Merge pull request #8383 from csukuangfj/patch-10

* Improve documentation.

* Update imgproc.hpp

modules/imgproc/include/opencv2/imgproc.hpp

@@ -4080,7 +4080,13 @@ CV_EXPORTS Ptr<GeneralizedHoughBallard> createGeneralizedHoughBallard();
 //! Detects position, translation and rotation
 CV_EXPORTS Ptr<GeneralizedHoughGuil> createGeneralizedHoughGuil();
 
-//! Performs linear blending of two images
+//! Performs linear blending of two images:
+//! \f[ \texttt{dst}(i,j) = \texttt{weights1}(i,j)*\texttt{src1}(i,j) + \texttt{weights2}(i,j)*\texttt{src2}(i,j) \f]
+//! @param src1 It has a type of CV_8UC(n) or CV_32FC(n), where n is a positive integer.
+//! @param src2 It has the same type and size as src1.
+//! @param weights1 It has a type of CV_32FC1 and the same size with src1.
+//! @param weights2 It has a type of CV_32FC1 and the same size with src1.
+//! @param dst It is created if it does not have the same size and type with src1.
 CV_EXPORTS void blendLinear(InputArray src1, InputArray src2, InputArray weights1, InputArray weights2, OutputArray dst);
 
 //! @addtogroup imgproc_colormap