features2d: fix retainBest() implementation

2018-12-18 05:33:21 +00:00
parent 55171b25f8
commit 3f3c8823ac
2 changed files with 39 additions and 1 deletions
@@ -77,7 +77,7 @@ void KeyPointsFilter::retainBest(std::vector<KeyPoint>& keypoints, int n_points)
            return;
        }
        //first use nth element to partition the keypoints into the best and worst.
-        std::nth_element(keypoints.begin(), keypoints.begin() + n_points, keypoints.end(), KeypointResponseGreater());
+        std::nth_element(keypoints.begin(), keypoints.begin() + n_points - 1, keypoints.end(), KeypointResponseGreater());
        //this is the boundary response, and in the case of FAST may be ambiguous
        float ambiguous_response = keypoints[n_points - 1].response;
        //use std::partition to grab all of the keypoints with the boundary response.