Doxygen documentation: cuda submodules reorganized

modules/cuda/include/opencv2/cuda.hpp

@@ -53,6 +53,9 @@
 @defgroup cuda CUDA-accelerated Computer Vision
     @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
     @}