"""
DICOM - Grayscale Standard Display Function
===========================================
Define the *DICOM - Grayscale Standard Display Function* electro-optical
transfer function (EOTF) and its inverse:
- :func:`colour.models.eotf_inverse_DICOMGSDF`
- :func:`colour.models.eotf_DICOMGSDF`
The Grayscale Standard Display Function is defined for the Luminance Range from
:math:`0.05` to :math:`4000 cd/m^2`. The minimum Luminance corresponds to the
lowest practically useful Luminance of cathode-ray-tube (CRT) monitors and the
maximum exceeds the unattenuated Luminance of very bright light-boxes used for
interpreting X-Ray mammography. The Grayscale Standard Display Function
explicitly includes the effects of the diffused ambient Illuminance.
References
----------
- :cite:`NationalElectricalManufacturersAssociation2004b` : National
Electrical Manufacturers Association. (2004). Digital Imaging and
Communications in Medicine (DICOM) Part 14: Grayscale Standard Display
Function. http://medical.nema.org/dicom/2004/04_14PU.PDF
"""
from __future__ import annotations
import numpy as np
from colour.hints import ArrayLike, NDArrayFloat, NDArrayReal
from colour.utilities import (
Structure,
as_float,
as_int,
from_range_1,
to_domain_1,
)
__author__ = "Colour Developers"
__copyright__ = "Copyright 2013 Colour Developers"
__license__ = "BSD-3-Clause - https://opensource.org/licenses/BSD-3-Clause"
__maintainer__ = "Colour Developers"
__email__ = "colour-developers@colour-science.org"
__status__ = "Production"
__all__ = [
"CONSTANTS_DICOMGSDF",
"eotf_inverse_DICOMGSDF",
"eotf_DICOMGSDF",
]
CONSTANTS_DICOMGSDF: Structure = Structure(
a=-1.3011877,
b=-2.5840191e-2,
c=8.0242636e-2,
d=-1.0320229e-1,
e=1.3646699e-1,
f=2.8745620e-2,
g=-2.5468404e-2,
h=-3.1978977e-3,
k=1.2992634e-4,
m=1.3635334e-3,
A=71.498068,
B=94.593053,
C=41.912053,
D=9.8247004,
E=0.28175407,
F=-1.1878455,
G=-0.18014349,
H=0.14710899,
I=-0.017046845,
)
"""*DICOM Grayscale Standard Display Function* constants."""
[docs]
def eotf_inverse_DICOMGSDF(
L: ArrayLike,
out_int: bool = False,
constants: Structure = CONSTANTS_DICOMGSDF,
) -> NDArrayReal:
"""
Define the *DICOM - Grayscale Standard Display Function* inverse
electro-optical transfer function (EOTF).
Parameters
----------
L
*Luminance* :math:`L`.
out_int
Whether to return value as int code value or float equivalent of a
code value at a given bit-depth.
constants
*DICOM - Grayscale Standard Display Function* constants.
Returns
-------
:class:`numpy.ndarray`
Just-Noticeable Difference (JND) Index, :math:`j`.
Notes
-----
+------------+-----------------------+---------------+
| **Domain** | **Scale - Reference** | **Scale - 1** |
+============+=======================+===============+
| ``L`` | [0, 1] | [0, 1] |
+------------+-----------------------+---------------+
+------------+-----------------------+---------------+
| **Range** | **Scale - Reference** | **Scale - 1** |
+============+=======================+===============+
| ``J`` | [0, 1] | [0, 1] |
+------------+-----------------------+---------------+
References
----------
:cite:`NationalElectricalManufacturersAssociation2004b`
Examples
--------
>>> eotf_inverse_DICOMGSDF(130.0662) # doctest: +ELLIPSIS
0.5004862...
>>> eotf_inverse_DICOMGSDF(130.0662, out_int=True)
512
"""
L = to_domain_1(L)
L_lg = np.log10(L)
A = constants.A
B = constants.B
C = constants.C
D = constants.D
E = constants.E
F = constants.F
G = constants.G
H = constants.H
I = constants.I # noqa: E741
J = (
A
+ B * L_lg
+ C * L_lg**2
+ D * L_lg**3
+ E * L_lg**4
+ F * L_lg**5
+ G * L_lg**6
+ H * L_lg**7
+ I * L_lg**8
)
if out_int:
return as_int(np.round(J))
else:
return as_float(from_range_1(J / 1023))
[docs]
def eotf_DICOMGSDF(
J: ArrayLike,
in_int: bool = False,
constants: Structure = CONSTANTS_DICOMGSDF,
) -> NDArrayFloat:
"""
Define the *DICOM - Grayscale Standard Display Function* electro-optical
transfer function (EOTF).
Parameters
----------
J
Just-Noticeable Difference (JND) Index, :math:`j`.
in_int
Whether to treat the input value as int code value or float
equivalent of a code value at a given bit-depth.
constants
*DICOM - Grayscale Standard Display Function* constants.
Returns
-------
:class:`numpy.ndarray`
Corresponding *luminance* :math:`L`.
Notes
-----
+------------+-----------------------+---------------+
| **Domain** | **Scale - Reference** | **Scale - 1** |
+============+=======================+===============+
| ``J`` | [0, 1] | [0, 1] |
+------------+-----------------------+---------------+
+------------+-----------------------+---------------+
| **Range** | **Scale - Reference** | **Scale - 1** |
+============+=======================+===============+
| ``L`` | [0, 1] | [0, 1] |
+------------+-----------------------+---------------+
References
----------
:cite:`NationalElectricalManufacturersAssociation2004b`
Examples
--------
>>> eotf_DICOMGSDF(0.500486263438448) # doctest: +ELLIPSIS
130.0628647...
>>> eotf_DICOMGSDF(512, in_int=True) # doctest: +ELLIPSIS
130.0652840...
"""
J = to_domain_1(J)
if not in_int:
J = J * 1023
a = constants.a
b = constants.b
c = constants.c
d = constants.d
e = constants.e
f = constants.f
g = constants.g
h = constants.h
k = constants.k
m = constants.m
J_ln = np.log(J)
J_ln2 = J_ln**2
J_ln3 = J_ln**3
J_ln4 = J_ln**4
J_ln5 = J_ln**5
L = (a + c * J_ln + e * J_ln2 + g * J_ln3 + m * J_ln4) / (
1 + b * J_ln + d * J_ln2 + f * J_ln3 + h * J_ln4 + k * J_ln5
)
L = 10**L
return as_float(from_range_1(L))
