anyomyous's profile - activity

@imran I have predefined patterns and in the image I captured from camera , I need to detect if those pattern exist or not and if then their position in image.

Hi all, My objective is to find the pattern in the image captured from camera for this I found the cv::matchShapes method of opencv to implement it.

When I have implemented this method it is making the app crash on matchShapes method.Might be I have done something wrong:-

I exactly do not know how to use this method in order to find the match shape in my query image.This is what I tried.

Please help me in providing some code that can run properly.

Here is my code:-

    - (std::vector<std::vector<cv::Point> >)tryingMatchShapes:(cv::Mat)_image _image1:(cv::Mat)_image1
    {
        std::vector<std::vector<cv::Point> > squares;

        cv::Mat pyr, timg, gray0(_image.size(), CV_8U), gray;
        int thresh = 50, N = 11;
        cv::pyrDown(_image, pyr, cv::Size(_image.cols/2, _image.rows/2));
        cv::pyrUp(pyr, timg, _image.size());
        std::vector<std::vector<cv::Point> > contours;
        for( int c = 0; c < 3; c++ ) {
            int ch[] = {c, 0};
            mixChannels(&timg, 1, &gray0, 1, ch, 1);
            for( int l = 0; l < N; l++ ) {
                if( l == 0 ) {
                    cv::Canny(gray0, gray, 0, thresh, 5);
                    cv::dilate(gray, gray, cv::Mat(), cv::Point(-1,-1));
                }
                else {
                    gray = gray0 >= (l+1)*255/N;
                }
                cv::findContours(gray, contours, CV_RETR_LIST, CV_CHAIN_APPROX_SIMPLE);

            }
        }
                cv::Mat pyr1, timg1, gray2(_image1.size(), CV_8U), gray1;
                cv::pyrDown(_image1, pyr1, cv::Size(_image1.cols/2, _image1.rows/2));
                cv::pyrUp(pyr1, timg1, _image1.size());
                std::vector<std::vector<cv::Point> > contours1;
                for( int c = 0; c < 3; c++ ) {
                    int ch[] = {c, 0};
                    mixChannels(&timg1, 1, &gray2, 1, ch, 1);
                    for( int l = 0; l < N; l++ ) {
                        if( l == 0 ) {
                            cv::Canny(gray2, gray1, 0, thresh, 5);
                            cv::dilate(gray1, gray1, cv::Mat(), cv::Point(-1,-1));
                        }
                        else {
                            gray1 = gray2 >= (l+1)*255/N;
                        }
                        cv::findContours(gray1, contours1, CV_RETR_LIST, CV_CHAIN_APPROX_SIMPLE);



                    }
                }
for( size_t i = 0; i < contours.size(); i++ )
    {
  double value=  cv::matchShapes(contours[i], contours1[i], CV_CONTOURS_MATCH_I1, 0);
        NSLog(@"%f",value);
    }  
   return squares;
    }


    UIImage *testImage = [UIImage imageNamed:@"note_with_marks (1).png"];    
    [self.imageView setImage:testImage];
    cv::Mat forground = [testImage CVMat]; 
    UIImage *testImage2 = [UIImage imageNamed:@"1.png"];    
    cv::Mat forground2 = [testImage2 CVMat];
    [self tryingMatchShapes:forground _image1:forground2];


    Error:-

    OpenCV Error: Assertion failed (contour1.checkVector(2) >= 0 && contour2.checkVector(2) >= 0 && (contour1.depth() == CV_32F || contour1.depth() == CV_32S) && contour1.depth() == contour2.depth()) in matchShapes, file /Users/Aziz/Documents/Projects/opencv_sources/trunk/modules/imgproc/src/contours.cpp, line 1705

I am sure I am doing something wrong in the code but exactly what that I am not able to figure out.

Please some body help me in implementing this method from coding point of view. Please I need some coding help.I have already gone through I lot of theoretical concepts.

Thanks in advance!