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
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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 ()
137 static ColourConversion* c = new ColourConversion (
138 shared_ptr<const TransferFunction> (new GammaTransferFunction (2.4)),
140 Chromaticity (0.708, 0.292),
141 Chromaticity (0.170, 0.797),
142 Chromaticity (0.131, 0.046),
144 Chromaticity (0.3127, 0.329),
145 optional<Chromaticity> (),
146 shared_ptr<const TransferFunction> (new GammaTransferFunction (2.6))
151 ColourConversion::ColourConversion (
152 shared_ptr<const TransferFunction> in,
158 optional<Chromaticity> adjusted_white,
159 shared_ptr<const TransferFunction> out
162 , _yuv_to_rgb (yuv_to_rgb)
167 , _adjusted_white (adjusted_white)
174 ColourConversion::about_equal (ColourConversion const & other, float epsilon) const
176 if (!_in->about_equal (other._in, epsilon) ||
177 _yuv_to_rgb != other._yuv_to_rgb ||
178 !_red.about_equal (other._red, epsilon) ||
179 !_green.about_equal (other._green, epsilon) ||
180 !_blue.about_equal (other._blue, epsilon) ||
181 !_white.about_equal (other._white, epsilon) ||
182 !_out->about_equal (other._out, epsilon)) {
186 if (!_adjusted_white && !other._adjusted_white) {
191 _adjusted_white && other._adjusted_white &&
192 fabs (_adjusted_white.get().x - other._adjusted_white.get().x) < epsilon &&
193 fabs (_adjusted_white.get().y - other._adjusted_white.get().y) < epsilon
198 /* Otherwise one has an adjusted white and other hasn't, or they both have but different */
202 boost::numeric::ublas::matrix<double>
203 ColourConversion::rgb_to_xyz () const
205 /* See doc/design/colour.tex */
207 double const D = (_red.x - _white.x) * (_white.y - _blue.y) - (_white.x - _blue.x) * (_red.y - _white.y);
208 double const E = (_white.x - _green.x) * (_red.y - _white.y) - (_red.x - _white.x) * (_white.y - _green.y);
209 double const F = (_white.x - _green.x) * (_white.y - _blue.y) - (_white.x - _blue.x) * (_white.y - _green.y);
210 double const P = _red.y + _green.y * D / F + _blue.y * E / F;
212 boost::numeric::ublas::matrix<double> C (3, 3);
213 C(0, 0) = _red.x / P;
214 C(0, 1) = _green.x * D / (F * P);
215 C(0, 2) = _blue.x * E / (F * P);
216 C(1, 0) = _red.y / P;
217 C(1, 1) = _green.y * D / (F * P);
218 C(1, 2) = _blue.y * E / (F * P);
219 C(2, 0) = _red.z() / P;
220 C(2, 1) = _green.z() * D / (F * P);
221 C(2, 2) = _blue.z() * E / (F * P);
225 boost::numeric::ublas::matrix<double>
226 ColourConversion::xyz_to_rgb () const
228 boost::numeric::ublas::matrix<double> A (rgb_to_xyz ());
230 /* permutation matrix for the LU-factorization */
231 boost::numeric::ublas::permutation_matrix<std::size_t> pm (A.size1 ());
233 /* perform LU-factorization */
234 int const r = lu_factorize (A, pm);
237 /* create identity matrix of inverse */
238 boost::numeric::ublas::matrix<double> xyz_to_rgb (3, 3);
239 xyz_to_rgb.assign (boost::numeric::ublas::identity_matrix<double> (A.size1 ()));
241 /* backsubstitute to get the inverse */
242 lu_substitute (A, pm, xyz_to_rgb);
247 boost::numeric::ublas::matrix<double>
248 ColourConversion::bradford () const
250 if (!_adjusted_white || fabs (_adjusted_white.get().x) < 1e-6 || fabs (_adjusted_white.get().y) < 1e-6) {
251 boost::numeric::ublas::matrix<double> B = boost::numeric::ublas::zero_matrix<double> (3, 3);
258 /* See doc/design/colour.tex */
260 boost::numeric::ublas::matrix<double> M (3, 3);
271 boost::numeric::ublas::matrix<double> Mi (3, 3);
272 Mi(0, 0) = 0.9869929055;
273 Mi(0, 1) = -0.1470542564;
274 Mi(0, 2) = 0.1599626517;
275 Mi(1, 0) = 0.4323052697;
276 Mi(1, 1) = 0.5183602715;
277 Mi(1, 2) = 0.0492912282;
278 Mi(2, 0) = -0.0085286646;
279 Mi(2, 1) = 0.0400428217;
280 Mi(2, 2) = 0.9684866958;
282 boost::numeric::ublas::matrix<double> Gp (3, 1);
283 Gp(0, 0) = _white.x / _white.y;
285 Gp(2, 0) = (1 - _white.x - _white.y) / _white.y;
287 boost::numeric::ublas::matrix<double> G = boost::numeric::ublas::prod (M, Gp);
289 boost::numeric::ublas::matrix<double> Hp (3, 1);
290 Hp(0, 0) = _adjusted_white.get().x / _adjusted_white.get().y;
292 Hp(2, 0) = (1 - _adjusted_white.get().x - _adjusted_white.get().y) / _adjusted_white.get().y;
294 boost::numeric::ublas::matrix<double> H = boost::numeric::ublas::prod (M, Hp);
296 boost::numeric::ublas::matrix<double> C = boost::numeric::ublas::zero_matrix<double> (3, 3);
297 C(0, 0) = H(0, 0) / G(0, 0);
298 C(1, 1) = H(1, 0) / G(1, 0);
299 C(2, 2) = H(2, 0) / G(2, 0);
301 boost::numeric::ublas::matrix<double> CM = boost::numeric::ublas::prod (C, M);
302 return boost::numeric::ublas::prod (Mi, CM);