opencv/modules/features2d/doc/drawing_function_of_keypoints_and_matches.rst

Drawing Function of Keypoints and Matches
=========================================

.. highlight:: cpp



.. index:: drawMatches


cv::drawMatches
---------------

`id=0.919261687295 Comments from the Wiki <http://opencv.willowgarage.com/wiki/documentation/cpp/features2d/drawMatches>`__




.. cfunction:: void drawMatches( const Mat\& img1, const vector<KeyPoint>\& keypoints1,          const Mat\& img2, const vector<KeyPoint>\& keypoints2,          const vector<DMatch>\& matches1to2, Mat\& outImg,          const Scalar\& matchColor=Scalar::all(-1),           const Scalar\& singlePointColor=Scalar::all(-1),          const vector<char>\& matchesMask=vector<char>(),          int flags=DrawMatchesFlags::DEFAULT )

    This function draws matches of keypints from two images on output image. 
Match is a line connecting two keypoints (circles).





.. cfunction:: void drawMatches( const Mat\& img1, const vector<KeyPoint>\& keypoints1,           const Mat\& img2, const vector<KeyPoint>\& keypoints2,           const vector<vector<DMatch> >\& matches1to2, Mat\& outImg,           const Scalar\& matchColor=Scalar::all(-1),            const Scalar\& singlePointColor=Scalar::all(-1),           const vector<vector<char>>\& matchesMask=           vector<vector<char> >(),           int flags=DrawMatchesFlags::DEFAULT )





    
    :param img1: First source image. 
    
    
    :param keypoints1: Keypoints from first source image. 
    
    
    :param img2: Second source image. 
    
    
    :param keypoints2: Keypoints from second source image. 
    
    
    :param matches: Matches from first image to second one, i.e.  ``keypoints1[i]``  
                                        has corresponding point  ``keypoints2[matches[i]]`` .  
    
    
    :param outImg: Output image. Its content depends on  ``flags``  value 
                                   what is drawn in output image. See below possible  ``flags``  bit values.  
    
    
    :param matchColor: Color of matches (lines and connected keypoints). 
                                           If  ``matchColor==Scalar::all(-1)``  color will be generated randomly. 
    
    
    :param singlePointColor: Color of single keypoints (circles), i.e. keypoints not having the matches. 
                                                If  ``singlePointColor==Scalar::all(-1)``  color will be generated randomly. 
    
    
    :param matchesMask: Mask determining which matches will be drawn. If mask is empty all matches will be drawn.  
    
    
    :param flags: Each bit of  ``flags``  sets some feature of drawing. 
                                  Possible  ``flags``  bit values is defined by  ``DrawMatchesFlags`` , see below.  
    
    
    



::


    
    struct DrawMatchesFlags
    {
        enum{ DEFAULT = 0, // Output image matrix will be created (Mat::create),
                           // i.e. existing memory of output image may be reused.
                           // Two source image, matches and single keypoints 
                           // will be drawn.
                           // For each keypoint only the center point will be 
                           // drawn (without the circle around keypoint with 
                           // keypoint size and orientation).
              DRAW_OVER_OUTIMG = 1, // Output image matrix will not be 
                           // created (Mat::create). Matches will be drawn 
                           // on existing content of output image.
              NOT_DRAW_SINGLE_POINTS = 2, // Single keypoints will not be drawn.
              DRAW_RICH_KEYPOINTS = 4 // For each keypoint the circle around 
                           // keypoint with keypoint size and orientation will 
                           // be drawn.
            };
    };
    

..


.. index:: drawKeypoints


cv::drawKeypoints
-----------------

`id=0.694314481427 Comments from the Wiki <http://opencv.willowgarage.com/wiki/documentation/cpp/features2d/drawKeypoints>`__




.. cfunction:: void drawKeypoints( const Mat\& image,           const vector<KeyPoint>\& keypoints,           Mat\& outImg, const Scalar\& color=Scalar::all(-1),           int flags=DrawMatchesFlags::DEFAULT )

    Draw keypoints.





    
    :param image: Source image. 
    
    
    :param keypoints: Keypoints from source image. 
    
    
    :param outImg: Output image. Its content depends on  ``flags``  value 
                                   what is drawn in output image. See possible  ``flags``  bit values.  
    
    
    :param color: Color of keypoints 
    
    . 
    
    :param flags: Each bit of  ``flags``  sets some feature of drawing. 
                                  Possible  ``flags``  bit values is defined by  ``DrawMatchesFlags`` , 
                                  see above in  :func:`drawMatches` .