Add reflection option for boundary handling in 1D correlation

include/boost/gil/algorithm.hpp

@@ -1416,11 +1416,12 @@ void view_multiplies_scalar(SrcView const& src_view, Scalar const& scalar, DstVi
 /// \brief Boundary options for image boundary extension
 enum class boundary_option
 {
- output_ignore, /// do nothing to the output
- output_zero, /// set the output to zero
- extend_padded, /// assume the source boundaries to be padded already
- extend_zero, /// assume the source boundaries to be zero
- extend_constant /// assume the source boundaries to be the boundary value
+ output_ignore, /// do nothing to the output
+ output_zero, /// set the output to zero
+ extend_padded, /// assume the source boundaries to be padded already
+ extend_zero, /// assume the source boundaries to be zero
+ extend_constant, /// assume the source boundaries to be the boundary value
+ extend_reflection /// assumes boundary values as reflection of source row pixels
 };
 
 namespace detail

include/boost/gil/image_processing/convolve.hpp

@@ -2,6 +2,7 @@
 // Copyright 2005-2007 Adobe Systems Incorporated
 // Copyright 2019 Miral Shah <[email protected]>
 // Copyright 2019-2021 Pranam Lashkari <[email protected]>
+// Copyright 2021 Prathamesh Tagore <[email protected]>
 //
 // Distributed under the Boost Software License, Version 1.0
 // See accompanying file LICENSE_1_0.txt or copy at
@@ -143,6 +144,18 @@ void correlate_rows_impl(
  pixel_assigns_t<src_pixel_ref_t, PixelAccum>()(src_view.row_end(y)[-1], filler);
  std::fill_n(it_buffer, kernel.right_size(), filler);
  }
+ else if (option == boundary_option::extend_reflection)
+ {
+ assign_pixels(src_view.row_begin(y), src_view.row_begin(y) + kernel.left_size(),
+ it_buffer);
+ std::reverse(buffer.begin(), buffer.begin() + kernel.left_size());
+ it_buffer += kernel.left_size();
+ assign_pixels(src_view.row_begin(y), src_view.row_end(y), it_buffer);
+ it_buffer += width;
+ assign_pixels(src_view.row_end(y) - kernel.right_size(), src_view.row_end(y),
+ it_buffer);
+ std::reverse(buffer.end() - kernel.right_size(), buffer.end());
+ }
 
  correlator(
  &buffer.front(), &buffer.front() + width,

test/core/image_processing/convolve.cpp

@@ -1,6 +1,7 @@
 //
 // Copyright 2019-2020 Mateusz Loskot <mateusz at loskot dot net>
 // Copyright 2021 Pranam Lashkari <[email protected]>
+// Copyright 2021 Prathamesh Tagore <[email protected]>
 //
 // Distributed under the Boost Software License, Version 1.0
 // See accompanying file LICENSE_1_0.txt or copy at
@@ -111,12 +112,81 @@ struct test_image_5x5_kernel_3x3_identity
  }
 };
 
+struct test_image_5x5_kernel_1x9_boundary_extend_reflection
+{
+ template <typename Image>
+ void operator()(Image const&)
+ {
+ using image_t = Image;
+ using pixel_t = typename image_t::value_type;
+ using channel_t = typename gil::channel_type<pixel_t>::type;
+ auto img = fixture::generate_image<image_t>(5, 5, fixture::random_value<channel_t>{});
+ auto img_view = gil::view(img);
+ image_t img_out_up_left_offset(img), img_expected_row_up_offset(img);
+ image_t img_expected_col_left_offset(img), img_out_down_right_offset(img);
+ image_t img_expected_row_down_offset(img), img_expected_col_right_offset(img);
+ int kernel_shift_up_left_offset = 2, kernel_shift_down_right_offset = -2;
+
+ fixture::row_conv1D_offset_img_generator(img_view, gil::view(img_expected_row_up_offset),
+ kernel_shift_up_left_offset);
+ fixture::row_conv1D_offset_img_generator(img_view, gil::view(img_expected_row_up_offset),
+ -1, 0, 1, img_view.height(), 1);
+ fixture::row_conv1D_offset_img_generator(img_view, gil::view(img_expected_row_up_offset),
+ 1, 0, 0, img_view.height(), 2);
+
+ fixture::col_conv1D_offset_img_generator(gil::view(img_expected_row_up_offset),
+ gil::view(img_expected_col_left_offset), kernel_shift_up_left_offset);
+ fixture::col_conv1D_offset_img_generator(gil::view(img_expected_row_up_offset),
+ gil::view(img_expected_col_left_offset), -1, 1, 0, 1, img_view.width());
+ fixture::col_conv1D_offset_img_generator(gil::view(img_expected_row_up_offset),
+ gil::view(img_expected_col_left_offset), 1, 0, 0, 2, img_view.width());
+
+ fixture::row_conv1D_offset_img_generator(img_view, gil::view(img_expected_row_down_offset),
+ kernel_shift_down_right_offset, 0, 2, img_view.height(), img_view.width());
+ fixture::row_conv1D_offset_img_generator(img_view, gil::view(img_expected_row_down_offset),
+ -1, 0, img_view.width() - 1, img_view.height(), img_view.width());
+ fixture::row_conv1D_offset_img_generator(img_view, gil::view(img_expected_row_down_offset),
+ 1, 0, img_view.width() - 2, img_view.height(), img_view.width());
+
+ fixture::col_conv1D_offset_img_generator(gil::view(img_expected_row_down_offset),
+ gil::view(img_expected_col_right_offset), kernel_shift_down_right_offset, 2, 0,
+ img_view.height(), img_view.width());
+ fixture::col_conv1D_offset_img_generator(gil::view(img_expected_row_down_offset),
+ gil::view(img_expected_col_right_offset), -1, img_view.height() - 1, 0,
+ img_view.height(), img_view.width());
+ fixture::col_conv1D_offset_img_generator(gil::view(img_expected_row_down_offset),
+ gil::view(img_expected_col_right_offset), 1, img_view.height() - 2, 0,
+ img_view.height(), img_view.width());
+
+ auto const kernel_up_left_offset = fixture::create_kernel<channel_t>(
+ {0, 0, 0, 0, 0, 0, 1, 0, 0});
+ gil::detail::convolve_1d<pixel_t>(gil::const_view(img), kernel_up_left_offset,
+ gil::view(img_out_up_left_offset), gil::boundary_option::extend_reflection);
+
+ auto const kernel_down_right_offset = fixture::create_kernel<channel_t>(
+ {0, 0, 1, 0, 0, 0, 0, 0, 0});
+ gil::detail::convolve_1d<pixel_t>(gil::const_view(img), kernel_down_right_offset, 
+ gil::view(img_out_down_right_offset), gil::boundary_option::extend_reflection);
+
+ BOOST_TEST(gil::equal_pixels(gil::const_view(img_out_up_left_offset), 
+ gil::const_view(img_expected_col_left_offset)));
+ BOOST_TEST(gil::equal_pixels(gil::const_view(img_out_down_right_offset), 
+ gil::const_view(img_expected_col_right_offset)));
+ }
+ static void run()
+ {
+ boost::mp11::mp_for_each<fixture::image_types>(
+ test_image_5x5_kernel_1x9_boundary_extend_reflection{});
+ }
+};
+
 int main()
 {
  test_image_1x1_kernel_1x1_identity::run();
  test_image_1x1_kernel_3x3_identity::run();
  test_image_3x3_kernel_3x3_identity::run();
  test_image_5x5_kernel_3x3_identity::run();
 
+ test_image_5x5_kernel_1x9_boundary_extend_reflection::run();
  return ::boost::report_errors();
 }

test/core/image_processing/convolve_cols.cpp

@@ -1,6 +1,7 @@
 //
 // Copyright 2019-2020 Mateusz Loskot <mateusz at loskot dot net>
 // Copyright 2021 Pranam Lashkari <[email protected]>
+// Copyright 2021 Prathamesh Tagore <[email protected]>
 //
 // Distributed under the Boost Software License, Version 1.0
 // See accompanying file LICENSE_1_0.txt or copy at
@@ -65,10 +66,61 @@ struct test_image_1x1_kernel_3x3_identity
  }
 };
 
+struct test_image_5x5_kernel_1x9_boundary_extend_reflection
+{
+ template <typename Image>
+ void operator()(Image const&)
+ {
+ using image_t = Image;
+ using pixel_t = typename image_t::value_type;
+ using channel_t = typename gil::channel_type<pixel_t>::type;
+ auto img = fixture::generate_image<image_t>(5, 5, fixture::random_value<channel_t>{});
+ auto img_view = gil::view(img);
+ image_t img_out_left_offset(img), img_expected_left_offset(img);
+ image_t img_out_right_offset(img), img_expected_right_offset(img);
+ int kernel_shift_left_offset = 2, kernel_shift_right_offset = -2;
+
+ fixture::col_conv1D_offset_img_generator(img_view, gil::view(img_expected_left_offset),
+ kernel_shift_left_offset);
+ fixture::col_conv1D_offset_img_generator(img_view, gil::view(img_expected_left_offset),
+ -1, 1, 0, 1, img_view.width());
+ fixture::col_conv1D_offset_img_generator(img_view, gil::view(img_expected_left_offset),
+ 1, 0, 0, 2, img_view.width());
+
+ fixture::col_conv1D_offset_img_generator(img_view, gil::view(img_expected_right_offset), 
+ kernel_shift_right_offset, 2, 0, img_view.height(), img_view.width());
+ fixture::col_conv1D_offset_img_generator(img_view, gil::view(img_expected_right_offset),
+ -1, img_view.height() - 1, 0, img_view.height(), img_view.width());
+ fixture::col_conv1D_offset_img_generator(img_view, gil::view(img_expected_right_offset),
+ 1, img_view.height() - 2, 0, img_view.height(), img_view.width());
+
+ auto const kernel_left_offset = fixture::create_kernel<channel_t>(
+ {0, 0, 0, 0, 0, 0, 1, 0, 0});
+ gil::convolve_cols<pixel_t>(gil::const_view(img), kernel_left_offset,
+ gil::view(img_out_left_offset), gil::boundary_option::extend_reflection);
+
+ auto const kernel_right_offset = fixture::create_kernel<channel_t>(
+ {0, 0, 1, 0, 0, 0, 0, 0, 0});
+ gil::convolve_cols<pixel_t>(gil::const_view(img), kernel_right_offset,
+ gil::view(img_out_right_offset), gil::boundary_option::extend_reflection);
+
+ BOOST_TEST(gil::equal_pixels(gil::const_view(img_out_left_offset),
+ gil::const_view(img_expected_left_offset)));
+ BOOST_TEST(gil::equal_pixels(gil::const_view(img_out_right_offset),
+ gil::const_view(img_expected_right_offset)));
+ }
+ static void run()
+ {
+ boost::mp11::mp_for_each<fixture::image_types>(
+ test_image_5x5_kernel_1x9_boundary_extend_reflection{});
+ }
+};
+
 int main()
 {
  test_image_1x1_kernel_1x1_identity::run();
  test_image_1x1_kernel_3x3_identity::run();
 
+ test_image_5x5_kernel_1x9_boundary_extend_reflection::run();
  return ::boost::report_errors();
 }

test/core/image_processing/convolve_rows.cpp

@@ -1,6 +1,7 @@
 //
 // Copyright 2019-2020 Mateusz Loskot <mateusz at loskot dot net>
 // Copyright 2021 Pranam Lashkari <[email protected]>
+// Copyright 2021 Prathamesh Tagore <[email protected]>
 //
 // Distributed under the Boost Software License, Version 1.0
 // See accompanying file LICENSE_1_0.txt or copy at
@@ -65,10 +66,61 @@ struct test_image_1x1_kernel_3x3_identity
  }
 };
 
+struct test_image_5x5_kernel_1x9_boundary_extend_reflection
+{
+ template <typename Image>
+ void operator()(Image const&)
+ {
+ using image_t = Image;
+ using pixel_t = typename image_t::value_type;
+ using channel_t = typename gil::channel_type<pixel_t>::type;
+ auto img = fixture::generate_image<image_t>(5, 5, fixture::random_value<channel_t>{});
+ auto img_view = gil::view(img);
+ image_t img_out_up_offset(img), img_expected_up_offset(img);
+ image_t img_out_down_offset(img), img_expected_down_offset(img);
+ int kernel_shift_up_offset = 2, kernel_shift_down_offset = -2;
+
+ fixture::row_conv1D_offset_img_generator(img_view, gil::view(img_expected_up_offset),
+ kernel_shift_up_offset);
+ fixture::row_conv1D_offset_img_generator(img_view, gil::view(img_expected_up_offset),
+ -1, 0, 1, img_view.height(), 1);
+ fixture::row_conv1D_offset_img_generator(img_view, gil::view(img_expected_up_offset),
+ 1, 0, 0, img_view.height(), 2);
+
+ fixture::row_conv1D_offset_img_generator(img_view, gil::view(img_expected_down_offset),
+ kernel_shift_down_offset, 0, 2, img_view.height(), img_view.width());
+ fixture::row_conv1D_offset_img_generator(img_view, gil::view(img_expected_down_offset),
+ -1, 0, img_view.width() - 1, img_view.height(), img_view.width());
+ fixture::row_conv1D_offset_img_generator(img_view, gil::view(img_expected_down_offset),
+ 1, 0, img_view.width() - 2, img_view.height(), img_view.width());
+
+ auto const kernel_up_offset = fixture::create_kernel<channel_t>(
+ {0, 0, 0, 0, 0, 0, 1, 0, 0});
+ gil::convolve_rows<pixel_t>(gil::const_view(img), kernel_up_offset, 
+ gil::view(img_out_up_offset), gil::boundary_option::extend_reflection);
+
+ auto const kernel_down_offset = fixture::create_kernel<channel_t>(
+ {0, 0, 1, 0, 0, 0, 0, 0, 0});
+ gil::convolve_rows<pixel_t>(gil::const_view(img), kernel_down_offset, 
+ gil::view(img_out_down_offset), gil::boundary_option::extend_reflection);
+
+ BOOST_TEST(gil::equal_pixels(gil::const_view(img_out_up_offset),
+ gil::const_view(img_expected_up_offset)));
+ BOOST_TEST(gil::equal_pixels(gil::const_view(img_out_down_offset), 
+ gil::const_view(img_expected_down_offset)));
+ }
+ static void run()
+ {
+ boost::mp11::mp_for_each<fixture::image_types>(
+ test_image_5x5_kernel_1x9_boundary_extend_reflection{});
+ }
+};
+
 int main()
 {
  test_image_1x1_kernel_1x1_identity::run();
  test_image_1x1_kernel_3x3_identity::run();
 
+ test_image_5x5_kernel_1x9_boundary_extend_reflection::run();
  return ::boost::report_errors();
 }

test/core/image_processing/test_fixture.hpp

@@ -1,6 +1,7 @@
 //
 // Copyright 2019 Mateusz Loskot <mateusz at loskot dot net>
 // Copyright 2021 Pranam Lashkari <[email protected]>
+// Copyright 2021 Prathamesh Tagore <[email protected]>
 //
 // Distributed under the Boost Software License, Version 1.0
 // See accompanying file LICENSE_1_0.txt or copy at
@@ -28,4 +29,58 @@ auto create_kernel(std::initializer_list<T> const& values)
  return kernel;
 }
 
+// Adds an offset similar to 1D row convolution with kernel {0, 0, 0, 0, 0, 0, 1, 0, 0} 
+// (for offset = 2) having its anchor point at 5th element and boundary option as "extend_zero".
+template <typename SrcView, typename DstView>
+void row_conv1D_offset_img_generator(SrcView src_view, DstView dst_view, int const offset,
+ std::ptrdiff_t start_row = 0, std::ptrdiff_t start_col = 0, std::ptrdiff_t end_row = -1,
+ std::ptrdiff_t end_col = -1)
+{
+ BOOST_ASSERT(src_view.dimensions() == dst_view.dimensions());
+ static_assert(color_spaces_are_compatible
+ <
+ typename color_space_type<SrcView>::type,
+ typename color_space_type<DstView>::type
+ >::value, "Source and destination views must have pixels with the same color space");
+
+ if (end_row == -1)
+ end_row = src_view.height();
+ if (end_col == -1)
+ end_col = src_view.width();
+ for (std::ptrdiff_t y = start_row; y < end_row; ++y)
+ {
+ auto src_it = src_view.row_begin(y);
+ auto dst_it = dst_view.row_begin(y);
+ for (std::ptrdiff_t x = offset + start_col; x < end_col; ++x)
+ dst_it[x] = src_it[x - offset];
+ }
+}
+
+// Adds an offset similar to 1D column convolution with kernel {0, 0, 0, 0, 0, 0, 1, 0, 0} 
+// (for offset = 2) having its anchor point at 5th element and boundary option as "extend_zero".
+template <typename SrcView, typename DstView>
+void col_conv1D_offset_img_generator(SrcView src_view, DstView dst_view, int const offset,
+ std::ptrdiff_t start_row = 0, std::ptrdiff_t start_col = 0, std::ptrdiff_t end_row = -1,
+ std::ptrdiff_t end_col = -1)
+{
+ BOOST_ASSERT(src_view.dimensions() == dst_view.dimensions());
+ static_assert(color_spaces_are_compatible
+ <
+ typename color_space_type<SrcView>::type,
+ typename color_space_type<DstView>::type
+ >::value, "Source and destination views must have pixels with the same color space");
+
+ if (end_row == -1)
+ end_row = src_view.height();
+ if (end_col == -1)
+ end_col = src_view.width();
+ for (std::ptrdiff_t x = start_col; x < end_col; ++x)
+ {
+ auto src_it = src_view.col_begin(x);
+ auto dst_it = dst_view.col_begin(x);
+ for (std::ptrdiff_t y = offset + start_row; y < end_row; ++y)
+ dst_it[y] = src_it[y - offset];
+ }
+}
+
 }}}} // namespace boost::gil::test::fixture