Load many images in vector Opencv

Question

I'm trying to store multiple images in a folder on a vector for later processing. The problem is that I get the error:

*Debug Assertion Failed!

Expression: vector subscript out of range.*

The code that I'm testing is as follows.

stringstream Nombre2;
vector<Mat> Imagen2;
for (int a=0; a<=Count;a++) 
{
    Nombre2.clear();
    Nombre2 << "C:\\Users\\Azu\\Documents\\Visual Studio 2010\\Projects\\SIFT2\\SIFT2\\BBDDFaces\\"<< a+1 << ".pgm";
    imread(Nombre2.str()).copyTo(Imagen2[a]);
}

The images names are numerical: 1.pgm, 2.pgm, so on..

I'd appreciate, if anyone can help me fix it!

berak · Answer 1 · 2014-08-16T12:05:35.030

1

so, in your code:

// since Imagen2 is empty, Imagen2[a] is an access violation.
imread(Nombre2.str()).copyTo(Imagen2[a]);

don't overcomplicate it, just use cv::format instead of the stringstream, and do without the useless copyTo():

vector<Mat> images;         // another thing. use english for variable names, nothing else...
for (int a=0; a<Count;a++)  // a <=Count would do one too many...
{
    string name = format("C:\\bla\\BBDDFaces\\%d.pgm", a);
    Mat img = imread(name); // pgm implies grayscale, maybe even: imread(name,0); to return CV_8U
    if ( img.empty() )      // please, *always check* resource-loading.
    {
        cerr << "whaa " << name << " can't be loaded!" << endl;
        continue;
    }
    images.push_back(img);

    // show result:
    imshow("test",img);
    waitKey();              // yes, you need the waitKey()
}

edited Aug 16 '14 at 12:05

answered Aug 16 '14 at 11:49

berak

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Thanks for your answer! But now, how can I show each vector image? Or how I can access them? If I do: `imshow ("1" images [0]);` I visualize the first image loaded, but not with any index. Thanks in advance! – Azucena Lobato Aug 16 '14 at 12:01
Thanks!! I try with this modification and it works!! – Azucena Lobato Aug 16 '14 at 12:32
so, have fun, flying opencv ;) – berak Aug 16 '14 at 12:37
what's with the "use english and nothing else" :( – blorgggg Jan 24 '20 at 16:03

score 1 · Answer 2 · answered Feb 20 '17 at 17:53

im lauro reyes. I find this form.

String filename = "lg.mp4";   //SOLO FUNCIONA CON VIDEOS TIPO MP4
    VideoCapture capture(filename);
    Mat frame;
    Mat imagenesT;
    vector<Mat> images;  // almacenar imagenes en la cola
    Mat converted_image;
 double dHeight = capture.get(CV_CAP_PROP_FRAME_COUNT);
 cout<< "tiene frames ___" << dHeight << endl;  
    if( !capture.isOpened() )
        throw "Error when reading steam_avi";
    capture >> frame;
    cvtColor(frame, converted_image, CV_BGR2GRAY);//2XYZ);

    for(int i=0 ;i< 584;i++ )
       {
        capture >> frame;
        if(frame.empty())
            break;
        cvtColor(frame, converted_image, CV_BGR2GRAY);//2XYZ);

        images.push_back(converted_image.clone()); //almacenar imagenes en la cola
       imshow("out", converted_image);
       imshow("in",frame);
       waitKey(20); // waits to display frame
        }  

    for(int i=0 ;i< 584;i++ )
       {    
     imshow("salida1",images[i]);
       waitKey(30);
       }

sorry, I probe with mp4 and avi videos – lauro reyes Feb 20 '17 at 17:55 — lauro reyes, Feb 20 '17 at 17:55

Load many images in vector Opencv

2 Answers2