diff --git a/modules/calib3d/src/circlesgrid.cpp b/modules/calib3d/src/circlesgrid.cpp
index 7fe60ef92a..39abd8ac50 100644
--- a/modules/calib3d/src/circlesgrid.cpp
+++ b/modules/calib3d/src/circlesgrid.cpp
@@ -69,7 +69,7 @@ void drawPoints(const std::vector<Point2f> &points, Mat &outImage, int radius =
 void CirclesGridClusterFinder::hierarchicalClustering(const std::vector<Point2f> &points, const Size &patternSz, std::vector<Point2f> &patternPoints)
 {
 #ifdef HAVE_TEGRA_OPTIMIZATION
-    if(cv::tegra::useTegra() && tegra::hierarchicalClustering(points, patternSz, patternPoints))
+    if(tegra::useTegra() && tegra::hierarchicalClustering(points, patternSz, patternPoints))
         return;
 #endif
     int j, n = (int)points.size();
diff --git a/modules/core/include/opencv2/core/private.hpp b/modules/core/include/opencv2/core/private.hpp
index ececd30f2a..03d69bd436 100644
--- a/modules/core/include/opencv2/core/private.hpp
+++ b/modules/core/include/opencv2/core/private.hpp
@@ -270,7 +270,7 @@ typedef enum CvStatus
 CvStatus;
 
 #ifdef HAVE_TEGRA_OPTIMIZATION
-namespace cv { namespace tegra {
+namespace tegra {
 
 CV_EXPORTS bool useTegra();
 CV_EXPORTS void setUseTegra(bool flag);
diff --git a/modules/core/src/arithm.cpp b/modules/core/src/arithm.cpp
index 02ef627c24..15b0759f77 100644
--- a/modules/core/src/arithm.cpp
+++ b/modules/core/src/arithm.cpp
@@ -2256,7 +2256,7 @@ void cv::subtract( InputArray _src1, InputArray _src2, OutputArray _dst,
                InputArray mask, int dtype )
 {
 #ifdef HAVE_TEGRA_OPTIMIZATION
-    if (cv::tegra::useTegra())
+    if (tegra::useTegra())
     {
         int kind1 = _src1.kind(), kind2 = _src2.kind();
         Mat src1 = _src1.getMat(), src2 = _src2.getMat();
diff --git a/modules/core/src/mathfuncs.cpp b/modules/core/src/mathfuncs.cpp
index f1bb0c2126..446b62731b 100644
--- a/modules/core/src/mathfuncs.cpp
+++ b/modules/core/src/mathfuncs.cpp
@@ -127,7 +127,7 @@ static void FastAtan2_32f(const float *Y, const float *X, float *angle, int len,
     float scale = angleInDegrees ? 1 : (float)(CV_PI/180);
 
 #ifdef HAVE_TEGRA_OPTIMIZATION
-    if (cv::tegra::useTegra() && tegra::FastAtan2_32f(Y, X, angle, len, scale))
+    if (tegra::useTegra() && tegra::FastAtan2_32f(Y, X, angle, len, scale))
         return;
 #endif
 
diff --git a/modules/core/src/system.cpp b/modules/core/src/system.cpp
index 31f9c48849..74d73c44e5 100644
--- a/modules/core/src/system.cpp
+++ b/modules/core/src/system.cpp
@@ -1257,13 +1257,15 @@ void setUseIPP(bool flag)
 
 } // namespace ipp
 
+} // namespace cv
+
 #ifdef HAVE_TEGRA_OPTIMIZATION
 
 namespace tegra {
 
 bool useTegra()
 {
-    CoreTLSData* data = getCoreTlsData().get();
+    cv::CoreTLSData* data = cv::getCoreTlsData().get();
 
     if (data->useTegra < 0)
     {
@@ -1279,7 +1281,7 @@ bool useTegra()
 
 void setUseTegra(bool flag)
 {
-    CoreTLSData* data = getCoreTlsData().get();
+    cv::CoreTLSData* data = cv::getCoreTlsData().get();
     data->useTegra = flag;
 }
 
@@ -1287,12 +1289,14 @@ void setUseTegra(bool flag)
 
 #endif
 
+namespace cv {
+
 void setOptimizations(bool enabled)
 {
-    cv::ipp::setUseIPP(enabled);
-    cv::ocl::setUseOpenCL(enabled);
+    ipp::setUseIPP(enabled);
+    ocl::setUseOpenCL(enabled);
 #ifdef HAVE_TEGRA_OPTIMIZATION
-    cv::tegra::setUseTegra(enabled);
+    ::tegra::setUseTegra(enabled);
 #endif
 }
 
diff --git a/modules/features2d/src/fast.cpp b/modules/features2d/src/fast.cpp
index b82572bbeb..11c039a0cc 100644
--- a/modules/features2d/src/fast.cpp
+++ b/modules/features2d/src/fast.cpp
@@ -346,7 +346,7 @@ void FAST(InputArray _img, std::vector<KeyPoint>& keypoints, int threshold, bool
       break;
     case FastFeatureDetector::TYPE_9_16:
 #ifdef HAVE_TEGRA_OPTIMIZATION
-      if(cv::tegra::useTegra() && tegra::FAST(_img, keypoints, threshold, nonmax_suppression))
+      if(tegra::useTegra() && tegra::FAST(_img, keypoints, threshold, nonmax_suppression))
         break;
 #endif
       FAST_t<16>(_img, keypoints, threshold, nonmax_suppression);
diff --git a/modules/imgproc/src/canny.cpp b/modules/imgproc/src/canny.cpp
index 2bc9de426e..8893be8839 100644
--- a/modules/imgproc/src/canny.cpp
+++ b/modules/imgproc/src/canny.cpp
@@ -261,7 +261,7 @@ void cv::Canny( InputArray _src, OutputArray _dst,
     Mat src = _src.getMat(), dst = _dst.getMat();
 
 #ifdef HAVE_TEGRA_OPTIMIZATION
-    if (cv::tegra::useTegra() && tegra::canny(src, dst, low_thresh, high_thresh, aperture_size, L2gradient))
+    if (tegra::useTegra() && tegra::canny(src, dst, low_thresh, high_thresh, aperture_size, L2gradient))
         return;
 #endif
 
diff --git a/modules/imgproc/src/color.cpp b/modules/imgproc/src/color.cpp
index c464e8234a..f8bc095891 100644
--- a/modules/imgproc/src/color.cpp
+++ b/modules/imgproc/src/color.cpp
@@ -6128,7 +6128,7 @@ struct YUV420sp2RGB888Invoker : ParallelLoopBody
         const uchar* y1 = my1 + rangeBegin * stride, *uv = muv + rangeBegin * stride / 2;
 
 #ifdef HAVE_TEGRA_OPTIMIZATION
-        if(cv::tegra::useTegra() && tegra::cvtYUV4202RGB(bIdx, uIdx, 3, y1, uv, stride, dst->ptr<uchar>(rangeBegin), dst->step, rangeEnd - rangeBegin, dst->cols))
+        if(tegra::useTegra() && tegra::cvtYUV4202RGB(bIdx, uIdx, 3, y1, uv, stride, dst->ptr<uchar>(rangeBegin), dst->step, rangeEnd - rangeBegin, dst->cols))
             return;
 #endif
 
@@ -6197,7 +6197,7 @@ struct YUV420sp2RGBA8888Invoker : ParallelLoopBody
         const uchar* y1 = my1 + rangeBegin * stride, *uv = muv + rangeBegin * stride / 2;
 
 #ifdef HAVE_TEGRA_OPTIMIZATION
-        if(cv::tegra::useTegra() && tegra::cvtYUV4202RGB(bIdx, uIdx, 4, y1, uv, stride, dst->ptr<uchar>(rangeBegin), dst->step, rangeEnd - rangeBegin, dst->cols))
+        if(tegra::useTegra() && tegra::cvtYUV4202RGB(bIdx, uIdx, 4, y1, uv, stride, dst->ptr<uchar>(rangeBegin), dst->step, rangeEnd - rangeBegin, dst->cols))
             return;
 #endif
 
@@ -7418,7 +7418,7 @@ void cv::cvtColor( InputArray _src, OutputArray _dst, int code, int dcn )
             if( depth == CV_8U )
             {
 #ifdef HAVE_TEGRA_OPTIMIZATION
-                if(cv::tegra::useTegra() && tegra::cvtBGR2RGB(src, dst, bidx))
+                if(tegra::useTegra() && tegra::cvtBGR2RGB(src, dst, bidx))
                     break;
 #endif
                 CvtColorLoop(src, dst, RGB2RGB<uchar>(scn, dcn, bidx));
@@ -7486,7 +7486,7 @@ void cv::cvtColor( InputArray _src, OutputArray _dst, int code, int dcn )
 
 #ifdef HAVE_TEGRA_OPTIMIZATION
             if(code == CV_BGR2BGR565 || code == CV_BGRA2BGR565 || code == CV_RGB2BGR565  || code == CV_RGBA2BGR565)
-                if(cv::tegra::useTegra() && tegra::cvtRGB2RGB565(src, dst, code == CV_RGB2BGR565 || code == CV_RGBA2BGR565 ? 0 : 2))
+                if(tegra::useTegra() && tegra::cvtRGB2RGB565(src, dst, code == CV_RGB2BGR565 || code == CV_RGBA2BGR565 ? 0 : 2))
                     break;
 #endif
 
@@ -7612,7 +7612,7 @@ void cv::cvtColor( InputArray _src, OutputArray _dst, int code, int dcn )
             if( depth == CV_8U )
             {
 #ifdef HAVE_TEGRA_OPTIMIZATION
-                if(cv::tegra::useTegra() && tegra::cvtRGB2Gray(src, dst, bidx))
+                if(tegra::useTegra() && tegra::cvtRGB2Gray(src, dst, bidx))
                     break;
 #endif
                 CvtColorLoop(src, dst, RGB2Gray<uchar>(scn, bidx, 0));
@@ -7665,7 +7665,7 @@ void cv::cvtColor( InputArray _src, OutputArray _dst, int code, int dcn )
             if( depth == CV_8U )
             {
 #ifdef HAVE_TEGRA_OPTIMIZATION
-                if(cv::tegra::useTegra() && tegra::cvtGray2RGB(src, dst))
+                if(tegra::useTegra() && tegra::cvtGray2RGB(src, dst))
                     break;
 #endif
                 CvtColorLoop(src, dst, Gray2RGB<uchar>(dcn));
@@ -7745,7 +7745,7 @@ void cv::cvtColor( InputArray _src, OutputArray _dst, int code, int dcn )
             if( depth == CV_8U )
             {
 #ifdef HAVE_TEGRA_OPTIMIZATION
-                if((code == CV_RGB2YCrCb || code == CV_BGR2YCrCb) && cv::tegra::useTegra() && tegra::cvtRGB2YCrCb(src, dst, bidx))
+                if((code == CV_RGB2YCrCb || code == CV_BGR2YCrCb) && tegra::useTegra() && tegra::cvtRGB2YCrCb(src, dst, bidx))
                     break;
 #endif
                 CvtColorLoop(src, dst, RGB2YCrCb_i<uchar>(scn, bidx, coeffs_i));
@@ -8039,7 +8039,7 @@ void cv::cvtColor( InputArray _src, OutputArray _dst, int code, int dcn )
                 code == CV_BGR2HSV_FULL || code == CV_RGB2HSV_FULL )
             {
 #ifdef HAVE_TEGRA_OPTIMIZATION
-                if(cv::tegra::useTegra() && tegra::cvtRGB2HSV(src, dst, bidx, hrange))
+                if(tegra::useTegra() && tegra::cvtRGB2HSV(src, dst, bidx, hrange))
                     break;
 #endif
                 if( depth == CV_8U )
diff --git a/modules/imgproc/src/corner.cpp b/modules/imgproc/src/corner.cpp
index a5d2442efe..38f9676007 100644
--- a/modules/imgproc/src/corner.cpp
+++ b/modules/imgproc/src/corner.cpp
@@ -269,7 +269,7 @@ cornerEigenValsVecs( const Mat& src, Mat& eigenv, int block_size,
                      int borderType=BORDER_DEFAULT )
 {
 #ifdef HAVE_TEGRA_OPTIMIZATION
-    if (cv::tegra::useTegra() && tegra::cornerEigenValsVecs(src, eigenv, block_size, aperture_size, op_type, k, borderType))
+    if (tegra::useTegra() && tegra::cornerEigenValsVecs(src, eigenv, block_size, aperture_size, op_type, k, borderType))
         return;
 #endif
 #if CV_SSE2
diff --git a/modules/imgproc/src/deriv.cpp b/modules/imgproc/src/deriv.cpp
index ef28441d05..d1e3a0b129 100644
--- a/modules/imgproc/src/deriv.cpp
+++ b/modules/imgproc/src/deriv.cpp
@@ -562,7 +562,7 @@ void cv::Sobel( InputArray _src, OutputArray _dst, int ddepth, int dx, int dy,
     _dst.create( _src.size(), dtype );
 
 #ifdef HAVE_TEGRA_OPTIMIZATION
-    if (cv::tegra::useTegra() && scale == 1.0 && delta == 0)
+    if (tegra::useTegra() && scale == 1.0 && delta == 0)
     {
         Mat src = _src.getMat(), dst = _dst.getMat();
         if (ksize == 3 && tegra::sobel3x3(src, dst, dx, dy, borderType))
@@ -620,7 +620,7 @@ void cv::Scharr( InputArray _src, OutputArray _dst, int ddepth, int dx, int dy,
     _dst.create( _src.size(), dtype );
 
 #ifdef HAVE_TEGRA_OPTIMIZATION
-    if (cv::tegra::useTegra() && scale == 1.0 && delta == 0)
+    if (tegra::useTegra() && scale == 1.0 && delta == 0)
     {
         Mat src = _src.getMat(), dst = _dst.getMat();
         if (tegra::scharr(src, dst, dx, dy, borderType))
@@ -873,7 +873,7 @@ void cv::Laplacian( InputArray _src, OutputArray _dst, int ddepth, int ksize,
 #endif
 
 #ifdef HAVE_TEGRA_OPTIMIZATION
-    if (cv::tegra::useTegra() && scale == 1.0 && delta == 0)
+    if (tegra::useTegra() && scale == 1.0 && delta == 0)
     {
         Mat src = _src.getMat(), dst = _dst.getMat();
         if (ksize == 1 && tegra::laplace1(src, dst, borderType))
diff --git a/modules/imgproc/src/filter.cpp b/modules/imgproc/src/filter.cpp
index 700ec68170..fb43eee0a1 100644
--- a/modules/imgproc/src/filter.cpp
+++ b/modules/imgproc/src/filter.cpp
@@ -4659,7 +4659,7 @@ void cv::filter2D( InputArray _src, OutputArray _dst, int ddepth,
 #endif
 
 #ifdef HAVE_TEGRA_OPTIMIZATION
-    if( cv::tegra::useTegra() && tegra::filter2D(src, dst, kernel, anchor, delta, borderType) )
+    if( tegra::useTegra() && tegra::filter2D(src, dst, kernel, anchor, delta, borderType) )
         return;
 #endif
 
diff --git a/modules/imgproc/src/imgwarp.cpp b/modules/imgproc/src/imgwarp.cpp
index 511fc5aea5..79ab3eca21 100644
--- a/modules/imgproc/src/imgwarp.cpp
+++ b/modules/imgproc/src/imgwarp.cpp
@@ -3227,7 +3227,7 @@ void cv::resize( InputArray _src, OutputArray _dst, Size dsize,
     Mat dst = _dst.getMat();
 
 #ifdef HAVE_TEGRA_OPTIMIZATION
-    if (cv::tegra::useTegra() && tegra::resize(src, dst, (float)inv_scale_x, (float)inv_scale_y, interpolation))
+    if (tegra::useTegra() && tegra::resize(src, dst, (float)inv_scale_x, (float)inv_scale_y, interpolation))
         return;
 #endif
 
@@ -5572,7 +5572,7 @@ void cv::warpAffine( InputArray _src, OutputArray _dst,
     M0.convertTo(matM, matM.type());
 
 #ifdef HAVE_TEGRA_OPTIMIZATION
-    if( cv::tegra::useTegra() && tegra::warpAffine(src, dst, M, flags, borderType, borderValue) )
+    if( tegra::useTegra() && tegra::warpAffine(src, dst, M, flags, borderType, borderValue) )
         return;
 #endif
 
@@ -6098,7 +6098,7 @@ void cv::warpPerspective( InputArray _src, OutputArray _dst, InputArray _M0,
     M0.convertTo(matM, matM.type());
 
 #ifdef HAVE_TEGRA_OPTIMIZATION
-    if( cv::tegra::useTegra() && tegra::warpPerspective(src, dst, M, flags, borderType, borderValue) )
+    if( tegra::useTegra() && tegra::warpPerspective(src, dst, M, flags, borderType, borderValue) )
         return;
 #endif
 
diff --git a/modules/imgproc/src/pyramids.cpp b/modules/imgproc/src/pyramids.cpp
index c45c33429c..4018e08f70 100644
--- a/modules/imgproc/src/pyramids.cpp
+++ b/modules/imgproc/src/pyramids.cpp
@@ -1180,7 +1180,7 @@ void cv::pyrDown( InputArray _src, OutputArray _dst, const Size& _dsz, int borde
     int depth = src.depth();
 
 #ifdef HAVE_TEGRA_OPTIMIZATION
-    if(borderType == BORDER_DEFAULT && cv::tegra::useTegra() && tegra::pyrDown(src, dst))
+    if(borderType == BORDER_DEFAULT && tegra::useTegra() && tegra::pyrDown(src, dst))
         return;
 #endif
 
@@ -1257,7 +1257,7 @@ void cv::pyrUp( InputArray _src, OutputArray _dst, const Size& _dsz, int borderT
     int depth = src.depth();
 
 #ifdef HAVE_TEGRA_OPTIMIZATION
-    if(borderType == BORDER_DEFAULT && cv::tegra::useTegra() && tegra::pyrUp(src, dst))
+    if(borderType == BORDER_DEFAULT && tegra::useTegra() && tegra::pyrUp(src, dst))
         return;
 #endif
 
diff --git a/modules/imgproc/src/smooth.cpp b/modules/imgproc/src/smooth.cpp
index b901314095..53cd8269ce 100644
--- a/modules/imgproc/src/smooth.cpp
+++ b/modules/imgproc/src/smooth.cpp
@@ -1324,7 +1324,7 @@ void cv::boxFilter( InputArray _src, OutputArray _dst, int ddepth,
             ksize.width = 1;
     }
 #ifdef HAVE_TEGRA_OPTIMIZATION
-    if ( cv::tegra::useTegra() && tegra::box(src, dst, ksize, anchor, normalize, borderType) )
+    if ( tegra::useTegra() && tegra::box(src, dst, ksize, anchor, normalize, borderType) )
         return;
 #endif
 
@@ -1650,7 +1650,7 @@ void cv::GaussianBlur( InputArray _src, OutputArray _dst, Size ksize,
 #ifdef HAVE_TEGRA_OPTIMIZATION
     Mat src = _src.getMat();
     Mat dst = _dst.getMat();
-    if(sigma1 == 0 && sigma2 == 0 && cv::tegra::useTegra() && tegra::gaussian(src, dst, ksize, borderType))
+    if(sigma1 == 0 && sigma2 == 0 && tegra::useTegra() && tegra::gaussian(src, dst, ksize, borderType))
         return;
 #endif
 
@@ -2698,7 +2698,7 @@ void cv::medianBlur( InputArray _src0, OutputArray _dst, int ksize )
 #endif
 
 #ifdef HAVE_TEGRA_OPTIMIZATION
-    if (cv::tegra::useTegra() && tegra::medianBlur(src0, dst, ksize))
+    if (tegra::useTegra() && tegra::medianBlur(src0, dst, ksize))
         return;
 #endif
 
diff --git a/modules/imgproc/src/templmatch.cpp b/modules/imgproc/src/templmatch.cpp
index 726ec53f7b..c3d583bcca 100644
--- a/modules/imgproc/src/templmatch.cpp
+++ b/modules/imgproc/src/templmatch.cpp
@@ -933,7 +933,7 @@ void cv::matchTemplate( InputArray _img, InputArray _templ, OutputArray _result,
     Mat result = _result.getMat();
 
 #ifdef HAVE_TEGRA_OPTIMIZATION
-    if (cv::tegra::useTegra() && tegra::matchTemplate(img, templ, result, method))
+    if (tegra::useTegra() && tegra::matchTemplate(img, templ, result, method))
         return;
 #endif
 
diff --git a/modules/imgproc/src/thresh.cpp b/modules/imgproc/src/thresh.cpp
index 8ef7fef8be..490bdff3e5 100644
--- a/modules/imgproc/src/thresh.cpp
+++ b/modules/imgproc/src/thresh.cpp
@@ -64,7 +64,7 @@ thresh_8u( const Mat& _src, Mat& _dst, uchar thresh, uchar maxval, int type )
     }
 
 #ifdef HAVE_TEGRA_OPTIMIZATION
-    if (cv::tegra::useTegra() && tegra::thresh_8u(_src, _dst, roi.width, roi.height, thresh, maxval, type))
+    if (tegra::useTegra() && tegra::thresh_8u(_src, _dst, roi.width, roi.height, thresh, maxval, type))
         return;
 #endif
 
@@ -408,7 +408,7 @@ thresh_16s( const Mat& _src, Mat& _dst, short thresh, short maxval, int type )
     }
 
 #ifdef HAVE_TEGRA_OPTIMIZATION
-    if (cv::tegra::useTegra() && tegra::thresh_16s(_src, _dst, roi.width, roi.height, thresh, maxval, type))
+    if (tegra::useTegra() && tegra::thresh_16s(_src, _dst, roi.width, roi.height, thresh, maxval, type))
         return;
 #endif
 
@@ -676,7 +676,7 @@ thresh_32f( const Mat& _src, Mat& _dst, float thresh, float maxval, int type )
     }
 
 #ifdef HAVE_TEGRA_OPTIMIZATION
-    if (cv::tegra::useTegra() && tegra::thresh_32f(_src, _dst, roi.width, roi.height, thresh, maxval, type))
+    if (tegra::useTegra() && tegra::thresh_32f(_src, _dst, roi.width, roi.height, thresh, maxval, type))
         return;
 #endif
 
diff --git a/modules/objdetect/src/cascadedetect.cpp b/modules/objdetect/src/cascadedetect.cpp
index 01f83d3d8c..1c0bbf1b0b 100644
--- a/modules/objdetect/src/cascadedetect.cpp
+++ b/modules/objdetect/src/cascadedetect.cpp
@@ -937,11 +937,10 @@ Ptr<CascadeClassifierImpl::MaskGenerator> CascadeClassifierImpl::getMaskGenerato
 Ptr<BaseCascadeClassifier::MaskGenerator> createFaceDetectionMaskGenerator()
 {
 #ifdef HAVE_TEGRA_OPTIMIZATION
-    if (cv::tegra::useTegra())
+    if (tegra::useTegra())
         return tegra::getCascadeClassifierMaskGenerator();
-#else
-    return Ptr<BaseCascadeClassifier::MaskGenerator>();
 #endif
+    return Ptr<BaseCascadeClassifier::MaskGenerator>();
 }
 
 class CascadeClassifierInvoker : public ParallelLoopBody
diff --git a/modules/photo/src/denoising.cpp b/modules/photo/src/denoising.cpp
index 90b76a8ec7..b4767a738d 100644
--- a/modules/photo/src/denoising.cpp
+++ b/modules/photo/src/denoising.cpp
@@ -58,7 +58,7 @@ void cv::fastNlMeansDenoising( InputArray _src, OutputArray _dst, float h,
     Mat dst = _dst.getMat();
 
 #ifdef HAVE_TEGRA_OPTIMIZATION
-    if(cv::tegra::useTegra() && tegra::fastNlMeansDenoising(src, dst, h, templateWindowSize, searchWindowSize))
+    if(tegra::useTegra() && tegra::fastNlMeansDenoising(src, dst, h, templateWindowSize, searchWindowSize))
         return;
 #endif
 
diff --git a/modules/stitching/src/blenders.cpp b/modules/stitching/src/blenders.cpp
index 7be914be86..82e65fa388 100644
--- a/modules/stitching/src/blenders.cpp
+++ b/modules/stitching/src/blenders.cpp
@@ -481,7 +481,7 @@ void normalizeUsingWeightMap(InputArray _weight, InputOutputArray _src)
 #ifdef HAVE_TEGRA_OPTIMIZATION
     src = _src.getMat();
     weight = _weight.getMat();
-    if(cv::tegra::useTegra() && tegra::normalizeUsingWeightMap(weight, src))
+    if(tegra::useTegra() && tegra::normalizeUsingWeightMap(weight, src))
         return;
 #endif
 
@@ -552,7 +552,7 @@ void createLaplacePyr(InputArray img, int num_levels, std::vector<UMat> &pyr)
 {
 #ifdef HAVE_TEGRA_OPTIMIZATION
     cv::Mat imgMat = img.getMat();
-    if(cv::tegra::useTegra() && tegra::createLaplacePyr(imgMat, num_levels, pyr))
+    if(tegra::useTegra() && tegra::createLaplacePyr(imgMat, num_levels, pyr))
         return;
 #endif
 
diff --git a/modules/stitching/src/matchers.cpp b/modules/stitching/src/matchers.cpp
index 43669b2544..2587da914c 100644
--- a/modules/stitching/src/matchers.cpp
+++ b/modules/stitching/src/matchers.cpp
@@ -148,7 +148,7 @@ void CpuMatcher::match(const ImageFeatures &features1, const ImageFeatures &feat
     CV_Assert(features2.descriptors.depth() == CV_8U || features2.descriptors.depth() == CV_32F);
 
 #ifdef HAVE_TEGRA_OPTIMIZATION
-    if (cv::tegra::useTegra() && tegra::match2nearest(features1, features2, matches_info, match_conf_))
+    if (tegra::useTegra() && tegra::match2nearest(features1, features2, matches_info, match_conf_))
         return;
 #endif
 
diff --git a/modules/ts/src/ts_func.cpp b/modules/ts/src/ts_func.cpp
index f40b38237f..f5fed678d5 100644
--- a/modules/ts/src/ts_func.cpp
+++ b/modules/ts/src/ts_func.cpp
@@ -3068,7 +3068,7 @@ void printVersionInfo(bool useStdOut)
     if (useStdOut) std::cout << "CPU features: " << cpu_features << std::endl;
 
 #ifdef HAVE_TEGRA_OPTIMIZATION
-    const char * tegra_optimization = cv::tegra::useTegra() && tegra::isDeviceSupported() ? "enabled" : "disabled";
+    const char * tegra_optimization = tegra::useTegra() && tegra::isDeviceSupported() ? "enabled" : "disabled";
     ::testing::Test::RecordProperty("cv_tegra_optimization", tegra_optimization);
     if (useStdOut) std::cout << "Tegra optimization: " << tegra_optimization << std::endl;
 #endif
diff --git a/modules/video/src/lkpyramid.cpp b/modules/video/src/lkpyramid.cpp
index 22b65dfbda..43dde7df78 100644
--- a/modules/video/src/lkpyramid.cpp
+++ b/modules/video/src/lkpyramid.cpp
@@ -58,7 +58,7 @@ static void calcSharrDeriv(const cv::Mat& src, cv::Mat& dst)
     dst.create(rows, cols, CV_MAKETYPE(DataType<deriv_type>::depth, cn*2));
 
 #ifdef HAVE_TEGRA_OPTIMIZATION
-    if (cv::tegra::useTegra() && tegra::calcSharrDeriv(src, dst))
+    if (tegra::useTegra() && tegra::calcSharrDeriv(src, dst))
         return;
 #endif