PoseStateExponentialMap.h

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// Copyright 2015 Sensics, Inc.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//        http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

#ifndef INCLUDED_PoseStateExponentialMap_h_GUID_3D1B779A_6DBE_4993_0AE7_C28344E55A51
#define INCLUDED_PoseStateExponentialMap_h_GUID_3D1B779A_6DBE_4993_0AE7_C28344E55A51

// Internal Includes
#include "FlexibleKalmanBase.h"
#include "MatrixExponentialMap.h"

// Library/third-party includes
// - none

// Standard includes
// - none

namespace osvr {
namespace kalman {
    namespace pose_exp_map {

        using Dimension = types::DimensionConstant<12>;
        using StateVector = types::DimVector<Dimension>;
        using StateVectorBlock3 = StateVector::FixedSegmentReturnType<3>::Type;
        using ConstStateVectorBlock3 =
            StateVector::ConstFixedSegmentReturnType<3>::Type;

        using StateVectorBlock6 = StateVector::FixedSegmentReturnType<6>::Type;
        using StateSquareMatrix = types::DimSquareMatrix<Dimension>;

        inline StateVectorBlock3 position(StateVector &vec) {
            return vec.head<3>();
        }
        inline ConstStateVectorBlock3 position(StateVector const &vec) {
            return vec.head<3>();
        }

        inline StateVectorBlock3 orientation(StateVector &vec) {
            return vec.segment<3>(3);
        }
        inline ConstStateVectorBlock3 orientation(StateVector const &vec) {
            return vec.segment<3>(3);
        }

        inline StateVectorBlock3 velocity(StateVector &vec) {
            return vec.segment<3>(6);
        }
        inline ConstStateVectorBlock3 velocity(StateVector const &vec) {
            return vec.segment<3>(6);
        }

        inline StateVectorBlock3 angularVelocity(StateVector &vec) {
            return vec.segment<3>(9);
        }
        inline ConstStateVectorBlock3 angularVelocity(StateVector const &vec) {
            return vec.segment<3>(9);
        }

        inline StateVectorBlock6 velocities(StateVector &vec) {
            return vec.segment<6>(6);
        }

        inline StateSquareMatrix stateTransitionMatrix(double dt) {
            // eq. 4.5 in Welch 1996 - except we have all the velocities at the
            // end
            StateSquareMatrix A = StateSquareMatrix::Identity();
            A.topRightCorner<6, 6>() = types::SquareMatrix<6>::Identity() * dt;

            return A;
        }
        inline double computeAttenuation(double damping, double dt) {
            return std::pow(damping, dt);
        }
        inline StateSquareMatrix
        stateTransitionMatrixWithVelocityDamping(double dt, double damping) {

            // eq. 4.5 in Welch 1996

            auto A = stateTransitionMatrix(dt);
            auto attenuation = computeAttenuation(damping, dt);
            A.bottomRightCorner<6, 6>() *= attenuation;
            return A;
        }
        inline StateVector applyVelocity(StateVector const &state, double dt) {
            // eq. 4.5 in Welch 1996


            StateVector ret = state;
            position(ret) += velocity(state) * dt;
            orientation(ret) += angularVelocity(state) * dt;
            return ret;
        }

        inline void dampenVelocities(StateVector &state, double damping,
                                     double dt) {
            auto attenuation = computeAttenuation(damping, dt);
            velocities(state) *= attenuation;
        }
        class State : public HasDimension<12> {
          public:
            EIGEN_MAKE_ALIGNED_OPERATOR_NEW

            State()
                : m_state(StateVector::Zero()),
                  m_errorCovariance(
                      StateSquareMatrix::
                          Identity() ) {}
            void setStateVector(StateVector const &state) { m_state = state; }
            StateVector const &stateVector() const { return m_state; }
            // set P
            void setErrorCovariance(StateSquareMatrix const &errorCovariance) {
                m_errorCovariance = errorCovariance;
            }
            StateSquareMatrix const &errorCovariance() const {
                return m_errorCovariance;
            }

            void postCorrect() {
                matrix_exponential_map::avoidSingularities(
                    orientation(m_state));
                m_cacheData.reset(Eigen::Vector3d(orientation(m_state)));
            }

            StateVectorBlock3 position() {
                return pose_exp_map::position(m_state);
            }

            ConstStateVectorBlock3 position() const {
                return pose_exp_map::position(m_state);
            }

            Eigen::Quaterniond const &getQuaternion() {
                return m_cacheData.getQuaternion();
            }
            Eigen::Matrix3d const &getRotationMatrix() {
                return m_cacheData.getRotationMatrix();
            }

            StateVectorBlock3 velocity() {
                return pose_exp_map::velocity(m_state);
            }

            ConstStateVectorBlock3 velocity() const {
                return pose_exp_map::velocity(m_state);
            }

            StateVectorBlock3 angularVelocity() {
                return pose_exp_map::angularVelocity(m_state);
            }

            ConstStateVectorBlock3 angularVelocity() const {
                return pose_exp_map::angularVelocity(m_state);
            }

          private:
            StateVector m_state;
            StateSquareMatrix m_errorCovariance;

            matrix_exponential_map::ExponentialMapData m_cacheData;
        };

        template <typename OutputStream>
        inline OutputStream &operator<<(OutputStream &os, State const &state) {
            os << "State:" << state.stateVector().transpose() << "\n";
            os << "error:\n" << state.errorCovariance() << "\n";
            return os;
        }
    } // namespace pose_exp_map
} // namespace kalman
} // namespace osvr
#endif // INCLUDED_PoseStateExponentialMap_h_GUID_3D1B779A_6DBE_4993_0AE7_C28344E55A51