added docs for GPU Filter Engine

doc/imgproc_image_filtering.tex

-\section{Image Filtering}
+\section{Image Filtering}\ifCpp\label{section.cpp.cpu.ImageFiltering}\fi
 
 Functions and classes described in this section are used to perform various linear or non-linear filtering operations on 2D images (represented as \cvCppCross{Mat}'s), that is, for each pixel location $(x,y)$ in the source image some its (normally rectangular) neighborhood is considered and used to compute the response. In case of a linear filter it is a weighted sum of pixel values, in case of morphological operations it is the minimum or maximum etc. The computed response is stored to the destination image at the same location $(x,y)$. It means, that the output image will be of the same size as the input image. Normally, the functions supports multi-channel arrays, in which case every channel is processed independently, therefore the output image will also have the same number of channels as the input one.
 

doc/opencvref_body.tex

@@ -63,6 +63,8 @@
 \chapter{gpu. GPU-based Functionality}
 \renewcommand{\curModule}{gpu}
 \input{gpu}
+\input{gpu_features2d}
+\input{gpu_image_filtering}
 \fi
 
 

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

@@ -804,7 +804,7 @@ namespace cv
         };
 
         //! returns the non-separable filter engine with the specified filter
-        CV_EXPORTS Ptr<FilterEngine_GPU> createFilter2D_GPU(const Ptr<BaseFilter_GPU> filter2D, int srcType, int dstType);
+        CV_EXPORTS Ptr<FilterEngine_GPU> createFilter2D_GPU(const Ptr<BaseFilter_GPU>& filter2D, int srcType, int dstType);
 
         //! returns the separable filter engine with the specified filters
         CV_EXPORTS Ptr<FilterEngine_GPU> createSeparableFilter_GPU(const Ptr<BaseRowFilter_GPU>& rowFilter,

modules/gpu/src/filtering.cpp

@@ -48,7 +48,7 @@ using namespace cv::gpu;
 
 #if !defined (HAVE_CUDA)
 
-Ptr<FilterEngine_GPU> cv::gpu::createFilter2D_GPU(const Ptr<BaseFilter_GPU>, int, int) { throw_nogpu(); return Ptr<FilterEngine_GPU>(0); }
+Ptr<FilterEngine_GPU> cv::gpu::createFilter2D_GPU(const Ptr<BaseFilter_GPU>&, int, int) { throw_nogpu(); return Ptr<FilterEngine_GPU>(0); }
 Ptr<FilterEngine_GPU> cv::gpu::createSeparableFilter_GPU(const Ptr<BaseRowFilter_GPU>&, const Ptr<BaseColumnFilter_GPU>&, int, int, int) { throw_nogpu(); return Ptr<FilterEngine_GPU>(0); }
 Ptr<BaseRowFilter_GPU> cv::gpu::getRowSumFilter_GPU(int, int, int, int) { throw_nogpu(); return Ptr<BaseRowFilter_GPU>(0); }
 Ptr<BaseColumnFilter_GPU> cv::gpu::getColumnSumFilter_GPU(int, int, int, int) { throw_nogpu(); return Ptr<BaseColumnFilter_GPU>(0); }
@@ -159,7 +159,7 @@ namespace
     };
 }
 
-Ptr<FilterEngine_GPU> cv::gpu::createFilter2D_GPU(const Ptr<BaseFilter_GPU> filter2D, int srcType, int dstType)
+Ptr<FilterEngine_GPU> cv::gpu::createFilter2D_GPU(const Ptr<BaseFilter_GPU>& filter2D, int srcType, int dstType)
 {
     return Ptr<FilterEngine_GPU>(new Filter2DEngine_GPU(filter2D, srcType, dstType));
 }