text: // g2o - General Graph Optimization
  // Copyright (C) 2011 R. Kuemmerle, G. Grisetti, W. Burgard
  // All rights reserved.
  //
  // Redistribution and use in source and binary forms, with or without
  // modification, are permitted provided that the following conditions are
  // met:
  //
  // * Redistributions of source code must retain the above copyright notice,
  //   this list of conditions and the following disclaimer.
  // * Redistributions in binary form must reproduce the above copyright
  //   notice, this list of conditions and the following disclaimer in the
  //   documentation and/or other materials provided with the distribution.
  //
  // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
  // IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
  // TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
  // PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  // HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
  // TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
  // PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
  // LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
  // NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
  // SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  
  #ifndef G2O_EDGE_PROJECT_DEPTH_H_
  #define G2O_EDGE_PROJECT_DEPTH_H_
  
  #include "g2o/core/base_binary_edge.h"
  
  #include "vertex_se3.h"
  #include "vertex_pointxyz.h"
  #include "parameter_camera.h"
  #include "g2o_types_slam3d_api.h"
  
  namespace g2o {
  
    /*! \class EdgeProjectDepth
     * \brief g2o edge from a track to a depth camera node using a depth measurement (true distance, not disparity)
     */
    class G2O_TYPES_SLAM3D_API EdgeSE3PointXYZDepth : public BaseBinaryEdge<3, Vector3D, VertexSE3, VertexPointXYZ> {
    public:
      EIGEN_MAKE_ALIGNED_OPERATOR_NEW
      EdgeSE3PointXYZDepth();
      virtual bool read(std::istream& is);
      virtual bool write(std::ostream& os) const;
  
      // return the error estimate as a 3-vector
      void computeError();
      // jacobian
      virtual void linearizeOplus();
      
  
      virtual void setMeasurement(const Vector3D& m){
        _measurement = m;
      }
  
      virtual bool setMeasurementData(const double* d){
        Eigen::Map<const Vector3D> v(d);
        _measurement = v;
        return true;
      }
  
      virtual bool getMeasurementData(double* d) const{
        Eigen::Map<Vector3D> v(d);
        v=_measurement;
        return true;
      }
      
      virtual int measurementDimension() const {return 3;}
  
      virtual bool setMeasurementFromState() ;
  
      virtual double initialEstimatePossible(const OptimizableGraph::VertexSet& from, 
               OptimizableGraph::Vertex* to) { 
        (void) to; 
        return (from.count(_vertices[0]) == 1 ? 1.0 : -1.0);
      }
  
      virtual void initialEstimate(const OptimizableGraph::VertexSet& from, OptimizableGraph::Vertex* to);
  
    private:
      Eigen::Matrix<double,3,9,Eigen::ColMajor> J; // jacobian before projection
  
      virtual bool resolveCaches();
      ParameterCamera* params;
      CacheCamera* cache;
    };
  
  }
  #endif
  