add comments to class declaration

modules/gpu/include/opencv2/gpu/gpu.hpp

@@ -1570,13 +1570,22 @@ public:
     // Load cascade config.
     virtual void read(const FileNode& fn);
 
-    // Return the vector of Decection objcts.
+    // Return the matrix of of detectioned objects.
     // Param image is a frame on which detector will be applied.
-    // Param rois is a vector of regions of interest. Only the objects that fall into one of the regions will be returned.
-    // Param objects is an output array of Detections
+    // Param rois is a regions of interests mask generated by genRoi.
+    //    Only the objects that fall into one of the regions will be returned.
+    // Param objects is an output array of Detections represented as GpuMat of detections (SCascade::Detection)
+    //    The first element of the matrix is  actually a count of detections.
+    // Param stream is stream is a high-level CUDA stream abstraction used for asynchronous execution
+    // Param level used for execution cascade on specific scales pyramid level.
     virtual void detect(InputArray image, InputArray rois, OutputArray objects, Stream& stream = Stream::Null()) const;
     virtual void detect(InputArray image, InputArray rois, OutputArray objects, const int level, Stream& stream = Stream::Null()) const;
 
+    // Convert ROI matrix into the suitable for detect method.
+    // Param roi is an input matrix of the same size as the image.
+    //    There non zero value mean that detector should be executed in this point.
+    // Param mask is an output mask
+    // Param stream is stream is a high-level CUDA stream abstraction used for asynchronous execution
     void genRoi(InputArray roi, OutputArray mask, Stream& stream = Stream::Null()) const;
 
 private: