fixed empty image fatal error when updating objects on ROS

src/FindObject.cpp

@@ -802,8 +802,24 @@ void FindObject::updateObjects(const QList<int> & ids)
 				QVector<ExtractFeaturesThread*> threads;
 				for(int k=i; k<i+threadCounts && k<objectsList.size(); ++k)
 				{
-					threads.push_back(new ExtractFeaturesThread(detector_, extractor_, objectsList.at(k)->id(), objectsList.at(k)->image()));
+					if(!objectsList.at(k)->image().empty())
-					threads.back()->start();
+					{
+						threads.push_back(new ExtractFeaturesThread(detector_, extractor_, objectsList.at(k)->id(), objectsList.at(k)->image()));
+						threads.back()->start();
+					}
+					else
+					{
+						objects_.value(objectsList.at(k)->id())->setData(std::vector<cv::KeyPoint>(), cv::Mat());
+						if(keepImagesInRAM_)
+						{
+							UERROR("Empty image detected for object %d!? No features can be detected.", objectsList.at(k)->id());
+
+						}
+						else
+						{
+							UWARN("Empty image detected for object %d! No features can be detected. Note that images are in not kept in RAM.", objectsList.at(k)->id());
+						}
+					}
 				}
 
 				for(int j=0; j<threads.size(); ++j)

src/ObjWidget.cpp

@@ -287,6 +287,10 @@ void ObjWidget::updateData(const std::vector<cv::KeyPoint> & keypoints, const QM
 	{
 		this->setupGraphicsView();
 	}
+	else
+	{
+		this->update();
+	}
 }
 
 void ObjWidget::updateWords(const QMultiMap<int,int> & words)

src/ros/FindObjectROS.cpp

@@ -35,7 +35,7 @@ SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 using namespace find_object;
 
 FindObjectROS::FindObjectROS(const std::string & objFramePrefix, QObject * parent) :
-	FindObject(parent),
+	FindObject(true, parent),
 	objFramePrefix_("object")
 {
 	ros::NodeHandle pnh("~"); // public