# Revision history [back]

### Matching features across three images?

I have three images. I have the storage:

    cv::Mat desc1;
cv::Mat desc2;
cv::Mat desc3;
std::vector<cv::KeyPoint> keyPnts1;
std::vector<cv::KeyPoint> keyPnts2;
std::vector<cv::KeyPoint> keyPnts3;
std::vector<cv::DMatch> match12;
std::vector<cv::DMatch> match23;


I detect keypoints on all three, and fill the desc Mats. I match 1and 2, and fill match12

Now, i need to match the already matched features of image 2 with image 3, so that features are matched across all three images.

How can i do this? thanks!