Example: maps_gridmap_likelihood_characterization

C++ example source code:

/* +------------------------------------------------------------------------+
   |                     Mobile Robot Programming Toolkit (MRPT)            |
   |                          https://www.mrpt.org/                         |
   |                                                                        |
   | Copyright (c) 2005-2023, 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/config/CConfigFile.h>
#include <mrpt/maps/COccupancyGridMap2D.h>
#include <mrpt/maps/CSimplePointsMap.h>
#include <mrpt/obs/CObservation2DRangeScan.h>
#include <mrpt/poses/CPose2D.h>
#include <mrpt/system/CTicTac.h>
#include <mrpt/system/filesystem.h>
#include <mrpt/system/os.h>

#include <iostream>

using namespace mrpt;
using namespace mrpt::system;
using namespace mrpt::obs;
using namespace mrpt::maps;
using namespace mrpt::poses;
using namespace std;

#include <mrpt/examples_config.h>
string myDataDir(
    MRPT_EXAMPLES_BASE_DIRECTORY +
    string("maps_gridmap_likelihood_characterization/"));

// Default .ini file:
string iniFile(myDataDir + string("config_likelihood.ini"));

// ------------------------------------------------------
//              theMainThing
// ------------------------------------------------------
void theMainThing()
{
    COccupancyGridMap2D gridMap;
    CObservation2DRangeScan obsScan;
    CTicTac tictac;

    // Load the grid map from file
    // ----------------------------------------------
    obsScan.aperture = M_2PIf;

    ASSERT_(mrpt::system::fileExists(iniFile));
    mrpt::config::CConfigFile cfgFile(iniFile);

    string bmp = cfgFile.read_string("Params", "bitmap_file", "", true);
    float res =
        cfgFile.read_float("Params", "evaluation_grid_resolution", 0.1f, true);

    float evalgrid_x_min = 0, evalgrid_x_max = 0;
    float evalgrid_y_min = 0, evalgrid_y_max = 0;

    MRPT_LOAD_CONFIG_VAR_NO_DEFAULT(evalgrid_x_min, float, cfgFile, "Params");
    MRPT_LOAD_CONFIG_VAR_NO_DEFAULT(evalgrid_x_max, float, cfgFile, "Params");
    MRPT_LOAD_CONFIG_VAR_NO_DEFAULT(evalgrid_y_min, float, cfgFile, "Params");
    MRPT_LOAD_CONFIG_VAR_NO_DEFAULT(evalgrid_y_max, float, cfgFile, "Params");

    int type_experiment = 0;
    MRPT_LOAD_CONFIG_VAR_NO_DEFAULT(type_experiment, int, cfgFile, "Params");

    // Gridmap:
    string GRIDMAP_FILE(myDataDir + bmp);

    gridMap.loadFromBitmapFile(GRIDMAP_FILE, 0.05f);
    gridMap.saveAsBitmapFile("./out_gridmap.png");

    if (type_experiment == 0)
    {
        // Simulate scan:
        // ----------------------------------------------
        obsScan.aperture = M_PIf;
        obsScan.maxRange = 80.0f;
        obsScan.rightToLeft = true;
        gridMap.laserScanSimulator(obsScan, CPose2D(0, 0, 0), 0.5f, 180);
    }
    else
    {
        // Lik. of each 2D  position
        // ------------------------------------
        obsScan.aperture = 0;
        obsScan.maxRange = 80.0f;
        obsScan.rightToLeft = true;
        obsScan.resizeScanAndAssign(1, 0.0, true);
    }

    // Set options:
    // ----------------------------------------------
    gridMap.likelihoodOptions.loadFromConfigFile(cfgFile, "LikelihoodOptions");
    gridMap.likelihoodOptions.dumpToConsole();

    // Perform simulation:
    // ----------------------------------------------
    printf("Performing simulation (saving to out_lik.txt)...");

    FILE* f = os::fopen("out_lik.txt", "wt");
    ASSERT_(f);

    CSimplePointsMap pointsMap;
    pointsMap.clear();
    pointsMap.insertPoint(0, 0);

    tictac.Tic();

    float phi = (float)0.0_deg;

    auto nullPose = CPose3D(0, 0, 0, phi, 0, 0);

    for (float y = evalgrid_y_min; y < evalgrid_y_max; y += res)
    {
        for (float x = evalgrid_x_min; x < evalgrid_x_max; x += res)
        {
            nullPose.x(x);
            nullPose.y(y);
            fprintf(
                f, "%e ",
                gridMap.computeObservationLikelihood(obsScan, nullPose));
        }  // for y
        fprintf(f, "\n");
    }  // for x

    printf("Done!\n");

    printf("Time:%fms\n", 1000.0f * tictac.Tac());

    os::fclose(f);
}

int main()
{
    try
    {
        theMainThing();

        return 0;
    }
    catch (const std::exception& e)
    {
        std::cout << "MRPT exception:\n" << e.what() << std::endl;
        return -1;
    }
    catch (...)
    {
        printf("Runtime exception!!");
        return -1;
    }
}