def _cri_ref_i(cct,
wl3=_WL,
ref_type='iestm30',
mix_range=[4000, 5000],
cieobs='1931_2',
force_daylight_below4000K=False,
n=None,
daylight_locus=None):
"""
Calculates a reference illuminant spectrum based on cct
for color rendering index calculations.
"""
if mix_range is None:
mix_range = _CRI_REF_TYPES[ref_type]
if (cct < mix_range[0]) | (ref_type == 'BB'):
return blackbody(cct, wl3, n=n)
elif (cct > mix_range[0]) | (ref_type == 'DL'):
return daylightphase(
cct,
wl3,
force_daylight_below4000K=force_daylight_below4000K,
cieobs=cieobs,
daylight_locus=daylight_locus)
else:
SrBB = blackbody(cct, wl3, n=n)
SrDL = daylightphase(
cct,
wl3,
verbosity=None,
force_daylight_below4000K=force_daylight_below4000K,
cieobs=cieobs,
daylight_locus=daylight_locus)
cmf = _CMF[cieobs]['bar'] if isinstance(cieobs, str) else cieobs
wl = SrBB[0]
ld = getwld(wl)
SrBB = 100.0 * SrBB[1] / np.array(np.sum(SrBB[1] * cmf[2] * ld))
SrDL = 100.0 * SrDL[1] / np.array(np.sum(SrDL[1] * cmf[2] * ld))
Tb, Te = float(mix_range[0]), float(mix_range[1])
cBB, cDL = (Te - cct) / (Te - Tb), (cct - Tb) / (Te - Tb)
if cBB < 0.0:
cBB = 0.0
elif cBB > 1:
cBB = 1.0
if cDL < 0.0:
cDL = 0.0
elif cDL > 1:
cDL = 1.0
Sr = SrBB * cBB + SrDL * cDL
Sr[Sr == float('NaN')] = 0.0
Sr = np.vstack((wl, (Sr / Sr[_POS_WL560])))
return Sr
def calculate_lut(ccts=None, cieobs=None, add_to_lut=True):
"""
Function that calculates LUT for the ccts stored in
./data/cctluts/cct_lut_cctlist.dat or given as input argument.
Calculation is performed for CMF set specified in cieobs.
Adds a new (temprorary) field to the _CCT_LUT dict.
Args:
:ccts:
| ndarray or str, optional
| list of ccts for which to (re-)calculate the LUTs.
| If str, ccts contains path/filename.dat to list.
:cieobs:
| None or str, optional
| str specifying cmf set.
Returns:
:returns:
| ndarray with cct and duv.
Note:
Function changes the global variable: _CCT_LUT!
"""
if ccts is None:
ccts = getdata('{}cct_lut_cctlist.dat'.format(_CCT_LUT_PATH))
elif isinstance(ccts, str):
ccts = getdata(ccts)
Yuv = np.ones((ccts.shape[0], 2)) * np.nan
for i, cct in enumerate(ccts):
Yuv[i, :] = xyz_to_Yuv(
spd_to_xyz(blackbody(cct, wl3=[360, 830, 1]), cieobs=cieobs))[:,
1:3]
u = Yuv[:, 0, None] # get CIE 1960 u
v = (2.0 / 3.0) * Yuv[:, 1, None] # get CIE 1960 v
cctuv = np.hstack((ccts, u, v))
if add_to_lut == True:
_CCT_LUT[cieobs] = cctuv
return cctuv
def spd_to_COI_ASNZS1680(S=None,
tf=_COI_CSPACE,
cieobs=_COI_CIEOBS,
out='COI,cct',
extrapolate_rfl=False):
"""
Calculate the Cyanosis Observation Index (COI) [ASNZS 1680.2.5-1995].
Args:
:S:
| ndarray with light source spectrum (first column are wavelengths).
:tf:
| _COI_CSPACE, optional
| Color space in which to calculate the COI.
| Default is CIELAB.
:cieobs:
| _COI_CIEOBS, optional
| CMF set to use.
| Default is '1931_2'.
:out:
| 'COI,cct' or str, optional
| Determines output.
:extrapolate_rfl:
| False, optional
| If False:
| limit the wavelength range of the source to that of the standard
| reflectance spectra for the 50% and 100% oxygenated blood.
Returns:
:COI:
| ndarray with cyanosis indices for input sources.
:cct:
| ndarray with correlated color temperatures.
Note:
Clause 7.2 of the ASNZS 1680.2.5-1995. standard mentions the properties
demanded of the light source used in region where visual conditions
suitable to the detection of cyanosis should be provided:
1. The correlated color temperature (CCT) of the source should be from
3300 to 5300 K.
2. The cyanosis observation index should not exceed 3.3
"""
if S is None: #use default
S = _CIE_ILLUMINANTS['F4']
if extrapolate_rfl == False: # _COI_RFL do not cover the full 360-830nm range.
wl_min = _COI_RFL_BLOOD[0].min()
wl_max = _COI_RFL_BLOOD[0].max()
S = S[:, np.where((S[0] >= wl_min) & (S[0] <= wl_max))[0]]
# Calculate reference spd:
Sr = blackbody(4000, wl3=S[0]) # same wavelength range
# Calculate xyz of blood under test source and ref. source:
xyzt, xyzwt = spd_to_xyz(S,
rfl=_COI_RFL_BLOOD,
relative=True,
cieobs=cieobs,
out=2)
xyzr, xyzwr = spd_to_xyz(Sr,
rfl=_COI_RFL_BLOOD,
relative=True,
cieobs=cieobs,
out=2)
# Calculate color difference between blood under test and ref.
DEi = deltaE.DE_cspace(xyzt, xyzr, xyzwt=xyzwt, xyzwr=xyzwr, tf=tf)
# Calculate Cyanosis Observation Index:
COI = np.nanmean(DEi, axis=0)[:, None]
# Calculate cct, if requested:
if 'cct' in out.split(','):
cct, duv = xyz_to_cct(xyzwt, cieobs=cieobs, out=2)
# manage output:
if out == 'COI':
return COI
elif out == 'COI,cct':
return COI, cct
else:
return eval(out)
'_COI_RFL_BLOOD', '_COI_CIEOBS', '_COI_CSPACE', 'spd_to_COI_ASNZS1680'
]
# Reflectance spectra of 100% and 50% oxygenated blood
_COI_RFL_BLOOD = getdata(_PKG_PATH + _SEP + 'toolboxes' + _SEP +
'photbiochem' + _SEP + 'data' + _SEP +
'ASNZS_1680.2.5_1997_cyanosisindex_100_50.dat',
header=None,
kind='np',
verbosity=0).T
_COI_CIEOBS = '1931_2' # default CMF set
_COI_CSPACE = 'lab'
_COI_REF = blackbody(4000, )
def spd_to_COI_ASNZS1680(S=None,
tf=_COI_CSPACE,
cieobs=_COI_CIEOBS,
out='COI,cct',
extrapolate_rfl=False):
"""
Calculate the Cyanosis Observation Index (COI) [ASNZS 1680.2.5-1995].
Args:
:S:
| ndarray with light source spectrum (first column are wavelengths).
:tf:
| _COI_CSPACE, optional