Example: graphslam_example

graphslam_example screenshot

C++ example source code:

/* +------------------------------------------------------------------------+
   |                     Mobile Robot Programming Toolkit (MRPT)            |
   |                          https://www.mrpt.org/                         |
   |                                                                        |
   | Copyright (c) 2005-2022, Individual contributors, see AUTHORS file     |
   | See: https://www.mrpt.org/Authors - All rights reserved.               |
   | Released under BSD License. See: https://www.mrpt.org/License          |
   +------------------------------------------------------------------------+ */

#include <mrpt/containers/yaml.h>
#include <mrpt/graphslam/levmarq.h>
#include <mrpt/gui/CDisplayWindow3D.h>
#include <mrpt/gui/CDisplayWindowPlots.h>
#include <mrpt/img/TColor.h>
#include <mrpt/opengl/COpenGLScene.h>
#include <mrpt/opengl/CSetOfObjects.h>
#include <mrpt/opengl/graph_tools.h>
#include <mrpt/random.h>

#include <chrono>
#include <iostream>
#include <thread>

using namespace mrpt;
using namespace mrpt::graphs;
using namespace mrpt::graphslam;
using namespace mrpt::poses;
using namespace mrpt::math;
using namespace mrpt::gui;
using namespace mrpt::opengl;
using namespace mrpt::random;
using namespace mrpt::img;
using namespace std;
using namespace mrpt::system;

// Level of noise in nodes initial positions:
const double STD_NOISE_NODE_XYZ = 0.5;
const double STD_NOISE_NODE_ANG = 5.0_deg;

// Level of noise in edges:
const double STD_NOISE_EDGE_XYZ = 0.001;
const double STD_NOISE_EDGE_ANG = 0.01_deg;

const double STD4EDGES_COV_MATRIX = 10;
const double ERROR_IN_INCOMPATIBLE_EDGE = 0.3;  // ratio [0,1]

template <class GRAPH, bool EDGES_ARE_PDF = GRAPH::edge_t::is_PDF_val>
struct EdgeAdders;

template <class GRAPH>
struct EdgeAdders<GRAPH, false>
{
    static const int DIM = GRAPH::edge_t::type_value::static_size;
    typedef CMatrixFixed<double, DIM, DIM> cov_t;

    static void addEdge(
        TNodeID from, TNodeID to,
        const typename GRAPH::global_poses_t& real_poses, GRAPH& graph,
        const cov_t& COV_MAT)
    {
        typename GRAPH::edge_t RelativePose(
            real_poses.find(to)->second - real_poses.find(from)->second);
        graph.insertEdge(from, to, RelativePose);
    }
};
// PDF version:
template <class GRAPH>
struct EdgeAdders<GRAPH, true>
{
    static const int DIM = GRAPH::edge_t::type_value::static_size;
    typedef CMatrixFixed<double, DIM, DIM> cov_t;

    static void addEdge(
        TNodeID from, TNodeID to,
        const typename GRAPH::global_poses_t& real_poses, GRAPH& graph,
        const cov_t& COV_MAT)
    {
        typename GRAPH::edge_t RelativePose(
            real_poses.find(to)->second - real_poses.find(from)->second,
            COV_MAT);
        graph.insertEdge(from, to, RelativePose);
    }
};

// Container to handle the propagation of the square root error of the problem
vector<double> log_sq_err_evolution;

// This example lives inside this template class, which can be instanced for
// different kind of graphs (see main()):
template <class my_graph_t>
struct ExampleDemoGraphSLAM
{
    template <class GRAPH_T>
    static void my_levmarq_feedback(
        const GRAPH_T& graph, const size_t iter, const size_t max_iter,
        const double cur_sq_error)
    {
        log_sq_err_evolution.push_back(std::log(cur_sq_error));
        if ((iter % 100) == 0)
            cout << "Progress: " << iter << " / " << max_iter
                 << ", total sq err = " << cur_sq_error << endl;
    }

    // ------------------------------------------------------
    //              GraphSLAMDemo
    // ------------------------------------------------------
    void run(bool add_extra_tightening_edge)
    {
        // The graph: nodes + edges:
        my_graph_t graph;

        // The global poses of the graph nodes (without covariance):
        typename my_graph_t::global_poses_t real_node_poses;

        getRandomGenerator().randomize(123);

        // ----------------------------
        // Create a random graph:
        // ----------------------------
        const size_t N_VERTEX = 50;
        const double DIST_THRES = 7;
        const double NODES_XY_MAX = 20;

        for (TNodeID j = 0; j < N_VERTEX; j++)
        {
            // Use evenly distributed nodes:
            static double ang = 2 * M_PI / N_VERTEX;
            const double R = NODES_XY_MAX + 2 * (j % 2 ? 1 : -1);
            CPose2D p(R * cos(ang * j), R * sin(ang * j), ang);

            // Save real pose:
            real_node_poses[j] = p;

            // Copy the nodes to the graph, and add some noise:
            graph.nodes[j] = p;
        }

        typedef EdgeAdders<my_graph_t> edge_adder_t;
        typename edge_adder_t::cov_t inf_matrix;
        inf_matrix.setDiagonal(
            edge_adder_t::cov_t::RowsAtCompileTime,
            square(1.0 / STD4EDGES_COV_MATRIX));

        for (TNodeID i = 0; i < N_VERTEX; i++)
        {
            for (TNodeID j = i + 1; j < N_VERTEX; j++)
            {
                if (real_node_poses[i].distanceTo(real_node_poses[j]) <
                    DIST_THRES)
                    edge_adder_t::addEdge(
                        i, j, real_node_poses, graph, inf_matrix);
            }
        }

        // Add an additional edge to deform the graph?
        if (add_extra_tightening_edge)
        {
            // inf_matrix.setIdentity(square(1.0/(STD4EDGES_COV_MATRIX)));
            edge_adder_t::addEdge(
                0, N_VERTEX / 2, real_node_poses, graph, inf_matrix);

            // Tweak this last node to make it incompatible with the rest:
            // It must exist, don't check errors...
            typename my_graph_t::edge_t& ed =
                graph.edges.find(make_pair(TNodeID(0), TNodeID(N_VERTEX / 2)))
                    ->second;
            ed.getPoseMean().x(
                (1 - ERROR_IN_INCOMPATIBLE_EDGE) * ed.getPoseMean().x());
        }

        // The root node (the origin of coordinates):
        graph.root = TNodeID(0);

        // This is the ground truth graph (make a copy for later use):
        const my_graph_t graph_GT = graph;

        cout << "graph nodes: " << graph_GT.nodeCount() << endl;
        cout << "graph edges: " << graph_GT.edgeCount() << endl;

        // Add noise to edges & nodes:
        for (typename my_graph_t::edges_map_t::iterator itEdge =
                 graph.edges.begin();
             itEdge != graph.edges.end(); ++itEdge)
        {
            const typename my_graph_t::edge_t::type_value delta_noise(CPose3D(
                getRandomGenerator().drawGaussian1D(0, STD_NOISE_EDGE_XYZ),
                getRandomGenerator().drawGaussian1D(0, STD_NOISE_EDGE_XYZ),
                getRandomGenerator().drawGaussian1D(0, STD_NOISE_EDGE_XYZ),
                getRandomGenerator().drawGaussian1D(0, STD_NOISE_EDGE_ANG),
                getRandomGenerator().drawGaussian1D(0, STD_NOISE_EDGE_ANG),
                getRandomGenerator().drawGaussian1D(0, STD_NOISE_EDGE_ANG)));
            itEdge->second.getPoseMean() +=
                typename my_graph_t::edge_t::type_value(delta_noise);
        }

        for (typename my_graph_t::global_poses_t::iterator itNode =
                 graph.nodes.begin();
             itNode != graph.nodes.end(); ++itNode)
            if (itNode->first != graph.root)
                itNode->second.getPoseMean() +=
                    typename my_graph_t::edge_t::type_value(CPose3D(
                        getRandomGenerator().drawGaussian1D(
                            0, STD_NOISE_NODE_XYZ),
                        getRandomGenerator().drawGaussian1D(
                            0, STD_NOISE_NODE_XYZ),
                        getRandomGenerator().drawGaussian1D(
                            0, STD_NOISE_NODE_XYZ),
                        getRandomGenerator().drawGaussian1D(
                            0, STD_NOISE_NODE_ANG),
                        getRandomGenerator().drawGaussian1D(
                            0, STD_NOISE_NODE_ANG),
                        getRandomGenerator().drawGaussian1D(
                            0, STD_NOISE_NODE_ANG)));

        // This is the initial input graph (make a copy for later use):
        const my_graph_t graph_initial = graph;
        //  graph_GT.saveToTextFile("test_GT.graph");
        //  graph_initial.saveToTextFile("test.graph");

        // ----------------------------
        //  Run graph slam:
        // ----------------------------
        mrpt::containers::yaml params;
        // params["verbose"]  = 1;
        params["profiler"] = true;
        params["max_iterations"] = 500;
        params["scale_hessian"] = 0.1;  // If <1, will "exagerate" the scale of
        // the gradient and, normally, will
        // converge much faster.
        params["tau"] = 1e-3;

        // e2: Lev-marq algorithm iteration stopping criterion #2: |delta_incr|
        // < e2*(x_norm+e2)
        //      params["e1"] = 1e-6;
        //      params["e2"] = 1e-6;

        graphslam::TResultInfoSpaLevMarq levmarq_info;
        log_sq_err_evolution.clear();

        cout << "Global graph RMS error / edge = "
             << std::sqrt(graph.getGlobalSquareError(false) / graph.edgeCount())
             << endl;
        cout << "Global graph RMS error / edge = "
             << std::sqrt(graph.getGlobalSquareError(true) / graph.edgeCount())
             << " (ignoring information matrices)." << endl;

        // Do the optimization
        graphslam::optimize_graph_spa_levmarq(
            graph, levmarq_info,
            nullptr,  // List of nodes to optimize. nullptr -> all but the root
            // node.
            params, &my_levmarq_feedback<my_graph_t>);

        cout << "Global graph RMS error / edge = "
             << std::sqrt(graph.getGlobalSquareError(false) / graph.edgeCount())
             << endl;
        cout << "Global graph RMS error / edge = "
             << std::sqrt(graph.getGlobalSquareError(true) / graph.edgeCount())
             << " (ignoring information matrices)." << endl;

        // ----------------------------
        //  Display results:
        // ----------------------------
        CDisplayWindow3D win("graph-slam demo");

        // The final optimized graph:
        mrpt::containers::yaml graph_render_params1;
        graph_render_params1["show_edges"] = true;
        graph_render_params1["edge_width"] = 1;
        graph_render_params1["nodes_corner_scale"] = 1;
        CSetOfObjects::Ptr gl_graph1 =
            mrpt::opengl::graph_tools::graph_visualize(
                graph, graph_render_params1);

        // The initial noisy graph:
        mrpt::containers::yaml graph_render_params2;
        graph_render_params2["show_ground_grid"] = false;
        graph_render_params2["show_edges"] = false;
        graph_render_params2["show_node_corners"] = false;
        graph_render_params2["nodes_point_size"] = 7;

        CSetOfObjects::Ptr gl_graph2 =
            mrpt::opengl::graph_tools::graph_visualize(
                graph_initial, graph_render_params2);

        graph_render_params2["nodes_point_size"] = 5;
        CSetOfObjects::Ptr gl_graph5 =
            mrpt::opengl::graph_tools::graph_visualize(
                graph, graph_render_params2);

        // The ground truth graph:
        mrpt::containers::yaml graph_render_params3;
        graph_render_params3["show_ground_grid"] = false;
        graph_render_params3["show_ID_labels"] = true;
        graph_render_params3["show_edges"] = true;
        graph_render_params3["edge_width"] = 3;
        graph_render_params3["nodes_corner_scale"] = 2;
        CSetOfObjects::Ptr gl_graph3 =
            mrpt::opengl::graph_tools::graph_visualize(
                graph_GT, graph_render_params3);
        CSetOfObjects::Ptr gl_graph4 =
            mrpt::opengl::graph_tools::graph_visualize(
                graph_initial, graph_render_params3);

        win.addTextMessage(
            5, 5, "Ground truth: Big corners & thick edges",
            1000 /* arbitrary, unique text label ID */);
        win.addTextMessage(
            5, 5 + 15, "Initial graph: Gray thick points.",
            1001 /* arbitrary, unique text label ID */);
        win.addTextMessage(
            5, 5 + 30, "Final graph: Small corners & thin edges",
            1002 /* arbitrary, unique text label ID */);

        {
            COpenGLScene::Ptr& scene = win.get3DSceneAndLock();
            scene->insert(gl_graph1);
            scene->insert(gl_graph3);
            scene->insert(gl_graph2);
            scene->insert(gl_graph5);
            win.unlockAccess3DScene();
            win.repaint();
        }

        // Show progress of error:
        CDisplayWindowPlots win_err("Evolution of log(sq. error)");
        win_err.plot(log_sq_err_evolution, "-b");
        win_err.axis_fit();

        // wait end:
        cout << "Close any window to end...\n";
        while (win.isOpen() && win_err.isOpen() && !mrpt::system::os::kbhit())
        {
            std::this_thread::sleep_for(10ms);
        }
    }
};

int main()
{
    try
    {
        // typedef CNetworkOfPoses<CPose2D,map_traits_map_as_vector> my_graph_t;

        cout << "Select the type of graph to optimize:\n"
                "1.  CNetworkOfPoses2D \n"
                "2.  CNetworkOfPoses2DInf \n"
                "3.  CNetworkOfPoses3D \n"
                "4.  CNetworkOfPoses3DInf \n";

        cout << ">> ";

        int i = 0;
        {
            string l;
            std::getline(cin, l);
            l = mrpt::system::trim(l);
            i = atoi(&l[0]);
        }

        bool add_extra_tightening_edge;
        cout << "Add an extra, incompatible tightening edge? [y/N] ";
        {
            string l;
            std::getline(cin, l);
            l = mrpt::system::trim(l);
            add_extra_tightening_edge = l[0] == 'Y' || l[0] == 'y';
        }

        switch (i)
        {
            case 1:
            {
                ExampleDemoGraphSLAM<CNetworkOfPoses2D> demo;
                demo.run(add_extra_tightening_edge);
            }
            break;
            case 2:
            {
                ExampleDemoGraphSLAM<CNetworkOfPoses2DInf> demo;
                demo.run(add_extra_tightening_edge);
            }
            break;
            case 3:
            {
                ExampleDemoGraphSLAM<CNetworkOfPoses3D> demo;
                demo.run(add_extra_tightening_edge);
            }
            break;
            case 4:
            {
                ExampleDemoGraphSLAM<CNetworkOfPoses3DInf> demo;
                demo.run(add_extra_tightening_edge);
            }
            break;
        };

        std::this_thread::sleep_for(20ms);
        return 0;
    }
    catch (exception& e)
    {
        cout << "MRPT exception caught: " << e.what() << endl;
        return -1;
    }
    catch (...)
    {
        printf("Another exception!!");
        return -1;
    }
}