From 98db804541accd2ffd920037bf7a8f5ec55c801f Mon Sep 17 00:00:00 2001
From: Nishant Arora <wrongnumber.fu@gmail.com>
Date: Thu, 17 Aug 2017 10:32:53 -0600
Subject: [PATCH] Merge pull request #9210 from whizzzkid/fixing-cuda

Fixing explicitly call download method for cuda::GpuMat object
---
 modules/stitching/src/matchers.cpp | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/modules/stitching/src/matchers.cpp b/modules/stitching/src/matchers.cpp
index 47ef253d7a..212f0003a6 100644
--- a/modules/stitching/src/matchers.cpp
+++ b/modules/stitching/src/matchers.cpp
@@ -51,6 +51,10 @@ using namespace cv::cuda;
 using xfeatures2d::SURF;
 #endif
 
+#ifdef HAVE_OPENCV_CUDAIMGPROC
+#  include "opencv2/cudaimgproc.hpp"
+#endif
+
 namespace {
 
 struct DistIdxPair
@@ -583,7 +587,12 @@ void SurfFeaturesFinderGpu::find(InputArray image, ImageFeatures &features)
     image_.upload(image);
 
     ensureSizeIsEnough(image.size(), CV_8UC1, gray_image_);
+
+#ifdef HAVE_OPENCV_CUDAIMGPROC
+    cv::cuda::cvtColor(image_, gray_image_, COLOR_BGR2GRAY);
+#else
     cvtColor(image_, gray_image_, COLOR_BGR2GRAY);
+#endif
 
     surf_.nOctaves = num_octaves_;
     surf_.nOctaveLayers = num_layers_;