69 lines
1.7 KiB
C
69 lines
1.7 KiB
C
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/**
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* @file RangeFactor.H
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* @authors Frank Dellaert
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**/
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#pragma once
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#include "Pose2.h"
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#include "Point2.h"
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#include "NonlinearFactor.h"
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namespace gtsam {
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/**
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* Calculate range to a landmark
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* @param pose 2D pose of robot
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* @param point 2D location of landmark
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* @return range (double)
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*/
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double range(const Pose2& pose, const Point2& point) {
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Point2 d = transform_to(pose, point);
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return d.norm();
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}
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/**
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* Calculate range and optional derivative(s)
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*/
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double range(const Pose2& pose, const Point2& point,
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boost::optional<Matrix&> H1, boost::optional<Matrix&> H2) {
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if (!H1 && !H2) return range(pose, point);
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Point2 d = transform_to(pose, point);
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double x = d.x(), y = d.y(), d2 = x * x + y * y, n = sqrt(d2);
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Matrix D_result_d = Matrix_(1, 2, x / n, y / n);
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if (H1) *H1 = D_result_d * Dtransform_to1(pose, point);
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if (H2) *H2 = D_result_d * Dtransform_to2(pose, point);
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return n;
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}
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/**
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* Non-linear factor for a constraint derived from a 2D measurement,
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* i.e. the main building block for visual SLAM.
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*/
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template<class Config, class PoseKey, class PointKey>
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class RangeFactor: public NonlinearFactor2<Config, PoseKey, Pose2, PointKey,
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Point2> {
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private:
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double z_; /** measurement */
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typedef NonlinearFactor2<Config, PoseKey, Pose2, PointKey, Point2> Base;
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public:
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RangeFactor(); /* Default constructor */
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RangeFactor(double z, double sigma, const PoseKey& i, const PointKey& j) :
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Base(sigma, i, j), z_(z) {
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}
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/** h(x)-z */
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Vector evaluateError(const Pose2& pose, const Point2& point,
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boost::optional<Matrix&> H1, boost::optional<Matrix&> H2) const {
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double hx = gtsam::range(pose, point, H1, H2);
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return Vector_(1, hx - z_);
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}
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}; // RangeFactor
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} // namespace gtsam
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