Coverage for models/ragoo2021.py: 8%

1""" 

2Ragoo and Farup (2021) Optimised IPT Colourspace 

3================================================ 

4 

5Define the *Ragoo and Farup (2021)* *Optimised IPT* colourspace 

6transformations. 

7 

8- :func:`colour.XYZ_to_IPT_Ragoo2021` 

9- :func:`colour.IPT_Ragoo2021_to_XYZ` 

10 

11References 

12---------- 

13- :cite:`Ragoo2021` : Ragoo, L., & Farup, I. (2021). Optimising a Euclidean 

14 Colour Space Transform for Colour Order and Perceptual Uniformity. 

15 Color and Imaging Conference, 29(1), 282-287. 

16 doi:10.2352/issn.2169-2629.2021.29.282 

17""" 

18 

19from __future__ import annotations 

20 

21from functools import partial 

22 

23import numpy as np 

24 

25from colour.algebra import spow 

26from colour.hints import ( # noqa: TC001 

27 Domain1, 

28 NDArrayFloat, 

29 Range1, 

30) 

31from colour.models import Iab_to_XYZ, XYZ_to_Iab 

32 

33__author__ = "Colour Developers" 

34__copyright__ = "Copyright 2013 Colour Developers" 

35__license__ = "BSD-3-Clause - https://opensource.org/licenses/BSD-3-Clause" 

36__maintainer__ = "Colour Developers" 

37__email__ = "colour-developers@colour-science.org" 

38__status__ = "Production" 

39 

40__all__ = [ 

41 "MATRIX_IPT_XYZ_TO_LMS", 

42 "MATRIX_IPT_LMS_TO_XYZ", 

43 "MATRIX_IPT_LMS_P_TO_IPT", 

44 "MATRIX_IPT_IPT_TO_LMS_P", 

45 "XYZ_to_IPT_Ragoo2021", 

46 "IPT_Ragoo2021_to_XYZ", 

47] 

48 

49MATRIX_IPT_XYZ_TO_LMS: NDArrayFloat = np.array( 

50 [ 

51 [0.4321, 0.6906, -0.0930], 

52 [-0.1793, 1.1458, 0.0226], 

53 [0.0631, 0.1532, 0.7226], 

54 ] 

55) 

56"""*CIE XYZ* tristimulus values to normalised cone responses matrix.""" 

57 

58MATRIX_IPT_LMS_TO_XYZ: NDArrayFloat = np.linalg.inv(MATRIX_IPT_XYZ_TO_LMS) 

59"""Normalised cone responses to *CIE XYZ* tristimulus values matrix.""" 

60 

61MATRIX_IPT_LMS_P_TO_IPT: NDArrayFloat = np.array( 

62 [ 

63 [0.3037, 0.6688, 0.0276], 

64 [3.9247, -4.7339, 0.8093], 

65 [1.5932, -0.5205, -1.0727], 

66 ] 

67) 

68""" 

69Normalised non-linear cone responses to *Ragoo and Farup (2021)* 

70*Optimised IPT* colourspace matrix. 

71""" 

72 

73MATRIX_IPT_IPT_TO_LMS_P: NDArrayFloat = np.linalg.inv(MATRIX_IPT_LMS_P_TO_IPT) 

74""" 

75*Ragoo and Farup (2021)* *Optimised IPT* colourspace to normalised 

76non-linear cone responses matrix. 

77""" 

78 

79 

80def XYZ_to_IPT_Ragoo2021(XYZ: Domain1) -> Range1: 

81 """ 

82 Convert from *CIE XYZ* tristimulus values to *Ragoo and Farup (2021)* 

83 *Optimised IPT* colourspace. 

84 

85 Parameters 

86 ---------- 

87 XYZ 

88 *CIE XYZ* tristimulus values. 

89 

90 Returns 

91 ------- 

92 :class:`numpy.ndarray` 

93 *Ragoo and Farup (2021)* *Optimised IPT* colourspace array. 

94 

95 Notes 

96 ----- 

97 +------------+-----------------------+-----------------+ 

98 | **Domain** | **Scale - Reference** | **Scale - 1** | 

99 +============+=======================+=================+ 

100 | ``XYZ`` | 1 | 1 | 

101 +------------+-----------------------+-----------------+ 

102 

103 +------------+-----------------------+-----------------+ 

104 | **Range** | **Scale - Reference** | **Scale - 1** | 

105 +============+=======================+=================+ 

106 | ``IPT`` | 1 | 1 | 

107 +------------+-----------------------+-----------------+ 

108 

109 - Input *CIE XYZ* tristimulus values must be adapted to 

110 *CIE Standard Illuminant D Series* *D65*. 

111 

112 References 

113 ---------- 

114 :cite:`Ragoo2021` 

115 

116 Examples 

117 -------- 

118 >>> XYZ = np.array([0.20654008, 0.12197225, 0.05136952]) 

119 >>> XYZ_to_IPT_Ragoo2021(XYZ) # doctest: +ELLIPSIS 

120 array([ 0.4224824..., 0.2910514..., 0.2041066...]) 

121 """ 

122 

123 return XYZ_to_Iab( 

124 XYZ, 

125 partial(spow, p=0.4071), 

126 MATRIX_IPT_XYZ_TO_LMS, 

127 MATRIX_IPT_LMS_P_TO_IPT, 

128 ) 

129 

130 

131def IPT_Ragoo2021_to_XYZ( 

132 IPT: Domain1, 

133) -> Range1: 

134 """ 

135 Convert from *Ragoo and Farup (2021)* *Optimised IPT* colourspace to 

136 *CIE XYZ* tristimulus values. 

137 

138 Parameters 

139 ---------- 

140 IPT 

141 *Ragoo and Farup (2021)* *Optimised IPT* colourspace array. 

142 

143 Returns 

144 ------- 

145 :class:`numpy.ndarray` 

146 *CIE XYZ* tristimulus values. 

147 

148 Notes 

149 ----- 

150 +------------+-----------------------+-----------------+ 

151 | **Domain** | **Scale - Reference** | **Scale - 1** | 

152 +============+=======================+=================+ 

153 | ``IPT`` | 1 | 1 | 

154 +------------+-----------------------+-----------------+ 

155 

156 +------------+-----------------------+-----------------+ 

157 | **Range** | **Scale - Reference** | **Scale - 1** | 

158 +============+=======================+=================+ 

159 | ``XYZ`` | 1 | 1 | 

160 +------------+-----------------------+-----------------+ 

161 

162 References 

163 ---------- 

164 :cite:`Ragoo2021` 

165 

166 Examples 

167 -------- 

168 >>> IPT = np.array([0.42248243, 0.2910514, 0.20410663]) 

169 >>> IPT_Ragoo2021_to_XYZ(IPT) # doctest: +ELLIPSIS 

170 array([ 0.2065400..., 0.1219722..., 0.0513695...]) 

171 """ 

172 

173 return Iab_to_XYZ( 

174 IPT, 

175 partial(spow, p=1 / 0.4071), 

176 MATRIX_IPT_IPT_TO_LMS_P, 

177 MATRIX_IPT_LMS_TO_XYZ, 

178 )