I had some exception Error while using a loadmodel function of vpMbEdgeTracker for *.wrl in Visp 3.2.1

[DavidLeeDoosan]

Hello, I have a problem for a tracker.

I had some exception Error while using a loadmodel function of vpMbEdgeTracker for *.wrl in Visp 3.2.1

What happen to me? I did not have any idea for the problem. Could you help me? Thanks.

#include <opencv2/opencv.hpp>
#include <iostream>
#include <opencv2/imgproc/imgproc.hpp>
#include <visp3/core/vpImageConvert.h>
#include <visp/vpConfig.h>
#include <visp/vpImage.h>
#include <visp/vpImageConvert.h>
#include <visp/vpMbEdgeTracker.h>
#include <visp/vpImageSimulator.h>
#include <visp/vpOpenCVGrabber.h>
#include <visp/vpDisplayOpenCV.h>
#include <visp/vpDisplayGDI.h>
#include <visp/vpDisplayX.h>

using namespace cv;
using namespace std;

int main()
{
    Mat img_color;
    cv::Mat gray;
    vpImage<unsigned char> Ig; // A grayscale image

    VideoCapture cap(0);
    cap.read(img_color);

    cv::cvtColor(img_color, gray, cv::COLOR_BGR2GRAY);

    vpImageConvert::convert(gray, Ig);

    //Display initialisation
#if defined VISP_HAVE_X11
    vpDisplayX d;
#elif defined VISP_HAVE_GDI
    vpDisplayGDI d;
#elif defined VISP_HAVE_OPEN_CV
    vpDisplayOpenCV d;
#endif

    d.init(Ig, 0, 0, "");

    vpDisplay::display(Ig);
    vpDisplay::flush(Ig);

    //Model-based tracker initialisation
    vpMbEdgeTracker tracker;
    tracker.setDisplayFeatures(true);
    vpHomogeneousMatrix cMo;

    tracker.loadConfigFile("cadre.xml");

    vpCameraParameters cam;
    tracker.getCameraParameters(cam);

    tracker.loadModel("cadre.wrl");   // Here is my exception error!!

    tracker.initClick(Ig, "cadre", true);
    vpDisplay::flush(Ig);
    vpDisplay::getClick(Ig);
    tracker.track(Ig);

    //Pose computation
    tracker.getPose(cMo);

    while (1)
    {
        cap.read(img_color);        
        cv::cvtColor(img_color, gray, cv::COLOR_BGR2GRAY);

        vpImageConvert::convert(gray, Ig);

        vpDisplay::display(Ig);
        vpDisplay::flush(Ig);

    }

    return 0;
}

////////////////////////////////////// cadre.wrl

#VRML V2.0 utf8

DEF fst_0 Group {
children [

Shape {
appearance Appearance { 
 material Material {
  diffuseColor 1 1 1
  specularColor 0.5 0.5 0.5
  emissiveColor 0 0 0
  shininess 10.000000
  transparency 0.000000
 }
}
geometry IndexedFaceSet {
solid FALSE
creaseAngle 0.5
coord Coordinate { 
point [
-2, -2,  0.0
 2, -2,  0.0
 2,  2,  0.0 
 -2,  2,  0.0 
-2.5, -2.5,  0.0
 2.5, -2.5,  0.0
 2.5,  2.5,  0.0 
 -2.5,  2.5,  0.0 ]
}

coordIndex [
 0, 3,2,1,-1
 4, 7,6,5,-1]}
}

]
}

[fspindle]

Sorry for the delay.

You didn't add the exception message you got.

I see multiple reasons:

• Your init file should be named cadre.init and loaded using:

  tracker.initClick(Ig, "cadre.init", true);

• In your cadre.wrl file, don't forget that 3D point coordinates should be expressed in meter. Here you consider a 5 by 5 meter square. Is this correct ?
• Moreover in your cadre.wrl file, the faces are not oriented such as the normal of the faces are going toward the camera for visibility check. If I'm right you should get an exception like Catch a ViSP exception: Error [1]: No data found to compute the interaction matrix.... You should rather use:

  coordIndex [
  0, 1,2,3,-1
  4, 5, 6, 7,-1]}
  }