minor reorganization for CUDA doxygen groups:

move main CUDA group to modules/core/cuda.hpp

modules/core/include/opencv2/core/cuda.hpp

@@ -51,9 +51,20 @@
 #include "opencv2/core.hpp"
 #include "opencv2/core/cuda_types.hpp"
 
+/**
+  @defgroup cuda CUDA-accelerated Computer Vision
+  @{
+    @defgroup cudacore Core part
+    @{
+      @defgroup cudacore_init Initalization and Information
+      @defgroup cudacore_struct Data Structures
+    @}
+  @}
+ */
+
 namespace cv { namespace cuda {
 
-//! @addtogroup cuda_struct
+//! @addtogroup cudacore_struct
 //! @{
 
 //////////////////////////////// GpuMat ///////////////////////////////
@@ -514,11 +525,11 @@ private:
     friend struct EventAccessor;
 };
 
-//! @} cuda_struct
+//! @} cudacore_struct
 
 //////////////////////////////// Initialization & Info ////////////////////////
 
-//! @addtogroup cuda_init
+//! @addtogroup cudacore_init
 //! @{
 
 /** @brief Returns the number of installed CUDA-enabled devices.
@@ -813,7 +824,7 @@ private:
 CV_EXPORTS void printCudaDeviceInfo(int device);
 CV_EXPORTS void printShortCudaDeviceInfo(int device);
 
-//! @} cuda_init
+//! @} cudacore_init
 
 }} // namespace cv { namespace cuda {
 

modules/core/include/opencv2/core/cuda_stream_accessor.hpp

@@ -47,10 +47,9 @@
 #  error cuda_stream_accessor.hpp header must be compiled as C++
 #endif
 
-// This is only header file that depends on Cuda. All other headers are independent.
+/** @file cuda_stream_accessor.hpp
-// So if you use OpenCV binaries you do noot need to install Cuda Toolkit.
+ * This is only header file that depends on CUDA Runtime API. All other headers are independent.
-// But of you wanna use CUDA by yourself, may get cuda stream instance using the class below.
+ */
-// In this case you have to install Cuda Toolkit.
 
 #include <cuda_runtime.h>
 #include "opencv2/core/cvdef.h"
@@ -60,22 +59,21 @@ namespace cv
     namespace cuda
     {
 
-//! @addtogroup cuda_struct
+//! @addtogroup cudacore_struct
 //! @{
 
         class Stream;
         class Event;
 
         /** @brief Class that enables getting cudaStream_t from cuda::Stream
-
-        because it is the only public header that depends on the CUDA Runtime API. Including it
-        brings a dependency to your code.
          */
         struct StreamAccessor
         {
             CV_EXPORTS static cudaStream_t getStream(const Stream& stream);
         };
 
+        /** @brief Class that enables getting cudaEvent_t from cuda::Event
+         */
         struct EventAccessor
         {
             CV_EXPORTS static cudaEvent_t getEvent(const Event& event);

modules/cuda/include/opencv2/cuda.hpp

@@ -50,15 +50,11 @@
 #include "opencv2/core/cuda.hpp"
 
 /**
-@defgroup cuda CUDA-accelerated Computer Vision
+    @addtogroup cuda
-    @ref cuda_intro "Introduction page"
     @{
-        @defgroup cuda_init Initalization and Information
-        @defgroup cuda_struct Data Structures
         @defgroup cuda_calib3d Camera Calibration and 3D Reconstruction
         @defgroup cuda_objdetect Object Detection
     @}
-
  */
 
 namespace cv { namespace cuda {