dnn: use OpenVINO 2020.4 defines

cmake/OpenCVDetectInferenceEngine.cmake

@@ -129,9 +129,9 @@ endif()
 
 if(INF_ENGINE_TARGET)
   if(NOT INF_ENGINE_RELEASE)
-    message(WARNING "InferenceEngine version has not been set, 2020.2 will be used by default. Set INF_ENGINE_RELEASE variable if you experience build errors.")
+    message(WARNING "InferenceEngine version has not been set, 2020.4 will be used by default. Set INF_ENGINE_RELEASE variable if you experience build errors.")
   endif()
-  set(INF_ENGINE_RELEASE "2020020000" CACHE STRING "Force IE version, should be in form YYYYAABBCC (e.g. 2020.1.0.2 -> 2020010002)")
+  set(INF_ENGINE_RELEASE "2020040000" CACHE STRING "Force IE version, should be in form YYYYAABBCC (e.g. 2020.1.0.2 -> 2020010002)")
   set_target_properties(${INF_ENGINE_TARGET} PROPERTIES
     INTERFACE_COMPILE_DEFINITIONS "HAVE_INF_ENGINE=1;INF_ENGINE_RELEASE=${INF_ENGINE_RELEASE}"
   )

modules/dnn/src/op_inf_engine.hpp

@@ -25,10 +25,12 @@
 #define INF_ENGINE_RELEASE_2019R3 2019030000
 #define INF_ENGINE_RELEASE_2020_1 2020010000
 #define INF_ENGINE_RELEASE_2020_2 2020020000
+#define INF_ENGINE_RELEASE_2020_3 2020030000
+#define INF_ENGINE_RELEASE_2020_4 2020040000
 
 #ifndef INF_ENGINE_RELEASE
-#warning("IE version have not been provided via command-line. Using 2020.2 by default")
-#define INF_ENGINE_RELEASE INF_ENGINE_RELEASE_2020_2
+#warning("IE version have not been provided via command-line. Using 2020.4 by default")
+#define INF_ENGINE_RELEASE INF_ENGINE_RELEASE_2020_4
 #endif
 
 #define INF_ENGINE_VER_MAJOR_GT(ver) (((INF_ENGINE_RELEASE) / 10000) > ((ver) / 10000))