Example: hwdrivers_kinect_to_2d_scan_example

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          |
   +------------------------------------------------------------------------+ */

/*
  Example  : kinect-to-2d-laser-demo
  Web page : https://www.mrpt.org/Example_Kinect_To_2D_laser_scan (includes
  video demo)

  Purpose  : Demonstrate grabbing from CKinect, multi-threading
             and converting the 3D range data into an equivalent
             2D planar scan.
*/

#include <mrpt/config/CConfigFile.h>
#include <mrpt/gui/CDisplayWindow3D.h>
#include <mrpt/hwdrivers/CKinect.h>
#include <mrpt/img/TColor.h>
#include <mrpt/opengl/CFrustum.h>
#include <mrpt/opengl/CGridPlaneXY.h>
#include <mrpt/opengl/CPlanarLaserScan.h>
#include <mrpt/opengl/CPointCloudColoured.h>
#include <mrpt/opengl/stock_objects.h>
#include <mrpt/system/CTicTac.h>
#include <mrpt/system/filesystem.h>

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

using namespace mrpt;
using namespace mrpt::hwdrivers;
using namespace mrpt::math;
using namespace mrpt::gui;
using namespace mrpt::obs;
using namespace mrpt::maps;
using namespace mrpt::opengl;
using namespace mrpt::system;
using namespace mrpt::img;
using namespace std;

// Thread for grabbing: Do this is another thread so we divide rendering and
// grabbing
//   and exploit multicore CPUs.
struct TThreadParam
{
    TThreadParam() {}
    volatile bool quit{false};
    volatile int pushed_key{0};
    volatile double Hz{0};

    CObservation3DRangeScan::Ptr new_obs;  // RGB+D (+3D points)
    CObservationIMU::Ptr new_obs_imu;  // Accelerometers
};

void thread_grabbing(TThreadParam& p)
{
    try
    {
        CKinect kinect;

        // Set params:
        // kinect.enableGrab3DPoints(true);
        // kinect.enablePreviewRGB(true);
        //...
        const std::string cfgFile = "kinect_calib.cfg";
        if (mrpt::system::fileExists(cfgFile))
        {
            cout << "Loading calibration from: " << cfgFile << endl;
            kinect.loadConfig(mrpt::config::CConfigFile(cfgFile), "KINECT");
        }
        else
            cerr << "Warning: Calibration file [" << cfgFile
                 << "] not found -> Using default params.\n";

        // Open:
        cout << "Calling CKinect::initialize()...";
        kinect.initialize();
        cout << "OK\n";

        CTicTac tictac;
        int nImgs = 0;
        bool there_is_obs = true, hard_error = false;

        while (!hard_error && !p.quit)
        {
            // Grab new observation from the camera:
            auto obs = CObservation3DRangeScan::Create();  // Smart pointers to
                                                           // observations
            CObservationIMU::Ptr obs_imu = CObservationIMU::Create();

            kinect.getNextObservation(*obs, *obs_imu, there_is_obs, hard_error);

            if (!hard_error && there_is_obs)
            {
                std::atomic_store(&p.new_obs, obs);
                std::atomic_store(&p.new_obs_imu, obs_imu);
            }

            if (p.pushed_key != 0)
            {
                switch (p.pushed_key)
                {
                    case 27: p.quit = true; break;
                }

                // Clear pushed key flag:
                p.pushed_key = 0;
            }

            nImgs++;
            if (nImgs > 10)
            {
                p.Hz = nImgs / tictac.Tac();
                nImgs = 0;
                tictac.Tic();
            }
        }
    }
    catch (const std::exception& e)
    {
        cout << "Exception in Kinect thread: " << e.what() << endl;
        p.quit = true;
    }
}

// ------------------------------------------------------
//              Test_Kinect
// ------------------------------------------------------
void Test_Kinect()
{
    // Launch grabbing thread:
    // --------------------------------------------------------
    TThreadParam thrPar;
    std::thread thHandle(thread_grabbing, std::ref(thrPar));

    // Wait until data stream starts so we can say for sure the sensor has been
    // initialized OK:
    cout << "Waiting for sensor initialization...\n";
    do
    {
        CObservation3DRangeScan::Ptr possiblyNewObs =
            std::atomic_load(&thrPar.new_obs);
        if (possiblyNewObs && possiblyNewObs->timestamp != INVALID_TIMESTAMP)
            break;
        else
            std::this_thread::sleep_for(10ms);
    } while (!thrPar.quit);

    // Check error condition:
    if (thrPar.quit) return;

    // Create window and prepare OpenGL object in the scene:
    // --------------------------------------------------------
    mrpt::gui::CDisplayWindow3D win3D("Kinect 3D -> 2D laser scan", 800, 600);

    win3D.setCameraAzimuthDeg(140);
    win3D.setCameraElevationDeg(30);
    win3D.setCameraZoom(10.0);
    win3D.setFOV(90);
    win3D.setCameraPointingToPoint(2.5, 0, 0);

    // The 3D point cloud OpenGL object:
    mrpt::opengl::CPointCloudColoured::Ptr gl_points =
        mrpt::opengl::CPointCloudColoured::Create();
    gl_points->setPointSize(2.5);

    // The 2D "laser scan" OpenGL object:
    mrpt::opengl::CPlanarLaserScan::Ptr gl_2d_scan =
        mrpt::opengl::CPlanarLaserScan::Create();
    gl_2d_scan->enablePoints(true);
    gl_2d_scan->enableLine(true);
    gl_2d_scan->enableSurface(true);
    gl_2d_scan->setSurfaceColor(0, 0, 1, 0.3);  // RGBA

    mrpt::opengl::CFrustum::Ptr gl_frustum = mrpt::opengl::CFrustum::Create(
        0.2f, 5.0f, 90.0f, 5.0f, 2.0f, true, true);

    const double aspect_ratio =
        480.0 / 640.0;  // kinect.rows() / double( kinect.cols() );

    opengl::COpenGLViewport::Ptr viewRange,
        viewInt;  // Extra viewports for the RGB & D images.
    {
        mrpt::opengl::COpenGLScene::Ptr& scene = win3D.get3DSceneAndLock();

        // Create the Opengl object for the point cloud:
        scene->insert(gl_points);
        scene->insert(gl_2d_scan);
        scene->insert(gl_frustum);

        {
            mrpt::opengl::CGridPlaneXY::Ptr gl_grid =
                mrpt::opengl::CGridPlaneXY::Create();
            gl_grid->setColor(0.6, 0.6, 0.6);
            scene->insert(gl_grid);
        }
        {
            mrpt::opengl::CSetOfObjects::Ptr gl_corner =
                mrpt::opengl::stock_objects::CornerXYZ();
            gl_corner->setScale(0.2);
            scene->insert(gl_corner);
        }

        const int VW_WIDTH =
            250;  // Size of the viewport into the window, in pixel units.
        const int VW_HEIGHT = aspect_ratio * VW_WIDTH;
        const int VW_GAP = 30;

        // Create the Opengl objects for the planar images, as textured planes,
        // each in a separate viewport:
        win3D.addTextMessage(
            30, -25 - 1 * (VW_GAP + VW_HEIGHT), "Range data", 1);
        viewRange = scene->createViewport("view2d_range");
        viewRange->setViewportPosition(
            5, -10 - 1 * (VW_GAP + VW_HEIGHT), VW_WIDTH, VW_HEIGHT);

        win3D.addTextMessage(
            30, -25 - 2 * (VW_GAP + VW_HEIGHT), "Intensity data", 2);
        viewInt = scene->createViewport("view2d_int");
        viewInt->setViewportPosition(
            5, -10 - 2 * (VW_GAP + VW_HEIGHT), VW_WIDTH, VW_HEIGHT);

        win3D.unlockAccess3DScene();
        win3D.repaint();
    }

    CObservation3DRangeScan::Ptr last_obs;
    CObservationIMU::Ptr last_obs_imu;

    while (win3D.isOpen() && !thrPar.quit)
    {
        CObservation3DRangeScan::Ptr possiblyNewObs =
            std::atomic_load(&thrPar.new_obs);
        if (possiblyNewObs && possiblyNewObs->timestamp != INVALID_TIMESTAMP &&
            (!last_obs || possiblyNewObs->timestamp != last_obs->timestamp))
        {
            // It IS a new observation:
            last_obs = possiblyNewObs;
            last_obs_imu = std::atomic_load(&thrPar.new_obs_imu);

            // Update visualization ---------------------------------------
            bool do_refresh = false;

            // Show 2D ranges as a grayscale image:
            if (last_obs->hasRangeImage)
            {
                mrpt::img::CImage img;

                // Normalize the image
                static CMatrixFloat range2D;  // Static to save time allocating
                // the matrix in every iteration
                range2D = last_obs->rangeImage;
                range2D *= (1.0 / last_obs->maxRange);

                img.setFromMatrix(range2D);

                win3D.get3DSceneAndLock();
                viewRange->setImageView(std::move(img));
                win3D.unlockAccess3DScene();
                do_refresh = true;
            }

            // Convert ranges to an equivalent 2D "fake laser" scan:
            if (last_obs->hasRangeImage)
            {
                // Convert to scan:
                CObservation2DRangeScan::Ptr obs_2d =
                    CObservation2DRangeScan::Create();
                const float vert_FOV = DEG2RAD(gl_frustum->getVertFOV());

                mrpt::obs::T3DPointsTo2DScanParams sp;
                sp.angle_inf = .5f * vert_FOV;
                sp.angle_sup = .5f * vert_FOV;
                sp.sensorLabel = "KINECT_2D_SCAN";

                last_obs->convertTo2DScan(*obs_2d, sp);

                // And load scan in the OpenGL object:
                gl_2d_scan->setScan(*obs_2d);
            }

            // Show intensity image:
            if (last_obs->hasIntensityImage)
            {
                win3D.get3DSceneAndLock();
                viewInt->setImageView(
                    last_obs->intensityImage);  // This is not "_fast" since the
                // intensity image is used below
                // in the coloured point cloud.
                win3D.unlockAccess3DScene();
                do_refresh = true;
            }

            // Show 3D points:
            if (last_obs->hasPoints3D)
            {
                win3D.get3DSceneAndLock();
                mrpt::obs::T3DPointsProjectionParams pp;
                pp.takeIntoAccountSensorPoseOnRobot = false;

                last_obs->unprojectInto(*gl_points, pp);
                win3D.unlockAccess3DScene();
                do_refresh = true;
            }

            // Some text messages:
            win3D.get3DSceneAndLock();
            // Estimated grabbing rate:
            win3D.addTextMessage(-100, -20, format("%.02f Hz", thrPar.Hz), 100);

            win3D.addTextMessage(
                10, 10,
                "'o'/'i'-zoom out/in, '2'/'3'/'f':show/hide 2D/3D/frustum "
                "data, mouse: orbit 3D, ESC: quit",
                110);

            win3D.addTextMessage(
                10, 25,
                format(
                    "Show: 3D=%s 2D=%s Frustum=%s (vert. FOV=%.1fdeg)",
                    gl_points->isVisible() ? "YES" : "NO",
                    gl_2d_scan->isVisible() ? "YES" : "NO",
                    gl_frustum->isVisible() ? "YES" : "NO",
                    gl_frustum->getVertFOV()),
                111);
            win3D.unlockAccess3DScene();

            // Do we have accelerometer data?
            if (last_obs_imu && last_obs_imu->dataIsPresent[IMU_X_ACC])
            {
                win3D.get3DSceneAndLock();
                win3D.addTextMessage(
                    10, 65,
                    format(
                        "Acc: x=%.02f y=%.02f z=%.02f",
                        last_obs_imu->rawMeasurements[IMU_X_ACC],
                        last_obs_imu->rawMeasurements[IMU_Y_ACC],
                        last_obs_imu->rawMeasurements[IMU_Z_ACC]),
                    102);
                win3D.unlockAccess3DScene();
                do_refresh = true;
            }

            // Force opengl repaint:
            if (do_refresh) win3D.repaint();

        }  // end update visualization:

        // Process possible keyboard commands:
        // --------------------------------------
        if (win3D.keyHit() && thrPar.pushed_key == 0)
        {
            const int key = tolower(win3D.getPushedKey());

            switch (key)
            {
                // Some of the keys are processed in this thread:
                case 'o':
                    win3D.setCameraZoom(win3D.getCameraZoom() * 1.2);
                    win3D.repaint();
                    break;
                case 'i':
                    win3D.setCameraZoom(win3D.getCameraZoom() / 1.2);
                    win3D.repaint();
                    break;
                case '2':
                    gl_2d_scan->setVisibility(!gl_2d_scan->isVisible());
                    break;
                case '3':
                    gl_points->setVisibility(!gl_points->isVisible());
                    break;
                case 'F':
                case 'f':
                    gl_frustum->setVisibility(!gl_frustum->isVisible());
                    break;
                case '+':
                    gl_frustum->setVertFOV(gl_frustum->getVertFOV() + 1);
                    break;
                case '-':
                    gl_frustum->setVertFOV(gl_frustum->getVertFOV() - 1);
                    break;
                // ...and the rest in the kinect thread:
                default: thrPar.pushed_key = key; break;
            };
        }

        std::this_thread::sleep_for(1ms);
    }

    cout << "Waiting for grabbing thread to exit...\n";
    thrPar.quit = true;
    thHandle.join();
    cout << "Bye!\n";
}

int main(int argc, char** argv)
{
    try
    {
        Test_Kinect();

        std::this_thread::sleep_for(50ms);
        return 0;
    }
    catch (const std::exception& e)
    {
        std::cerr << "MRPT error: " << mrpt::exception_to_str(e) << std::endl;
        return -1;
    }
    catch (...)
    {
        printf("Another exception!!");
        return -1;
    }
}