Generic Image Library: harris.hpp Source File

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harris.hpp
1//
2// Copyright 2019 Olzhas Zhumabek <anonymous.from.applecity@gmail.com>
3//
4// Use, modification and distribution are subject to the Boost Software License,
5// Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
6// http://www.boost.org/LICENSE_1_0.txt)
7//
8#ifndef BOOST_GIL_IMAGE_PROCESSING_HARRIS_HPP
9#define BOOST_GIL_IMAGE_PROCESSING_HARRIS_HPP
10
11#include <boost/gil/image_view.hpp>
12#include <boost/gil/typedefs.hpp>
13#include <boost/gil/image_processing/kernel.hpp>
14
15namespace boost { namespace gil {
21
22
33template <typename T, typename Allocator>
34 void compute_harris_responses(
35 boost::gil::gray32f_view_t m11,
36 boost::gil::gray32f_view_t m12_21,
37 boost::gil::gray32f_view_t m22,
38 boost::gil::detail::kernel_2d<T, Allocator> weights,
39 float k,
40 boost::gil::gray32f_view_t harris_response)
41{
42 if (m11.dimensions() != m12_21.dimensions() || m12_21.dimensions() != m22.dimensions()) {
43 throw std::invalid_argument("m prefixed arguments must represent"
44 " tensor from the same image");
45 }
46
47 std::ptrdiff_t const window_length = weights.size();
48 auto const width = m11.width();
49 auto const height = m11.height();
50 auto const half_length = window_length / 2;
51
52 for (auto y = half_length; y < height - half_length; ++y)
53 {
54 for (auto x = half_length; x < width - half_length; ++x)
55 {
56 float ddxx = 0;
57 float dxdy = 0;
58 float ddyy = 0;
59 for (gil::gray32f_view_t::coord_t y_kernel = 0;
60 y_kernel < window_length;
61 ++y_kernel) {
62 for (gil::gray32f_view_t::coord_t x_kernel = 0;
63 x_kernel < window_length;
64 ++x_kernel) {
65 ddxx += m11(x + x_kernel - half_length, y + y_kernel - half_length)
66 .at(std::integral_constant<int, 0>{}) * weights.at(x_kernel, y_kernel);
67 dxdy += m12_21(x + x_kernel - half_length, y + y_kernel - half_length)
68 .at(std::integral_constant<int, 0>{}) * weights.at(x_kernel, y_kernel);
69 ddyy += m22(x + x_kernel - half_length, y + y_kernel - half_length)
70 .at(std::integral_constant<int, 0>{}) * weights.at(x_kernel, y_kernel);
71 }
72 }
73 auto det = (ddxx * ddyy) - dxdy * dxdy;
74 auto trace = ddxx + ddyy;
75 auto harris_value = det - k * trace * trace;
76 harris_response(x, y).at(std::integral_constant<int, 0>{}) = harris_value;
77 }
78 }
79}
80
81}} //namespace boost::gil
82#endif
boost::gil::detail::kernel_2d
variable-size kernel
Definition kernel.hpp:273
boost::gil::compute_harris_responses
void compute_harris_responses(boost::gil::gray32f_view_t m11, boost::gil::gray32f_view_t m12_21, boost::gil::gray32f_view_t m22, boost::gil::detail::kernel_2d< T, Allocator > weights, float k, boost::gil::gray32f_view_t harris_response)
function to record Harris responses
Definition harris.hpp:34
boost
defined(BOOST_NO_CXX17_HDR_MEMORY_RESOURCE)
Definition algorithm.hpp:36