Coverage for colour/models/rgb/transfer_functions/smpte_240m.py: 100%

1""" 

2SMPTE 240M 

3========== 

4 

5Define the *SMPTE 240M* opto-electrical transfer function (OETF) and 

6electro-optical transfer function (EOTF). 

7 

8- :func:`colour.models.oetf_SMPTE240M` 

9- :func:`colour.models.eotf_SMPTE240M` 

10 

11References 

12---------- 

13- :cite:`SocietyofMotionPictureandTelevisionEngineers1999b` : Society of 

14 Motion Picture and Television Engineers. (1999). ANSI/SMPTE 240M-1995 - 

15 Signal Parameters - 1125-Line High-Definition Production Systems (pp. 1-7). 

16 http://car.france3.mars.free.fr/HD/INA-%2026%20jan%2006/\ 

17SMPTE%20normes%20et%20confs/s240m.pdf 

18""" 

19 

20from __future__ import annotations 

21 

22import numpy as np 

23 

24from colour.algebra import spow 

25from colour.hints import ( # noqa: TC001 

26 Domain1, 

27 Range1, 

28) 

29from colour.utilities import as_float, domain_range_scale, from_range_1, to_domain_1 

30 

31__author__ = "Colour Developers" 

32__copyright__ = "Copyright 2013 Colour Developers" 

33__license__ = "BSD-3-Clause - https://opensource.org/licenses/BSD-3-Clause" 

34__maintainer__ = "Colour Developers" 

35__email__ = "colour-developers@colour-science.org" 

36__status__ = "Production" 

37 

38__all__ = [ 

39 "oetf_SMPTE240M", 

40 "eotf_SMPTE240M", 

41] 

42 

43 

44def oetf_SMPTE240M(L_c: Domain1) -> Range1: 

45 """ 

46 Apply the *SMPTE 240M* opto-electronic transfer function (OETF). 

47 

48 Parameters 

49 ---------- 

50 L_c 

51 Light input :math:`L_c` to the reference camera normalised to the 

52 system reference white. 

53 

54 Returns 

55 ------- 

56 :class:`numpy.ndarray` 

57 Video signal output :math:`V_c` of the reference camera normalised 

58 to the system reference white. 

59 

60 Notes 

61 ----- 

62 +------------+-----------------------+---------------+ 

63 | **Domain** | **Scale - Reference** | **Scale - 1** | 

64 +============+=======================+===============+ 

65 | ``L_c`` | 1 | 1 | 

66 +------------+-----------------------+---------------+ 

67 

68 +------------+-----------------------+---------------+ 

69 | **Range** | **Scale - Reference** | **Scale - 1** | 

70 +============+=======================+===============+ 

71 | ``V_c`` | 1 | 1 | 

72 +------------+-----------------------+---------------+ 

73 

74 References 

75 ---------- 

76 :cite:`SocietyofMotionPictureandTelevisionEngineers1999b` 

77 

78 Examples 

79 -------- 

80 >>> oetf_SMPTE240M(0.18) # doctest: +ELLIPSIS 

81 0.4022857... 

82 """ 

83 

84 L_c = to_domain_1(L_c) 

85 

86 V_c = np.where(L_c < 0.0228, 4 * L_c, 1.1115 * spow(L_c, 0.45) - 0.1115) 

87 

88 return as_float(from_range_1(V_c)) 

89 

90 

91def eotf_SMPTE240M(V_r: Domain1) -> Range1: 

92 """ 

93 Apply the *SMPTE 240M* electro-optical transfer function (EOTF). 

94 

95 Parameters 

96 ---------- 

97 V_r 

98 Video signal level :math:`V_r` driving the reference reproducer 

99 normalised to the system reference white. 

100 

101 Returns 

102 ------- 

103 :class:`numpy.ndarray` 

104 Light output :math:`L_r` from the reference reproducer normalised 

105 to the system reference white. 

106 

107 Notes 

108 ----- 

109 +------------+-----------------------+---------------+ 

110 | **Domain** | **Scale - Reference** | **Scale - 1** | 

111 +============+=======================+===============+ 

112 | ``V_r`` | 1 | 1 | 

113 +------------+-----------------------+---------------+ 

114 

115 +------------+-----------------------+---------------+ 

116 | **Range** | **Scale - Reference** | **Scale - 1** | 

117 +============+=======================+===============+ 

118 | ``L_r`` | 1 | 1 | 

119 +------------+-----------------------+---------------+ 

120 

121 References 

122 ---------- 

123 :cite:`SocietyofMotionPictureandTelevisionEngineers1999b` 

124 

125 Examples 

126 -------- 

127 >>> eotf_SMPTE240M(0.402285796753870) # doctest: +ELLIPSIS 

128 0.1... 

129 """ 

130 

131 V_r = to_domain_1(V_r) 

132 

133 with domain_range_scale("ignore"): 

134 L_r = np.where( 

135 V_r < oetf_SMPTE240M(0.0228), 

136 V_r / 4, 

137 spow((V_r + 0.1115) / 1.1115, 1 / 0.45), 

138 ) 

139 

140 return as_float(from_range_1(L_r))