minor stitching optimization (improve buffer reuse)

modules/stitching/matchers.cpp

@@ -96,11 +96,17 @@ namespace
             num_layers_descr_ = num_layers_descr;
         }
 
+        void releaseMemory();
+
     protected:
         void find(const Mat &image, ImageFeatures &features);
 
     private:
+        GpuMat image_;
+        GpuMat gray_image_;
         SURF_GPU surf_;
+        GpuMat keypoints_;
+        GpuMat descriptors_;
         int num_octaves_, num_layers_;
         int num_octaves_descr_, num_layers_descr_;
     };
@@ -118,22 +124,34 @@ namespace
 
     void GpuSurfFeaturesFinder::find(const Mat &image, ImageFeatures &features)
     {
-        GpuMat gray_image;
         CV_Assert(image.depth() == CV_8U);
-        cvtColor(GpuMat(image), gray_image, CV_BGR2GRAY);
 
-        GpuMat d_keypoints;
-        GpuMat d_descriptors;
+        ensureSizeIsEnough(image.size(), image.type(), image_);
+        image_.upload(image);
+
+        ensureSizeIsEnough(image.size(), CV_8UC1, gray_image_);
+        cvtColor(image_, gray_image_, CV_BGR2GRAY);
+
         surf_.nOctaves = num_octaves_;
         surf_.nOctaveLayers = num_layers_;
-        surf_(gray_image, GpuMat(), d_keypoints);
+        surf_(gray_image_, GpuMat(), keypoints_);
 
         surf_.nOctaves = num_octaves_descr_;
         surf_.nOctaveLayers = num_layers_descr_;
-        surf_(gray_image, GpuMat(), d_keypoints, d_descriptors, true);
-        surf_.downloadKeypoints(d_keypoints, features.keypoints);
+        surf_.upright = true;
+        surf_(gray_image_, GpuMat(), keypoints_, descriptors_, true);
+        surf_.downloadKeypoints(keypoints_, features.keypoints);
 
-        d_descriptors.download(features.descriptors);
+        descriptors_.download(features.descriptors);
+    }
+
+    void GpuSurfFeaturesFinder::releaseMemory()
+    {
+        surf_.releaseMemory();
+        image_.release();
+        gray_image_.release();
+        keypoints_.release();
+        descriptors_.release();
     }
 } // anonymous namespace
 
@@ -153,6 +171,11 @@ void SurfFeaturesFinder::find(const Mat &image, ImageFeatures &features)
     (*impl_)(image, features);
 }
 
+void SurfFeaturesFinder::releaseMemory()
+{
+    impl_->releaseMemory();
+}
+
 
 //////////////////////////////////////////////////////////////////////////////
 
@@ -279,10 +302,13 @@ namespace
         GpuMatcher(float match_conf) : match_conf_(match_conf) {}
         void match(const ImageFeatures &features1, const ImageFeatures &features2, MatchesInfo& matches_info);
 
+        void releaseMemory();
+
     private:
         float match_conf_;
         GpuMat descriptors1_, descriptors2_;
         GpuMat train_idx_, distance_, all_dist_;
+        vector< vector<DMatch> > pair_matches;
     };
 
 
@@ -326,14 +352,19 @@ namespace
 
     void GpuMatcher::match(const ImageFeatures &features1, const ImageFeatures &features2, MatchesInfo& matches_info)
     {
-        matches_info.matches.clear();       
+        matches_info.matches.clear(); 
+
+        ensureSizeIsEnough(features1.descriptors.size(), features1.descriptors.type(), descriptors1_);
+        ensureSizeIsEnough(features2.descriptors.size(), features2.descriptors.type(), descriptors2_);
+
         descriptors1_.upload(features1.descriptors);
         descriptors2_.upload(features2.descriptors);
+
         BruteForceMatcher_GPU< L2<float> > matcher;
-        vector< vector<DMatch> > pair_matches;
         MatchesSet matches;
 
         // Find 1->2 matches
+        pair_matches.clear();
         matcher.knnMatch(descriptors1_, descriptors2_, train_idx_, distance_, all_dist_, 2);
         matcher.knnMatchDownload(train_idx_, distance_, pair_matches);
         for (size_t i = 0; i < pair_matches.size(); ++i)
@@ -365,6 +396,16 @@ namespace
         }
     }
 
+    void GpuMatcher::releaseMemory()
+    {
+        descriptors1_.release();
+        descriptors2_.release();
+        train_idx_.release();
+        distance_.release();
+        all_dist_.release();
+        vector< vector<DMatch> >().swap(pair_matches);
+    }
+
 } // anonymous namespace
 
 
@@ -456,3 +497,8 @@ void BestOf2NearestMatcher::match(const ImageFeatures &features1, const ImageFea
     // Rerun motion estimation on inliers only
     matches_info.H = findHomography(src_points, dst_points, CV_RANSAC);
 }
+
+void BestOf2NearestMatcher::releaseMemory()
+{
+    impl_->releaseMemory();
+}