Merge pull request #28887 from milllemonman:4.x

hal/riscv-rvv: implement laplacian #28887

OpenCV Extra: https://github.com/opencv/opencv_extra/pull/1353

An implementation of laplacian for riscv-rvv hal

Added benchmark in perf_laplacian.cpp
The performance is evaluated on K1 by running 
./opencv_perf_imgproc --gtest_filter="Perf_Laplacian*"
Results are attached in the figure below.

CV_8U fast path supports ksize=3 with BORDER_CONSTANT/BORDER_REPLICATE; unsupported combinations fall back to default implementation. See performance results bellow.

### 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
- [x] 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/imgproc/src/deriv.cpp

@@ -750,6 +750,22 @@ void cv::Laplacian( InputArray _src, OutputArray _dst, int ddepth, int ksize,
 
     if( ksize == 1 || ksize == 3 )
     {
+        Mat src = _src.getMat();
+        Mat dst = _dst.getMat();
+
+        Point ofs;
+        Size wsz(src.cols, src.rows);
+        if(!(borderType & BORDER_ISOLATED))
+            src.locateROI(wsz, ofs);
+
+        CALL_HAL(laplacian, cv_hal_laplacian,
+                src.ptr(), src.step,
+                dst.ptr(), dst.step,
+                src.cols, src.rows,
+                sdepth, ddepth, cn,
+                ksize, borderType & ~BORDER_ISOLATED,
+                (uint8_t)0);
+
         filter2D( _src, _dst, ddepth, kernel, Point(-1, -1), delta, borderType );
     }
     else

modules/imgproc/src/hal_replacement.hpp

@@ -1388,6 +1388,27 @@ inline int hal_ni_scharr(const uchar* src_data, size_t src_step, uchar* dst_data
 #define cv_hal_scharr hal_ni_scharr
 //! @endcond
 
+/**
+   @brief Computes Laplacian filter
+   @param src_data Source image data
+   @param src_step Source image step
+   @param dst_data Destination image data
+   @param dst_step Destination image step
+   @param width Source image width
+   @param height Source image height
+   @param src_depth Depth of source image
+   @param dst_depth Depth of destination image
+   @param cn Number of channels
+   @param ksize Kernel size (1, 3, or 5)
+   @param border_type Border type
+   @param border_value Border value for CONSTANT
+ */
+inline int hal_ni_laplacian(const uchar* src_data, size_t src_step, uchar* dst_data, size_t dst_step, int width, int height, int src_depth, int dst_depth, int cn, int ksize, int border_type, uchar border_value)  { return CV_HAL_ERROR_NOT_IMPLEMENTED;}
+
+//! @cond IGNORED
+#define cv_hal_laplacian hal_ni_laplacian
+//! @endcond
+
 /**
    @brief Perform Gaussian Blur and downsampling for input tile.
    @param depth Depths of source and destination image