ROS中的VISP-无法显示摄像机供稿

Question

I am trying to integrate a code already written in ROS with some basic Visp lines so as to display a camera feed using Visp functions. I am a beginner in visp and hence I am trying something basic.I am attaching the relevant code lines here

//Lots of lines of code above and blow this code block
cv::Mat src_gray;

cv::cvtColor(imageLeft, src_gray, CV_RGB2GRAY );//imageLeft is a colour image got from the camera through another node

vpImage<unsigned char> I;


vpImageConvert::convert(src_gray,I) ;
vpDisplayOpenCV display;

if(this->lt == false)//this if loop is to prevent from infinite windows coming out
{display.init(I, 100, 100, "Line tracking");
this->lt = true;}

vpDisplay::display(I);
vpDisplay::flush(I);

Let me ensure you that this piece of code is in a callback and hence it is equivalent to an infinte while loop unless the process is stopped.

I am not able to get the camera output in the window.When I run the node the window opens but no image.Any ideas?

Answer 1

The ViSP-ROS interfece has been changing recently. While ViSP Bridge provides low level interface between ROS and ViSP, Visp ROS is a better and higher level interface. From there you can reach to this tutorial where a regular ViSP code is modified to use ROS.

The ViSP code similar to yours:

#include <visp/vp1394TwoGrabber.h>
#include <visp/vpDisplayX.h>
#include <visp/vpImage.h>

int main()
{
#ifdef VISP_HAVE_DC1394_2
  try {
    vpImage<unsigned char> I; // Create a gray level image container
    bool reset = true; // Enable bus reset during construction (default)
    vp1394TwoGrabber g(reset); // Create a grabber based on libdc1394-2.x third party     lib

    g.setVideoMode(vp1394TwoGrabber::vpVIDEO_MODE_640x480_MONO8);
    g.setFramerate(vp1394TwoGrabber::vpFRAMERATE_60);
    g.open(I);

    std::cout << "Image size: " << I.getWidth() << " " << I.getHeight() << std::endl;

#ifdef VISP_HAVE_X11
    vpDisplayX d(I);
#else
    std::cout << "No image viewer is available..." << std::endl;
#endif

    while(1) {
      g.acquire(I);
      vpDisplay::display(I);
      vpDisplay::flush(I);
      if (vpDisplay::getClick(I, false))
        break;
    }
  }
  catch(vpException e) {
    std::cout << "Catch an exception: " << e << std::endl;
  }
#endif
}

And the ROS enabled code:

#include <visp/vpDisplayX.h>
#include <visp/vpImage.h>
#include <visp_ros/vpROSGrabber.h>

int main()
{
  try {
    //vpImage<unsigned char> I; // Create a gray level image container
    vpImage<vpRGBa> I; // Create a color image container
    vpROSGrabber g; // Create a grabber based on ROS

    g.setCameraInfoTopic("/camera/camera_info");
    g.setImageTopic("/camera/image_raw");
    g.setRectify(true);
    g.open(I);
    std::cout << "Image size: " << I.getWidth() << " " << I.getHeight() << std::endl;

#ifdef VISP_HAVE_X11
    vpDisplayX d(I);
#else
    std::cout << "No image viewer is available..." << std::endl;
#endif

    while(1) {
      g.acquire(I);
      vpDisplay::display(I);
      vpDisplay::flush(I);
      if (vpDisplay::getClick(I, false))
        break;
    }
  }
  catch(vpException e) {
    std::cout << "Catch an exception: " << e << std::endl;
  }
}

Hope this helps!