CODEWITHSUNDEEP
c++opencv
DarkSideUser
DarkSideUser

Reputation: 565

Opencv exception fillconvexppoly

I am trying to port a code from python to c++. I need to paint a part of an image (polygon) with black color.

In python, I had the list of points and then I call to fillconvexpolygon to do that. I tried the same in c++ but I get this exception:

OpenCV Error: Assertion failed (points.checkVector(2, CV_32S) >= 0) in fillConvexPoly, file /home/user/template_matching/repositories/opencv/modules/core/src/drawing.cpp, line 2017
terminate called after throwing an instance of 'cv::Exception'
  what():  /home/user/template_matching/repositories/opencv/modules/core/src/drawing.cpp:2017: error: (-215) points.checkVector(2, CV_32S) >= 0 in function fillConvexPoly

I am able to paint lines on the image and I have points in the list of points used as polygon contour:

drawMatches(img_object, TSMART_BANKNOTE[i].kp, img_orig, BankNote_t.kp,
            good, img_matches, Scalar::all(-1), Scalar::all(-1),
            vector<char>(), DrawMatchesFlags::NOT_DRAW_SINGLE_POINTS );
 line(img_matches, scene_corners[0] + Point2f(img_object.cols, 0), 
                       scene_corners[1] + Point2f(img_object.cols, 0), 
                                                  Scalar(0, 255, 0), 4);  //Left side

 line(img_matches, scene_corners[2] + Point2f(img_object.cols, 0),
                       scene_corners[3] + Point2f(img_object.cols, 0), 
                                                  Scalar(0, 255, 0), 4);  //right side

 line(img_matches, scene_corners[1] + Point2f(img_object.cols, 0), 
                       scene_corners[2] + Point2f(img_object.cols, 0),
                                                  Scalar(0, 255, 0), 4);    //Down line

 line(img_matches, scene_corners[3] + Point2f(img_object.cols, 0),
                       scene_corners[0] + Point2f(img_object.cols, 0),
                                                  Scalar(0, 255, 0), 4);       //Up line

    vector<Point2f> pt;
pt.push_back(Point2f(scene_corners[0].x + img_object.cols, 
                       scene_corners[1].y));

pt.push_back(Point2f(scene_corners[2].x + img_object.cols, 
                       scene_corners[3].y));

pt.push_back(Point2f(scene_corners[1].x + img_object.cols, 
                       scene_corners[2].y));

pt.push_back(Point2f(scene_corners[3].x + img_object.cols, 
                       scene_corners[0].y));
std::cout << "PT POINTS: " << pt.size() <<"\r\n";

    //fillConvexPoly(img_matches, pt, pt.size(), Scalar(1,1,1), 16, 0);

     fillConvexPoly(img_matches, pt, cv::Scalar(255), 16, 0);
    //-- Show detected matches
std::cout <<"H5\r\n"; 
imshow( "Good Matches & Object detection", img_matches);
    waitKey(0);

In documentation I found a fillconvexpoly function which receives size of vector. Mine seems not to accept that. I am using opencv 2.4.6

Upvotes: 1

Views: 1101

Answers (1)

user3002166
user3002166

Reputation: 730

The exception says it was checking for CV_32S type(signed integer), where your points are of float type.

Replace your 

std::vector<cv::Point2f> pt;

with

std::vector<cv::Point2i> pt;

Upvotes: 2

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