Merge remote-tracking branch 'upstream/3.4' into merge-3.4

modules/imgproc/include/opencv2/imgproc.hpp

@@ -78,11 +78,15 @@ Input depth (src.depth()) | Output depth (ddepth)
 --------------------------|----------------------
 CV_8U                     | -1/CV_16S/CV_32F/CV_64F
 CV_16U/CV_16S             | -1/CV_32F/CV_64F
-CV_32F                    | -1/CV_32F/CV_64F
+CV_32F                    | -1/CV_32F
 CV_64F                    | -1/CV_64F
 
 @note when ddepth=-1, the output image will have the same depth as the source.
 
+@note if you need double floating-point accuracy and using single floating-point input data
+(CV_32F input and CV_64F output depth combination), you can use @ref Mat.convertTo to convert
+the input data to the desired precision.
+
     @defgroup imgproc_transform Geometric Image Transformations
 
 The functions in this section perform various geometrical transformations of 2D images. They do not
@@ -1792,7 +1796,7 @@ with the following \f$3 \times 3\f$ aperture:
 
 @param src Source image.
 @param dst Destination image of the same size and the same number of channels as src .
-@param ddepth Desired depth of the destination image.
+@param ddepth Desired depth of the destination image, see @ref filter_depths "combinations".
 @param ksize Aperture size used to compute the second-derivative filters. See #getDerivKernels for
 details. The size must be positive and odd.
 @param scale Optional scale factor for the computed Laplacian values. By default, no scaling is
@@ -2279,7 +2283,7 @@ case of multi-channel images, each channel is processed independently.
 @param src input image; the number of channels can be arbitrary, but the depth should be one of
 CV_8U, CV_16U, CV_16S, CV_32F or CV_64F.
 @param dst output image of the same size and type as src.
-@param kernel structuring element used for dilation; if elemenat=Mat(), a 3 x 3 rectangular
+@param kernel structuring element used for dilation; if element=Mat(), a 3 x 3 rectangular
 structuring element is used. Kernel can be created using #getStructuringElement
 @param anchor position of the anchor within the element; default value (-1, -1) means that the
 anchor is at the element center.
@@ -2809,7 +2813,7 @@ 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)
@@ -3174,7 +3178,14 @@ CV_EXPORTS void calcHist( const Mat* images, int nimages,
                           const int* histSize, const float** ranges,
                           bool uniform = true, bool accumulate = false );
 
-/** @overload */
+/** @overload
+
+this variant supports only uniform histograms.
+
+ranges argument is either empty vector or a flattened vector of histSize.size()*2 elements
+(histSize.size() element pairs). The first and second elements of each pair specify the lower and
+upper boundaries.
+*/
 CV_EXPORTS_W void calcHist( InputArrayOfArrays images,
                             const std::vector<int>& channels,
                             InputArray mask, OutputArray hist,