Question

我是OpenCV的新手。我从极客那里得到了一个极客代码。我想检测图像中的人脸。

我正在用便携式相机拍摄图像。然后将其转换为灰度并调整大小。现在将其传递给detectMultiScale函数。然后，它应该在脸部和眼睛周围绘制圆圈，但事实并非如此。没有视频显示。它显示错误：

[ WARN:0] global /opt/opencv/modules/videoio/src/cap_gstreamer.cpp (935) open OpenCV | GStreamer warning: Cannot query video position: status=0, value=-1, duration=-1

我为此使用的代码是：

int main()
{
// VideoCapture class for playing video for which faces to be detected
    VideoCapture capture;
    Mat frame, image;


    // PreDefined trained XML classifiers with facial features
    CascadeClassifier cascade, nestedCascade;
    double scale=1;

    // Load classifiers from "opencv/data/haarcascades" directory
    nestedCascade.load( "../../opt/opencv/data/haarcascades/haarcascade_eye_tree_eyeglasses.xml" ) ;

    // Change path before execution
    cascade.load( "../../opt/opencv/data/haarcascades/haarcascade_frontalcatface.xml" ) ;

    capture.open(0);
    if( capture.isOpened() )
    {
        // Capture frames from video and detect faces
        cout << "Face Detection Started...." << endl;
        while(1)
        {
            capture >> frame;
            if( frame.empty() )
                break;
            Mat frame1 = frame.clone();
            detectAndDraw( frame1, cascade, nestedCascade, scale );
            char c = (char)waitKey(10);

            // Press q to exit from window
            if( c == 27 || c == 'q' || c == 'Q' )
                break;
        }

 }
    else
        cout<<"Could not Open Camera";
    return 0;
}



void detectAndDraw( Mat& img, CascadeClassifier& cascade,
                    CascadeClassifier& nestedCascade,
                    double scale)
{
    vector<Rect> faces, faces2;
    Mat gray, smallImg;

    cvtColor( img, gray, COLOR_BGR2GRAY ); // Convert to Gray Scale
    double fx = 1 / scale;

    // Resize the Grayscale Image
    resize( gray, smallImg, Size(), fx, fx, INTER_LINEAR );
    equalizeHist( smallImg, smallImg );

    cout<<"OK Till here"<<endl;

    // Detect faces of different sizes using cascade classifier
    cascade.detectMultiScale( smallImg, faces, 1.1,
                            2, 0|CASCADE_SCALE_IMAGE, Size(10, 10) );
    cout<<"OK Till here"<<endl;

    // Draw circles around the faces
    for ( size_t i = 0; i < faces.size(); i++ )
    {
        Rect r = faces[i];
        Mat smallImgROI;
        vector<Rect> nestedObjects;
        Point center;
        Scalar color = Scalar(255, 0, 0); // Color for Drawing tool
        int radius;

        double aspect_ratio = (double)r.width/r.height;
        if( 0.75 < aspect_ratio && aspect_ratio < 1.3 )
        {
            center.x = cvRound((r.x + r.width*0.5)*scale);
            center.y = cvRound((r.y + r.height*0.5)*scale);
            radius = cvRound((r.width + r.height)*0.25*scale);
            circle( img, center, radius, color, 3, 8, 0 );
        }
        else
            rectangle( img, cv::Point(cvRound(r.x*scale), cvRound(r.y*scale)),
                    cv::Point(cvRound((r.x + r.width-1)*scale),
                    cvRound((r.y + r.height-1)*scale)), color, 3, 8, 0);
        if( nestedCascade.empty() )
            continue;
        smallImgROI = smallImg( r );

        // Detection of eyes int the input image
        nestedCascade.detectMultiScale( smallImgROI, nestedObjects, 1.1, 2,
                                        0|CASCADE_SCALE_IMAGE, Size(30, 30) );

        // Draw circles around eyes
        for ( size_t j = 0; j < nestedObjects.size(); j++ )
        {
            Rect nr = nestedObjects[j];
            center.x = cvRound((r.x + nr.x + nr.width*0.5)*scale);
            center.y = cvRound((r.y + nr.y + nr.height*0.5)*scale);
            radius = cvRound((nr.width + nr.height)*0.25*scale);
            circle( img, center, radius, color, 3, 8, 0 );
        }
    }

    // Show Processed Image with detected faces
    imshow( "Face Detection", img );
}

opencv人脸检测代码中没有显示视频

0 个答案: