diff --git a/GPU_version/vio/include/vio/reprojector.h b/GPU_version/vio/include/vio/reprojector.h
index 9f859e4..6b6e2b9 100644
--- a/GPU_version/vio/include/vio/reprojector.h
+++ b/GPU_version/vio/include/vio/reprojector.h
@@ -22,6 +22,7 @@
 #include <CL/cl.h>
 #include <vio/cl_class.h>
 #include <vio/initialization.h>
+#include <vio/vision.h>
 
 namespace vk {
 class AbstractCamera;
@@ -68,7 +69,10 @@ public:
   void reprojectMap2(
       FramePtr frame,
       FramePtr last_frame,
-      std::vector< std::pair<FramePtr,std::size_t> >& overlap_kfs);
+      std::vector< std::pair<FramePtr,std::size_t> >& overlap_kfs,
+      opencl* gpu_fast_);
+
+  void fast_detector(cv::Mat img, opencl * gpu_fast_, std::vector<cv::KeyPoint>& keypoints_cur, double detection_threshold);
 
 private:
 
diff --git a/GPU_version/vio/src/frame_handler_mono.cpp b/GPU_version/vio/src/frame_handler_mono.cpp
index 56c102e..e84b1e4 100644
--- a/GPU_version/vio/src/frame_handler_mono.cpp
+++ b/GPU_version/vio/src/frame_handler_mono.cpp
@@ -221,7 +221,7 @@ FrameHandlerBase::UpdateResult FrameHandlerMono::processFrame()
     }
     fprintf(log_,"null : %d, null point : %d\n", nullcount, nullpointcount);
 #endif*/
-  reprojector_.reprojectMap2(new_frame_, last_frame_,overlap_kfs_);
+  reprojector_.reprojectMap2(new_frame_, last_frame_,overlap_kfs_, gpu_fast_);
   int n_point=0;
   for(auto i:overlap_kfs_)n_point+=i.second;
 #if VIO_DEBUG
diff --git a/GPU_version/vio/src/reprojector.cpp b/GPU_version/vio/src/reprojector.cpp
index 9dad605..b87c571 100644
--- a/GPU_version/vio/src/reprojector.cpp
+++ b/GPU_version/vio/src/reprojector.cpp
@@ -117,20 +117,50 @@ namespace vio {
                 break;
         }
     }
+////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
+// TODO - fast feature detector
+    void Reprojector::fast_detector(cv::Mat img, opencl * gpu_fast_, std::vector<cv::KeyPoint>& keypoints_cur, double detection_threshold = Config::triangMinCornerScore()) {
+        const int width = img.cols;
+        const int height = img.rows;
+        gpu_fast_->reload_buf(0,0,img);
+        int icorner[1]={0};
+        gpu_fast_->reload_buf(0,2, icorner);
+        gpu_fast_->run(0, img.cols, img.rows);
+        int count[1]={0};
+        gpu_fast_->read(0,2,1, count);
+        cl_int2 fast_corners[350000];
+        gpu_fast_->read(0,1,count[0], fast_corners);
+        for(uint i = 0; i < count[0]; ++i)
+        {
+            if(fast_corners[i].x < 0 || fast_corners[i].x > width || fast_corners[i].y < 0 || fast_corners[i].y > height)
+                continue;
 
+            const float score = vk::shiTomasiScore(img, fast_corners[i].x, fast_corners[i].y);
+            if(score > detection_threshold) {
+                cv::KeyPoint kp(fast_corners[i].x, fast_corners[i].y, 7);
+                keypoints_cur.push_back(kp);
+            }
+        }
+    }
 ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
 // TODO - second reimplementation
     void Reprojector::reprojectMap2(
             FramePtr frame,
             FramePtr last_frame,
-            std::vector<std::pair<FramePtr, std::size_t> > &overlap_kfs) {
+            std::vector<std::pair<FramePtr, std::size_t> > &overlap_kfs,
+            opencl* gpu_fast_) {
         if(frame->id_<1)return;
         resetGrid();
         cv::Mat descriptors_cur;
         std::vector<cv::KeyPoint> keypoints_cur;
         cv::Ptr<cv::xfeatures2d::FREAK> extractor = cv::xfeatures2d::FREAK::create(true, true, 22.0f, 4);
         cv::Ptr<cv::BFMatcher> matcher = cv::BFMatcher::create(cv::NORM_HAMMING, true);
-        cv::FAST(frame->img(), keypoints_cur, 50);
+        //cv::FAST(frame->img(), keypoints_cur, 50);
+        //for (int i = 0; i < keypoints_cur.size(); i++)
+        //    std::cerr<<keypoints_cur[i].pt.x<<"\t"<<keypoints_cur[i].pt.y<<"\t"<<keypoints_cur[i].size<<"\t"<<keypoints_cur[i].class_id<<"\t"<<keypoints_cur[i].octave<<"\t"<<keypoints_cur[i].angle<<std::endl;
+        fast_detector(frame->img(), gpu_fast_, keypoints_cur);
+        //for (int i = 0; i < keypoints_cur.size(); i++)
+        //    std::cerr<<keypoints_cur[i].pt.x<<"\t"<<keypoints_cur[i].pt.y<<"\t"<<keypoints_cur[i].size<<"\t"<<keypoints_cur[i].class_id<<"\t"<<keypoints_cur[i].octave<<"\t"<<keypoints_cur[i].angle<<std::endl;
         extractor->compute(frame->img(), keypoints_cur, descriptors_cur);
         list<pair<FramePtr, double> > close_kfs;
         map_.getCloseKeyframes(frame, close_kfs);