}
// Refer to: http://www5.informatik.uni-erlangen.de/Forschung/Publikationen/2005/Zinsser05-PSR.pdf Chapter 3
Similarity3 Similarity3::Align(const std::vector<Point3Pair>& abPointPairs) {
const size_t n = abPointPairs.size();
@ -112,32 +128,16 @@ Similarity3 Similarity3::Align(const std::vector<Point3Pair>& abPointPairs) {
// Add to form H matrix
Matrix3 H = Z_3x3;
vector<Point3Pair> d_abPairs;
d_abPairs.reserve(n);
for (const Point3Pair& abPair : abPointPairs) {
Point3 da = abPair.first - aCentroid;
Point3 db = abPair.second - bCentroid;
d_abPairs.emplace_back(da, db);
H += da * db.transpose();
}
// ClosestTo finds rotation matrix closest to H in Frobenius sense
Rot3 aRb = Rot3::ClosestTo(H);
// Calculate scale
double x = 0;
double y = 0;
for (const Point3Pair& d_abPair : d_abPairs) {
Point3 da = d_abPair.first;
Point3 db = d_abPair.second;
Vector3 Rdb = aRb * db;
y += da.transpose() * Rdb;
x += Rdb.transpose() * Rdb;
}
double s = y / x;
Point3 aTb = (aCentroid - s * (aRb * bCentroid)) / s;
return Similarity3(aRb, aTb, s);
return GetSim3(abPointPairs, aCentroid, bCentroid, aRb);
}
Similarity3 Similarity3::Align(const std::vector<Pose3Pair>& abPosePairs) {
@ -147,30 +147,20 @@ Similarity3 Similarity3::Align(const std::vector<Pose3Pair>& abPosePairs) {
// calculate rotation and centroids
Point3 aCentroid(0, 0, 0), bCentroid(0, 0, 0);
vector<Rot3> rotationList;
vector<Point3Pair> abPointPairs;
abPointPairs.reserve(n);
for (const Pose3Pair& abPair : abPosePairs) {
aCentroid += abPair.first.translation();
bCentroid += abPair.second.translation();
rotationList.emplace_back(abPair.first.rotation().compose(abPair.second.rotation().inverse()));
abPointPairs.emplace_back(abPair.first.translation(), abPair.second.translation());
}
const double f = 1.0 / n;
aCentroid *= f;
bCentroid *= f;
const Rot3 aRb = FindKarcherMean<Rot3>(rotationList);
// Calculate scale
double x = 0;
double y = 0;
for (const Pose3Pair& abPair : abPosePairs) {
Point3 da = abPair.first.translation() - aCentroid;
Point3 db = abPair.second.translation() - bCentroid;
Vector3 Rdb = aRb * db;
y += da.transpose() * Rdb;
x += Rdb.transpose() * Rdb;
}
double s = y / x;
Point3 aTb = (aCentroid - s * (aRb * bCentroid)) / s;
return Similarity3(aRb, aTb, s);
return GetSim3(abPointPairs, aCentroid, bCentroid, aRb);
}
Matrix4 Similarity3::wedge(const Vector7& xi) {

5
gtsam_unstable/geometry/Similarity3.h
View File

@ -199,10 +199,13 @@ public:
/// @name Helper functions
/// @{
/// Calculate expmap and logmap coefficients.
private:
/// Calculate expmap and logmap coefficients.
static Matrix3 GetV(Vector3 w, double lambda);
/// Calculate scale and translation with point pairs, rotation, and centroids.
static Similarity3 GetSim3(const std::vector<Point3Pair>& abPointPairs, const Point3 aCentroid, const Point3 bCentroid, const Rot3 aRb);
/// @}
};