Florence's profile - activity

Hello,

After your answer I tried to rewrite the same programm in a other file, and it worked... I looked in the previous one if there were hidden characters that may have cause a problem, and I couldn´t find anything...

So thanks a lot for your answer, problem solved I guess :)

Hello,

I´m trying to use CommandLineParser and I have a problem : even if I don´t put anything when I lauch the program (only ./prog ), the function parser.has returns true, as if something was given on the command line.

If someone has an idea of what I am doing wrong, it would be very helpful !

Thanks :)

Here is the code :

const char* keys =
    {
        "{help          |                   | show help message }"
        "{type          |                   | type of the camera}"
        "{camera_number |                   | camera number     }"
    };


int main(int argc, char* argv[])
{

        CommandLineParser parser(argc, argv, keys);

        bool t = parser.has("type");
        cout << " t = " << t << endl;

        bool cm = parser.has("camera_number"); 
        cout << "cm = " << cm << endl; 

        return 0;
}

Problem solved : It was a special camera, and it needed a particular software (ximea in my case) to work. It didn´t appear as a video device.

Hello,

I´m trying to use the optical flow functions of opencv, and in particular calcOpticalFlowSF.

The matrix I get has negative and float numbers - so the imshow function in the program below crashs. Does anyone has an idea why ?

Thanks a lot !

#include "opencv2/optflow.hpp"
#include <opencv2/core/utility.hpp>
#include "opencv2/imgproc.hpp"
#include "opencv2/imgcodecs.hpp"
#include "opencv2/highgui.hpp"

#include <cstdio>
#include <iostream>

using namespace cv;
using namespace cv::optflow;
using namespace std;



int main(int argc, char** argv)
{

  if (argc < 3) {
    cout << "missing arguments" << endl;
    exit(1);
  }

  cout << argv[0] << endl;

  Mat frame1 = imread(argv[1]);
  Mat frame2 = imread(argv[2]);

  if (frame1.empty()) {
    cout << "frame 1 cannot be read" << endl; 
    exit(1);
  }

  if (frame2.empty()) {
    cout << "frame 2 cannot be read" << endl; 
    exit(1);
  }

  if (frame1.rows != frame2.rows && frame1.cols != frame2.cols) {
    cout << "Images should be of equal sizes" << endl;
    exit(1);
  }

 if (frame1.type() != 16 || frame2.type() != 16) {
    cout <<"Images should be of equal type CV_8UC3" << endl;
   exit(1);
  }


  cout << "images read" << endl;

  Mat flow;

  //calcOpticalFlowSF(frame1, frame2, flow,3, 2, 4, 4.1, 25.5, 18, 55.0, 25.5, 0.35, 18, 55.0, 25.5, 10);
    calcOpticalFlowSF(frame1, frame2, flow,3, 2, 4);




  imshow("Optical Flow" , flow);
  waitKey(0);

  return 0 ;
}

No there are no new devices when I plug the camera... But when I type dmesg then I see that the usb device is connected and recognized. And no, no virtual machine.

Oh you're right, it actually doesn't exist. But I'm sure the camera is connected and recognized by the computer. I've also tried to replace VideoCapture cap(0) by VideoCapture cap(CV_CAP_XIAPI) which actually works better as it doesn't crach, but the video cannot be opened...

Hello,

I'm trying read the video from a camera connected to my computer using OpenCV.

I tried this first test, and I got the following error message :

"GStreamer Plugin: Embedded video playback halted; module v4l2src0 reported: Cannot identify device '/dev/video0'. OpenCV Error: Unspecified error (GStreamer: unable to start pipeline ) in cvCaptureFromCAM_GStreamer, file 'file_location'/opencv-3.1.0/modules/videoio/src/cap_gstreamer.cpp, line 818 terminate called after throwing an instance of 'cv::Exception' what(): 'file_location'/opencv-3.1.0/modules/videoio/src/cap_gstreamer.cpp:818: error: (-2) GStreamer: unable to start pipeline in function cvCaptureFromCAM_GStreamer

Aborted"

Here is the code :

   #include "opencv2/opencv.hpp"
#include <stdio.h>

using namespace cv;

int main(int, char**)
{
    VideoCapture cap(0); // open the default camera
    if(!cap.isOpened())  // check if we succeeded
    {
        std::cout << " Cannot open video" << std::endl;
        return -1;
    }

    Mat edges;
    namedWindow("edges",1);
    for(;;)
    {
        Mat frame;
        cap >> frame; // get a new frame from camera
        cvtColor(frame, edges, COLOR_BGR2GRAY);
        GaussianBlur(edges, edges, Size(7,7), 1.5, 1.5);
        Canny(edges, edges, 0, 30, 3);
        imshow("edges", edges);
        if(waitKey(30) >= 0) break;
    }
    // the camera will be deinitialized automatically in VideoCapture destructorcd ,,
    return 0;
}

If someone has an idea that would be very helpful !

Thank you very much in advance.

Florence

Great it works like a charm ! Thank you very much !