- fix a possible crash when only asking for features and not descriptors

modules/features2d/src/orb.cpp

@@ -523,8 +523,6 @@ void ORB::operator()(const cv::Mat &image, const cv::Mat &mask, std::vector<cv::
   if ((!do_keypoints) && (!do_descriptors))
     return;
 
-  if (do_keypoints)
-    keypoints_in_out.clear();
   if (do_descriptors)
     descriptors.release();
 
@@ -560,6 +558,7 @@ void ORB::operator()(const cv::Mat &image, const cv::Mat &mask, std::vector<cv::
       all_keypoints[keypoint->octave].push_back(*keypoint);
   }
 
+  keypoints_in_out.clear();
   for (unsigned int level = 0; level < params_.n_levels_; ++level)
   {
     // Compute the resized image
@@ -583,11 +582,6 @@ void ORB::operator()(const cv::Mat &image, const cv::Mat &mask, std::vector<cv::
       computeDescriptors(working_mat, integral_image, level, keypoints, desc);
 
     // Copy to the output data
-    if (!desc.empty())
-    {
-      if (do_keypoints)
-      {
-        // Rescale the coordinates
     if (level != params_.first_level_)
     {
       float scale = std::pow(params_.scale_factor_, float(level - params_.first_level_));
@@ -597,7 +591,6 @@ void ORB::operator()(const cv::Mat &image, const cv::Mat &mask, std::vector<cv::
     }
     // And add the keypoints to the output
     keypoints_in_out.insert(keypoints_in_out.end(), keypoints.begin(), keypoints.end());
-      }
 
     if (do_descriptors)
     {
@@ -608,7 +601,6 @@ void ORB::operator()(const cv::Mat &image, const cv::Mat &mask, std::vector<cv::
     }
   }
 }
-}
 
 /** Compute the ORB keypoints on an image
  * @param image_pyramid the image pyramid to compute the features and descriptors on