Merge pull request #26903 from asmorkalov:as/openvx_hal

Migrate remaning OpenVX integrations to OpenVX HAL (core) #26903

Tested with OpenVX 1.2 & 1.3 sample implementation.

Steps to build and test:
```
git clone git@github.com:KhronosGroup/OpenVX-sample-impl.git
cd OpenVX-sample-impl
python3 Build.py --os=Linux --conf=Release
cd ..
mkdir build
cmake -DWITH_OPENVX=ON -DOPENVX_ROOT=/mnt/Projects/Projects/OpenVX-sample-impl/install/Linux/x64/Release/ ../opencv
make -j8
```

### Pull Request Readiness Checklist

See details at https://github.com/opencv/opencv/wiki/How_to_contribute#making-a-good-pull-request

- [x] I agree to contribute to the project under Apache 2 License.
- [x] To the best of my knowledge, the proposed patch is not based on a code under GPL or another license that is incompatible with OpenCV
- [ ] The PR is proposed to the proper branch
- [ ] There is a reference to the original bug report and related work
- [ ] There is accuracy test, performance test and test data in opencv_extra repository, if applicable
      Patch to opencv_extra has the same branch name.
- [ ] The feature is well documented and sample code can be built with the project CMake

modules/core/src/mean.dispatch.cpp

@@ -5,7 +5,6 @@
 
 #include "precomp.hpp"
 #include "opencl_kernels_core.hpp"
-#include "opencv2/core/openvx/ovx_defs.hpp"
 #include "stat.hpp"
 
 #ifndef OPENCV_IPP_MEAN
@@ -328,70 +327,6 @@ static bool ocl_meanStdDev( InputArray _src, OutputArray _mean, OutputArray _sdv
 }
 #endif
 
-#ifdef HAVE_OPENVX
-    static bool openvx_meanStdDev(Mat& src, OutputArray _mean, OutputArray _sdv, Mat& mask)
-    {
-        size_t total_size = src.total();
-        int rows = src.size[0], cols = rows ? (int)(total_size / rows) : 0;
-        if (src.type() != CV_8UC1|| !mask.empty() ||
-               (src.dims != 2 && !(src.isContinuous() && cols > 0 && (size_t)rows*cols == total_size))
-           )
-        return false;
-
-        try
-        {
-            ivx::Context ctx = ovx::getOpenVXContext();
-#ifndef VX_VERSION_1_1
-            if (ctx.vendorID() == VX_ID_KHRONOS)
-                return false; // Do not use OpenVX meanStdDev estimation for sample 1.0.1 implementation due to lack of accuracy
-#endif
-
-            ivx::Image
-                ia = ivx::Image::createFromHandle(ctx, VX_DF_IMAGE_U8,
-                    ivx::Image::createAddressing(cols, rows, 1, (vx_int32)(src.step[0])), src.ptr());
-
-            vx_float32 mean_temp, stddev_temp;
-            ivx::IVX_CHECK_STATUS(vxuMeanStdDev(ctx, ia, &mean_temp, &stddev_temp));
-
-            if (_mean.needed())
-            {
-                if (!_mean.fixedSize())
-                    _mean.create(1, 1, CV_64F, -1, true);
-                Mat mean = _mean.getMat();
-                CV_Assert(mean.type() == CV_64F && mean.isContinuous() &&
-                    (mean.cols == 1 || mean.rows == 1) && mean.total() >= 1);
-                double *pmean = mean.ptr<double>();
-                pmean[0] = mean_temp;
-                for (int c = 1; c < (int)mean.total(); c++)
-                    pmean[c] = 0;
-            }
-
-            if (_sdv.needed())
-            {
-                if (!_sdv.fixedSize())
-                    _sdv.create(1, 1, CV_64F, -1, true);
-                Mat stddev = _sdv.getMat();
-                CV_Assert(stddev.type() == CV_64F && stddev.isContinuous() &&
-                    (stddev.cols == 1 || stddev.rows == 1) && stddev.total() >= 1);
-                double *pstddev = stddev.ptr<double>();
-                pstddev[0] = stddev_temp;
-                for (int c = 1; c < (int)stddev.total(); c++)
-                    pstddev[c] = 0;
-            }
-        }
-        catch (const ivx::RuntimeError & e)
-        {
-            VX_DbgThrow(e.what());
-        }
-        catch (const ivx::WrapperError & e)
-        {
-            VX_DbgThrow(e.what());
-        }
-
-        return true;
-    }
-#endif
-
 #ifdef HAVE_IPP
 static bool ipp_meanStdDev(Mat& src, OutputArray _mean, OutputArray _sdv, Mat& mask)
 {
@@ -543,9 +478,6 @@ void meanStdDev(InputArray _src, OutputArray _mean, OutputArray _sdv, InputArray
 
     CV_Assert(mask.empty() || src.size == mask.size);
 
-    CV_OVX_RUN(!ovx::skipSmallImages<VX_KERNEL_MEAN_STDDEV>(src.cols, src.rows),
-               openvx_meanStdDev(src, _mean, _sdv, mask))
-
     CV_IPP_RUN(IPP_VERSION_X100 >= 700, ipp_meanStdDev(src, _mean, _sdv, mask));
 
     int k, cn = src.channels(), depth = src.depth();