1 #ifndef BOOST_GIL_IMAGE_PROCESSING_HESSIAN_HPP 2 #define BOOST_GIL_IMAGE_PROCESSING_HESSIAN_HPP 4 #include <boost/gil/image_view.hpp> 5 #include <boost/gil/typedefs.hpp> 6 #include <boost/gil/extension/numeric/kernel.hpp> 9 namespace boost {
namespace gil {
19 template <
typename GradientView,
typename T,
typename Allocator,
typename OutputView>
20 inline void compute_hessian_responses(
24 const detail::kernel_2d<T, Allocator>& weights,
27 if (ddxx.dimensions() != ddyy.dimensions()
28 || ddyy.dimensions() != dxdy.dimensions()
29 || dxdy.dimensions() != dst.dimensions()
30 || weights.center_x() != weights.center_y())
32 throw std::invalid_argument(
"dimensions of views are not the same" 33 " or weights don't have equal width and height" 34 " or weights' dimensions are not odd");
37 using pixel_t =
typename std::remove_reference<decltype(std::declval<OutputView>()(0, 0))>::type;
39 using channel_t =
typename std::remove_reference
41 decltype(std::declval<pixel_t>().at(std::integral_constant<int, 0>{}))
45 auto center = weights.center_y();
46 for (
auto y = center; y < dst.height() - center; ++y)
48 for (
auto x = center; x < dst.width() - center; ++x)
50 auto ddxx_i = channel_t();
51 auto ddyy_i = channel_t();
52 auto dxdy_i = channel_t();
53 for (
typename OutputView::coord_t w_y = 0; w_y < weights.size(); ++w_y)
55 for (
typename OutputView::coord_t w_x = 0; w_x < weights.size(); ++w_x)
57 ddxx_i += ddxx(x + w_x - center, y + w_y - center)
58 .at(std::integral_constant<int, 0>{}) * weights.at(w_x, w_y);
59 ddyy_i += ddyy(x + w_x - center, y + w_y - center)
60 .at(std::integral_constant<int, 0>{}) * weights.at(w_x, w_y);
61 dxdy_i += dxdy(x + w_x - center, y + w_y - center)
62 .at(std::integral_constant<int, 0>{}) * weights.at(w_x, w_y);
65 auto determinant = ddxx_i * ddyy_i - dxdy_i * dxdy_i;
66 dst(x, y).at(std::integral_constant<int, 0>{}) = determinant;