Add ANMS (SSC method) (#1276)

corelib/include/rtabmap/core/util2d.h

@@ -164,6 +164,9 @@ void RTABMAP_CORE_EXPORT NMS(
 		cv::Mat & descriptorsOut,
 		int border, int dist_thresh, int img_width, int img_height);
 
+std::vector<int> RTABMAP_CORE_EXPORT SSC(
+	const std::vector<cv::KeyPoint> & keypoints, int maxKeypoints, float tolerance, int cols, int rows);
+
 /**
  * @brief Rotate images and camera model so that the top of the image is up.
  *