Merge remote-tracking branch 'upstream/3.4' into merge-3.4

modules/objdetect/src/hog.cpp

@@ -136,6 +136,8 @@ void HOGDescriptor::setSVMDetector(InputArray _svmDetector)
 
 bool HOGDescriptor::read(FileNode& obj)
 {
+    CV_Assert(!obj["winSize"].empty());
+
     if( !obj.isMap() )
         return false;
     FileNodeIterator it = obj["winSize"].begin();