Added documentation for cirlces' grid detection

doc/calib3d.tex

@@ -621,6 +621,43 @@ drawChessboardCorners(img, patternsize, Mat(corners), patternfound);
 
 \textbf{Note:} the function requires some white space (like a square-thick border, the wider the better) around the board to make the detection more robust in various environment (otherwise if there is no border and the background is dark, the outer black squares could not be segmented properly and so the square grouping and ordering algorithm will fail).
 
+
+\cvCppFunc{findCirclesGrid}
+Finds the centers of the cirlces' grid.
+\cvdefCpp{bool findCirclesGrid( const Mat\& image, Size patternSize,\par
+                            vector<Point2f>\& centers,\par
+                            int flags=0 );}
+\begin{description}
+\cvarg{image}{Source circles' grid view; it must be an 8-bit grayscale or color
+image}
+\cvarg{patternSize}{The number of circles per grid row and column
+( patternSize = Size( points\_per\_row, points\_per\_colum ) =
+Size( columns, rows ) )}
+\cvarg{centers}{The output array of centers detected}
+\cvarg{flags}{Various operation flags, no flags are supported currently} 
+\end{description}
+
+The function attempts to determine
+whether the input image is a view of the circles' grid pattern and
+locate the circles' centers. The function returns a
+non-zero value if all of the centers have been found and they have been placed
+in a certain order (row by row, left to right in every row),
+otherwise, if the function fails to find all the corners or reorder
+them, it returns 0.
+
+Sample usage of detecting and drawing circles' centers:
+\begin{lstlisting}
+Size patternsize(7,7); //number of centers
+Mat gray = ....; //source image
+vector<Point2f> centers; //this will be filled by the detected centers
+
+bool patternfound = findCirclesGrid(gray, patternsize, centers);
+    
+drawChessboardCorners(img, patternsize, Mat(centers), patternfound);
+\end{lstlisting}
+
+\textbf{Note:} the function requires some white space (like a square-thick border, the wider the better) around the board to make the detection more robust in various environment.
+
 \ifCPy
 \cvCPyFunc{FindExtrinsicCameraParams2}
 \else