co-ordinate of the matched SIFT keypoints

问题:

I am doing a project with openCV, where I matched two images with the SIFT keypoints and got good match from the same using K nearest neighbor search. where k=2.

Now I want to get the co-ordinate value of the SIFT keypoints which has good match in the image2 and also the co-ordinate value for the corresponding keypoints in Image2. Can any body help me with this. thanks.

I find out the solution...It was very easy...silly me...I just converted the keypoints into CvPoints and from that I can easily get the co-ordinate values....

回答1:

All.. I have solved the problem...at frist i converted the good matched keypoints into Cvpoints and then got the co-ordinate from the Cvpoints..the code for the same is as below-

 for( i =0; i <good_matches.size(); i++ )
  {
    // the keypoints from the good matches only
    points1.push_back( keypoints1[ good_matches[i].queryIdx ].pt );
    points2.push_back( keypoints2[ good_matches[i].trainIdx ].pt );

    printf("xco-ordinate of good mathched keypoints in image1   %d\n\n",points1[i].x);
    printf("y co-ordinate for image 1    %d \n\n",points1[i].y);
    printf("x co-ordinate for image2    %d \n\n",points2[i].x);
    printf("y co-ordinate for image2    %d\n\n",points2[i].y);

  }  

回答2:

You can get the neighbor vectors using CvKNearest::find_nearest(...). I believe you're looking for the parameter neighbors.

References:

http://docs.opencv.org/modules/ml/doc/k_nearest_neighbors.html?highlight=cvknearest#cvknearest-find-nearest

Older documentation but w/code example:

http://opencv.willowgarage.com/documentation/cpp/k_nearest_neighbors.html