Coverage for colour/models/rgb/transfer_functions/xiaomi_mi_log.py: 100%

1""" 

2Xiaomi Mi-Log Profile Log Encoding 

3================================== 

4 

5Define the *Xiaomi Mi-Log Profile* log encoding. 

6 

7- :func:`colour.models.log_encoding_MiLog` 

8- :func:`colour.models.log_decoding_MiLog` 

9 

10References 

11---------- 

12- :cite:`Zhang2024` : Xiaomi Inc. (2024). Xiaomi Log Profile White Paper. 

13 December 2024. 

14""" 

15 

16from __future__ import annotations 

17 

18from colour.hints import ( # noqa: TC001 

19 Domain1, 

20 Range1, 

21) 

22from colour.utilities import Structure, optional 

23 

24from .apple_log_profile import ( 

25 log_decoding_AppleLogProfile, 

26 log_encoding_AppleLogProfile, 

27) 

28 

29__author__ = "Colour Developers" 

30__copyright__ = "Copyright 2013 Colour Developers" 

31__license__ = "BSD-3-Clause - https://opensource.org/licenses/BSD-3-Clause" 

32__maintainer__ = "Colour Developers" 

33__email__ = "colour-developers@colour-science.org" 

34__status__ = "Production" 

35 

36__all__ = [ 

37 "CONSTANTS_MI_LOG", 

38 "log_encoding_MiLog", 

39 "log_decoding_MiLog", 

40] 

41 

42CONSTANTS_MI_LOG: Structure = Structure( 

43 R_0=-0.09023729, 

44 R_t=0.01974185, 

45 sigma=18.10531998, # 'c' in whitepaper, 'sigma' for Apple compatibility 

46 beta=0.01384578, 

47 gamma=0.09271529, 

48 delta=0.67291850, 

49) 

50"""*Xiaomi Mi-Log Profile* constants.""" 

51 

52 

53def log_encoding_MiLog( 

54 R: Domain1, 

55 constants: Structure | None = None, 

56) -> Range1: 

57 """ 

58 Apply the *Xiaomi Mi-Log Profile* log encoding opto-electronic transfer 

59 function (OETF). 

60 

61 Parameters 

62 ---------- 

63 R 

64 Linear reflection data :math:`R`. 

65 constants 

66 *Xiaomi Mi-Log Profile* constants. 

67 

68 Returns 

69 ------- 

70 :class:`numpy.ndarray` 

71 Logarithmically encoded value :math:`P`. 

72 

73 References 

74 ---------- 

75 :cite:`Zhang2024` 

76 

77 Notes 

78 ----- 

79 - The scene reflection signal :math:`R` captured by the camera is 

80 represented using a floating point encoding. The :math:`R` value 

81 of 0.18 corresponds to the signal produced by an 18% reflectance 

82 reference gray chart. 

83 

84 +------------+-----------------------+---------------+ 

85 | **Domain** | **Scale - Reference** | **Scale - 1** | 

86 +============+=======================+===============+ 

87 | ``R`` | 1 | 1 | 

88 +------------+-----------------------+---------------+ 

89 

90 +------------+-----------------------+---------------+ 

91 | **Range** | **Scale - Reference** | **Scale - 1** | 

92 +============+=======================+===============+ 

93 | ``P`` | 1 | 1 | 

94 +------------+-----------------------+---------------+ 

95 

96 Examples 

97 -------- 

98 >>> log_encoding_MiLog(0.18) # doctest: +ELLIPSIS 

99 0.4534596... 

100 """ 

101 

102 return log_encoding_AppleLogProfile(R, optional(constants, CONSTANTS_MI_LOG)) 

103 

104 

105def log_decoding_MiLog( 

106 P: Domain1, 

107 constants: Structure | None = None, 

108) -> Range1: 

109 """ 

110 Apply the *Xiaomi Mi-Log Profile* log decoding inverse opto-electronic transfer 

111 function (OETF). 

112 

113 Parameters 

114 ---------- 

115 P 

116 Logarithmically encoded value :math:`P`. 

117 constants 

118 *Xiaomi Mi-Log Profile* constants. 

119 

120 Returns 

121 ------- 

122 :class:`numpy.ndarray` 

123 Linear reflection data :math:`R`. 

124 

125 References 

126 ---------- 

127 :cite:`Zhang2024` 

128 

129 Notes 

130 ----- 

131 - The captured pixel :math:`P` value uses floating point encoding 

132 normalized to the [0, 1] range. 

133 

134 +------------+-----------------------+---------------+ 

135 | **Domain** | **Scale - Reference** | **Scale - 1** | 

136 +============+=======================+===============+ 

137 | ``P`` | 1 | 1 | 

138 +------------+-----------------------+---------------+ 

139 

140 +------------+-----------------------+---------------+ 

141 | **Range** | **Scale - Reference** | **Scale - 1** | 

142 +============+=======================+===============+ 

143 | ``R`` | 1 | 1 | 

144 +------------+-----------------------+---------------+ 

145 

146 Examples 

147 -------- 

148 >>> log_decoding_MiLog(0.45345968) # doctest: +ELLIPSIS 

149 0.1800000... 

150 """ 

151 

152 return log_decoding_AppleLogProfile(P, optional(constants, CONSTANTS_MI_LOG))