1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
|
/*
Copyright (C) 2014-2019 Carl Hetherington <cth@carlh.net>
This file is part of libdcp.
libdcp is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
libdcp is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with libdcp. If not, see <http://www.gnu.org/licenses/>.
In addition, as a special exception, the copyright holders give
permission to link the code of portions of this program with the
OpenSSL library under certain conditions as described in each
individual source file, and distribute linked combinations
including the two.
You must obey the GNU General Public License in all respects
for all of the code used other than OpenSSL. If you modify
file(s) with this exception, you may extend this exception to your
version of the file(s), but you are not obligated to do so. If you
do not wish to do so, delete this exception statement from your
version. If you delete this exception statement from all source
files in the program, then also delete it here.
*/
#include "gamma_transfer_function.h"
#include "colour_conversion.h"
#include "modified_gamma_transfer_function.h"
#include <boost/test/unit_test.hpp>
#include <cmath>
using std::pow;
using std::shared_ptr;
using namespace dcp;
static void
check_gamma (shared_ptr<const TransferFunction> tf, int bit_depth, bool inverse, float gamma)
{
auto lut = tf->double_lut(0, 1, bit_depth, inverse);
int const count = rint (pow (2.0, bit_depth));
for (int i = 0; i < count; ++i) {
BOOST_CHECK_CLOSE (lut[i], pow (float(i) / (count - 1), gamma), 0.001);
}
}
static void
check_modified_gamma (shared_ptr<const TransferFunction> tf, int bit_depth, bool inverse, double power, double threshold, double A, double B)
{
auto lut = tf->double_lut(0, 1, bit_depth, inverse);
int const count = rint (pow (2.0, bit_depth));
for (int i = 0; i < count; ++i) {
double const x = double(i) / (count - 1);
if (x > threshold) {
BOOST_CHECK_CLOSE (lut[i], pow ((x + A) / (1 + A), power), 0.001);
} else {
BOOST_CHECK_CLOSE (lut[i], (x / B), 0.001);
}
}
}
/** Check that the gamma correction LUTs are right for sRGB */
BOOST_AUTO_TEST_CASE (colour_conversion_test1)
{
ColourConversion cc = ColourConversion::srgb_to_xyz ();
check_modified_gamma (cc.in(), 8, false, 2.4, 0.04045, 0.055, 12.92);
check_modified_gamma (cc.in(), 12, false, 2.4, 0.04045, 0.055, 12.92);
check_modified_gamma (cc.in(), 16, false, 2.4, 0.04045, 0.055, 12.92);
check_gamma (cc.out(), 8, true, 1 / 2.6);
check_gamma (cc.out(), 12, true, 1 / 2.6);
check_gamma (cc.out(), 16, true, 1 / 2.6);
}
/** Check that the gamma correction LUTs are right for REC709 */
BOOST_AUTO_TEST_CASE (colour_conversion_test2)
{
ColourConversion cc = ColourConversion::rec709_to_xyz ();
check_gamma (cc.in(), 8, false, 2.2);
check_gamma (cc.in(), 12, false, 2.2);
check_gamma (cc.in(), 16, false, 2.2);
check_gamma (cc.out(), 8, true, 1 / 2.6);
check_gamma (cc.out(), 12, true, 1 / 2.6);
check_gamma (cc.out(), 16, true, 1 / 2.6);
}
/** Check that the xyz_to_rgb matrix is the inverse of the rgb_to_xyz one */
BOOST_AUTO_TEST_CASE (colour_conversion_matrix_test)
{
ColourConversion c = ColourConversion::srgb_to_xyz ();
boost::numeric::ublas::matrix<double> A = c.rgb_to_xyz ();
boost::numeric::ublas::matrix<double> B = c.xyz_to_rgb ();
BOOST_CHECK_CLOSE (A(0, 0) * B(0, 0) + A(0, 1) * B(1, 0) + A(0, 2) * B(2, 0), 1, 0.1);
BOOST_CHECK (fabs (A(0, 0) * B(0, 1) + A(0, 1) * B(1, 1) + A(0, 2) * B(2, 1)) < 1e-6);
BOOST_CHECK (fabs (A(0, 0) * B(0, 2) + A(0, 1) * B(1, 2) + A(0, 2) * B(2, 2)) < 1e-6);
BOOST_CHECK (fabs (A(1, 0) * B(0, 0) + A(1, 1) * B(1, 0) + A(1, 2) * B(2, 0)) < 1e-6);
BOOST_CHECK_CLOSE (A(1, 0) * B(0, 1) + A(1, 1) * B(1, 1) + A(1, 2) * B(2, 1), 1, 0.1);
BOOST_CHECK (fabs (A(1, 0) * B(0, 2) + A(1, 1) * B(1, 2) + A(1, 2) * B(2, 2)) < 1e-6);
BOOST_CHECK (fabs (A(2, 0) * B(0, 0) + A(2, 1) * B(1, 0) + A(2, 2) * B(2, 0)) < 1e-6);
BOOST_CHECK (fabs (A(2, 0) * B(0, 1) + A(2, 1) * B(1, 1) + A(2, 2) * B(2, 1)) < 1e-6);
BOOST_CHECK_CLOSE (A(2, 0) * B(0, 2) + A(2, 1) * B(1, 2) + A(2, 2) * B(2, 2), 1, 0.1);
}
BOOST_AUTO_TEST_CASE (colour_conversion_bradford_test)
{
ColourConversion c = ColourConversion::srgb_to_xyz ();
/* CIE "A" illuminant from http://www.brucelindbloom.com/index.html?Eqn_ChromAdapt.html
un-normalised using a factor k where k = 1 / (1 + x + z)
*/
c.set_adjusted_white (Chromaticity (0.447576324, 0.407443172));
boost::numeric::ublas::matrix<double> b = c.bradford ();
/* Check the conversion matrix against the one quoted on brucelindbloom.com */
BOOST_CHECK_CLOSE (b(0, 0), 1.2164557, 0.1);
BOOST_CHECK_CLOSE (b(0, 1), 0.1109905, 0.1);
BOOST_CHECK_CLOSE (b(0, 2), -0.1549325, 0.1);
BOOST_CHECK_CLOSE (b(1, 0), 0.1533326, 0.1);
BOOST_CHECK_CLOSE (b(1, 1), 0.9152313, 0.1);
BOOST_CHECK_CLOSE (b(1, 2), -0.0559953, 0.1);
BOOST_CHECK_CLOSE (b(2, 0), -0.0239469, 0.1);
BOOST_CHECK_CLOSE (b(2, 1), 0.0358984, 0.1);
BOOST_CHECK_CLOSE (b(2, 2), 0.3147529, 0.1);
/* Same for CIE "B" illuminant */
c.set_adjusted_white (Chromaticity (0.99072 * 0.351747305, 0.351747305));
b = c.bradford ();
BOOST_CHECK_CLOSE (b(0, 0), 1.0641402, 0.1);
BOOST_CHECK_CLOSE (b(0, 1), 0.0325780, 0.1);
BOOST_CHECK_CLOSE (b(0, 2), -0.0489436, 0.1);
BOOST_CHECK_CLOSE (b(1, 0), 0.0446103, 0.1);
BOOST_CHECK_CLOSE (b(1, 1), 0.9766379, 0.1);
BOOST_CHECK_CLOSE (b(1, 2), -0.0174854, 0.1);
BOOST_CHECK_CLOSE (b(2, 0), -0.0078485, 0.1);
BOOST_CHECK_CLOSE (b(2, 1), 0.0119945, 0.1);
BOOST_CHECK_CLOSE (b(2, 2), 0.7785377, 0.1);
}
|
