def cct_to_neutral_loci_smet2018(cct, nlocitype='uw', out='duv,D'):
"""
Calculate the most neutral appearing Duv10 in and the degree of neutrality for a specified CCT using the models in Smet et al. (2018).
Args:
:cct10:
| ndarray CCT
:nlocitype:
| 'uw', optional
| 'uw': use unique white models published in Smet et al. (2014).
| 'ca': use degree of chromatic adaptation model from Smet et al. (2017).
:out:
| 'duv,D', optional
| Specifies requested output (other options: 'duv', 'D').
Returns:
:duv:
| ndarray with most neutral Duv10 value corresponding to the cct input.
:D:
| ndarray with the degree of neutrality at (cct, duv).
References:
1. `Smet, K.A.G., (2018),
Two Neutral White Illumination Loci Based on Unique White Rating and Degree of Chromatic Adaptation.
LEUKOS, 14(2), 55–67. <https://doi.org/10.1080/15502724.2017.1385400>`_
Notes:
1. Duv is specified in the CIE 1960 u10v10 chromatity diagram as the models were developed using CIE 1964 10° tristimulus, chromaticity and CCT values.
2. The parameter +0.0172 in Eq. 4b should be -0.0172.
"""
if nlocitype == 'uw':
duv = 0.0202 * np.log(cct / 3325) * np.exp(
-1.445 * np.log(cct / 3325)**2) - 0.0137
D = np.exp(-(6368 * ((1 / cct) -
(1 / 6410)))**2) # degree of neutrality
elif nlocitype == 'ca':
duv = 0.0382 * np.log(cct / 2194) * np.exp(
-0.679 * np.log(cct / 2194)**2) - 0.0172
D = np.exp(-(3912 * ((1 / cct) -
(1 / 6795)))**2) # degree of adaptation
else:
raise Exception('Unrecognized nlocitype')
if out == 'duv,D':
return duv, D
elif out == 'duv':
return duv
elif out == 'D':
return D
else:
raise Exception('smet_white_loci(): Requested output unrecognized.')
def log_scale(data,
scale_factor=[6.73],
scale_max=100.0): # defaults from cie-224-2017 cri
"""
Log-based color rendering index scale from Davis & Ohno (2009):
| Rfi,a = 10 * ln(exp((100 - c1*DEi,a)/10) + 1).
Args:
:data:
| float or list[floats] or ndarray
:scale_factor:
| [6.73] or list[float] or ndarray, optional
| Rescales color differences before subtracting them from :scale_max:
| Note that the default value is the one from cie-224-2017.
:scale_max:
| 100.0, optional
| Maximum value of linear scale
Returns:
:returns:
| float or list[floats] or ndarray
References:
1. `W. Davis and Y. Ohno,
“Color quality scale,” (2010),
Opt. Eng., vol. 49, no. 3, pp. 33602–33616.
<http://spie.org/Publications/Journal/10.1117/1.3360335>`_
2. `CIE224:2017. CIE 2017 Colour Fidelity Index for accurate scientific use.
Vienna, Austria: CIE. (2017).
<http://www.cie.co.at/index.php?i_ca_id=1027>`_
"""
return 10.0 * np.log(
np.exp((scale_max - scale_factor[0] * data) / 10.0) + 1.0)
def bvgpdf(x, y = None, mu = None, sigmainv = None):
"""
Evaluate bivariate Gaussian probability density function (BVGPDF)
Args:
:x:
| scalar or list or ndarray (.ndim = 1 or 2) with
| x(y)-coordinates at which to evaluate bivariate Gaussian PD.
:y:
| None or scalar or list or ndarray (.ndim = 1) with
| y-coordinates at which to evaluate bivariate Gaussian PD, optional.
| If :y: is None, :x: should be a 2d array.
:mu:
| None or ndarray (.ndim = 2) with center coordinates of
| bivariate Gaussian PD, optional.
| None defaults to ndarray([0,0]).
:sigmainv:
| None or ndarray with 'inverse covariance matrix', optional
| Determines the shape and orientation of the PD.
| None default to numpy.eye(2).
Returns:
:returns:
| ndarray with magnitude of BVGPDF(x,y)
"""
return np.exp(-0.5*mahalanobis2(x, y = y, mu = mu, sigmainv = sigmainv))
def psy_scale(data,
scale_factor=[1.0 / 55.0, 3.0 / 2.0, 2.0],
scale_max=100.0): # defaults for cri2012
"""
Psychometric based color rendering index scale from CRI2012:
| Rfi,a = 100 * (2 / (exp(c1*abs(DEi,a)**(c2) + 1))) ** c3.
Args:
:data:
| float or list[floats] or ndarray
:scale_factor:
| [1/55, 3/2, 2.0] or list[float] or ndarray, optional
| Rescales color differences before subtracting them from :scale_max:
| Note that the default value is the one from (Smet et al. 2013, LRT).
:scale_max:
| 100.0, optional
| Maximum value of linear scale
Returns:
:returns:
| float or list[floats] or ndarray
References:
1. `Smet, K., Schanda, J., Whitehead, L., & Luo, R. (2013).
CRI2012: A proposal for updating the CIE colour rendering index.
Lighting Research and Technology, 45, 689–709.
<http://lrt.sagepub.com/content/45/6/689>`_
"""
return scale_max * np.power(
2.0 /
(np.exp(scale_factor[0] * np.power(np.abs(data), scale_factor[1])) +
1.0), scale_factor[2])
def spdBB(CCT=5500, wl=[400, 700, 5], Lw=25000, cieobs='1964_10'):
wl = getwlr(wl)
dl = wl[1] - wl[0]
spd = 2 * np.pi * 6.626068E-34 * (299792458**2) / (
(wl * 0.000000001)**
5) / (np.exp(6.626068E-34 * 299792458 /
(wl * 0.000000001) / 1.3806503E-23 / CCT) - 1)
spd = Lw * spd / (dl * 683 * (spd * cie_interp(
_CMF[cieobs]['bar'].copy(), wl, kind='cmf')[2, :]).sum())
return np.vstack((wl, spd))
def xyz_to_neutrality_smet2018(xyz10, nlocitype='uw', uw_model='Linvar'):
"""
Calculate degree of neutrality using the unique white model in Smet et al. (2014) or the normalized (max = 1) degree of chromatic adaptation model from Smet et al. (2017).
Args:
:xyz10:
| ndarray with CIE 1964 10° xyz tristimulus values.
:nlocitype:
| 'uw', optional
| 'uw': use unique white models published in Smet et al. (2014).
| 'ca': use degree of chromatic adaptation model from Smet et al. (2017).
:uw_model:
| 'Linvar', optional
| Use Luminance invariant unique white model from Smet et al. (2014).
| Other options: 'L200' (200 cd/m²), 'L1000' (1000 cd/m²) and 'L2000' (2000 cd/m²).
Returns:
:N:
| ndarray with calculated neutrality
References:
1. `Smet, K., Deconinck, G., & Hanselaer, P., (2014),
Chromaticity of unique white in object mode.
Optics Express, 22(21), 25830–25841.
<https://www.osapublishing.org/oe/abstract.cfm?uri=oe-22-21-25830>`_
2. `Smet, K.A.G., Zhai, Q., Luo, M.R., Hanselaer, P., (2017),
Study of chromatic adaptation using memory color matches,
Part II: colored illuminants,
Opt. Express, 25(7), pp. 8350-8365.
<https://www.osapublishing.org/oe/abstract.cfm?uri=oe-25-7-8350&origin=search)>`_
"""
if nlocitype == 'uw':
uv = xyz_to_Yuv(xyz10)[..., 1:]
G0 = lambda up, vp, a: np.exp(-0.5 * (a[0] * (up - a[2])**2 + a[1] *
(vp - a[3])**2 + 2 * a[4] *
(up - a[2]) * (vp - a[3])))
return G0(uv[..., 0:1], uv[..., 1:2],
_UW_NEUTRALITY_PARAMETERS_SMET2014[uw_model])
elif nlocitype == 'ca':
return cat.smet2017_D(xyz10, Dmax=1).T
else:
raise Exception('Unrecognized nlocitype')
def fCLa(wl, Elv, integral, Norm = None, k = None, a_b_y = None, a_rod = None, RodSat = None,\
Vphotl = None, Vscotl = None, Vl_mpl = None, Scl_mpl = None, Mcl = None, WL = None):
"""
Local helper function that calculate CLa from El based on Eq. 1
in Rea et al (2012).
Args:
The various model parameters as described in the paper and contained
in the dict _LRC_CONST.
Returns:
ndarray with CLa values.
References:
1. `Rea MS, Figueiro MG, Bierman A, and Hamner R (2012).
Modelling the spectral sensitivity of the human circadian system.
Light. Res. Technol. 44, 386–396.
<https://doi.org/10.1177/1477153511430474>`_
2. `Rea MS, Figueiro MG, Bierman A, and Hamner R (2012).
Erratum: Modeling the spectral sensitivity of the human circadian system
(Lighting Research and Technology (2012) 44:4 (386-396)).
Light. Res. Technol. 44, 516.
<https://doi.org/10.1177/1477153512467607>`_
"""
dl = getwld(wl)
# Calculate piecewise function in Eq. 1 in Rea et al. 2012:
#calculate value of condition function (~second term of 1st fcn):
cond_number = integral(Elv*Scl_mpl*dl) - k*integral(Elv*Vl_mpl*dl)
# Calculate second fcn:
fcn2 = integral(Elv*Mcl*dl)
# Calculate last term of 1st fcn:
fcn1_3 = a_rod * (1 - np.exp(-integral(Vscotl*Elv*dl)/RodSat))
# Satisfying cond. is effectively adding fcn1_2 and fcn1_3 to fcn1_1:
CLa = Norm*(fcn2 + 1*(cond_number>=0)*(a_b_y*cond_number - fcn1_3))
return CLa
def run(data,
xyzw=None,
outin='J,aM,bM',
cieobs=_CIEOBS,
conditions=None,
forward=True,
mcat='cat16',
**kwargs):
"""
Run the Jz,az,bz based color appearance model in forward or backward modes.
Args:
:data:
| ndarray with relative sample xyz values (forward mode) or J'a'b' coordinates (inverse mode)
:xyzw:
| ndarray with relative white point tristimulus values
| None defaults to D65
:cieobs:
| _CIEOBS, optional
| CMF set to use when calculating :xyzw: if this is None.
:conditions:
| None, optional
| Dictionary with viewing condition parameters for:
| La, Yb, D and surround.
| surround can contain:
| - str (options: 'avg','dim','dark') or
| - dict with keys c, Nc, F.
| None results in:
| {'La':100, 'Yb':20, 'D':1, 'surround':'avg'}
:forward:
| True, optional
| If True: run in CAM in forward mode, else: inverse mode.
:outin:
| 'J,aM,bM', optional
| String with requested output (e.g. "J,aM,bM,M,h") [Forward mode]
| String with inputs in data.
| Input must have data.shape[-1]==3 and last dim of data must have
| the following structure:
| * data[...,0] = J or Q,
| * data[...,1:] = (aM,bM) or (aC,bC) or (aS,bS)
:mcat:
| 'cat16', optional
| Specifies CAT sensor space.
| - options:
| - None defaults to 'cat16'
| - str: see see luxpy.cat._MCATS.keys() for options
| (details on type, ?luxpy.cat)
| - ndarray: matrix with sensor primaries
Returns:
:camout:
| ndarray with color appearance correlates (forward mode)
| or
| XYZ tristimulus values (inverse mode)
References:
1. `Safdar, M., Cui, G., Kim,Y. J., and Luo, M. R.(2017).
Perceptually uniform color space for image signals including high dynamic range and wide gamut.
Opt. Express, vol. 25, no. 13, pp. 15131–15151, Jun. 2017.
<https://www.opticsexpress.org/abstract.cfm?URI=oe-25-13-15131>`_
2. `Safdar, M., Hardeberg, J., Cui, G., Kim, Y. J., and Luo, M. R.(2018).
A Colour Appearance Model based on Jzazbz Colour Space,
26th Color and Imaging Conference (2018), Vancouver, Canada, November 12-16, 2018, pp96-101.
<https://doi.org/10.2352/ISSN.2169-2629.2018.26.96>`_
"""
outin = outin.split(',') if isinstance(outin, str) else outin
#--------------------------------------------
# Get condition parameters:
if conditions is None:
conditions = _DEFAULT_CONDITIONS
D, Dtype, La, Yb, surround = (conditions[x]
for x in sorted(conditions.keys()))
surround_parameters = _SURROUND_PARAMETERS
if isinstance(surround, str):
surround = surround_parameters[conditions['surround']]
F, FLL, Nc, c = [surround[x] for x in sorted(surround.keys())]
# Define cone/chromatic adaptation sensor space:
if (mcat is None) | (mcat == 'cat16'):
mcat = cat._MCATS['cat16']
elif isinstance(mcat, str):
mcat = cat._MCATS[mcat]
invmcat = np.linalg.inv(mcat)
#--------------------------------------------
# Get white point of D65 fro chromatic adaptation transform (CAT)
xyzw_d65 = np.array([[
9.5047e+01, 1.0000e+02, 1.0888e+02
]]) if cieobs == '1931_2' else spd_to_xyz(_CIE_D65, cieobs=cieobs)
#--------------------------------------------
# Get default white point:
if xyzw is None:
xyzw = xyzw_d65.copy()
#--------------------------------------------
# calculate condition dependent parameters:
Yw = xyzw[..., 1].T
k = 1.0 / (5.0 * La + 1.0)
FL = 0.2 * (k**4.0) * (5.0 * La) + 0.1 * ((1.0 - k**4.0)**2.0) * (
(5.0 * La)**(1.0 / 3.0)) # luminance adaptation factor
n = Yb / Yw
Nbb = 0.725 * (1 / n)**0.2
z = 1.48 + FLL * n**0.5
#--------------------------------------------
# Calculate degree of chromatic adaptation:
if D is None:
D = F * (1.0 - (1.0 / 3.6) * np.exp((-La - 42.0) / 92.0))
#===================================================================
# WHITE POINT transformations (common to forward and inverse modes):
#--------------------------------------------
# Apply CAT to white point:
xyzwc = cat.apply_vonkries1(xyzw,
xyzw,
xyzw_d65,
D=D,
mcat=mcat,
invmcat=invmcat)
#--------------------------------------------
# Get Iz,az,bz coordinates:
iabzw = xyz_to_jabz(xyzwc, ztype='iabz')
#===================================================================
# STIMULUS transformations:
#--------------------------------------------
# massage shape of data for broadcasting:
original_ndim = data.ndim
if data.ndim == 2: data = data[:, None]
if forward:
# Apply CAT to D65:
xyzc = cat.apply_vonkries1(data,
xyzw,
xyzw_d65,
D=D,
mcat=mcat,
invmcat=invmcat)
# Get Iz,az,bz coordinates:
iabz = xyz_to_jabz(xyzc, ztype='iabz')
#--------------------------------------------
# calculate hue h and eccentricity factor, et:
h = hue_angle(iabz[..., 1], iabz[..., 2], htype='deg')
et = 1.01 + np.cos(h * np.pi / 180 + 1.55)
#--------------------------------------------
# calculate Hue quadrature (if requested in 'out'):
if 'H' in outin:
H = hue_quadrature(h, unique_hue_data=_UNIQUE_HUE_DATA)
else:
H = None
#--------------------------------------------
# calculate lightness, J:
if ('J' in outin) | ('Q' in outin) | ('C' in outin) | (
'M' in outin) | ('s' in outin) | ('aS' in outin) | (
'aC' in outin) | ('aM' in outin):
J = 100.0 * (iabz[..., 0] / iabzw[..., 0])**(c * z)
#--------------------------------------------
# calculate brightness, Q:
if ('Q' in outin) | ('s' in outin) | ('aS' in outin):
Q = 192.5 * (J / c) * (FL**0.64)
#--------------------------------------------
# calculate chroma, C:
if ('C' in outin) | ('M' in outin) | ('s' in outin) | (
'aS' in outin) | ('aC' in outin) | ('aM' in outin):
C = ((1 / n)**0.074) * (
(iabz[..., 1]**2.0 + iabz[..., 2]**2.0)**0.37) * (et**0.067)
#--------------------------------------------
# calculate colorfulness, M:
if ('M' in outin) | ('s' in outin) | ('aM' in outin) | ('aS' in outin):
M = 1.42 * C * FL**0.25
#--------------------------------------------
# calculate saturation, s:
if ('s' in outin) | ('aS' in outin):
s = 100.0 * (M / Q)**0.5
#--------------------------------------------
# calculate cartesian coordinates:
if ('aS' in outin):
aS = s * np.cos(h * np.pi / 180.0)
bS = s * np.sin(h * np.pi / 180.0)
if ('aC' in outin):
aC = C * np.cos(h * np.pi / 180.0)
bC = C * np.sin(h * np.pi / 180.0)
if ('aM' in outin):
aM = M * np.cos(h * np.pi / 180.0)
bM = M * np.sin(h * np.pi / 180.0)
#--------------------------------------------
if outin != ['J', 'aM', 'bM']:
camout = eval('ajoin((' + ','.join(outin) + '))')
else:
camout = ajoin((J, aM, bM))
if (camout.shape[1] == 1) & (original_ndim < 3):
camout = camout[:, 0, :]
return camout
elif forward == False:
#--------------------------------------------
# Get Lightness J from data:
if ('J' in outin[0]):
J = data[..., 0].copy()
elif ('Q' in outin[0]):
Q = data[..., 0].copy()
J = c * (Q / (192.25 * FL**0.64))
else:
raise Exception(
'No lightness or brightness values in data[...,0]. Inverse CAM-transform not possible!'
)
#--------------------------------------------
if 'a' in outin[1]:
# calculate hue h:
h = hue_angle(data[..., 1], data[..., 2], htype='deg')
#--------------------------------------------
# calculate Colorfulness M or Chroma C or Saturation s from a,b:
MCs = (data[..., 1]**2.0 + data[..., 2]**2.0)**0.5
else:
h = data[..., 2]
MCs = data[..., 1]
if ('aS' in outin):
Q = 192.5 * (J / c) * (FL**0.64)
M = Q * (MCs / 100.0)**2.0
C = M / (1.42 * FL**0.25)
if ('aM' in outin): # convert M to C:
C = MCs / (1.42 * FL**0.25)
if ('aC' in outin):
C = MCs
#--------------------------------------------
# calculate achromatic signal, Iz:
Iz = iabzw[..., 0] * (J / 100.0)**(1.0 / (c * z))
#--------------------------------------------
# calculate eccentricity factor, et:
et = 1.01 + np.cos(h * np.pi / 180 + 1.55)
#--------------------------------------------
# calculate t (=a**2+b**2) from C:
t = (n**0.074 * C * (1 / et)**0.067)**(1 / 0.37)
#--------------------------------------------
# Calculate az, bz:
az = (t / (1 + np.tan(h * np.pi / 180)**2))**0.5
bz = az * np.tan(h * np.pi / 180)
#--------------------------------------------
# join values and convert to xyz:
xyzc = jabz_to_xyz(ajoin((Iz, az, bz)), ztype='iabz')
#-------------------------------------------
# Apply CAT from D65:
xyz = cat.apply_vonkries1(xyzc,
xyzw_d65,
xyzw,
D=D,
mcat=mcat,
invmcat=invmcat)
return xyz
def _xyz_to_jab_cam02ucs(xyz, xyzw, ucs=True, conditions=None):
"""
Calculate CAM02-UCS J'a'b' coordinates from xyz tristimulus values of sample and white point.
Args:
:xyz:
| ndarray with sample tristimulus values
:xyzw:
| ndarray with white point tristimulus values
:conditions:
| None, optional
| Dictionary with viewing conditions.
| None results in:
| {'La':100, 'Yb':20, 'D':1, 'surround':'avg'}
| For more info see luxpy.cam.ciecam02()?
Returns:
:jab:
| ndarray with J'a'b' coordinates.
"""
#--------------------------------------------
# Get/ set conditions parameters:
if conditions is not None:
surround_parameters = {
'surrounds': ['avg', 'dim', 'dark'],
'avg': {
'c': 0.69,
'Nc': 1.0,
'F': 1.0,
'FLL': 1.0
},
'dim': {
'c': 0.59,
'Nc': 0.9,
'F': 0.9,
'FLL': 1.0
},
'dark': {
'c': 0.525,
'Nc': 0.8,
'F': 0.8,
'FLL': 1.0
}
}
La = conditions['La']
Yb = conditions['Yb']
D = conditions['D']
surround = conditions['surround']
if isinstance(surround, str):
surround = surround_parameters[conditions['surround']]
F, FLL, Nc, c = [surround[x] for x in sorted(surround.keys())]
else:
# set defaults:
La, Yb, D, F, FLL, Nc, c = 100, 20, 1, 1, 1, 1, 0.69
#--------------------------------------------
# Define sensor space and cat matrices:
mhpe = np.array([[0.38971, 0.68898, -0.07868], [-0.22981, 1.1834, 0.04641],
[0.0, 0.0, 1.0]
]) # Hunt-Pointer-Estevez sensors (cone fundamentals)
mcat = np.array([[0.7328, 0.4296, -0.1624], [-0.7036, 1.6975, 0.0061],
[0.0030, 0.0136, 0.9834]]) # CAT02 sensor space
#--------------------------------------------
# pre-calculate some matrices:
invmcat = np.linalg.inv(mcat)
mhpe_x_invmcat = np.dot(mhpe, invmcat)
#--------------------------------------------
# calculate condition dependent parameters:
Yw = xyzw[..., 1:2].T
k = 1.0 / (5.0 * La + 1.0)
FL = 0.2 * (k**4.0) * (5.0 * La) + 0.1 * ((1.0 - k**4.0)**2.0) * (
(5.0 * La)**(1.0 / 3.0)) # luminance adaptation factor
n = Yb / Yw
Nbb = 0.725 * (1 / n)**0.2
Ncb = Nbb
z = 1.48 + FLL * n**0.5
if D is None:
D = F * (1.0 - (1.0 / 3.6) * np.exp((-La - 42.0) / 92.0))
#--------------------------------------------
# transform from xyz, xyzw to cat sensor space:
rgb = math.dot23(mcat, xyz.T)
rgbw = mcat @ xyzw.T
#--------------------------------------------
# apply von Kries cat:
rgbc = (
(D * Yw / rgbw)[..., None] + (1 - D)
) * rgb # factor 100 from ciecam02 is replaced with Yw[i] in ciecam16, but see 'note' in Fairchild's "Color Appearance Models" (p291 ni 3ed.)
rgbwc = (
(D * Yw / rgbw) + (1 - D)
) * rgbw # factor 100 from ciecam02 is replaced with Yw[i] in ciecam16, but see 'note' in Fairchild's "Color Appearance Models" (p291 ni 3ed.)
#--------------------------------------------
# convert from cat02 sensor space to cone sensors (hpe):
rgbp = math.dot23(mhpe_x_invmcat, rgbc).T
rgbwp = (mhpe_x_invmcat @ rgbwc).T
#--------------------------------------------
# apply Naka_rushton repsonse compression:
naka_rushton = lambda x: 400 * x**0.42 / (x**0.42 + 27.13) + 0.1
rgbpa = naka_rushton(FL * rgbp / 100.0)
p = np.where(rgbp < 0)
rgbpa[p] = 0.1 - (naka_rushton(FL * np.abs(rgbp[p]) / 100.0) - 0.1)
rgbwpa = naka_rushton(FL * rgbwp / 100.0)
pw = np.where(rgbwp < 0)
rgbwpa[pw] = 0.1 - (naka_rushton(FL * np.abs(rgbwp[pw]) / 100.0) - 0.1)
#--------------------------------------------
# Calculate achromatic signal:
A = (2.0 * rgbpa[..., 0] + rgbpa[..., 1] +
(1.0 / 20.0) * rgbpa[..., 2] - 0.305) * Nbb
Aw = (2.0 * rgbwpa[..., 0] + rgbwpa[..., 1] +
(1.0 / 20.0) * rgbwpa[..., 2] - 0.305) * Nbb
#--------------------------------------------
# calculate initial opponent channels:
a = rgbpa[..., 0] - 12.0 * rgbpa[..., 1] / 11.0 + rgbpa[..., 2] / 11.0
b = (1.0 / 9.0) * (rgbpa[..., 0] + rgbpa[..., 1] - 2.0 * rgbpa[..., 2])
#--------------------------------------------
# calculate hue h and eccentricity factor, et:
h = np.arctan2(b, a)
et = (1.0 / 4.0) * (np.cos(h + 2.0) + 3.8)
#--------------------------------------------
# calculate lightness, J:
J = 100.0 * (A / Aw)**(c * z)
#--------------------------------------------
# calculate chroma, C:
t = ((50000.0 / 13.0) * Nc * Ncb * et *
((a**2.0 + b**2.0)**0.5)) / (rgbpa[..., 0] + rgbpa[..., 1] +
(21.0 / 20.0 * rgbpa[..., 2]))
C = (t**0.9) * ((J / 100.0)**0.5) * (1.64 - 0.29**n)**0.73
#--------------------------------------------
# Calculate colorfulness, M:
M = C * FL**0.25
#--------------------------------------------
# convert to cam02ucs J', aM', bM':
if ucs == True:
KL, c1, c2 = 1.0, 0.007, 0.0228
Jp = (1.0 + 100.0 * c1) * J / (1.0 + c1 * J)
Mp = (1.0 / c2) * np.log(1.0 + c2 * M)
else:
Jp = J
Mp = M
aMp = Mp * np.cos(h)
bMp = Mp * np.sin(h)
return np.dstack((Jp, aMp, bMp))
def run(data, xyzw, conditions=None, ucs_type='ucs', forward=True):
"""
Run the CAM02-UCS[,-LCD,-SDC] color appearance difference model in forward or backward modes.
Args:
:data:
| ndarray with sample xyz values (forward mode) or J'a'b' coordinates (inverse mode)
:xyzw:
| ndarray with white point tristimulus values
:conditions:
| None, optional
| Dictionary with viewing conditions.
| None results in:
| {'La':100, 'Yb':20, 'D':1, 'surround':'avg'}
| For more info see luxpy.cam.ciecam02()?
:ucs_type:
| 'ucs', optional
| String with type of color difference appearance space
| options: 'ucs', 'scd', 'lcd'
:forward:
| True, optional
| If True: run in CAM in forward mode, else: inverse mode.
Returns:
:camout:
| ndarray with J'a'b' coordinates or whatever correlates requested in out.
Note:
* This is a simplified, less flexible, but faster version than the main cam02ucs().
"""
# get ucs parameters:
if isinstance(ucs_type, str):
ucs_pars = {
'ucs': {
'KL': 1.0,
'c1': 0.007,
'c2': 0.0228
},
'lcd': {
'KL': 0.77,
'c1': 0.007,
'c2': 0.0053
},
'scd': {
'KL': 1.24,
'c1': 0.007,
'c2': 0.0363
}
}
ucs = ucs_pars[ucs_type]
else:
ucs = ucs_type
KL, c1, c2 = ucs['KL'], ucs['c1'], ucs['c2']
if forward == True:
# run ciecam02 to get JMh:
data = ciecam02(data,
xyzw,
out='J,M,h',
conditions=conditions,
forward=True)
camout = np.zeros_like(data) # for output
#--------------------------------------------
# convert to cam02ucs J', aM', bM':
camout[...,
0] = (1.0 + 100.0 * c1) * data[...,
0] / (1.0 + c1 * data[..., 0])
Mp = (1.0 / c2) * np.log(1.0 + c2 * data[..., 1])
camout[..., 1] = Mp * np.cos(data[..., 2] * np.pi / 180)
camout[..., 2] = Mp * np.sin(data[..., 2] * np.pi / 180)
return camout
else:
#--------------------------------------------
# convert cam02ucs J', aM', bM' to xyz:
# calc CAM02 hue angle
#Jp, aMp, bMp = asplit(data)
h = np.arctan2(data[..., 2], data[..., 1])
# calc CAM02 and CIECAM02 colourfulness
Mp = (data[..., 1]**2.0 + data[..., 2]**2.0)**0.5
M = (np.exp(c2 * Mp) - 1.0) / c2
# calculate ciecam02 aM, bM:
aM = M * np.cos(h)
bM = M * np.sin(h)
# calc CAM02 lightness
J = data[..., 0] / (1.0 + (100.0 - data[..., 0]) * c1)
# run ciecam02 in inverse mode to get xyz:
return ciecam02(ajoin((J, aM, bM)),
xyzw,
out='J,aM,bM',
conditions=conditions,
forward=False)
def apply_poly_model_at_hue_x(poly_model, pmodel, dCHoverC_res, \
hx = None, Cxr = 40, sig = _VF_SIG):
"""
Applies base color shift model at (hue,chroma) coordinates
Args:
:poly_model:
| function handle to model
:pmodel:
| ndarray with model parameters.
:dCHoverC_res:
| ndarray with residuals between 'dCoverC,dH' of samples
| and 'dCoverC,dH' predicted by the model.
| Note: dCoverC = (Ct - Cr)/Cr and dH = ht - hr
| (predicted from model, see notes luxpy.cri.get_poly_model())
:hx:
| None or ndarray, optional
| None defaults to np.arange(np.pi/10.0,2*np.pi,2*np.pi/10.0)
:Cxr:
| 40, optional
:sig:
| _VF_SIG or float, optional
| Determines smooth transition between hue-bin-boundaries (no hard
| cutoff at hue bin boundary).
Returns:
:returns:
| ndarrays with dCoverC_x, dCoverC_x_sig, dH_x, dH_x_sig
| Note '_sig' denotes the uncertainty:
| e.g. dH_x_sig is the uncertainty of dH at input (hue/chroma).
"""
if hx is None:
dh = 2 * np.pi / 10.0
hx = np.arange(
dh / 2, 2 * np.pi, dh
) #hue angles at which to apply model, i.e. calculate 'average' measures
# A calculate reference coordinates:
axr = Cxr * np.cos(hx)
bxr = Cxr * np.sin(hx)
# B apply model at reference coordinates to obtain test coordinates:
axt, bxt, Cxt, hxt, axr, bxr, Cxr, hxr = apply_poly_model_at_x(
poly_model, pmodel, axr, bxr)
# C Calculate dC/C, dH for test and ref at fixed hues:
dCoverC_x = (Cxt - Cxr) / (np.hstack((Cxr + Cxt)).max())
dH_x = (180 / np.pi) * (hxt - hxr)
# dCoverC_x = np.round(dCoverC_x,decimals = 2)
# dH_x = np.round(dH_x,decimals = 0)
# D calculate 'average' noise measures using sig-value:
href = dCHoverC_res[:, 0:1]
dCoverC_res = dCHoverC_res[:, 1:2]
dHoverC_res = dCHoverC_res[:, 2:3]
dHsigi = np.exp((np.dstack(
(np.abs(hx - href), np.abs((hx - href - 2 * np.pi)),
np.abs(hx - href - 2 * np.pi))).min(axis=2)**2) / (-2) / sig)
dH_x_sig = (180 / np.pi) * (np.sqrt(
(dHsigi * (dHoverC_res**2)).sum(axis=0, keepdims=True) /
dHsigi.sum(axis=0, keepdims=True)))
#dH_x_sig_avg = np.sqrt(np.sum(dH_x_sig**2,axis=1)/hx.shape[0])
dCoverC_x_sig = (np.sqrt(
(dHsigi * (dCoverC_res**2)).sum(axis=0, keepdims=True) /
dHsigi.sum(axis=0, keepdims=True)))
#dCoverC_x_sig_avg = np.sqrt(np.sum(dCoverC_x_sig**2,axis=1)/hx.shape[0])
return dCoverC_x, dCoverC_x_sig, dH_x, dH_x_sig
def cie2006cmfsEx(age = 32,fieldsize = 10, wl = None,\
var_od_lens = 0, var_od_macula = 0, \
var_od_L = 0, var_od_M = 0, var_od_S = 0,\
var_shft_L = 0, var_shft_M = 0, var_shft_S = 0,\
out = 'LMS', allow_negative_values = False):
"""
Generate Individual Observer CMFs (cone fundamentals)
based on CIE2006 cone fundamentals and published literature
on observer variability in color matching and in physiological parameters.
Args:
:age:
| 32 or float or int, optional
| Observer age
:fieldsize:
| 10, optional
| Field size of stimulus in degrees (between 2° and 10°).
:wl:
| None, optional
| Interpolation/extraplation of :LMS: output to specified wavelengths.
| None: output original _WL = np.array([390,780,5])
:var_od_lens:
| 0, optional
| Std Dev. in peak optical density [%] of lens.
:var_od_macula:
| 0, optional
| Std Dev. in peak optical density [%] of macula.
:var_od_L:
| 0, optional
| Std Dev. in peak optical density [%] of L-cone.
:var_od_M:
| 0, optional
| Std Dev. in peak optical density [%] of M-cone.
:var_od_S:
| 0, optional
| Std Dev. in peak optical density [%] of S-cone.
:var_shft_L:
| 0, optional
| Std Dev. in peak wavelength shift [nm] of L-cone.
:var_shft_L:
| 0, optional
| Std Dev. in peak wavelength shift [nm] of M-cone.
:var_shft_S:
| 0, optional
| Std Dev. in peak wavelength shift [nm] of S-cone.
:out:
| 'LMS' or , optional
| Determines output.
:allow_negative_values:
| False, optional
| Cone fundamentals or color matching functions
should not have negative values.
| If False: X[X<0] = 0.
Returns:
:returns:
| - 'LMS' : ndarray with individual observer area-normalized
| cone fundamentals. Wavelength have been added.
| [- 'trans_lens': ndarray with lens transmission
| (no wavelengths added, no interpolation)
| - 'trans_macula': ndarray with macula transmission
| (no wavelengths added, no interpolation)
| - 'sens_photopig' : ndarray with photopigment sens.
| (no wavelengths added, no interpolation)]
References:
1. `Asano Y, Fairchild MD, and Blondé L (2016).
Individual Colorimetric Observer Model.
PLoS One 11, 1–19.
<http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0145671>`_
2. `Asano Y, Fairchild MD, Blondé L, and Morvan P (2016).
Color matching experiment for highlighting interobserver variability.
Color Res. Appl. 41, 530–539.
<https://onlinelibrary.wiley.com/doi/abs/10.1002/col.21975>`_
3. `CIE, and CIE (2006).
Fundamental Chromaticity Diagram with Physiological Axes - Part I
(Vienna: CIE).
<http://www.cie.co.at/publications/fundamental-chromaticity-diagram-physiological-axes-part-1>`_
4. `Asano's Individual Colorimetric Observer Model
<https://www.rit.edu/cos/colorscience/re_AsanoObserverFunctions.php>`_
"""
fs = fieldsize
rmd = _INDVCMF_DATA['rmd'].copy()
LMSa = _INDVCMF_DATA['LMSa'].copy()
docul = _INDVCMF_DATA['docul'].copy()
# field size corrected macular density:
pkOd_Macula = 0.485 * np.exp(-fs / 6.132) * (
1 + var_od_macula / 100) # varied peak optical density of macula
corrected_rmd = rmd * pkOd_Macula
# age corrected lens/ocular media density:
if (age <= 60):
correct_lomd = docul[:1] * (1 + 0.02 * (age - 32)) + docul[1:2]
else:
correct_lomd = docul[:1] * (1.56 + 0.0667 * (age - 60)) + docul[1:2]
correct_lomd = correct_lomd * (1 + var_od_lens / 100
) # varied overall optical density of lens
# Peak Wavelength Shift:
wl_shifted = np.empty(LMSa.shape)
wl_shifted[0] = _WL + var_shft_L
wl_shifted[1] = _WL + var_shft_M
wl_shifted[2] = _WL + var_shft_S
LMSa_shft = np.empty(LMSa.shape)
kind = 'cubic'
LMSa_shft[0] = sp.interpolate.interp1d(wl_shifted[0],
LMSa[0],
kind=kind,
bounds_error=False,
fill_value="extrapolate")(_WL)
LMSa_shft[1] = sp.interpolate.interp1d(wl_shifted[1],
LMSa[1],
kind=kind,
bounds_error=False,
fill_value="extrapolate")(_WL)
LMSa_shft[2] = sp.interpolate.interp1d(wl_shifted[2],
LMSa[2],
kind=kind,
bounds_error=False,
fill_value="extrapolate")(_WL)
# LMSa[2,np.where(_WL >= _WL_CRIT)] = 0 #np.nan # Not defined above 620nm
# LMSa_shft[2,np.where(_WL >= _WL_CRIT)] = 0
ssw = np.hstack(
(0, np.sign(np.diff(LMSa_shft[2, :]))
)) #detect poor interpolation (sign switch due to instability)
LMSa_shft[2, np.where((ssw >= 0) & (_WL > 560))] = np.nan
# corrected LMS (no age correction):
pkOd_L = (0.38 + 0.54 * np.exp(-fs / 1.333)) * (
1 + var_od_L / 100) # varied peak optical density of L-cone
pkOd_M = (0.38 + 0.54 * np.exp(-fs / 1.333)) * (
1 + var_od_M / 100) # varied peak optical density of M-cone
pkOd_S = (0.30 + 0.45 * np.exp(-fs / 1.333)) * (
1 + var_od_S / 100) # varied peak optical density of S-cone
alpha_lms = 0. * LMSa_shft
alpha_lms[0] = 1 - 10**(-pkOd_L * (10**LMSa_shft[0]))
alpha_lms[1] = 1 - 10**(-pkOd_M * (10**LMSa_shft[1]))
alpha_lms[2] = 1 - 10**(-pkOd_S * (10**LMSa_shft[2]))
# this fix is required because the above math fails for alpha_lms[2,:]==0
alpha_lms[2, np.where(_WL >= _WL_CRIT)] = 0
# Corrected to Corneal Incidence:
lms_barq = alpha_lms * (10**(-corrected_rmd - correct_lomd)) * np.ones(
alpha_lms.shape)
# Corrected to Energy Terms:
lms_bar = lms_barq * _WL
# Set NaN values to zero:
lms_bar[np.isnan(lms_bar)] = 0
# normalized:
LMS = 100 * lms_bar / np.nansum(lms_bar, axis=1, keepdims=True)
# Output extra:
trans_lens = 10**(-correct_lomd)
trans_macula = 10**(-corrected_rmd)
sens_photopig = alpha_lms * _WL
# Add wavelengths:
LMS = np.vstack((_WL, LMS))
if ('xyz' in out.lower().split(',')):
LMS = lmsb_to_xyzb(LMS,
fieldsize,
out='xyz',
allow_negative_values=allow_negative_values)
out = out.replace('xyz', 'LMS').replace('XYZ', 'LMS')
if ('lms' in out.lower().split(',')):
out = out.replace('lms', 'LMS')
# Interpolate/extrapolate:
if wl is None:
interpolation = None
else:
interpolation = 'cubic'
LMS = spd(LMS, wl=wl, interpolation=interpolation, norm_type='area')
if (out == 'LMS'):
return LMS
elif (out == 'LMS,trans_lens,trans_macula,sens_photopig'):
return LMS, trans_lens, trans_macula, sens_photopig
elif (out == 'LMS,trans_lens,trans_macula,sens_photopig,LMSa'):
return LMS, trans_lens, trans_macula, sens_photopig, LMSa
else:
return eval(out)
def run(data,
xyzw=_DEFAULT_WHITE_POINT,
Yw=None,
conditions=None,
ucstype='ucs',
forward=True,
yellowbluepurplecorrect=False,
mcat='cat02'):
"""
Run the CAM02-UCS[,-LCD,-SDC] color appearance difference model in forward or backward modes.
Args:
:data:
| ndarray with sample xyz values (forward mode) or J'a'b' coordinates (inverse mode)
:xyzw:
| ndarray with white point tristimulus values
:conditions:
| None, optional
| Dictionary with viewing conditions.
| None results in:
| {'La':100, 'Yb':20, 'D':1, 'surround':'avg'}
| For more info see luxpy.cam.ciecam02()?
:ucstype:
| 'ucs', optional
| String with type of color difference appearance space
| options: 'ucs', 'scd', 'lcd'
:forward:
| True, optional
| If True: run in CAM in forward mode, else: inverse mode.
:yellowbluepurplecorrect:
| False, optional
| If False: don't correct for yellow-blue and purple problems in ciecam02.
| If 'brill-suss':
| for yellow-blue problem, see:
| - Brill [Color Res Appl, 2006; 31, 142-145] and
| - Brill and Süsstrunk [Color Res Appl, 2008; 33, 424-426]
| If 'jiang-luo':
| for yellow-blue problem + purple line problem, see:
| - Jiang, Jun et al. [Color Res Appl 2015: 40(5), 491-503]
:mcat:
| 'cat02', optional
| Specifies CAT sensor space.
| - options:
| - None defaults to 'cat02'
| (others e.g. 'cat02-bs', 'cat02-jiang',
| all trying to correct gamut problems of original cat02 matrix)
| - str: see see luxpy.cat._MCATS.keys() for options
| (details on type, ?luxpy.cat)
| - ndarray: matrix with sensor primaries
Returns:
:camout:
| ndarray with J'a'b' coordinates (forward mode)
| or
| XYZ tristimulus values (inverse mode)
References:
1. `M.R. Luo, G. Cui, and C. Li,
'Uniform colour spaces based on CIECAM02 colour appearance model,'
Color Res. Appl., vol. 31, no. 4, pp. 320–330, 2006.
<http://onlinelibrary.wiley.com/doi/10.1002/col.20227/abstract)>`_
"""
# get ucs parameters:
if isinstance(ucstype, str):
ucs_pars = _CAM_UCS_PARAMETERS
ucs = ucs_pars[ucstype]
else:
ucs = ucstype
KL, c1, c2 = ucs['KL'], ucs['c1'], ucs['c2']
# set conditions to use in CIECAM02 (overrides None-default in ciecam02() !!!)
if conditions is None:
conditions = _DEFAULT_CONDITIONS
if forward == True:
# run ciecam02 to get JMh:
data = ciecam02(data,
xyzw,
outin='J,M,h',
conditions=conditions,
forward=True,
mcat=mcat,
yellowbluepurplecorrect=yellowbluepurplecorrect)
camout = np.zeros_like(data) # for output
#--------------------------------------------
# convert to cam02ucs J', aM', bM':
camout[...,
0] = (1.0 + 100.0 * c1) * data[...,
0] / (1.0 + c1 * data[..., 0])
Mp = ((1.0 / c2) *
np.log(1.0 + c2 * data[..., 1])) if (c2 != 0) else data[..., 1]
camout[..., 1] = Mp * np.cos(data[..., 2] * np.pi / 180)
camout[..., 2] = Mp * np.sin(data[..., 2] * np.pi / 180)
return camout
else:
#--------------------------------------------
# convert cam02ucs J', aM', bM' to xyz:
# calc ciecam02 hue angle
#Jp, aMp, bMp = asplit(data)
h = np.arctan2(data[..., 2], data[..., 1])
# calc cam02ucs and CIECAM02 colourfulness
Mp = (data[..., 1]**2.0 + data[..., 2]**2.0)**0.5
M = ((np.exp(c2 * Mp) - 1.0) / c2) if (c2 != 0) else Mp
# calculate ciecam02 aM, bM:
aM = M * np.cos(h)
bM = M * np.sin(h)
# calc ciecam02 lightness
J = data[..., 0] / (1.0 + (100.0 - data[..., 0]) * c1)
# run ciecam02 in inverse mode to get xyz:
return ciecam02(ajoin((J, aM, bM)),
xyzw,
outin='J,aM,bM',
conditions=conditions,
forward=False,
mcat=mcat,
yellowbluepurplecorrect=yellowbluepurplecorrect)
def run(data,
xyzw=_DEFAULT_WHITE_POINT,
Yw=None,
outin='J,aM,bM',
conditions=None,
forward=True,
yellowbluepurplecorrect=False,
mcat='cat02'):
"""
Run CIECAM02 color appearance model in forward or backward modes.
Args:
:data:
| ndarray with relative sample xyz values (forward mode) or J'a'b' coordinates (inverse mode)
:xyzw:
| ndarray with relative white point tristimulus values
:Yw:
| None, optional
| Luminance factor of white point.
| If None: xyz (in data) and xyzw are entered as relative tristimulus values
| (normalized to Yw = 100).
| If not None: input tristimulus are absolute and Yw is used to
| rescale the absolute values to relative ones
| (relative to a reference perfect white diffuser
| with Ywr = 100).
| Yw can be < 100 for e.g. paper as white point. If Yw is None, it
| is assumed that the relative Y-tristimulus value in xyzw
| represents the luminance factor Yw.
:conditions:
| None, optional
| Dictionary with viewing condition parameters for:
| La, Yb, D and surround.
| surround can contain:
| - str (options: 'avg','dim','dark') or
| - dict with keys c, Nc, F.
| None results in:
| {'La':100, 'Yb':20, 'D':1, 'surround':'avg'}
:forward:
| True, optional
| If True: run in CAM in forward mode, else: inverse mode.
:outin:
| 'J,aM,bM', optional
| String with requested output (e.g. "J,aM,bM,M,h") [Forward mode]
| - attributes: 'J': lightness,'Q': brightness,
| 'M': colorfulness,'C': chroma, 's': saturation,
| 'h': hue angle, 'H': hue quadrature/composition,
| String with inputs in data [inverse mode].
| Input must have data.shape[-1]==3 and last dim of data must have
| the following structure for inverse mode:
| * data[...,0] = J or Q,
| * data[...,1:] = (aM,bM) or (aC,bC) or (aS,bS) or (M,h) or (C, h), ...
:yellowbluepurplecorrect:
| False, optional
| If False: don't correct for yellow-blue and purple problems in ciecam02.
| If 'brill-suss':
| for yellow-blue problem, see:
| - Brill [Color Res Appl, 2006; 31, 142-145] and
| - Brill and Süsstrunk [Color Res Appl, 2008; 33, 424-426]
| If 'jiang-luo':
| for yellow-blue problem + purple line problem, see:
| - Jiang, Jun et al. [Color Res Appl 2015: 40(5), 491-503]
:mcat:
| 'cat02', optional
| Specifies CAT sensor space.
| - options:
| - None defaults to 'cat02'
| (others e.g. 'cat02-bs', 'cat02-jiang',
| all trying to correct gamut problems of original cat02 matrix)
| - str: see see luxpy.cat._MCATS.keys() for options
| (details on type, ?luxpy.cat)
| - ndarray: matrix with sensor primaries
Returns:
:camout:
| ndarray with color appearance correlates (forward mode)
| or
| XYZ tristimulus values (inverse mode)
References:
1. `N. Moroney, M. D. Fairchild, R. W. G. Hunt, C. Li, M. R. Luo, and T. Newman, (2002),
"The CIECAM02 color appearance model,”
IS&T/SID Tenth Color Imaging Conference. p. 23, 2002.
<http://rit-mcsl.org/fairchild/PDFs/PRO19.pdf>`_
"""
outin = outin.split(',') if isinstance(outin, str) else outin
#--------------------------------------------
# Get condition parameters:
if conditions is None:
conditions = _DEFAULT_CONDITIONS
D, Dtype, La, Yb, surround = (conditions[x]
for x in sorted(conditions.keys()))
surround_parameters = _SURROUND_PARAMETERS
if isinstance(surround, str):
surround = surround_parameters[conditions['surround']]
F, FLL, Nc, c = [surround[x] for x in sorted(surround.keys())]
#--------------------------------------------
# Define sensor space and cat matrices:
# Hunt-Pointer-Estevez sensors (cone fundamentals)
mhpe = cat._MCATS['hpe']
# chromatic adaptation sensors:
if (mcat is None) | (mcat == 'cat02'):
mcat = cat._MCATS['cat02']
if yellowbluepurplecorrect == 'brill-suss':
mcat = cat._MCATS[
'cat02-bs'] # for yellow-blue problem, Brill [Color Res Appl 2006;31:142-145] and Brill and Süsstrunk [Color Res Appl 2008;33:424-426]
elif yellowbluepurplecorrect == 'jiang-luo':
mcat = cat._MCATS[
'cat02-jiang-luo'] # for yellow-blue problem + purple line problem
elif isinstance(mcat, str):
mcat = cat._MCATS[mcat]
#--------------------------------------------
# pre-calculate some matrices:
invmcat = np.linalg.inv(mcat)
mhpe_x_invmcat = np.dot(mhpe, invmcat)
if not forward: mcat_x_invmhpe = np.dot(mcat, np.linalg.inv(mhpe))
#--------------------------------------------
# Set Yw:
if Yw is not None:
Yw = (Yw * np.ones_like(xyzw2[..., 1:2]).T)
else:
Yw = xyzw[..., 1:2].T
#--------------------------------------------
# calculate condition dependent parameters:
k = 1.0 / (5.0 * La + 1.0)
FL = 0.2 * (k**4.0) * (5.0 * La) + 0.1 * ((1.0 - k**4.0)**2.0) * (
(5.0 * La)**(1.0 / 3.0)) # luminance adaptation factor
n = Yb / Yw
Nbb = 0.725 * (1 / n)**0.2
Ncb = Nbb
z = 1.48 + FLL * n**0.5
yw = xyzw[..., 1:2].T # original Y in xyzw (pre-transposed)
#--------------------------------------------
# Calculate degree of chromatic adaptation:
if D is None:
D = F * (1.0 - (1.0 / 3.6) * np.exp((-La - 42.0) / 92.0))
#===================================================================
# WHITE POINT transformations (common to forward and inverse modes):
#--------------------------------------------
# Normalize white point (keep transpose for next step):
xyzw = Yw * xyzw.T / yw
#--------------------------------------------
# transform from xyzw to cat sensor space:
rgbw = math.dot23(mcat, xyzw)
#--------------------------------------------
# apply von Kries cat:
rgbwc = (
(D * Yw / rgbw) + (1 - D)
) * rgbw # factor 100 from ciecam02 is replaced with Yw[i] in ciecam16, but see 'note' in Fairchild's "Color Appearance Models" (p291 ni 3ed.)
#--------------------------------------------
# convert from cat02 sensor space to cone sensors (hpe):
rgbwp = math.dot23(mhpe_x_invmcat, rgbwc).T
#--------------------------------------------
# apply Naka_rushton repsonse compression to white:
NK = lambda x, forward: naka_rushton(x,
scaling=400,
n=0.42,
sig=27.13**(1 / 0.42),
noise=0.1,
forward=forward)
pw = np.where(rgbwp < 0)
# if requested apply yellow-blue correction:
if (yellowbluepurplecorrect == 'brill-suss'
): # Brill & Susstrunck approach, for purple line problem
rgbwp[pw] = 0.0
rgbwpa = NK(FL * rgbwp / 100.0, True)
rgbwpa[pw] = 0.1 - (NK(FL * np.abs(rgbwp[pw]) / 100.0, True) - 0.1)
#--------------------------------------------
# Calculate achromatic signal of white:
Aw = (2.0 * rgbwpa[..., 0] + rgbwpa[..., 1] +
(1.0 / 20.0) * rgbwpa[..., 2] - 0.305) * Nbb
# massage shape of data for broadcasting:
original_ndim = data.ndim
if data.ndim == 2: data = data[:, None]
#===================================================================
# STIMULUS transformations
if forward:
#--------------------------------------------
# Normalize xyz (keep transpose for matrix multiplication in next step):
xyz = (Yw / yw)[..., None] * data.T
#--------------------------------------------
# transform from xyz to cat sensor space:
rgb = math.dot23(mcat, xyz)
#--------------------------------------------
# apply von Kries cat:
rgbc = (
(D * Yw / rgbw)[..., None] + (1 - D)
) * rgb # factor 100 from ciecam02 is replaced with Yw[i] in ciecam16, but see 'note' in Fairchild's "Color Appearance Models" (p291 ni 3ed.)
#--------------------------------------------
# convert from cat02 sensor space to cone sensors (hpe):
rgbp = math.dot23(mhpe_x_invmcat, rgbc).T
#--------------------------------------------
# apply Naka_rushton repsonse compression:
p = np.where(rgbp < 0)
if (yellowbluepurplecorrect == 'brill-suss'
): # Brill & Susstrunck approach, for purple line problem
rgbp[p] = 0.0
rgbpa = NK(FL * rgbp / 100.0, forward)
rgbpa[p] = 0.1 - (NK(FL * np.abs(rgbp[p]) / 100.0, forward) - 0.1)
#--------------------------------------------
# Calculate achromatic signal:
A = (2.0 * rgbpa[..., 0] + rgbpa[..., 1] +
(1.0 / 20.0) * rgbpa[..., 2] - 0.305) * Nbb
#--------------------------------------------
# calculate initial opponent channels:
a = rgbpa[..., 0] - 12.0 * rgbpa[..., 1] / 11.0 + rgbpa[..., 2] / 11.0
b = (1.0 / 9.0) * (rgbpa[..., 0] + rgbpa[..., 1] - 2.0 * rgbpa[..., 2])
#--------------------------------------------
# calculate hue h and eccentricity factor, et:
h = hue_angle(a, b, htype='deg')
et = (1.0 / 4.0) * (np.cos(h * np.pi / 180 + 2.0) + 3.8)
#--------------------------------------------
# calculate Hue quadrature (if requested in 'out'):
if 'H' in outin:
H = hue_quadrature(h, unique_hue_data=_UNIQUE_HUE_DATA)
else:
H = None
#--------------------------------------------
# calculate lightness, J:
J = 100.0 * (A / Aw)**(c * z)
#--------------------------------------------
# calculate brightness, Q:
Q = (4.0 / c) * ((J / 100.0)**0.5) * (Aw + 4.0) * (FL**0.25)
#--------------------------------------------
# calculate chroma, C:
t = ((50000.0 / 13.0) * Nc * Ncb * et *
((a**2.0 + b**2.0)**0.5)) / (rgbpa[..., 0] + rgbpa[..., 1] +
(21.0 / 20.0 * rgbpa[..., 2]))
C = (t**0.9) * ((J / 100.0)**0.5) * (1.64 - 0.29**n)**0.73
#--------------------------------------------
# calculate colorfulness, M:
M = C * FL**0.25
#--------------------------------------------
# calculate saturation, s:
s = 100.0 * (M / Q)**0.5
S = s # make extra variable, jsut in case 'S' is called
#--------------------------------------------
# calculate cartesian coordinates:
if ('aS' in outin):
aS = s * np.cos(h * np.pi / 180.0)
bS = s * np.sin(h * np.pi / 180.0)
if ('aC' in outin):
aC = C * np.cos(h * np.pi / 180.0)
bC = C * np.sin(h * np.pi / 180.0)
if ('aM' in outin):
aM = M * np.cos(h * np.pi / 180.0)
bM = M * np.sin(h * np.pi / 180.0)
#--------------------------------------------
if outin != ['J', 'aM', 'bM']:
camout = eval('ajoin((' + ','.join(outin) + '))')
else:
camout = ajoin((J, aM, bM))
if (camout.shape[1] == 1) & (original_ndim < 3):
camout = camout[:, 0, :]
return camout
elif forward == False:
#--------------------------------------------
# Get Lightness J from data:
if ('J' in outin[0]):
J = data[..., 0].copy()
elif ('Q' in outin[0]):
Q = data[..., 0].copy()
J = 100.0 * (Q / ((Aw + 4.0) * (FL**0.25) * (4.0 / c)))**2.0
else:
raise Exception(
'No lightness or brightness values in data. Inverse CAM-transform not possible!'
)
#--------------------------------------------
if 'a' in outin[1]:
# calculate hue h:
h = hue_angle(data[..., 1], data[..., 2], htype='deg')
#--------------------------------------------
# calculate Colorfulness M or Chroma C or Saturation s from a,b:
MCs = (data[..., 1]**2.0 + data[..., 2]**2.0)**0.5
else:
h = data[..., 2]
MCs = data[..., 1]
if ('S' in outin[1]):
Q = (4.0 / c) * ((J / 100.0)**0.5) * (Aw + 4.0) * (FL**0.25)
M = Q * (MCs / 100.0)**2.0
C = M / (FL**0.25)
if ('M' in outin[1]): # convert M to C:
C = MCs / (FL**0.25)
if ('C' in outin[1]):
C = MCs
#--------------------------------------------
# calculate t from J, C:
t = (C / ((J / 100.0)**(1.0 / 2.0) * (1.64 - 0.29**n)**0.73))**(1.0 /
0.9)
#--------------------------------------------
# calculate eccentricity factor, et:
et = (np.cos(h * np.pi / 180.0 + 2.0) + 3.8) / 4.0
#--------------------------------------------
# calculate achromatic signal, A:
A = Aw * (J / 100.0)**(1.0 / (c * z))
#--------------------------------------------
# calculate temporary cart. co. at, bt and p1,p2,p3,p4,p5:
at = np.cos(h * np.pi / 180.0)
bt = np.sin(h * np.pi / 180.0)
p1 = (50000.0 / 13.0) * Nc * Ncb * et / t
p2 = A / Nbb + 0.305
p3 = 21.0 / 20.0
p4 = p1 / bt
p5 = p1 / at
#--------------------------------------------
#q = np.where(np.abs(bt) < np.abs(at))[0]
q = (np.abs(bt) < np.abs(at))
b = p2 * (2.0 + p3) * (460.0 / 1403.0) / (p4 + (2.0 + p3) *
(220.0 / 1403.0) *
(at / bt) -
(27.0 / 1403.0) + p3 *
(6300.0 / 1403.0))
a = b * (at / bt)
a[q] = p2[q] * (2.0 + p3) * (460.0 / 1403.0) / (p5[q] + (2.0 + p3) *
(220.0 / 1403.0) -
((27.0 / 1403.0) - p3 *
(6300.0 / 1403.0)) *
(bt[q] / at[q]))
b[q] = a[q] * (bt[q] / at[q])
#--------------------------------------------
# calculate post-adaptation values
rpa = (460.0 * p2 + 451.0 * a + 288.0 * b) / 1403.0
gpa = (460.0 * p2 - 891.0 * a - 261.0 * b) / 1403.0
bpa = (460.0 * p2 - 220.0 * a - 6300.0 * b) / 1403.0
#--------------------------------------------
# join values:
rgbpa = ajoin((rpa, gpa, bpa))
#--------------------------------------------
# decompress signals:
rgbp = (100.0 / FL) * NK(rgbpa, forward)
# apply yellow-blue correction:
if (yellowbluepurplecorrect == 'brill-suss'
): # Brill & Susstrunck approach, for purple line problem
p = np.where(rgbp < 0.0)
rgbp[p] = 0.0
#--------------------------------------------
# convert from to cone sensors (hpe) cat02 sensor space:
rgbc = math.dot23(mcat_x_invmhpe, rgbp.T)
#--------------------------------------------
# apply inverse von Kries cat:
rgb = rgbc / ((D * Yw / rgbw)[..., None] + (1.0 - D))
#--------------------------------------------
# transform from cat sensor space to xyz:
xyz = math.dot23(invmcat, rgb)
#--------------------------------------------
# unnormalize xyz:
xyz = ((yw / Yw)[..., None] * xyz).T
return xyz
def get_degree_of_adaptation(Dtype=None, **kwargs):
"""
Calculates the degree of adaptation according to some function
published in literature.
Args:
:Dtype:
| None, optional
| If None: kwargs should contain 'D' with value.
| If 'manual: kwargs should contain 'D' with value.
| If 'cat02' or 'cat16': kwargs should contain keys 'F' and 'La'.
| Calculate D according to CAT02 or CAT16 model:
| D = F*(1-(1/3.6)*numpy.exp((-La-42)/92))
| If 'cmc': kwargs should contain 'La', 'La0'(or 'La2') and 'order'
| for 'order' = '1>0': 'La' is set La1 and 'La0' to La0.
| for 'order' = '0>2': 'La' is set La0 and 'La0' to La1.
| for 'order' = '1>2': 'La' is set La1 and 'La2' to La0.
| D is calculated as follows:
| D = 0.08*numpy.log10(La1+La0)+0.76-0.45*(La1-La0)/(La1+La0)
| If 'smet2017': kwargs should contain 'xyzw' and 'Dmax'
| (see Smet2017_D for more details).
| If "? user defined", then D is calculated by:
| D = ndarray(eval(:Dtype:))
Returns:
:D:
| ndarray with degree of adaptation values.
Notes:
1. D passes either right through or D is calculated following some
D-function (Dtype) published in literature.
2. D is limited to values between zero and one
3. If kwargs do not contain the required parameters,
an exception is raised.
"""
try:
if Dtype is None:
PAR = ["D"]
D = np.array([kwargs['D']])
elif Dtype == 'manual':
PAR = ["D"]
D = np.array([kwargs['D']])
elif (Dtype == 'cat02') | (Dtype == 'cat16'):
PAR = ["F, La"]
F = kwargs['F']
if isinstance(F, str): #CIECAM02 / CAT02 surround based F values
if (F == 'avg') | (F == 'average'):
F = 1
elif (F == 'dim'):
F = 0.9
elif (F == 'dark'):
F = 0.8
elif (F == 'disp') | (F == 'display'):
F = 0.0
else:
F = eval(F)
F = np.array([F])
La = np.array([kwargs['La']])
D = F * (1 - (1 / 3.6) * np.exp((-La - 42) / 92))
elif Dtype == 'cmc':
PAR = ["La, La0, order"]
order = np.array([kwargs['order']])
if order == '1>0':
La1 = np.array([kwargs['La']])
La0 = np.array([kwargs['La0']])
elif order == '0>2':
La0 = np.array([kwargs['La']])
La1 = np.array([kwargs['La0']])
elif order == '1>2':
La1 = np.array([kwargs['La']])
La0 = np.array([kwargs['La2']])
D = 0.08 * np.log10(La1 + La0) + 0.76 - 0.45 * (La1 - La0) / (La1 +
La0)
elif 'smet2017':
PAR = ['xyzw', 'Dmax']
xyzw = np.array([kwargs['xyzw']])
Dmax = np.array([kwargs['Dmax']])
D = smet2017_D(xyzw, Dmax=Dmax)
else:
PAR = ["? user defined"]
D = np.array(eval(Dtype))
D[np.where(D < 0)] = 0
D[np.where(D > 1)] = 1
except:
raise Exception(
'degree_of_adaptation_D(): **kwargs does not contain the necessary parameters ({}) for Dtype = {}'
.format(PAR, Dtype))
return D
def fSr(x):
return (1/np.pi)*_BB['c1']*((x*1.0e-9)**(-5))*(n**(-2.0))*(np.exp(_BB['c2']*((n*x*1.0e-9*(cct+_EPS))**(-1.0)))-1.0)**(-1.0)
def spd_to_mcri(SPD, D = 0.9, E = None, Yb = 20.0, out = 'Rm', wl = None):
"""
Calculates the MCRI or Memory Color Rendition Index, Rm
Args:
:SPD:
| ndarray with spectral data (can be multiple SPDs,
| first axis are the wavelengths)
:D:
| 0.9, optional
| Degree of adaptation.
:E:
| None, optional
| Illuminance in lux
| (used to calculate La = (Yb/100)*(E/pi) to then calculate D
| following the 'cat02' model).
| If None: the degree is determined by :D:
| If (:E: is not None) & (:Yb: is None): :E: is assumed to contain
| the adapting field luminance La (cd/m²).
:Yb:
| 20.0, optional
| Luminance factor of background. (used when calculating La from E)
| If None, E contains La (cd/m²).
:out:
| 'Rm' or str, optional
| Specifies requested output (e.g. 'Rm,Rmi,cct,duv')
:wl:
| None, optional
| Wavelengths (or [start, end, spacing]) to interpolate the SPDs to.
| None: default to no interpolation
Returns:
:returns:
| float or ndarray with MCRI Rm for :out: 'Rm'
| Other output is also possible by changing the :out: str value.
References:
1. `K.A.G. Smet, W.R. Ryckaert, M.R. Pointer, G. Deconinck, P. Hanselaer,(2012)
“A memory colour quality metric for white light sources,”
Energy Build., vol. 49, no. C, pp. 216–225.
<http://www.sciencedirect.com/science/article/pii/S0378778812000837>`_
"""
SPD = np2d(SPD)
if wl is not None:
SPD = spd(data = SPD, interpolation = _S_INTERP_TYPE, kind = 'np', wl = wl)
# unpack metric default values:
avg, catf, cieobs, cri_specific_pars, cspace, ref_type, rg_pars, sampleset, scale = [_MCRI_DEFAULTS[x] for x in sorted(_MCRI_DEFAULTS.keys())]
similarity_ai = cri_specific_pars['similarity_ai']
Mxyz2lms = cspace['Mxyz2lms']
scale_fcn = scale['fcn']
scale_factor = scale['cfactor']
sampleset = eval(sampleset)
# A. calculate xyz:
xyzti, xyztw = spd_to_xyz(SPD, cieobs = cieobs['xyz'], rfl = sampleset, out = 2)
if 'cct' in out.split(','):
cct, duv = xyz_to_cct(xyztw, cieobs = cieobs['cct'], out = 'cct,duv',mode = 'lut')
# B. perform chromatic adaptation to adopted whitepoint of ipt color space, i.e. D65:
if catf is not None:
Dtype_cat, F, Yb_cat, catmode_cat, cattype_cat, mcat_cat, xyzw_cat = [catf[x] for x in sorted(catf.keys())]
# calculate degree of adaptationn D:
if E is not None:
if Yb is not None:
La = (Yb/100.0)*(E/np.pi)
else:
La = E
D = cat.get_degree_of_adaptation(Dtype = Dtype_cat, F = F, La = La)
else:
Dtype_cat = None # direct input of D
if (E is None) and (D is None):
D = 1.0 # set degree of adaptation to 1 !
if D > 1.0: D = 1.0
if D < 0.6: D = 0.6 # put a limit on the lowest D
# apply cat:
xyzti = cat.apply(xyzti, cattype = cattype_cat, catmode = catmode_cat, xyzw1 = xyztw,xyzw0 = None, xyzw2 = xyzw_cat, D = D, mcat = [mcat_cat], Dtype = Dtype_cat)
xyztw = cat.apply(xyztw, cattype = cattype_cat, catmode = catmode_cat, xyzw1 = xyztw,xyzw0 = None, xyzw2 = xyzw_cat, D = D, mcat = [mcat_cat], Dtype = Dtype_cat)
# C. convert xyz to ipt and split:
ipt = xyz_to_ipt(xyzti, cieobs = cieobs['xyz'], M = Mxyz2lms) #input matrix as published in Smet et al. 2012, Energy and Buildings
I,P,T = asplit(ipt)
# D. calculate specific (hue dependent) similarity indicators, Si:
if len(xyzti.shape) == 3:
ai = np.expand_dims(similarity_ai, axis = 1)
else:
ai = similarity_ai
a1,a2,a3,a4,a5 = asplit(ai)
mahalanobis_d2 = (a3*np.power((P - a1),2.0) + a4*np.power((T - a2),2.0) + 2.0*a5*(P-a1)*(T-a2))
if (len(mahalanobis_d2.shape)==3) & (mahalanobis_d2.shape[-1]==1):
mahalanobis_d2 = mahalanobis_d2[:,:,0].T
Si = np.exp(-0.5*mahalanobis_d2)
# E. calculate general similarity indicator, Sa:
Sa = avg(Si, axis = 0,keepdims = True)
# F. rescale similarity indicators (Si, Sa) with a 0-1 scale to memory color rendition indices (Rmi, Rm) with a 0 - 100 scale:
Rmi = scale_fcn(np.log(Si),scale_factor = scale_factor)
Rm = np2d(scale_fcn(np.log(Sa),scale_factor = scale_factor))
# G. calculate Rg (polyarea of test / polyarea of memory colours):
if 'Rg' in out.split(','):
I = I[...,None] #broadcast_shape(I, target_shape = None,expand_2d_to_3d = 0)
a1 = a1[:,None]*np.ones(I.shape)#broadcast_shape(a1, target_shape = None,expand_2d_to_3d = 0)
a2 = a2[:,None]*np.ones(I.shape) #broadcast_shape(a2, target_shape = None,expand_2d_to_3d = 0)
a12 = np.concatenate((a1,a2),axis=2) #broadcast_shape(np.hstack((a1,a2)), target_shape = ipt.shape,expand_2d_to_3d = 0)
ipt_mc = np.concatenate((I,a12),axis=2)
nhbins, normalize_gamut, normalized_chroma_ref, start_hue = [rg_pars[x] for x in sorted(rg_pars.keys())]
hue_bin_data = _get_hue_bin_data(ipt, ipt_mc,
start_hue = start_hue, nhbins = nhbins,
normalized_chroma_ref = normalized_chroma_ref)
Rg = _hue_bin_data_to_rg(hue_bin_data)
if (out != 'Rm'):
return eval(out)
else:
return Rm
def cam_sww16(data,
dataw=None,
Yb=20.0,
Lw=400.0,
Ccwb=None,
relative=True,
inputtype='xyz',
direction='forward',
parameters=None,
cieobs='2006_10',
match_to_conversionmatrix_to_cieobs=True):
"""
A simple principled color appearance model based on a mapping of
the Munsell color system.
| This function implements the JOSA A (parameters = 'JOSA') published model.
Args:
:data:
| ndarray with input tristimulus values
| or spectral data
| or input color appearance correlates
| Can be of shape: (N [, xM], x 3), whereby:
| N refers to samples and M refers to light sources.
| Note that for spectral input shape is (N x (M+1) x wl)
:dataw:
| None or ndarray, optional
| Input tristimulus values or spectral data of white point.
| None defaults to the use of CIE illuminant C.
:Yb:
| 20.0, optional
| Luminance factor of background (perfect white diffuser, Yw = 100)
:Lw:
| 400.0, optional
| Luminance (cd/m²) of white point.
:Ccwb:
| None, optional
| Degree of cognitive adaptation (white point balancing)
| If None: use [..,..] from parameters dict.
:relative:
| True or False, optional
| True: xyz tristimulus values are relative (Yw = 100)
:parameters:
| None or str or dict, optional
| Dict with model parameters.
| - None: defaults to luxpy.cam._CAM_SWW_2016_PARAMETERS['JOSA']
| - str: 'best-fit-JOSA' or 'best-fit-all-Munsell'
| - dict: user defined model parameters
| (dict should have same structure)
:inputtype:
| 'xyz' or 'spd', optional
| Specifies the type of input:
| tristimulus values or spectral data for the forward mode.
:direction:
| 'forward' or 'inverse', optional
| -'forward': xyz -> cam_sww_2016
| -'inverse': cam_sww_2016 -> xyz
:cieobs:
| '2006_10', optional
| CMF set to use to perform calculations where spectral data
| is involved (inputtype == 'spd'; dataw = None)
| Other options: see luxpy._CMF['types']
:match_to_conversionmatrix_to_cieobs:
| When channging to a different CIE observer, change the xyz-to_lms
| matrix to the one corresponding to that observer. If False: use
| the one set in parameters or _CAM_SWW16_PARAMETERS
Returns:
:returns:
| ndarray with color appearance correlates (:direction: == 'forward')
| or
| XYZ tristimulus values (:direction: == 'inverse')
Notes:
| This function implements the JOSA A (parameters = 'JOSA')
| published model.
| With:
| 1. A correction for the parameter
| in Eq.4 of Fig. 11: 0.952 --> -0.952
|
| 2. The delta_ac and delta_bc white-balance shifts in Eq. 5e & 5f
| should be: -0.028 & 0.821
|
| (cfr. Ccwb = 0.66 in:
| ab_test_out = ab_test_int - Ccwb*ab_gray_adaptation_field_int))
References:
1. `Smet, K. A. G., Webster, M. A., & Whitehead, L. A. (2016).
A simple principled approach for modeling and understanding uniform color metrics.
Journal of the Optical Society of America A, 33(3), A319–A331.
<https://doi.org/10.1364/JOSAA.33.00A319>`_
"""
#--------------------------------------------------------------------------
# Get model parameters:
#--------------------------------------------------------------------------
args = locals().copy()
parameters = _update_parameter_dict(
args,
parameters=parameters,
match_to_conversionmatrix_to_cieobs=match_to_conversionmatrix_to_cieobs
)
#unpack model parameters:
Cc, Ccwb, Cf, Mxyz2lms, cLMS, cab_int, cab_out, calpha, cbeta, cga1, cga2, cgb1, cgb2, cl_int, clambda, lms0 = [
parameters[x] for x in sorted(parameters.keys())
]
#--------------------------------------------------------------------------
# Setup default adaptation field:
#--------------------------------------------------------------------------
dataw = _setup_default_adaptation_field(dataw=dataw,
Lw=Lw,
inputtype=inputtype,
relative=relative,
cieobs=cieobs)
#--------------------------------------------------------------------------
# Redimension input data to ensure most appropriate sizes
# for easy and efficient looping and initialize output array:
#--------------------------------------------------------------------------
data, dataw, camout, originalshape = _massage_input_and_init_output(
data, dataw, inputtype=inputtype, direction=direction)
#--------------------------------------------------------------------------
# Do precomputations needed for both the forward and inverse model,
# and which do not depend on sample or light source data:
#--------------------------------------------------------------------------
Mxyz2lms = np.dot(
np.diag(cLMS), Mxyz2lms
) # weight the xyz-to-lms conversion matrix with cLMS (cfr. stage 1 calculations)
invMxyz2lms = np.linalg.inv(
Mxyz2lms) # Calculate the inverse lms-to-xyz conversion matrix
MAab = np.array(
[clambda, calpha, cbeta]
) # Create matrix with scale factors for L, M, S for quick matrix multiplications
invMAab = np.linalg.inv(
MAab) # Pre-calculate its inverse to avoid repeat in loop.
#--------------------------------------------------------------------------
# Apply forward/inverse model by looping over each row (=light source dim.)
# in data:
#--------------------------------------------------------------------------
N = data.shape[0]
for i in range(N):
#++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
# START FORWARD MODE and common part of inverse mode
#++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
#-----------------------------------------------------------------------------
# Get absolute tristimulus values for stimulus field and white point for row i:
#-----------------------------------------------------------------------------
xyzt, xyzw, xyzw_abs = _get_absolute_xyz_xyzw(data,
dataw,
i=i,
Lw=Lw,
direction=direction,
cieobs=cieobs,
inputtype=inputtype,
relative=relative)
#-----------------------------------------------------------------------------
# stage 1: calculate photon rates of stimulus and white white, and
# adapting field: i.e. lmst, lmsw and lmsf
#-----------------------------------------------------------------------------
# Convert to white point l,m,s:
lmsw = 683.0 * np.dot(Mxyz2lms, xyzw.T).T / _CMF[cieobs]['K']
# Calculate adaptation field and convert to l,m,s:
lmsf = (Yb / 100.0) * lmsw
# Calculate lms of stimulus
# or put adaptation lmsf in test field lmst for later use in inverse-mode (no xyz in 'inverse' mode!!!):
lmst = (683.0 * np.dot(Mxyz2lms, xyzt.T).T /
_CMF[cieobs]['K']) if (direction == 'forward') else lmsf
#-----------------------------------------------------------------------------
# stage 2: calculate cone outputs of stimulus lmstp
#-----------------------------------------------------------------------------
lmstp = math.erf(Cc *
(np.log(lmst / lms0) +
Cf * np.log(lmsf / lms0))) # stimulus test field
lmsfp = math.erf(Cc * (np.log(lmsf / lms0) +
Cf * np.log(lmsf / lms0))) # adaptation field
# add adaptation field lms temporarily to lmstp for quick calculation
lmstp = np.vstack((lmsfp, lmstp))
#-----------------------------------------------------------------------------
# stage 3: calculate optic nerve signals, lam*, alphp, betp:
#-----------------------------------------------------------------------------
lstar, alph, bet = asplit(np.dot(MAab, lmstp.T).T)
alphp = cga1[0] * alph
alphp[alph < 0] = cga1[1] * alph[alph < 0]
betp = cgb1[0] * bet
betp[bet < 0] = cgb1[1] * bet[bet < 0]
#-----------------------------------------------------------------------------
# stage 4: calculate recoded nerve signals, alphapp, betapp:
#-----------------------------------------------------------------------------
alphpp = cga2[0] * (alphp + betp)
betpp = cgb2[0] * (alphp - betp)
#-----------------------------------------------------------------------------
# stage 5: calculate conscious color perception:
#-----------------------------------------------------------------------------
lstar_int = cl_int[0] * (lstar + cl_int[1])
alph_int = cab_int[0] * (np.cos(cab_int[1] * np.pi / 180.0) * alphpp -
np.sin(cab_int[1] * np.pi / 180.0) * betpp)
bet_int = cab_int[0] * (np.sin(cab_int[1] * np.pi / 180.0) * alphpp +
np.cos(cab_int[1] * np.pi / 180.0) * betpp)
lstar_out = lstar_int
#++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
# stage 5 continued but SPLIT IN FORWARD AND INVERSE MODES:
#++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
#--------------------------------------
# FORWARD MODE TO PERCEPTUAL SIGNALS:
#--------------------------------------
if direction == 'forward':
if Ccwb is None:
alph_out = alph_int - cab_out[0]
bet_out = bet_int - cab_out[1]
else:
Ccwb = Ccwb * np.ones((2))
Ccwb[Ccwb < 0.0] = 0.0
Ccwb[Ccwb > 1.0] = 1.0
# white balance shift using adaptation gray background (Yb=20%), with Ccw: degree of adaptation:
alph_out = alph_int - Ccwb[0] * alph_int[0]
bet_out = bet_int - Ccwb[1] * bet_int[0]
# stack together and remove adaptation field from vertical stack
# camout is an ndarray with perceptual signals:
camout[i] = np.vstack((lstar_out[1:], alph_out[1:], bet_out[1:])).T
#--------------------------------------
# INVERSE MODE FROM PERCEPTUAL SIGNALS:
#--------------------------------------
elif direction == 'inverse':
# stack cognitive pre-adapted adaptation field signals (first on stack) together:
#labf_int = np.hstack((lstar_int[0],alph_int[0],bet_int[0]))
# get lstar_out, alph_out & bet_out for data
#(contains model perceptual signals in inverse mode!!!):
lstar_out, alph_out, bet_out = asplit(data[i])
#------------------------------------------------------------------------
# Inverse stage 5: undo cortical white-balance:
#------------------------------------------------------------------------
if Ccwb is None:
alph_int = alph_out + cab_out[0]
bet_int = bet_out + cab_out[1]
else:
Ccwb = Ccwb * np.ones((2))
Ccwb[Ccwb < 0.0] = 0.0
Ccwb[Ccwb > 1.0] = 1.0
# inverse white balance shift using adaptation gray background (Yb=20%), with Ccw: degree of adaptation
alph_int = alph_out + Ccwb[0] * alph_int[0]
bet_int = bet_out + Ccwb[1] * bet_int[0]
alphpp = (1.0 / cab_int[0]) * (
np.cos(-cab_int[1] * np.pi / 180.0) * alph_int -
np.sin(-cab_int[1] * np.pi / 180.0) * bet_int)
betpp = (1.0 / cab_int[0]) * (
np.sin(-cab_int[1] * np.pi / 180.0) * alph_int +
np.cos(-cab_int[1] * np.pi / 180.0) * bet_int)
lstar_int = lstar_out
lstar = (lstar_int / cl_int[0]) - cl_int[1]
#---------------------------------------------------------------------------
# Inverse stage 4: pre-adapted perceptual signals to recoded nerve signals:
#---------------------------------------------------------------------------
alphp = 0.5 * (alphpp / cga2[0] + betpp / cgb2[0]
) # <-- alphpp = (Cga2.*(alphp+betp));
betp = 0.5 * (alphpp / cga2[0] - betpp / cgb2[0]
) # <-- betpp = (Cgb2.*(alphp-betp));
#---------------------------------------------------------------------------
# Inverse stage 3: recoded nerve signals to optic nerve signals:
#---------------------------------------------------------------------------
alph = alphp / cga1[0]
bet = betp / cgb1[0]
sa = np.sign(cga1[1])
sb = np.sign(cgb1[1])
alph[(sa * alphp) < 0.0] = alphp[(sa * alphp) < 0] / cga1[1]
bet[(sb * betp) < 0.0] = betp[(sb * betp) < 0] / cgb1[1]
lab = ajoin((lstar, alph, bet))
#---------------------------------------------------------------------------
# Inverse stage 2: optic nerve signals to cone outputs:
#---------------------------------------------------------------------------
lmstp = np.dot(invMAab, lab.T).T
lmstp[lmstp < -1.0] = -1.0
lmstp[lmstp > 1.0] = 1.0
#---------------------------------------------------------------------------
# Inverse stage 1: cone outputs to photon rates:
#---------------------------------------------------------------------------
lmstp = math.erfinv(lmstp) / Cc - Cf * np.log(lmsf / lms0)
lmst = np.exp(lmstp) * lms0
#---------------------------------------------------------------------------
# Photon rates to absolute or relative tristimulus values:
#---------------------------------------------------------------------------
xyzt = np.dot(invMxyz2lms, lmst.T).T * (_CMF[cieobs]['K'] / 683.0)
if relative == True:
xyzt = (100 / Lw) * xyzt
# store in same named variable as forward mode:
camout[i] = xyzt
#++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
# END inverse mode
#++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
return _massage_output_data_to_original_shape(camout, originalshape)
def cam_sww16(data, dataw = None, Yb = 20.0, Lw = 400.0, Ccwb = None, relative = True, \
parameters = None, inputtype = 'xyz', direction = 'forward', \
cieobs = '2006_10'):
"""
A simple principled color appearance model based on a mapping
of the Munsell color system.
| This function implements the JOSA A (parameters = 'JOSA') published model.
Args:
:data:
| ndarray with input tristimulus values
| or spectral data
| or input color appearance correlates
| Can be of shape: (N [, xM], x 3), whereby:
| N refers to samples and M refers to light sources.
| Note that for spectral input shape is (N x (M+1) x wl)
:dataw:
| None or ndarray, optional
| Input tristimulus values or spectral data of white point.
| None defaults to the use of CIE illuminant C.
:Yb:
| 20.0, optional
| Luminance factor of background (perfect white diffuser, Yw = 100)
:Lw:
| 400.0, optional
| Luminance (cd/m²) of white point.
:Ccwb:
| None, optional
| Degree of cognitive adaptation (white point balancing)
| If None: use [..,..] from parameters dict.
:relative:
| True or False, optional
| True: xyz tristimulus values are relative (Yw = 100)
:parameters:
| None or str or dict, optional
| Dict with model parameters.
| - None: defaults to luxpy.cam._CAM_SWW_2016_PARAMETERS['JOSA']
| - str: 'best-fit-JOSA' or 'best-fit-all-Munsell'
| - dict: user defined model parameters
| (dict should have same structure)
:inputtype:
| 'xyz' or 'spd', optional
| Specifies the type of input:
| tristimulus values or spectral data for the forward mode.
:direction:
| 'forward' or 'inverse', optional
| -'forward': xyz -> cam_sww_2016
| -'inverse': cam_sww_2016 -> xyz
:cieobs:
| '2006_10', optional
| CMF set to use to perform calculations where spectral data
is involved (inputtype == 'spd'; dataw = None)
| Other options: see luxpy._CMF['types']
Returns:
:returns:
| ndarray with color appearance correlates (:direction: == 'forward')
| or
| XYZ tristimulus values (:direction: == 'inverse')
Notes:
| This function implements the JOSA A (parameters = 'JOSA')
published model.
| With:
| 1. A correction for the parameter
| in Eq.4 of Fig. 11: 0.952 --> -0.952
|
| 2. The delta_ac and delta_bc white-balance shifts in Eq. 5e & 5f
| should be: -0.028 & 0.821
|
| (cfr. Ccwb = 0.66 in:
| ab_test_out = ab_test_int - Ccwb*ab_gray_adaptation_field_int))
References:
1. `Smet, K. A. G., Webster, M. A., & Whitehead, L. A. (2016).
A simple principled approach for modeling and understanding uniform color metrics.
Journal of the Optical Society of America A, 33(3), A319–A331.
<https://doi.org/10.1364/JOSAA.33.00A319>`_
"""
# get model parameters
args = locals().copy()
if parameters is None:
parameters = _CAM_SWW16_PARAMETERS['JOSA']
if isinstance(parameters, str):
parameters = _CAM_SWW16_PARAMETERS[parameters]
parameters = put_args_in_db(
parameters,
args) #overwrite parameters with other (not-None) args input
#unpack model parameters:
Cc, Ccwb, Cf, Mxyz2lms, cLMS, cab_int, cab_out, calpha, cbeta, cga1, cga2, cgb1, cgb2, cl_int, clambda, lms0 = [
parameters[x] for x in sorted(parameters.keys())
]
# setup default adaptation field:
if (dataw is None):
dataw = _CIE_ILLUMINANTS['C'].copy() # get illuminant C
xyzw = spd_to_xyz(dataw, cieobs=cieobs,
relative=False) # get abs. tristimulus values
if relative == False: #input is expected to be absolute
dataw[1:] = Lw * dataw[
1:] / xyzw[:, 1:2] #dataw = Lw*dataw # make absolute
else:
dataw = dataw # make relative (Y=100)
if inputtype == 'xyz':
dataw = spd_to_xyz(dataw, cieobs=cieobs, relative=relative)
# precomputations:
Mxyz2lms = np.dot(
np.diag(cLMS),
math.normalize_3x3_matrix(Mxyz2lms, np.array([[1, 1, 1]]))
) # normalize matrix for xyz-> lms conversion to ill. E weighted with cLMS
invMxyz2lms = np.linalg.inv(Mxyz2lms)
MAab = np.array([clambda, calpha, cbeta])
invMAab = np.linalg.inv(MAab)
#initialize data and camout:
data = np2d(data).copy(
) # stimulus data (can be upto NxMx3 for xyz, or [N x (M+1) x wl] for spd))
dataw = np2d(dataw).copy(
) # white point (can be upto Nx3 for xyz, or [(N+1) x wl] for spd)
# make axis 1 of dataw have 'same' dimensions as data:
if (data.ndim == 2):
data = np.expand_dims(data, axis=1) # add light source axis 1
if inputtype == 'xyz':
if dataw.shape[
0] == 1: #make dataw have same lights source dimension size as data
dataw = np.repeat(dataw, data.shape[1], axis=0)
else:
if dataw.shape[0] == 2:
dataw = np.vstack(
(dataw[0], np.repeat(dataw[1:], data.shape[1], axis=0)))
# Flip light source dim to axis 0:
data = np.transpose(data, axes=(1, 0, 2))
# Initialize output array:
dshape = list(data.shape)
dshape[-1] = 3 # requested number of correlates: l_int, a_int, b_int
if (inputtype != 'xyz') & (direction == 'forward'):
dshape[-2] = dshape[
-2] - 1 # wavelength row doesn't count & only with forward can the input data be spectral
camout = np.zeros(dshape)
camout.fill(np.nan)
# apply forward/inverse model for each row in data:
for i in range(data.shape[0]):
# stage 1: calculate photon rates of stimulus and adapting field, lmst & lmsf:
if (inputtype != 'xyz'):
if relative == True:
xyzw_abs = spd_to_xyz(np.vstack((dataw[0], dataw[i + 1])),
cieobs=cieobs,
relative=False)
dataw[i +
1] = Lw * dataw[i + 1] / xyzw_abs[0, 1] # make absolute
xyzw = spd_to_xyz(np.vstack((dataw[0], dataw[i + 1])),
cieobs=cieobs,
relative=False)
lmsw = 683.0 * np.dot(Mxyz2lms, xyzw.T).T / _CMF[cieobs]['K']
lmsf = (Yb / 100.0
) * lmsw # calculate adaptation field and convert to l,m,s
if (direction == 'forward'):
if relative == True:
data[i, 1:, :] = Lw * data[i, 1:, :] / xyzw_abs[
0, 1] # make absolute
xyzt = spd_to_xyz(data[i], cieobs=cieobs,
relative=False) / _CMF[cieobs]['K']
lmst = 683.0 * np.dot(Mxyz2lms, xyzt.T).T # convert to l,m,s
else:
lmst = lmsf # put lmsf in lmst for inverse-mode
elif (inputtype == 'xyz'):
if relative == True:
dataw[i] = Lw * dataw[i] / 100.0 # make absolute
lmsw = 683.0 * np.dot(
Mxyz2lms, dataw[i].T).T / _CMF[cieobs]['K'] # convert to lms
lmsf = (Yb / 100.0) * lmsw
if (direction == 'forward'):
if relative == True:
data[i] = Lw * data[i] / 100.0 # make absolute
lmst = 683.0 * np.dot(
Mxyz2lms,
data[i].T).T / _CMF[cieobs]['K'] # convert to lms
else:
lmst = lmsf # put lmsf in lmst for inverse-mode
# stage 2: calculate cone outputs of stimulus lmstp
lmstp = math.erf(Cc * (np.log(lmst / lms0) + Cf * np.log(lmsf / lms0)))
lmsfp = math.erf(Cc * (np.log(lmsf / lms0) + Cf * np.log(lmsf / lms0)))
lmstp = np.vstack(
(lmsfp, lmstp)
) # add adaptation field lms temporarily to lmsp for quick calculation
# stage 3: calculate optic nerve signals, lam*, alphp, betp:
lstar, alph, bet = asplit(np.dot(MAab, lmstp.T).T)
alphp = cga1[0] * alph
alphp[alph < 0] = cga1[1] * alph[alph < 0]
betp = cgb1[0] * bet
betp[bet < 0] = cgb1[1] * bet[bet < 0]
# stage 4: calculate recoded nerve signals, alphapp, betapp:
alphpp = cga2[0] * (alphp + betp)
betpp = cgb2[0] * (alphp - betp)
# stage 5: calculate conscious color perception:
lstar_int = cl_int[0] * (lstar + cl_int[1])
alph_int = cab_int[0] * (np.cos(cab_int[1] * np.pi / 180.0) * alphpp -
np.sin(cab_int[1] * np.pi / 180.0) * betpp)
bet_int = cab_int[0] * (np.sin(cab_int[1] * np.pi / 180.0) * alphpp +
np.cos(cab_int[1] * np.pi / 180.0) * betpp)
lstar_out = lstar_int
if direction == 'forward':
if Ccwb is None:
alph_out = alph_int - cab_out[0]
bet_out = bet_int - cab_out[1]
else:
Ccwb = Ccwb * np.ones((2))
Ccwb[Ccwb < 0.0] = 0.0
Ccwb[Ccwb > 1.0] = 1.0
alph_out = alph_int - Ccwb[0] * alph_int[
0] # white balance shift using adaptation gray background (Yb=20%), with Ccw: degree of adaptation
bet_out = bet_int - Ccwb[1] * bet_int[0]
camout[i] = np.vstack(
(lstar_out[1:], alph_out[1:], bet_out[1:])
).T # stack together and remove adaptation field from vertical stack
elif direction == 'inverse':
labf_int = np.hstack((lstar_int[0], alph_int[0], bet_int[0]))
# get lstar_out, alph_out & bet_out for data:
lstar_out, alph_out, bet_out = asplit(data[i])
# stage 5 inverse:
# undo cortical white-balance:
if Ccwb is None:
alph_int = alph_out + cab_out[0]
bet_int = bet_out + cab_out[1]
else:
Ccwb = Ccwb * np.ones((2))
Ccwb[Ccwb < 0.0] = 0.0
Ccwb[Ccwb > 1.0] = 1.0
alph_int = alph_out + Ccwb[0] * alph_int[
0] # inverse white balance shift using adaptation gray background (Yb=20%), with Ccw: degree of adaptation
bet_int = bet_out + Ccwb[1] * bet_int[0]
lstar_int = lstar_out
alphpp = (1.0 / cab_int[0]) * (
np.cos(-cab_int[1] * np.pi / 180.0) * alph_int -
np.sin(-cab_int[1] * np.pi / 180.0) * bet_int)
betpp = (1.0 / cab_int[0]) * (
np.sin(-cab_int[1] * np.pi / 180.0) * alph_int +
np.cos(-cab_int[1] * np.pi / 180.0) * bet_int)
lstar_int = lstar_out
lstar = (lstar_int / cl_int[0]) - cl_int[1]
# stage 4 inverse:
alphp = 0.5 * (alphpp / cga2[0] + betpp / cgb2[0]
) # <-- alphpp = (Cga2.*(alphp+betp));
betp = 0.5 * (alphpp / cga2[0] - betpp / cgb2[0]
) # <-- betpp = (Cgb2.*(alphp-betp));
# stage 3 invers:
alph = alphp / cga1[0]
bet = betp / cgb1[0]
sa = np.sign(cga1[1])
sb = np.sign(cgb1[1])
alph[(sa * alphp) < 0.0] = alphp[(sa * alphp) < 0] / cga1[1]
bet[(sb * betp) < 0.0] = betp[(sb * betp) < 0] / cgb1[1]
lab = ajoin((lstar, alph, bet))
# stage 2 inverse:
lmstp = np.dot(invMAab, lab.T).T
lmstp[lmstp < -1.0] = -1.0
lmstp[lmstp > 1.0] = 1.0
lmstp = math.erfinv(lmstp) / Cc - Cf * np.log(lmsf / lms0)
lmst = np.exp(lmstp) * lms0
# stage 1 inverse:
xyzt = np.dot(invMxyz2lms, lmst.T).T
if relative == True:
xyzt = (100.0 / Lw) * xyzt
camout[i] = xyzt
# if flipaxis0and1 == True: # loop over shortest dim.
# camout = np.transpose(camout, axes = (1,0,2))
# Flip light source dim back to axis 1:
camout = np.transpose(camout, axes=(1, 0, 2))
if camout.shape[0] == 1:
camout = np.squeeze(camout, axis=0)
return camout
def DE2000(xyzt,
xyzr,
dtype='xyz',
DEtype='jab',
avg=None,
avg_axis=0,
out='DEi',
xyzwt=None,
xyzwr=None,
KLCH=None):
"""
Calculate DE2000 color difference.
Args:
:xyzt:
| ndarray with tristimulus values of test data.
:xyzr:
| ndarray with tristimulus values of reference data.
:dtype:
| 'xyz' or 'lab', optional
| Specifies data type in :xyzt: and :xyzr:.
:xyzwt:
| None or ndarray, optional
| White point tristimulus values of test data
| None defaults to the one set in lx.xyz_to_lab()
:xyzwr:
| None or ndarray, optional
| Whitepoint tristimulus values of reference data
| None defaults to the one set in lx.xyz_to_lab()
:DEtype:
| 'jab' or str, optional
| Options:
| - 'jab' : calculates full color difference over all 3 dimensions.
| - 'ab' : calculates chromaticity difference.
| - 'j' : calculates lightness or brightness difference
| (depending on :outin:).
| - 'j,ab': calculates both 'j' and 'ab' options
| and returns them as a tuple.
:KLCH:
| None, optional
| Weigths for L, C, H
| None: default to [1,1,1]
:avg:
| None, optional
| None: don't calculate average DE,
| otherwise use function handle in :avg:.
:avg_axis:
| axis to calculate average over, optional
:out:
| 'DEi' or str, optional
| Requested output.
Note:
For the other input arguments, see specific color space used.
Returns:
:returns:
| ndarray with DEi [, DEa] or other as specified by :out:
References:
1. `Sharma, G., Wu, W., & Dalal, E. N. (2005).
The CIEDE2000 color‐difference formula: Implementation notes,
supplementary test data, and mathematical observations.
Color Research & Application, 30(1), 21–30.
<https://doi.org/10.1002/col.20070>`_
"""
if KLCH is None:
KLCH = [1, 1, 1]
if dtype == 'xyz':
labt = xyz_to_lab(xyzt, xyzw=xyzwt)
labr = xyz_to_lab(xyzr, xyzw=xyzwr)
else:
labt = xyzt
labr = xyzr
Lt = labt[..., 0:1]
at = labt[..., 1:2]
bt = labt[..., 2:3]
Ct = np.sqrt(at**2 + bt**2)
#ht = cam.hue_angle(at,bt,htype = 'rad')
Lr = labr[..., 0:1]
ar = labr[..., 1:2]
br = labr[..., 2:3]
Cr = np.sqrt(ar**2 + br**2)
#hr = cam.hue_angle(at,bt,htype = 'rad')
# Step 1:
Cavg = (Ct + Cr) / 2
G = 0.5 * (1 - np.sqrt((Cavg**7.0) / ((Cavg**7.0) + (25.0**7))))
apt = (1 + G) * at
apr = (1 + G) * ar
Cpt = np.sqrt(apt**2 + bt**2)
Cpr = np.sqrt(apr**2 + br**2)
Cpprod = Cpt * Cpr
hpt = cam.hue_angle(apt, bt, htype='deg')
hpr = cam.hue_angle(apr, br, htype='deg')
hpt[(apt == 0) * (bt == 0)] = 0
hpr[(apr == 0) * (br == 0)] = 0
# Step 2:
dL = np.abs(Lr - Lt)
dCp = np.abs(Cpr - Cpt)
dhp_ = hpr - hpt
dhp = dhp_.copy()
dhp[np.where(np.abs(dhp_) > 180)] = dhp[np.where(np.abs(dhp_) > 180)] - 360
dhp[np.where(
np.abs(dhp_) < -180)] = dhp[np.where(np.abs(dhp_) < -180)] + 360
dhp[np.where(Cpprod == 0)] = 0
#dH = 2*np.sqrt(Cpprod)*np.sin(dhp/2*np.pi/180)
dH = deltaH(dhp, Cpprod, htype='deg')
# Step 3:
Lp = (Lr + Lt) / 2
Cp = (Cpr + Cpt) / 2
hps = hpt + hpr
hp = (hpt + hpr) / 2
hp[np.where((np.abs(dhp_) > 180)
& (hps < 360))] = hp[np.where((np.abs(dhp_) > 180)
& (hps < 360))] + 180
hp[np.where((np.abs(dhp_) > 180)
& (hps >= 360))] = hp[np.where((np.abs(dhp_) > 180)
& (hps >= 360))] - 180
hp[np.where(Cpprod == 0)] = 0
T = 1 - 0.17*np.cos((hp - 30)*np.pi/180) + 0.24*np.cos(2*hp*np.pi/180) +\
0.32*np.cos((3*hp + 6)*np.pi/180) - 0.20*np.cos((4*hp - 63)*np.pi/180)
dtheta = 30 * np.exp(-((hp - 275) / 25)**2)
RC = 2 * np.sqrt((Cp**7) / ((Cp**7) + (25**7)))
SL = 1 + ((0.015 * (Lp - 50)**2) / np.sqrt(20 + (Lp - 50)**2))
SC = 1 + 0.045 * Cp
SH = 1 + 0.015 * Cp * T
RT = -np.sin(2 * dtheta * np.pi / 180) * RC
kL, kC, kH = KLCH
DEi = ((dL / (kL * SL))**2, (dCp / (kC * SC))**2 + (dH / (kH * SH))**2 +
RT * (dCp / (kC * SC)) * (dH / (kH * SH)))
return _process_DEi(DEi,
DEtype=DEtype,
avg=avg,
avg_axis=avg_axis,
out=out)
def run(data,
xyzw=None,
outin='J,aM,bM',
cieobs=_CIEOBS,
conditions=None,
forward=True,
mcat='cat02',
**kwargs):
"""
Run the Jz,az,bz based color appearance model in forward or backward modes.
Args:
:data:
| ndarray with relative sample xyz values (forward mode) or J'a'b' coordinates (inverse mode)
:xyzw:
| ndarray with relative white point tristimulus values
| None defaults to D65
:cieobs:
| _CIEOBS, optional
| CMF set to use when calculating :xyzw: if this is None.
:conditions:
| None, optional
| Dictionary with viewing condition parameters for:
| La, Yb, D and surround.
| surround can contain:
| - str (options: 'avg','dim','dark') or
| - dict with keys c, Nc, F.
| None results in:
| {'La':100, 'Yb':20, 'D':1, 'surround':'avg'}
:forward:
| True, optional
| If True: run in CAM in forward mode, else: inverse mode.
:outin:
| 'J,aM,bM', optional
| String with requested output (e.g. "J,aM,bM,M,h") [Forward mode]
| - attributes: 'J': lightness,'Q': brightness,
| 'M': colorfulness,'C': chroma, 's': saturation,
| 'h': hue angle, 'H': hue quadrature/composition,
| 'Wz': whiteness, 'Kz':blackness, 'Sz': saturation, 'V': vividness
| String with inputs in data [inverse mode].
| Input must have data.shape[-1]==3 and last dim of data must have
| the following structure for inverse mode:
| * data[...,0] = J or Q,
| * data[...,1:] = (aM,bM) or (aC,bC) or (aS,bS) or (M,h) or (C, h), ...
:mcat:
| 'cat02', optional
| Specifies CAT sensor space.
| - options:
| - None defaults to 'cat02'
| - str: see see luxpy.cat._MCATS.keys() for options
| (details on type, ?luxpy.cat)
| - ndarray: matrix with sensor primaries
Returns:
:camout:
| ndarray with color appearance correlates (forward mode)
| or
| XYZ tristimulus values (inverse mode)
References:
1. `Safdar, M., Cui, G., Kim,Y. J., and Luo, M. R.(2017).
Perceptually uniform color space for image signals including high dynamic range and wide gamut.
Opt. Express, vol. 25, no. 13, pp. 15131–15151, Jun. 2017.
<https://www.opticsexpress.org/abstract.cfm?URI=oe-25-13-15131>`_
2. `Safdar, M., Hardeberg, J., Cui, G., Kim, Y. J., and Luo, M. R.(2018).
A Colour Appearance Model based on Jzazbz Colour Space,
26th Color and Imaging Conference (2018), Vancouver, Canada, November 12-16, 2018, pp96-101.
<https://doi.org/10.2352/ISSN.2169-2629.2018.26.96>`_
3. Safdar, M., Hardeberg, J.Y., Luo, M.R. (2021)
"ZCAM, a psychophysical model for colour appearance prediction",
Optics Express.
"""
print(
"WARNING: Z-CAM is as yet unpublished and under development, so parameter values might change! (07 Oct, 2020"
)
outin = outin.split(',') if isinstance(outin, str) else outin
#--------------------------------------------
# Get condition parameters:
if conditions is None:
conditions = _DEFAULT_CONDITIONS
D, Dtype, La, Yb, surround = (conditions[x]
for x in sorted(conditions.keys()))
surround_parameters = _SURROUND_PARAMETERS
if isinstance(surround, str):
surround = surround_parameters[conditions['surround']]
F, FLL, Nc, c = [surround[x] for x in sorted(surround.keys())]
# Define cone/chromatic adaptation sensor space:
if (mcat is None):
mcat = cat._MCATS['cat02']
elif isinstance(mcat, str):
mcat = cat._MCATS[mcat]
invmcat = np.linalg.inv(mcat)
#--------------------------------------------
# Get white point of D65 fro chromatic adaptation transform (CAT)
xyzw_d65 = np.array([[
9.5047e+01, 1.0000e+02, 1.08883e+02
]]) if cieobs == '1931_2' else spd_to_xyz(_CIE_D65, cieobs=cieobs)
#--------------------------------------------
# Get default white point:
if xyzw is None:
xyzw = xyzw_d65.copy()
#--------------------------------------------
# calculate condition dependent parameters:
Yw = xyzw[..., 1].T
FL = 0.171 * La**(1 / 3) * (1 - np.exp(-48 / 9 * La)
) # luminance adaptation factor
n = Yb / Yw
Fb = 1.045 + 1.46 * n**0.5 # background factor
Fs = c # surround factor
#--------------------------------------------
# Calculate degree of chromatic adaptation:
if D is None:
D = F * (1.0 - (1.0 / 3.6) * np.exp((-La - 42.0) / 92.0))
#===================================================================
# WHITE POINT transformations (common to forward and inverse modes):
#--------------------------------------------
# Apply CAT to white point:
xyzwc = cat.apply_vonkries2(xyzw,
xyzw1=xyzw,
xyzw2=xyzw_d65,
D=D,
mcat=mcat,
invmcat=invmcat,
use_Yw=True)
#--------------------------------------------
# Get Iz,az,bz coordinates:
iabzw = xyz_to_jabz(xyzwc, ztype='iabz', use_zcam_parameters=True)
# Get brightness of white point:
Qw = 925 * iabzw[..., 0]**1.17 * (FL / Fs)**0.5
#===================================================================
# STIMULUS transformations:
#--------------------------------------------
# massage shape of data for broadcasting:
original_ndim = data.ndim
if data.ndim == 2: data = data[:, None]
if forward:
# Apply CAT to D65:
xyzc = cat.apply_vonkries2(data,
xyzw1=xyzw,
xyzw2=xyzw_d65,
D=D,
mcat=mcat,
invmcat=invmcat,
use_Yw=True)
# Get Iz,az,bz coordinates:
iabz = xyz_to_jabz(xyzc, ztype='iabz', use_zcam_parameters=True)
#--------------------------------------------
# calculate hue h and eccentricity factor, et:
h = hue_angle(iabz[..., 1], iabz[..., 2], htype='deg')
ez = 1.014 + np.cos((h + 89.038) * np.pi / 180)
# ez = 1.014 + np.cos((h*np.pi/180) + 89.038)
#--------------------------------------------
# calculate Hue quadrature (if requested in 'out'):
if 'H' in outin:
H = hue_quadrature(h, unique_hue_data=_UNIQUE_HUE_DATA)
else:
H = None
#--------------------------------------------
# calculate brightness, Q:
Q = 925 * iabz[..., 0]**1.17 * (FL / Fs)**0.5
#--------------------------------------------
# calculate lightness, J:
J = 100.0 * (Q / Qw)**(Fs * Fb)
#--------------------------------------------
# calculate colorfulness, M:
M = 50 * ((iabz[..., 1]**2.0 + iabz[..., 2]**2.0)**
0.368) * (ez**0.068) * (FL**0.2) / ((iabzw[..., 0]**2.52) *
(Fb**0.3))
#--------------------------------------------
# calculate chroma, C:
C = 100 * M / Qw
#--------------------------------------------
# calculate saturation, s:
s = 100.0 * (M / Q)
S = s # make extra variable, jsut in case 'S' is called
#--------------------------------------------
# calculate whiteness, W:
if ('Wz' in outin) | ('aWz' in outin):
Wz = 100 - 0.68 * ((100 - J)**2 + C**2)**0.5
#--------------------------------------------
# calculate blackness, K:
if ('Kz' in outin) | ('aKz' in outin):
Kz = 100 - 0.82 * (J**2 + C**2)**0.5
#--------------------------------------------
# calculate saturation, S:
if ('Sz' in outin) | ('aSz' in outin):
Sz = 8 + 0.5 * ((J - 55)**2 + C**2)**0.5
#--------------------------------------------
# calculate vividness, V:
if ('Vz' in outin) | ('aVz' in outin):
Sz = 8 + 0.4 * ((J - 70)**2 + C**2)**0.5
#--------------------------------------------
# calculate cartesian coordinates:
if ('aS' in outin):
aS = s * np.cos(h * np.pi / 180.0)
bS = s * np.sin(h * np.pi / 180.0)
if ('aC' in outin):
aC = C * np.cos(h * np.pi / 180.0)
bC = C * np.sin(h * np.pi / 180.0)
if ('aM' in outin):
aM = M * np.cos(h * np.pi / 180.0)
bM = M * np.sin(h * np.pi / 180.0)
#--------------------------------------------
if outin != ['J', 'aM', 'bM']:
camout = eval('ajoin((' + ','.join(outin) + '))')
else:
camout = ajoin((J, aM, bM))
if (camout.shape[1] == 1) & (original_ndim < 3):
camout = camout[:, 0, :]
return camout
elif forward == False:
#--------------------------------------------
# Get Lightness J and brightness Q from data:
if ('J' in outin[0]):
J = data[..., 0].copy()
Q = Qw * (J / 100)**(1 / (Fs * Fb))
elif ('Q' in outin[0]):
Q = data[..., 0].copy()
J = 100.0 * (Q / Qw)**(Fs * Fb)
else:
raise Exception(
'No lightness or brightness values in data[...,0]. Inverse CAM-transform not possible!'
)
#--------------------------------------------
# calculate achromatic signal, Iz:
Iz = (Qw / 925 * ((J / 100)**(1 / (Fs * Fb))) * (Fs / FL)**0.5)**(1 /
1.17)
#--------------------------------------------
if 'a' in outin[1]:
# calculate hue h:
h = hue_angle(data[..., 1], data[..., 2], htype='deg')
#--------------------------------------------
# calculate Colorfulness M or Chroma C or Saturation s from a,b:
MCs = (data[..., 1]**2.0 + data[..., 2]**2.0)**0.5
else:
h = data[..., 2]
MCs = data[..., 1]
if ('aS' in outin) | ('S' in outin):
Q = Qw * (J / 100)**(1 / (Fs * Fb))
M = Q * (MCs / 100.0)
C = 100 * M / Qw
if ('aM' in outin) | ('M' in outin):
C = 100 * MCs / Qw
if ('aC' in outin) | ('C' in outin): # convert C to M:
C = MCs
if ('Wz' in outin) | ('aWz' in outin): #whiteness
C = ((100 / 68 * (100 - MCs))**2 - (J - 100)**2)**0.5
if ('Kz' in outin) | ('aKz' in outin): # blackness
C = ((100 / 82 * (100 - MCs))**2 - (J)**2)**0.5
if ('Sz' in outin) | ('aSz' in outin): # saturation
C = ((10 / 5 * (MCs - 8))**2 - (J - 55)**2)**0.5
if ('Vz' in outin) | ('aVz' in outin): # vividness
C = ((10 / 4 * (MCs - 8))**2 - (J - 70)**2)**0.5
#--------------------------------------------
# Calculate colorfulness, M:
M = Qw * C / 100
#--------------------------------------------
# calculate eccentricity factor, et:
# ez = 1.014 + np.cos(h*np.pi/180 + 89.038)
ez = 1.014 + np.cos((h + 89.038) * np.pi / 180)
#--------------------------------------------
# calculate t (=sqrt(a**2+b**2)) from M:
t = (((M / 50) * (iabzw[..., 0]**2.52) * (Fb**0.3)) /
((ez**0.068) * (FL**0.2)))**(1 / 0.368 / 2)
#--------------------------------------------
# Calculate az, bz:
az = t * np.cos(h * np.pi / 180)
bz = t * np.sin(h * np.pi / 180)
#--------------------------------------------
# join values and convert to xyz:
xyzc = jabz_to_xyz(ajoin((Iz, az, bz)),
ztype='iabz',
use_zcam_parameters=True)
#-------------------------------------------
# Apply CAT from D65:
xyz = cat.apply_vonkries2(xyzc,
xyzw_d65,
xyzw,
D=D,
mcat=mcat,
invmcat=invmcat,
use_Yw=True)
return xyz
