2 Copyright (C) 2014-2015 Carl Hetherington <cth@carlh.net>
4 This file is part of libdcp.
6 libdcp is free software; you can redistribute it and/or modify
7 it under the terms of the GNU General Public License as published by
8 the Free Software Foundation; either version 2 of the License, or
9 (at your option) any later version.
11 libdcp is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 GNU General Public License for more details.
16 You should have received a copy of the GNU General Public License
17 along with libdcp. If not, see <http://www.gnu.org/licenses/>.
19 In addition, as a special exception, the copyright holders give
20 permission to link the code of portions of this program with the
21 OpenSSL library under certain conditions as described in each
22 individual source file, and distribute linked combinations
25 You must obey the GNU General Public License in all respects
26 for all of the code used other than OpenSSL. If you modify
27 file(s) with this exception, you may extend this exception to your
28 version of the file(s), but you are not obligated to do so. If you
29 do not wish to do so, delete this exception statement from your
30 version. If you delete this exception statement from all source
31 files in the program, then also delete it here.
34 #include "colour_conversion.h"
35 #include "gamma_transfer_function.h"
36 #include "modified_gamma_transfer_function.h"
37 #include "colour_matrix.h"
38 #include "dcp_assert.h"
39 #include <boost/numeric/ublas/matrix.hpp>
40 #include <boost/numeric/ublas/lu.hpp>
41 #include <boost/numeric/ublas/io.hpp>
43 using boost::shared_ptr;
44 using boost::optional;
47 ColourConversion const &
48 ColourConversion::srgb_to_xyz ()
50 static ColourConversion* c = new ColourConversion (
51 shared_ptr<const TransferFunction> (new ModifiedGammaTransferFunction (2.4, 0.04045, 0.055, 12.92)),
53 Chromaticity (0.64, 0.33),
54 Chromaticity (0.3, 0.6),
55 Chromaticity (0.15, 0.06),
57 Chromaticity (0.3127, 0.329),
58 optional<Chromaticity> (),
59 shared_ptr<const TransferFunction> (new GammaTransferFunction (2.6))
64 ColourConversion const &
65 ColourConversion::rec601_to_xyz ()
67 static ColourConversion* c = new ColourConversion (
68 shared_ptr<const TransferFunction> (new GammaTransferFunction (2.2)),
70 Chromaticity (0.64, 0.33),
71 Chromaticity (0.3, 0.6),
72 Chromaticity (0.15, 0.06),
74 Chromaticity (0.3127, 0.329),
75 optional<Chromaticity> (),
76 shared_ptr<const TransferFunction> (new GammaTransferFunction (2.6))
81 ColourConversion const &
82 ColourConversion::rec709_to_xyz ()
84 static ColourConversion* c = new ColourConversion (
85 shared_ptr<const TransferFunction> (new GammaTransferFunction (2.2)),
87 Chromaticity (0.64, 0.33),
88 Chromaticity (0.3, 0.6),
89 Chromaticity (0.15, 0.06),
91 Chromaticity (0.3127, 0.329),
92 optional<Chromaticity> (),
93 shared_ptr<const TransferFunction> (new GammaTransferFunction (2.6))
98 ColourConversion const &
99 ColourConversion::p3_to_xyz ()
101 static ColourConversion* c = new ColourConversion (
102 shared_ptr<const TransferFunction> (new GammaTransferFunction (2.6)),
104 Chromaticity (0.68, 0.32),
105 Chromaticity (0.265, 0.69),
106 Chromaticity (0.15, 0.06),
107 Chromaticity (0.314, 0.351),
108 optional<Chromaticity> (),
109 shared_ptr<const TransferFunction> (new GammaTransferFunction (2.6))
114 ColourConversion const &
115 ColourConversion::rec1886_to_xyz ()
117 /* According to Olivier on DCP-o-matic bug #832, Rec. 1886 is Rec. 709 with
118 2.4 gamma, so here goes ...
120 static ColourConversion* c = new ColourConversion (
121 shared_ptr<const TransferFunction> (new GammaTransferFunction (2.4)),
123 Chromaticity (0.64, 0.33),
124 Chromaticity (0.3, 0.6),
125 Chromaticity (0.15, 0.06),
127 Chromaticity (0.3127, 0.329),
128 optional<Chromaticity> (),
129 shared_ptr<const TransferFunction> (new GammaTransferFunction (2.6))
134 ColourConversion const &
135 ColourConversion::rec2020_to_xyz ()
138 static ColourConversion* c = new ColourConversion (
139 shared_ptr<const TransferFunction> (new ModifiedGammaTransferFunction (1 / 0.45, 0.08145, 0.0993, 4.5)),
141 Chromaticity (0.708, 0.292),
142 Chromaticity (0.170, 0.797),
143 Chromaticity (0.131, 0.046),
145 Chromaticity (0.3127, 0.329),
146 optional<Chromaticity> (),
147 shared_ptr<const TransferFunction> (new GammaTransferFunction (2.6))
152 ColourConversion::ColourConversion (
153 shared_ptr<const TransferFunction> in,
159 optional<Chromaticity> adjusted_white,
160 shared_ptr<const TransferFunction> out
163 , _yuv_to_rgb (yuv_to_rgb)
168 , _adjusted_white (adjusted_white)
175 ColourConversion::about_equal (ColourConversion const & other, float epsilon) const
177 if (!_in->about_equal (other._in, epsilon) ||
178 _yuv_to_rgb != other._yuv_to_rgb ||
179 !_red.about_equal (other._red, epsilon) ||
180 !_green.about_equal (other._green, epsilon) ||
181 !_blue.about_equal (other._blue, epsilon) ||
182 !_white.about_equal (other._white, epsilon) ||
183 !_out->about_equal (other._out, epsilon)) {
187 if (!_adjusted_white && !other._adjusted_white) {
192 _adjusted_white && other._adjusted_white &&
193 fabs (_adjusted_white.get().x - other._adjusted_white.get().x) < epsilon &&
194 fabs (_adjusted_white.get().y - other._adjusted_white.get().y) < epsilon
199 /* Otherwise one has an adjusted white and other hasn't, or they both have but different */
203 boost::numeric::ublas::matrix<double>
204 ColourConversion::rgb_to_xyz () const
206 /* See doc/design/colour.tex */
208 double const D = (_red.x - _white.x) * (_white.y - _blue.y) - (_white.x - _blue.x) * (_red.y - _white.y);
209 double const E = (_white.x - _green.x) * (_red.y - _white.y) - (_red.x - _white.x) * (_white.y - _green.y);
210 double const F = (_white.x - _green.x) * (_white.y - _blue.y) - (_white.x - _blue.x) * (_white.y - _green.y);
211 double const P = _red.y + _green.y * D / F + _blue.y * E / F;
213 boost::numeric::ublas::matrix<double> C (3, 3);
214 C(0, 0) = _red.x / P;
215 C(0, 1) = _green.x * D / (F * P);
216 C(0, 2) = _blue.x * E / (F * P);
217 C(1, 0) = _red.y / P;
218 C(1, 1) = _green.y * D / (F * P);
219 C(1, 2) = _blue.y * E / (F * P);
220 C(2, 0) = _red.z() / P;
221 C(2, 1) = _green.z() * D / (F * P);
222 C(2, 2) = _blue.z() * E / (F * P);
226 boost::numeric::ublas::matrix<double>
227 ColourConversion::xyz_to_rgb () const
229 boost::numeric::ublas::matrix<double> A (rgb_to_xyz ());
231 /* permutation matrix for the LU-factorization */
232 boost::numeric::ublas::permutation_matrix<std::size_t> pm (A.size1 ());
234 /* perform LU-factorization */
235 int const r = lu_factorize (A, pm);
238 /* create identity matrix of inverse */
239 boost::numeric::ublas::matrix<double> xyz_to_rgb (3, 3);
240 xyz_to_rgb.assign (boost::numeric::ublas::identity_matrix<double> (A.size1 ()));
242 /* backsubstitute to get the inverse */
243 lu_substitute (A, pm, xyz_to_rgb);
248 boost::numeric::ublas::matrix<double>
249 ColourConversion::bradford () const
251 if (!_adjusted_white || fabs (_adjusted_white.get().x) < 1e-6 || fabs (_adjusted_white.get().y) < 1e-6) {
252 boost::numeric::ublas::matrix<double> B = boost::numeric::ublas::zero_matrix<double> (3, 3);
259 /* See doc/design/colour.tex */
261 boost::numeric::ublas::matrix<double> M (3, 3);
272 boost::numeric::ublas::matrix<double> Mi (3, 3);
273 Mi(0, 0) = 0.9869929055;
274 Mi(0, 1) = -0.1470542564;
275 Mi(0, 2) = 0.1599626517;
276 Mi(1, 0) = 0.4323052697;
277 Mi(1, 1) = 0.5183602715;
278 Mi(1, 2) = 0.0492912282;
279 Mi(2, 0) = -0.0085286646;
280 Mi(2, 1) = 0.0400428217;
281 Mi(2, 2) = 0.9684866958;
283 boost::numeric::ublas::matrix<double> Gp (3, 1);
284 Gp(0, 0) = _white.x / _white.y;
286 Gp(2, 0) = (1 - _white.x - _white.y) / _white.y;
288 boost::numeric::ublas::matrix<double> G = boost::numeric::ublas::prod (M, Gp);
290 boost::numeric::ublas::matrix<double> Hp (3, 1);
291 Hp(0, 0) = _adjusted_white.get().x / _adjusted_white.get().y;
293 Hp(2, 0) = (1 - _adjusted_white.get().x - _adjusted_white.get().y) / _adjusted_white.get().y;
295 boost::numeric::ublas::matrix<double> H = boost::numeric::ublas::prod (M, Hp);
297 boost::numeric::ublas::matrix<double> C = boost::numeric::ublas::zero_matrix<double> (3, 3);
298 C(0, 0) = H(0, 0) / G(0, 0);
299 C(1, 1) = H(1, 0) / G(1, 0);
300 C(2, 2) = H(2, 0) / G(2, 0);
302 boost::numeric::ublas::matrix<double> CM = boost::numeric::ublas::prod (C, M);
303 return boost::numeric::ublas::prod (Mi, CM);