Update imgproc.hpp

fix Rect value of integral image example;

modules/imgproc/include/opencv2/imgproc.hpp

@@ -2725,7 +2725,7 @@ It makes possible to do a fast blurring or fast block correlation with a variabl
 example. In case of multi-channel images, sums for each channel are accumulated independently.
 
 As a practical example, the next figure shows the calculation of the integral of a straight
-rectangle Rect(3,3,3,2) and of a tilted rectangle Rect(5,1,2,3) . The selected pixels in the
+rectangle Rect(4,4,3,2) and of a tilted rectangle Rect(5,1,2,3) . The selected pixels in the
 original image are shown, as well as the relative pixels in the integral images sum and tilted .
 
 ![integral calculation example](pics/integral.png)