SimpleBlobDetector and blob contours

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Hi,

I'm adopting SimpleBlobDetector to detect a set of blobs, by calling:

vector<keypoint> keypoints; blobDetector->detect(frame,keypoints);

However, I can't find any method to retrieve and draw the contours associated to each blob. I can only draw their centroids, by using:

drawKeypoints(input, keypoints, output, CV_RGB(255,0,0),cv::DrawMatchesFlags::DEFAULT);

Digging into the SimpleBlobDetector source code, it seems to me that findContours is called, by the result is stored in a local variable, thereby not available with any public method. Am I right?

Thanks Gabriele