Added 2D convolution definitions to numeric extension

`convolve` function renamed to `convolve_1d`
boostorg · Aug 5, 2019 · 27ae550 · 27ae550
1 parent 308e4ea
commit 27ae550
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Showing 2 changed files with 39 additions and 2 deletions.
diff --git a/include/boost/gil/extension/numeric/convolve.hpp b/include/boost/gil/extension/numeric/convolve.hpp
@@ -274,7 +274,7 @@ void convolve_cols(
 /// \tparam DstView Models MutableImageViewConcept
 template <typename PixelAccum, typename SrcView, typename Kernel, typename DstView>
 BOOST_FORCEINLINE
-void convolve(
+void convolve_1d(
     SrcView const& src_view,
     Kernel const& kernel,
     DstView const& dst_view,
@@ -355,6 +355,43 @@ void convolve_cols_fixed(
         transposed_view(src_view), kernel, transposed_view(dst_view), option);
 }
 
+template <typename SrcView, typename DstView, typename Kernel>
+void convolve_2d(SrcView src_view, DstView dst_view, Kernel kernel)
+{
+
+    int flip_ker_row, flip_ker_col, row_boundary, col_boundary;
+    float aux_total;
+    for (std::ptrdiff_t view_row = 0; view_row < src_view.height(); ++view_row)              // rows
+    {
+        for (std::ptrdiff_t view_col = 0; view_col < src_view.width(); ++view_col)          // columns
+        {
+            aux_total = 0.0f;
+            for (std::size_t kernel_row = 0; kernel_row < kernel.size(); ++kernel_row)     // kernel rows
+            {
+                flip_ker_row = kernel.size() - 1 - kernel_row;      // row index of flipped kernel
+
+                for (std::size_t kernel_col = 0; kernel_col < kernel.size(); ++kernel_col) // kernel columns
+                {
+                    flip_ker_col = kernel.size() - 1 - kernel_col;  // column index of flipped kernel
+
+                    // index of input signal, used for checking boundary
+                    row_boundary = view_row + (kernel.center_vertical() - flip_ker_row);
+                    col_boundary = view_col + (kernel.center_horizontal() - flip_ker_col);
+
+                    // ignore input samples which are out of bound
+                    if (row_boundary >= 0 && row_boundary < src_view.height() &&
+                        col_boundary >= 0 && col_boundary < src_view.width())
+                    {
+                         aux_total +=
+                           src_view(col_boundary, row_boundary)*kernel.at(flip_ker_row, flip_ker_col);
+                    }
+                }
+            }
+            dst_view(view_col, view_row) = aux_total;
+        }
+    }
+}
+
 }} // namespace boost::gil
 
 #endif
diff --git a/include/boost/gil/image_processing/threshold.hpp b/include/boost/gil/image_processing/threshold.hpp
@@ -412,7 +412,7 @@ void threshold_adaptive
         typename image<typename SrcView::value_type>::view_t temp_view = view(temp_img);
         SrcView temp_conv(temp_view);
 
-        convolve<pixel<float, typename SrcView::value_type::layout_t>>(
+        convolve_1d<pixel<float, typename SrcView::value_type::layout_t>>(
             src_view, kernel, temp_view
         );