Merge pull request #69 from andre-nguyen/master

fix relocalization segfault

svo/src/frame_handler_mono.cpp

@@ -240,6 +240,11 @@ FrameHandlerMono::UpdateResult FrameHandlerMono::relocalizeFrame(
     FramePtr ref_keyframe)
 {
   SVO_WARN_STREAM_THROTTLE(1.0, "Relocalizing frame");
+  if(ref_keyframe == nullptr)
+  {
+    SVO_INFO_STREAM("Relocalization successful.");
+    return RESULT_FAILURE;
+  }
   SparseImgAlign img_align(Config::kltMaxLevel(), Config::kltMinLevel(),
                            30, SparseImgAlign::GaussNewton, false, false);
   size_t img_align_n_tracked = img_align.run(ref_keyframe, new_frame_);

svo/src/map.cpp

@@ -130,6 +130,11 @@ FramePtr Map::getClosestKeyframe(const FramePtr& frame) const
 {
   list< pair<FramePtr,double> > close_kfs;
   getCloseKeyframes(frame, close_kfs);
+  if(close_kfs.empty())
+  {
+    return nullptr;
+  }
+
 
   // Sort KFs with overlap according to their closeness
   close_kfs.sort(boost::bind(&std::pair<FramePtr, double>::second, _1) <