def normalize_3x3_matrix(M, xyz0=np.array([[1.0, 1.0, 1.0]])):
"""
Normalize 3x3 matrix M to xyz0 -- > [1,1,1]
If M.shape == (1,9): M is reshaped to (3,3)
Args:
:M:
| ndarray((3,3) or ndarray((1,9))
:xyz0:
| 2darray, optional
Returns:
:returns:
| normalized matrix such that M*xyz0 = [1,1,1]
"""
M = np2d(M)
if M.shape[-1] == 9:
M = M.reshape(3, 3)
if xyz0.shape[0] == 1:
return np.dot(np.diagflat(1 / (np.dot(M, xyz0.T))), M)
else:
return np.concatenate([
np.dot(np.diagflat(1 / (np.dot(M, xyz0[1].T))), M)
for i in range(xyz0.shape[0])
],
axis=0).reshape(xyz0.shape[0], 3, 3)
def dot(self, S):
"""
Take dot product with instance of SPD.
"""
if isinstance(S, SPD):
self.value = np.dot(self.value, S.value)
else:
self.value = np.dot(self.value, M)
self.shape = self.value.shape
self.N = self.shape[0]
return self
def fit_ellipse(xy):
"""
Fit an ellipse to supplied data points.
Args:
:xy:
| coordinates of points to fit (Nx2 array)
Returns:
:v:
| vector with ellipse parameters [Rmax,Rmin, xc,yc, theta]
"""
# remove centroid:
center = xy.mean(axis=0)
xy = xy - center
# Fit ellipse:
x, y = xy[:, 0:1], xy[:, 1:2]
D = np.hstack((x * x, x * y, y * y, x, y, np.ones_like(x)))
S, C = np.dot(D.T, D), np.zeros([6, 6])
C[0, 2], C[2, 0], C[1, 1] = 2, 2, -1
U, s, V = np.linalg.svd(np.dot(np.linalg.inv(S), C))
e = U[:, 0]
# get ellipse axis lengths, center and orientation:
b, c, d, f, g, a = e[1] / 2, e[2], e[3] / 2, e[4] / 2, e[5], e[0]
# get ellipse center:
num = b * b - a * c
xc = ((c * d - b * f) / num) + center[0]
yc = ((a * f - b * d) / num) + center[1]
# get ellipse orientation:
theta = np.arctan2(np.array(2 * b), np.array((a - c))) / 2
# axis lengths:
up = 2 * (a * f * f + c * d * d + g * b * b - 2 * b * d * f - a * c * g)
down1 = (b * b - a * c) * ((c - a) * np.sqrt(1 + 4 * b * b / ((a - c) *
(a - c))) -
(c + a))
down2 = (b * b - a * c) * ((a - c) * np.sqrt(1 + 4 * b * b / ((a - c) *
(a - c))) -
(c + a))
a, b = np.sqrt(up / down1), np.sqrt(up / down2)
# assert that a is the major axis (otherwise swap and correct angle)
if (b > a):
b, a = a, b
# ensure the angle is betwen 0 and 2*pi
theta = fmod(theta, 2.0 * np.pi)
return np.hstack((a, b, xc, yc, theta))
def line_intersect(a1, a2, b1, b2):
"""
Line intersections of series of two line segments a and b.
Args:
:a1:
| ndarray (.shape = (N,2)) specifying end-point 1 of line a
:a2:
| ndarray (.shape = (N,2)) specifying end-point 2 of line a
:b1:
| ndarray (.shape = (N,2)) specifying end-point 1 of line b
:b2:
| ndarray (.shape = (N,2)) specifying end-point 2 of line b
Note:
N is the number of line segments a and b.
Returns:
:returns:
| ndarray with line-intersections (.shape = (N,2))
References:
1. https://stackoverflow.com/questions/3252194/numpy-and-line-intersections
"""
T = np.array([[0.0, -1.0], [1.0, 0.0]])
da = np.atleast_2d(a2 - a1)
db = np.atleast_2d(b2 - b1)
dp = np.atleast_2d(a1 - b1)
dap = np.dot(da, T)
denom = np.sum(dap * db, axis=1)
num = np.sum(dap * dp, axis=1)
return np.atleast_2d(num / denom).T * db + b1
def check_posdef(A, atol = 1.0e-9, rtol = 1.0e-9):
"""
Checks positive definiteness of a matrix via Cholesky.
Args:
:A:
| ndarray
:atol:
| float, optional
| The absolute tolerance parameter (see Notes of numpy.allclose())
:rtol:
| float, optional
| The relative tolerance parameter (see Notes of numpy.allclose())
Returns:
:returns:
| Bool
| True: the array is positive-definite within the given tolerance
"""
try:
R = np.linalg.cholesky(A)
if np.allclose(A, np.dot(R,R.T), atol = atol,rtol = rtol):
return True
else:
return False
except np.linalg.LinAlgError:
return False
def dot(self, M):
"""
Take dot product with instance.
"""
self.value = np.dot(M, self.value.T).T
self.shape = self.value.shape
return self
def polyarea(x,y):
"""
Calculates area of polygon.
| First coordinate should also be last.
Args:
:x:
| ndarray of x-coordinates of polygon vertices.
:y:
| ndarray of x-coordinates of polygon vertices.
Returns:
:returns:
| float (area or polygon)
"""
return 0.5*np.abs(np.dot(x,np.roll(y,1).T)-np.dot(y,np.roll(x,1).T))
def normalize_3x3_matrix(M, xyz0 = np.array([[1.0,1.0,1.0]])):
"""
Normalize 3x3 matrix M to xyz0 -- > [1,1,1]
If M.shape == (1,9): M is reshaped to (3,3)
Args:
:M:
| ndarray((3,3) or ndarray((1,9))
:xyz0:
| 2darray, optional
Returns:
:returns:
| normalized matrix such that M*xyz0 = [1,1,1]
"""
M = np2d(M)
if M.shape[-1]==9:
M = M.reshape(3,3)
return np.dot(np.diagflat(1/(np.dot(M,xyz0.T))),M)
def lmsb_to_xyzb(lms, fieldsize=10, out='XYZ', allow_negative_values=False):
"""
Convert from LMS cone fundamentals to XYZ color matching functions.
Args:
:lms:
| ndarray with lms cone fundamentals, optional
:fieldsize:
| fieldsize in degrees, optional
| Defaults to 10°.
:out:
| 'xyz' or str, optional
| Determines output.
:allow_negative_values:
| False, optional
| XYZ color matching functions should not have negative values.
| If False: xyz[xyz<0] = 0.
Returns:
:returns:
| LMS
| - LMS: ndarray with population XYZ color matching functions.
Note:
For intermediate field sizes (2° < fieldsize < 10°) a conversion matrix
is calculated by linear interpolation between
the _INDVCMF_M_2d and _INDVCMF_M_10d matrices.
"""
wl = lms[None, 0] #store wavelengths
M = get_lms_to_xyz_matrix(fieldsize=fieldsize)
if lms.ndim > 2:
xyz = np.vstack((wl, math.dot23(M, lms[1:, ...], keepdims=False)))
else:
xyz = np.vstack((wl, np.dot(M, lms[1:, ...])))
if allow_negative_values == False:
xyz[np.where(xyz < 0)] = 0
return xyz
def spd_to_aopicE(sid, Ee = None, E = None, Q = None, cieobs = _CIEOBS, sid_units = 'W/m2', out = 'Eeas,Eas'):
"""
Calculate alpha-opic irradiance (Ee,α) and equivalent luminance (Eα) values
for the l-cone, m-cone, s-cone, rod and iprgc (α) photoreceptor cells
following CIE technical note TN 003:2015.
Args:
:sid:
| numpy.ndarray with retinal spectral irradiance in :sid_units:
| (if 'uW/cm2', sid will be converted to SI units 'W/m2')
:Ee:
| None, optional
| If not None: normalize :sid: to an irradiance of :Ee:
:E:
| None, optional
| If not None: normalize :sid: to an illuminance of :E:
| Note that E is calculate using a Km factor corrected to standard air.
:Q:
| None, optional
| If not None: nNormalize :sid: to a quantal energy of :Q:
:cieobs:
| _CIEOBS or str, optional
| Type of cmf set to use for photometric units.
:sid_units:
| 'W/m2', optional
| Other option 'uW/m2', input units of :sid:
:out:
| 'Eeas, Eas' or str, optional
| Determines values to return.
Returns:
:returns:
| (Eeas, Eas) with Eeas and Eas resp. numpy.ndarrays with the
α-opic irradiance and equivalent illuminance values
of all spectra in :sid: in SI-units.
| (other choice can be set using :out:)
"""
outlist = out.split(',')
# Convert to Watt/m²:
if sid_units == 'uW/cm2':
sid[1:] = sid[1:]/100
elif sid_units == 'W/m2':
pass
else:
raise Exception("spd_to_aopicE(): {} unsupported units for SID.".format(sid_units))
# Normalize sid to Ee:
if Ee is not None:
sid = spd_normalize(sid, norm_type = 'ru', norm_f = Ee)
elif E is not None:
sid = spd_normalize(sid, norm_type = 'pusa', norm_f = E)
elif Q is not None:
sid = spd_normalize(sid, norm_type = 'qu', norm_f = Q)
# Get sid irradiance (W/m²):
if 'Ee' in outlist:
Ee = spd_to_power(sid, cieobs = cieobs, ptype = 'ru')
# Get sid illuminance (lx):
if 'E' in outlist:
E = spd_to_power(sid, cieobs = cieobs, ptype = 'pusa') #photometric units (Km corrected to standard air)
# Get sid quantal energy (photons/m²/s):
if 'Q' in outlist:
Q = spd_to_power(sid, cieobs = cieobs, ptype = 'qu')
# get SI actinic action spectra, sa:
sa = spd(_ACTIONSPECTRA, wl = sid[0], interpolation = 'cmf', norm_type = 'max')
# get wavelength spacing:
dl = getwld(sid[0])
# Calculate all alpha-opics Ee's:
Eeas = (np.dot((sa[1:]*dl),sid[1:].T)).T
# Calculate equivalent alpha-opic E's:
Vl, Km = vlbar(cieobs = cieobs, wl_new = sid[0], out = 2)
Eas = Km*Km_correction_factor*Eeas*(Vl[1].sum()/sa[1:].sum(axis = 1))
#Prepare output:
if out == 'Eeas,Eas':
return Eeas,Eas
elif out == 'Eeas':
return Eeas
elif out == 'Eas':
return Eas
else:
eval(out)
def Ydlep_to_xyz(Ydlep,
cieobs=_CIEOBS,
xyzw=_COLORTF_DEFAULT_WHITE_POINT,
flip_axes=False,
**kwargs):
"""
Convert Y, dominant (complementary) wavelength and excitation purity to XYZ
tristimulus values.
Args:
:Ydlep:
| ndarray with Y, dominant (complementary) wavelength
and excitation purity
:xyzw:
| None or narray with tristimulus values of a single (!) native white point, optional
| None defaults to xyz of CIE D65 using the :cieobs: observer.
:cieobs:
| luxpy._CIEOBS, optional
| CMF set to use when calculating spectrum locus coordinates.
:flip_axes:
| False, optional
| If True: flip axis 0 and axis 1 in Ydelep to increase speed of loop in function.
| (single xyzw with is not flipped!)
Returns:
:xyz:
| ndarray with tristimulus values
"""
Ydlep3 = np3d(Ydlep).copy().astype(np.float)
# flip axis so that longest dim is on first axis (save time in looping):
if (Ydlep3.shape[0] < Ydlep3.shape[1]) & (flip_axes == True):
axes12flipped = True
Ydlep3 = Ydlep3.transpose((1, 0, 2))
else:
axes12flipped = False
# convert xyzw to Yxyw:
Yxyw = xyz_to_Yxy(xyzw)
Yxywo = Yxyw.copy()
# get spectrum locus Y,x,y and wavelengths:
SL = _CMF[cieobs]['bar']
wlsl = SL[0, None].T
Yxysl = xyz_to_Yxy(SL[1:4].T)[:, None]
# center on xyzw:
Yxysl = Yxysl - Yxyw
Yxyw = Yxyw - Yxyw
#split:
Y, dom, pur = asplit(Ydlep3)
Yw, xw, yw = asplit(Yxyw)
Ywo, xwo, ywo = asplit(Yxywo)
Ysl, xsl, ysl = asplit(Yxysl)
# loop over longest dim:
x = np.empty(Y.shape)
y = np.empty(Y.shape)
for i in range(Ydlep3.shape[1]):
# find closest wl's to dom:
#wlslb,wlib = meshblock(wlsl,np.abs(dom[i,:])) #abs because dom<0--> complemtary wl
wlib, wlslb = np.meshgrid(np.abs(dom[:, i]), wlsl)
dwl = np.abs(wlslb - wlib)
q1 = dwl.argmin(axis=0) # index of closest wl
dwl[q1] = 10000.0
q2 = dwl.argmin(axis=0) # index of second closest wl
# calculate x,y of dom:
x_dom_wl = xsl[q1, 0] + (xsl[q2, 0] - xsl[q1, 0]) * (
np.abs(dom[:, i]) - wlsl[q1, 0]) / (wlsl[q2, 0] - wlsl[q1, 0]
) # calculate x of dom. wl
y_dom_wl = ysl[q1, 0] + (ysl[q2, 0] - ysl[q1, 0]) * (
np.abs(dom[:, i]) - wlsl[q1, 0]) / (wlsl[q2, 0] - wlsl[q1, 0]
) # calculate y of dom. wl
# calculate x,y of test:
d_wl = (x_dom_wl**2.0 +
y_dom_wl**2.0)**0.5 # distance from white point to dom
d = pur[:, i] * d_wl
hdom = math.positive_arctan(x_dom_wl, y_dom_wl, htype='deg')
x[:, i] = d * np.cos(hdom * np.pi / 180.0)
y[:, i] = d * np.sin(hdom * np.pi / 180.0)
# complementary:
pc = np.where(dom[:, i] < 0.0)
hdom[pc] = hdom[pc] - np.sign(dom[:, i][pc] -
180.0) * 180.0 # get positive hue angle
# calculate intersection of line through white point and test point and purple line:
xy = np.vstack((x_dom_wl, y_dom_wl)).T
xyw = np.vstack((xw, yw)).T
xypl1 = np.vstack((xsl[0, None], ysl[0, None])).T
xypl2 = np.vstack((xsl[-1, None], ysl[-1, None])).T
da = (xy - xyw)
db = (xypl2 - xypl1)
dp = (xyw - xypl1)
T = np.array([[0.0, -1.0], [1.0, 0.0]])
dap = np.dot(da, T)
denom = np.sum(dap * db, axis=1, keepdims=True)
num = np.sum(dap * dp, axis=1, keepdims=True)
xy_linecross = (num / denom) * db + xypl1
d_linecross = np.atleast_2d(
(xy_linecross[:, 0]**2.0 + xy_linecross[:, 1]**2.0)**0.5).T[:, 0]
x[:, i][pc] = pur[:, i][pc] * d_linecross[pc] * np.cos(
hdom[pc] * np.pi / 180)
y[:, i][pc] = pur[:, i][pc] * d_linecross[pc] * np.sin(
hdom[pc] * np.pi / 180)
Yxy = np.dstack((Ydlep3[:, :, 0], x + xwo, y + ywo))
if axes12flipped == True:
Yxy = Yxy.transpose((1, 0, 2))
else:
Yxy = Yxy.transpose((0, 1, 2))
return Yxy_to_xyz(Yxy).reshape(Ydlep.shape)
def xyz_to_Ydlep(xyz,
cieobs=_CIEOBS,
xyzw=_COLORTF_DEFAULT_WHITE_POINT,
flip_axes=False,
**kwargs):
"""
Convert XYZ tristimulus values to Y, dominant (complementary) wavelength
and excitation purity.
Args:
:xyz:
| ndarray with tristimulus values
:xyzw:
| None or ndarray with tristimulus values of a single (!) native white point, optional
| None defaults to xyz of CIE D65 using the :cieobs: observer.
:cieobs:
| luxpy._CIEOBS, optional
| CMF set to use when calculating spectrum locus coordinates.
:flip_axes:
| False, optional
| If True: flip axis 0 and axis 1 in Ydelep to increase speed of loop in function.
| (single xyzw with is not flipped!)
Returns:
:Ydlep:
| ndarray with Y, dominant (complementary) wavelength
and excitation purity
"""
xyz3 = np3d(xyz).copy().astype(np.float)
# flip axis so that shortest dim is on axis0 (save time in looping):
if (xyz3.shape[0] < xyz3.shape[1]) & (flip_axes == True):
axes12flipped = True
xyz3 = xyz3.transpose((1, 0, 2))
else:
axes12flipped = False
# convert xyz to Yxy:
Yxy = xyz_to_Yxy(xyz3)
Yxyw = xyz_to_Yxy(xyzw)
# get spectrum locus Y,x,y and wavelengths:
SL = _CMF[cieobs]['bar']
wlsl = SL[0]
Yxysl = xyz_to_Yxy(SL[1:4].T)[:, None]
# center on xyzw:
Yxy = Yxy - Yxyw
Yxysl = Yxysl - Yxyw
Yxyw = Yxyw - Yxyw
#split:
Y, x, y = asplit(Yxy)
Yw, xw, yw = asplit(Yxyw)
Ysl, xsl, ysl = asplit(Yxysl)
# calculate hue:
h = math.positive_arctan(x, y, htype='deg')
hsl = math.positive_arctan(xsl, ysl, htype='deg')
hsl_max = hsl[0] # max hue angle at min wavelength
hsl_min = hsl[-1] # min hue angle at max wavelength
dominantwavelength = np.empty(Y.shape)
purity = np.empty(Y.shape)
for i in range(xyz3.shape[1]):
# find index of complementary wavelengths/hues:
pc = np.where(
(h[:, i] >= hsl_max) & (h[:, i] <= hsl_min + 360.0)
) # hue's requiring complementary wavelength (purple line)
h[:, i][pc] = h[:, i][pc] - np.sign(
h[:, i][pc] - 180.0
) * 180.0 # add/subtract 180° to get positive complementary wavelength
# find 2 closest hues in sl:
#hslb,hib = meshblock(hsl,h[:,i:i+1])
hib, hslb = np.meshgrid(h[:, i:i + 1], hsl)
dh = np.abs(hslb - hib)
q1 = dh.argmin(axis=0) # index of closest hue
dh[q1] = 1000.0
q2 = dh.argmin(axis=0) # index of second closest hue
dominantwavelength[:, i] = wlsl[q1] + np.divide(
np.multiply((wlsl[q2] - wlsl[q1]),
(h[:, i] - hsl[q1, 0])), (hsl[q2, 0] - hsl[q1, 0])
) # calculate wl corresponding to h: y = y1 + (y2-y1)*(x-x1)/(x2-x1)
dominantwavelength[:, i][pc] = -dominantwavelength[:, i][
pc] #complementary wavelengths are specified by '-' sign
# calculate excitation purity:
x_dom_wl = xsl[q1, 0] + (xsl[q2, 0] - xsl[q1, 0]) * (h[:, i] - hsl[
q1, 0]) / (hsl[q2, 0] - hsl[q1, 0]) # calculate x of dom. wl
y_dom_wl = ysl[q1, 0] + (ysl[q2, 0] - ysl[q1, 0]) * (h[:, i] - hsl[
q1, 0]) / (hsl[q2, 0] - hsl[q1, 0]) # calculate y of dom. wl
d_wl = (x_dom_wl**2.0 +
y_dom_wl**2.0)**0.5 # distance from white point to sl
d = (x[:, i]**2.0 +
y[:, i]**2.0)**0.5 # distance from white point to test point
purity[:, i] = d / d_wl
# correct for those test points that have a complementary wavelength
# calculate intersection of line through white point and test point and purple line:
xy = np.vstack((x[:, i], y[:, i])).T
xyw = np.hstack((xw, yw))
xypl1 = np.hstack((xsl[0, None], ysl[0, None]))
xypl2 = np.hstack((xsl[-1, None], ysl[-1, None]))
da = (xy - xyw)
db = (xypl2 - xypl1)
dp = (xyw - xypl1)
T = np.array([[0.0, -1.0], [1.0, 0.0]])
dap = np.dot(da, T)
denom = np.sum(dap * db, axis=1, keepdims=True)
num = np.sum(dap * dp, axis=1, keepdims=True)
xy_linecross = (num / denom) * db + xypl1
d_linecross = np.atleast_2d(
(xy_linecross[:, 0]**2.0 + xy_linecross[:, 1]**2.0)**0.5).T #[0]
purity[:, i][pc] = d[pc] / d_linecross[pc][:, 0]
Ydlep = np.dstack((xyz3[:, :, 1], dominantwavelength, purity))
if axes12flipped == True:
Ydlep = Ydlep.transpose((1, 0, 2))
else:
Ydlep = Ydlep.transpose((0, 1, 2))
return Ydlep.reshape(xyz.shape)
def symmM_to_posdefM(A = None, atol = 1.0e-9, rtol = 1.0e-9, method = 'make', forcesymm = True):
"""
Convert a symmetric matrix to a positive definite one.
Args:
:A:
| ndarray
:atol:
| float, optional
| The absolute tolerance parameter (see Notes of numpy.allclose())
:rtol:
| float, optional
| The relative tolerance parameter (see Notes of numpy.allclose())
:method:
| 'make' or 'nearest', optional (see notes for more info)
:forcesymm:
| True or False, optional
| If A is not symmetric, force symmetry using:
| A = numpy.triu(A) + numpy.triu(A).T - numpy.diag(numpy.diag(A))
Returns:
:returns:
| ndarray with positive-definite matrix.
Notes on supported methods:
1. `'make': A Python/Numpy port of Muhammad Asim Mubeen's matlab function
Spd_Mat.m
<https://nl.mathworks.com/matlabcentral/fileexchange/45873-positive-definite-matrix>`_
2. `'nearest': A Python/Numpy port of John D'Errico's `nearestSPD`
MATLAB code.
<https://stackoverflow.com/questions/43238173/python-convert-matrix-to-positive-semi-definite>`_
"""
if A is not None:
A = np2d(A)
# Make sure matrix A is symmetric up to a certain tolerance:
sn = check_symmetric(A, atol = atol, rtol = rtol)
if ((A.shape[0] != A.shape[1]) | (sn != True)):
if (forcesymm == True) & (A.shape[0] == A.shape[1]):
A = np.triu(A) + np.triu(A).T - np.diag(np.diag(A))
else:
raise Exception('symmM_to_posdefM(): matrix A not symmetric.')
if check_posdef(A, atol = atol, rtol = rtol) == True:
return A
else:
if method == 'make':
# A Python/Numpy port of Muhammad Asim Mubeen's matlab function Spd_Mat.m
#
# See: https://nl.mathworks.com/matlabcentral/fileexchange/45873-positive-definite-matrix
Val, Vec = np.linalg.eig(A)
Val = np.real(Val)
Vec = np.real(Vec)
Val[np.where(Val==0)] = _EPS #making zero eigenvalues non-zero
p = np.where(Val<0)
Val[p] = -Val[p] #making negative eigenvalues positive
return np.dot(Vec,np.dot(np.diag(Val) , Vec.T))
elif method == 'nearest':
# A Python/Numpy port of John D'Errico's `nearestSPD` MATLAB code [1], which
# credits [2].
#
# [1] https://www.mathworks.com/matlabcentral/fileexchange/42885-nearestspd
#
# [2] N.J. Higham, "Computing a nearest symmetric positive semidefinite
# matrix" (1988): https://doi.org/10.1016/0024-3795(88)90223-6
#
# See: https://stackoverflow.com/questions/43238173/python-convert-matrix-to-positive-semi-definite
B = (A + A.T) / 2.0
_, s, V = np.linalg.svd(B)
H = np.dot(V.T, np.dot(np.diag(s), V))
A2 = (B + H) / 2.0
A3 = (A2 + A2.T) / 2.0
if check_posdef(A3, atol = atol, rtol = rtol) == True:
return A3
spacing = np.spacing(np.linalg.norm(A))
I = np.eye(A.shape[0])
k = 1
while not check_posdef(A3, atol = atol, rtol = rtol):
mineig = np.min(np.real(np.linalg.eigvals(A3)))
A3 += I * (-mineig * k**2.0+ spacing)
k += 1
return A3
def plotellipse(v, cspace_in = 'Yxy', cspace_out = None, nsamples = 100, \
show = True, axh = None, \
line_color = 'darkgray', line_style = ':', line_width = 1, line_marker = '', line_markersize = 4,\
plot_center = False, center_marker = 'o', center_color = 'darkgray', center_markersize = 4,\
show_grid = True, label_fontname = 'Times New Roman', label_fontsize = 12,\
out = None):
"""
Plot ellipse(s) given in v-format [Rmax,Rmin,xc,yc,theta].
Args:
:v:
| (Nx5) ndarray
| ellipse parameters [Rmax,Rmin,xc,yc,theta]
:cspace_in:
| 'Yxy', optional
| Color space of v.
| If None: no color space assumed. Axis labels assumed ('x','y').
:cspace_out:
| None, optional
| Color space to plot ellipse(s) in.
| If None: plot in cspace_in.
:nsamples:
| 100 or int, optional
| Number of points (samples) in ellipse boundary
:show:
| True or boolean, optional
| Plot ellipse(s) (True) or not (False)
:axh:
| None, optional
| Ax-handle to plot ellipse(s) in.
| If None: create new figure with axes.
:line_color:
| 'darkgray', optional
| Color to plot ellipse(s) in.
:line_style:
| ':', optional
| Linestyle of ellipse(s).
:line_width':
| 1, optional
| Width of ellipse boundary line.
:line_marker:
| 'none', optional
| Marker for ellipse boundary.
:line_markersize:
| 4, optional
| Size of markers in ellipse boundary.
:plot_center:
| False, optional
| Plot center of ellipse: yes (True) or no (False)
:center_color:
| 'darkgray', optional
| Color to plot ellipse center in.
:center_marker:
| 'o', optional
| Marker for ellipse center.
:center_markersize:
| 4, optional
| Size of marker of ellipse center.
:show_grid:
| True, optional
| Show grid (True) or not (False)
:label_fontname:
| 'Times New Roman', optional
| Sets font type of axis labels.
:label_fontsize:
| 12, optional
| Sets font size of axis labels.
:out:
| None, optional
| Output of function
| If None: returns None. Can be used to output axh of newly created
| figure axes or to return Yxys an ndarray with coordinates of
| ellipse boundaries in cspace_out (shape = (nsamples,3,N))
Returns:
:returns: None, or whatever set by :out:.
"""
Yxys = np.zeros((nsamples,3,v.shape[0]))
ellipse_vs = np.zeros((v.shape[0],5))
for i,vi in enumerate(v):
# Set sample density of ellipse boundary:
t = np.linspace(0, 2*np.pi, nsamples)
a = vi[0] # major axis
b = vi[1] # minor axis
xyc = vi[2:4,None] # center
theta = vi[-1] # rotation angle
# define rotation matrix:
R = np.hstack(( np.vstack((np.cos(theta), np.sin(theta))), np.vstack((-np.sin(theta), np.cos(theta)))))
# Calculate ellipses:
Yxyc = np.vstack((1, xyc)).T
Yxy = np.vstack((np.ones((1,nsamples)), xyc + np.dot(R, np.vstack((a*np.cos(t), b*np.sin(t))) ))).T
Yxys[:,:,i] = Yxy
# Convert to requested color space:
if (cspace_out is not None) & (cspace_in is not None):
Yxy = colortf(Yxy, cspace_in + '>' + cspace_out)
Yxyc = colortf(Yxyc, cspace_in + '>' + cspace_out)
Yxys[:,:,i] = Yxy
# get ellipse parameters in requested color space:
ellipse_vs[i,:] = math.fit_ellipse(Yxy[:,1:])
#de = np.sqrt((Yxy[:,1]-Yxyc[:,1])**2 + (Yxy[:,2]-Yxyc[:,2])**2)
#ellipse_vs[i,:] = np.hstack((de.max(),de.min(),Yxyc[:,1],Yxyc[:,2],np.nan)) # nan because orientation is xy, but request is some other color space. Change later to actual angle when fitellipse() has been implemented
# plot ellipses:
if show == True:
if (axh is None) & (i == 0):
fig = plt.figure()
axh = fig.add_subplot(111)
if (cspace_in is None):
xlabel = 'x'
ylabel = 'y'
else:
xlabel = _CSPACE_AXES[cspace_in][1]
ylabel = _CSPACE_AXES[cspace_in][2]
if (cspace_out is not None):
xlabel = _CSPACE_AXES[cspace_out][1]
ylabel = _CSPACE_AXES[cspace_out][2]
if plot_center == True:
plt.plot(Yxyc[:,1],Yxyc[:,2],color = center_color, linestyle = 'none', marker = center_marker, markersize = center_markersize)
plt.plot(Yxy[:,1],Yxy[:,2],color = line_color, linestyle = line_style, linewidth = line_width, marker = line_marker, markersize = line_markersize)
plt.xlabel(xlabel, fontname = label_fontname, fontsize = label_fontsize)
plt.ylabel(ylabel, fontname = label_fontname, fontsize = label_fontsize)
if show_grid == True:
plt.grid()
#plt.show()
Yxys = np.transpose(Yxys,axes=(0,2,1))
if out is not None:
return eval(out)
else:
return None
def get_poly_model(jabt, jabr, modeltype = _VF_MODEL_TYPE):
"""
Setup base color shift model (delta_a, delta_b),
determine model parameters and accuracy.
| Calculates a base color shift (delta) from the ref. chromaticity ar, br.
Args:
:jabt:
| ndarray with jab color coordinates under the test SPD.
:jabr:
| ndarray with jab color coordinates under the reference SPD.
:modeltype:
| _VF_MODEL_TYPE or 'M6' or 'M5', optional
| Specifies degree 5 or degree 6 polynomial model in ab-coordinates.
(see notes below)
Returns:
:returns:
| (poly_model,
| pmodel,
| dab_model,
| dab_res,
| dCHoverC_res,
| dab_std,
| dCHoverC_std)
|
| :poly_model: function handle to model
| :pmodel: ndarray with model parameters
| :dab_model: ndarray with ab model predictions from ar, br.
| :dab_res: ndarray with residuals between 'da,db' of samples and
| 'da,db' predicted by the model.
| :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 below)
| :dab_std: ndarray with std of :dab_res:
| :dCHoverC_std: ndarray with std of :dCHoverC_res:
Notes:
1. Model types:
| poly5_model = lambda a,b,p: p[0]*a + p[1]*b + p[2]*(a**2) + p[3]*a*b + p[4]*(b**2)
| poly6_model = lambda a,b,p: p[0] + p[1]*a + p[2]*b + p[3]*(a**2) + p[4]*a*b + p[5]*(b**2)
2. Calculation of dCoverC and dH:
| dCoverC = (np.cos(hr)*da + np.sin(hr)*db)/Cr
| dHoverC = (np.cos(hr)*db - np.sin(hr)*da)/Cr
"""
at = jabt[...,1]
bt = jabt[...,2]
ar = jabr[...,1]
br = jabr[...,2]
# A. Calculate da, db:
da = at - ar
db = bt - br
# B.1 Calculate model matrix:
# 5-parameter model:
M5 = np.array([[np.sum(ar*ar), np.sum(ar*br), np.sum(ar*ar**2),np.sum(ar*ar*br),np.sum(ar*br**2)],
[np.sum(br*ar), np.sum(br*br), np.sum(br*ar**2),np.sum(br*ar*br),np.sum(br*br**2)],
[np.sum((ar**2)*ar), np.sum((ar**2)*br), np.sum((ar**2)*ar**2),np.sum((ar**2)*ar*br),np.sum((ar**2)*br**2)],
[np.sum(ar*br*ar), np.sum(ar*br*br), np.sum(ar*br*ar**2),np.sum(ar*br*ar*br),np.sum(ar*br*br**2)],
[np.sum((br**2)*ar), np.sum((br**2)*br), np.sum((br**2)*ar**2),np.sum((br**2)*ar*br),np.sum((br**2)*br**2)]])
#6-parameters model
M6 = np.array([[ar.size,np.sum(1.0*ar), np.sum(1.0*br), np.sum(1.0*ar**2),np.sum(1.0*ar*br),np.sum(1.0*br**2)],
[np.sum(ar*1.0),np.sum(ar*ar), np.sum(ar*br), np.sum(ar*ar**2),np.sum(ar*ar*br),np.sum(ar*br**2)],
[np.sum(br*1.0),np.sum(br*ar), np.sum(br*br), np.sum(br*ar**2),np.sum(br*ar*br),np.sum(br*br**2)],
[np.sum((ar**2)*1.0),np.sum((ar**2)*ar), np.sum((ar**2)*br), np.sum((ar**2)*ar**2),np.sum((ar**2)*ar*br),np.sum((ar**2)*br**2)],
[np.sum(ar*br*1.0),np.sum(ar*br*ar), np.sum(ar*br*br), np.sum(ar*br*ar**2),np.sum(ar*br*ar*br),np.sum(ar*br*br**2)],
[np.sum((br**2)*1.0),np.sum((br**2)*ar), np.sum((br**2)*br), np.sum((br**2)*ar**2),np.sum((br**2)*ar*br),np.sum((br**2)*br**2)]])
# B.2 Define model function:
poly5_model = lambda a,b,p: p[0]*a + p[1]*b + p[2]*(a**2) + p[3]*a*b + p[4]*(b**2)
poly6_model = lambda a,b,p: p[0] + p[1]*a + p[2]*b + p[3]*(a**2) + p[4]*a*b + p[5]*(b**2)
if modeltype == 'M5':
M = M5
poly_model = poly5_model
else:
M = M6
poly_model = poly6_model
M = np.linalg.inv(M)
# C.1 Data a,b analysis output:
if modeltype == 'M5':
da_model_parameters = np.dot(M, np.array([np.sum(da*ar), np.sum(da*br), np.sum(da*ar**2),np.sum(da*ar*br),np.sum(da*br**2)]))
db_model_parameters = np.dot(M, np.array([np.sum(db*ar), np.sum(db*br), np.sum(db*ar**2),np.sum(db*ar*br),np.sum(db*br**2)]))
else:
da_model_parameters = np.dot(M, np.array([np.sum(da*1.0),np.sum(da*ar), np.sum(da*br), np.sum(da*ar**2),np.sum(da*ar*br),np.sum(da*br**2)]))
db_model_parameters = np.dot(M, np.array([np.sum(db*1.0),np.sum(db*ar), np.sum(db*br), np.sum(db*ar**2),np.sum(db*ar*br),np.sum(db*br**2)]))
pmodel = np.vstack((da_model_parameters,db_model_parameters))
# D.1 Calculate model da, db:
da_model = poly_model(ar,br,pmodel[0])
db_model = poly_model(ar,br,pmodel[1])
dab_model = np.hstack((da_model,db_model))
# D.2 Calculate residuals for da & db:
da_res = da - da_model
db_res = db - db_model
dab_res = np.hstack((da_res,db_res))
dab_std = np.vstack((np.std(da_res,axis=0),np.std(db_res,axis=0)))
# E Calculate href, Cref:
href = np.arctan2(br,ar)
Cref = (ar**2 + br**2)**0.5
# F Calculate dC/C, dH/C for data and model and calculate residuals:
dCoverC = (np.cos(href)*da + np.sin(href)*db)/Cref
dHoverC = (np.cos(href)*db - np.sin(href)*da)/Cref
dCoverC_model = (np.cos(href)*da_model + np.sin(href)*db_model)/Cref
dHoverC_model = (np.cos(href)*db_model - np.sin(href)*da_model)/Cref
dCoverC_res = dCoverC - dCoverC_model
dHoverC_res = dHoverC - dHoverC_model
dCHoverC_std = np.vstack((np.std(dCoverC_res,axis = 0),np.std(dHoverC_res,axis = 0)))
dCHoverC_res = np.hstack((href,dCoverC_res,dHoverC_res))
return poly_model, pmodel, dab_model, dab_res, dCHoverC_res, dab_std, dCHoverC_std
def apply(data, catmode = '1>0>2', cattype = 'vonkries', xyzw1 = None, xyzw2 = None, xyzw0 = None,\
D = None, mcat = ['cat02'], normxyz0 = None, outtype = 'xyz', La = None, F = None, Dtype = None):
"""
Calculate corresponding colors by applying a von Kries chromatic adaptation
transform (CAT), i.e. independent rescaling of 'sensor sensitivity' to data
to adapt from current adaptation conditions (1) to the new conditions (2).
Args:
:data:
| ndarray of tristimulus values (can be NxMx3)
:catmode:
| '1>0>2, optional
| -'1>0>2': Two-step CAT
| from illuminant 1 to baseline illuminant 0 to illuminant 2.
| -'1>0': One-step CAT
| from illuminant 1 to baseline illuminant 0.
| -'0>2': One-step CAT
| from baseline illuminant 0 to illuminant 2.
:cattype:
| 'vonkries' (others: 'rlab', see Farchild 1990), optional
:xyzw1:
| None, depending on :catmode: optional (can be Mx3)
:xyzw2:
| None, depending on :catmode: optional (can be Mx3)
:xyzw0:
| None, depending on :catmode: optional (can be Mx3)
:D:
| None, optional
| Degrees of adaptation. Defaults to [1.0, 1.0].
:La:
| None, optional
| Adapting luminances.
| If None: xyz values are absolute or relative.
| If not None: xyz are relative.
:F:
| None, optional
| Surround parameter(s) for CAT02/CAT16 calculations
(:Dtype: == 'cat02' or 'cat16')
| Defaults to [1.0, 1.0].
:Dtype:
| None, optional
| Type of degree of adaptation function from literature
| See luxpy.cat.get_degree_of_adaptation()
:mcat:
| ['cat02'], optional
| List[str] or List[ndarray] of sensor space matrices for each
condition pair. If len(:mcat:) == 1, the same matrix is used.
:normxyz0:
| None, optional
| Set of xyz tristimulus values to normalize the sensor space matrix to.
:outtype:
| 'xyz' or 'lms', optional
| - 'xyz': return corresponding tristimulus values
| - 'lms': return corresponding sensor space excitation values
| (e.g. for further calculations)
Returns:
:returns:
| ndarray with corresponding colors
"""
if (xyzw1 is None) & (xyzw2 is None):
return data # do nothing
else:
# Make data 2d:
data = np2d(data)
data_original_shape = data.shape
if data.ndim < 3:
target_shape = np.hstack((1, data.shape))
data = data * np.ones(target_shape)
else:
target_shape = data.shape
target_shape = data.shape
# initialize xyzw0:
if (xyzw0 is None): # set to iLL.E
xyzw0 = np2d([100.0, 100.0, 100.0])
xyzw0 = np.ones(target_shape) * xyzw0
La0 = xyzw0[..., 1, None]
# Determine cat-type (1-step or 2-step) + make input same shape as data for block calculations:
expansion_axis = np.abs(1 * (len(data_original_shape) == 2) - 1)
if ((xyzw1 is not None) & (xyzw2 is not None)):
xyzw1 = xyzw1 * np.ones(target_shape)
xyzw2 = xyzw2 * np.ones(target_shape)
default_La12 = [xyzw1[..., 1, None], xyzw2[..., 1, None]]
elif (xyzw2 is None) & (xyzw1
is not None): # apply one-step CAT: 1-->0
catmode = '1>0' #override catmode input
xyzw1 = xyzw1 * np.ones(target_shape)
default_La12 = [xyzw1[..., 1, None], La0]
elif (xyzw1 is None) & (xyzw2 is not None):
raise Exception(
"von_kries(): cat transformation '0>2' not supported, use '1>0' !"
)
# Get or set La (La == None: xyz are absolute or relative, La != None: xyz are relative):
target_shape_1 = tuple(np.hstack((target_shape[:-1], 1)))
La1, La2 = parse_x1x2_parameters(La,
target_shape=target_shape_1,
catmode=catmode,
expand_2d_to_3d=expansion_axis,
default=default_La12)
# Set degrees of adaptation, D10, D20: (note D20 is degree of adaptation for 2-->0!!)
D10, D20 = parse_x1x2_parameters(D,
target_shape=target_shape_1,
catmode=catmode,
expand_2d_to_3d=expansion_axis)
# Set F surround in case of Dtype == 'cat02':
F1, F2 = parse_x1x2_parameters(F,
target_shape=target_shape_1,
catmode=catmode,
expand_2d_to_3d=expansion_axis)
# Make xyz relative to go to relative xyz0:
if La is None:
data = 100 * data / La1
xyzw1 = 100 * xyzw1 / La1
xyzw0 = 100 * xyzw0 / La0
if (catmode == '1>0>2') | (catmode == '1>2'):
xyzw2 = 100 * xyzw2 / La2
# transform data (xyz) to sensor space (lms) and perform cat:
xyzc = np.ones(data.shape) * np.nan
mcat = np.array(mcat)
if (mcat.shape[0] != data.shape[1]) & (mcat.shape[0] == 1):
mcat = np.repeat(mcat, data.shape[1], axis=0)
elif (mcat.shape[0] != data.shape[1]) & (mcat.shape[0] > 1):
raise Exception(
'von_kries(): mcat.shape[0] > 1 and does not match data.shape[0]!'
)
for i in range(xyzc.shape[1]):
# get cat sensor matrix:
if mcat[i].dtype == np.float64:
mcati = mcat[i]
else:
mcati = _MCATS[mcat[i]]
# normalize sensor matrix:
if normxyz0 is not None:
mcati = math.normalize_3x3_matrix(mcati, xyz0=normxyz0)
# convert from xyz to lms:
lms = np.dot(mcati, data[:, i].T).T
lmsw0 = np.dot(mcati, xyzw0[:, i].T).T
if (catmode == '1>0>2') | (catmode == '1>0'):
lmsw1 = np.dot(mcati, xyzw1[:, i].T).T
Dpar1 = dict(D=D10[:, i],
F=F1[:, i],
La=La1[:, i],
La0=La0[:, i],
order='1>0')
D10[:, i] = get_degree_of_adaptation(
Dtype=Dtype,
**Dpar1) #get degree of adaptation depending on Dtype
lmsw2 = None # in case of '1>0'
if (catmode == '1>0>2'):
lmsw2 = np.dot(mcati, xyzw2[:, i].T).T
Dpar2 = dict(D=D20[:, i],
F=F2[:, i],
La=La2[:, i],
La0=La0[:, i],
order='0>2')
D20[:, i] = get_degree_of_adaptation(
Dtype=Dtype,
**Dpar2) #get degree of adaptation depending on Dtype
if (catmode == '1>2'):
lmsw1 = np.dot(mcati, xyzw1[:, i].T).T
lmsw2 = np.dot(mcati, xyzw2[:, i].T).T
Dpar12 = dict(D=D10[:, i],
F=F1[:, i],
La=La1[:, i],
La2=La2[:, i],
order='1>2')
D10[:, i] = get_degree_of_adaptation(
Dtype=Dtype,
**Dpar12) #get degree of adaptation depending on Dtype
# Determine transfer function Dt:
Dt = get_transfer_function(cattype=cattype,
catmode=catmode,
lmsw1=lmsw1,
lmsw2=lmsw2,
lmsw0=lmsw0,
D10=D10[:, i],
D20=D20[:, i],
La1=La1[:, i],
La2=La2[:, i])
# Perform cat:
lms = np.dot(np.diagflat(Dt[0]), lms.T).T
# Make xyz, lms 'absolute' again:
if (catmode == '1>0>2'):
lms = (La2[:, i] / La1[:, i]) * lms
elif (catmode == '1>0'):
lms = (La0[:, i] / La1[:, i]) * lms
elif (catmode == '1>2'):
lms = (La2[:, i] / La1[:, i]) * lms
# transform back from sensor space to xyz (or not):
if outtype == 'xyz':
xyzci = np.dot(np.linalg.inv(mcati), lms.T).T
xyzci[np.where(xyzci < 0)] = _EPS
xyzc[:, i] = xyzci
else:
xyzc[:, i] = lms
# return data to original shape:
if len(data_original_shape) == 2:
xyzc = xyzc[0]
return xyzc
def cam15u(data,
fov=10.0,
inputtype='xyz',
direction='forward',
outin='Q,aW,bW',
parameters=None):
"""
Convert between CIE 2006 10° XYZ tristimulus values (or spectral data)
and CAM15u color appearance correlates.
Args:
:data:
| ndarray of CIE 2006 10° XYZ tristimulus values or spectral data
or color appearance attributes
:fov:
| 10.0, optional
| Field-of-view of stimulus (for size effect on brightness)
:inputtpe:
| '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 -> cam15u
| -'inverse': cam15u -> xyz
:outin:
| 'Q,aW,bW' or str, optional
| 'Q,aW,bW' (brightness and opponent signals for amount-of-neutral)
| other options: 'Q,aM,bM' (colorfulness) and 'Q,aS,bS' (saturation)
| Str specifying the type of
| input (:direction: == 'inverse') and
| output (:direction: == 'forward')
:parameters:
| None or dict, optional
| Set of model parameters.
| - None: defaults to luxpy.cam._CAM15U_PARAMETERS
| (see references below)
Returns:
:returns:
| ndarray with color appearance correlates (:direction: == 'forward')
| or
| XYZ tristimulus values (:direction: == 'inverse')
References:
1. `M. Withouck, K. A. G. Smet, W. R. Ryckaert, and P. Hanselaer,
“Experimental driven modelling of the color appearance of
unrelated self-luminous stimuli: CAM15u,”
Opt. Express, vol. 23, no. 9, pp. 12045–12064, 2015.
<https://www.osapublishing.org/oe/abstract.cfm?uri=oe-23-9-12045&origin=search>`_
2. `M. Withouck, K. A. G. Smet, and P. Hanselaer, (2015),
“Brightness prediction of different sized unrelated self-luminous stimuli,”
Opt. Express, vol. 23, no. 10, pp. 13455–13466.
<https://www.osapublishing.org/oe/abstract.cfm?uri=oe-23-10-13455&origin=search>`_
"""
if parameters is None:
parameters = _CAM15U_PARAMETERS
outin = outin.split(',')
#unpack model parameters:
Mxyz2rgb, cA, cAlms, cHK, cM, cW, ca, calms, cb, cblms, cfov, cp, k, unique_hue_data = [
parameters[x] for x in sorted(parameters.keys())
]
# precomputations:
invMxyz2rgb = np.linalg.inv(Mxyz2rgb)
MAab = np.array([cAlms, calms, cblms])
invMAab = np.linalg.inv(MAab)
#initialize data and camout:
data = np2d(data)
if len(data.shape) == 2:
data = np.expand_dims(data, axis=0) # avoid looping if not necessary
if (data.shape[0] > data.shape[1]): # loop over shortest dim.
flipaxis0and1 = True
data = np.transpose(data, axes=(1, 0, 2))
else:
flipaxis0and1 = False
dshape = list(data.shape)
dshape[-1] = len(outin) # requested number of correlates
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.nan * np.ones(dshape)
for i in range(data.shape[0]):
if (inputtype != 'xyz') & (direction == 'forward'):
xyz = spd_to_xyz(data[i], cieobs='2006_10', relative=False)
lms = np.dot(_CMF['2006_10']['M'], xyz.T).T # convert to l,m,s
rgb = (lms /
_CMF['2006_10']['K']) * k # convert to rho, gamma, beta
elif (inputtype == 'xyz') & (direction == 'forward'):
rgb = np.dot(Mxyz2rgb, data[i].T).T
if direction == 'forward':
# apply cube-root compression:
rgbc = rgb**(cp)
# calculate achromatic and color difference signals, A, a, b:
Aab = np.dot(MAab, rgbc.T).T
A, a, b = asplit(Aab)
A = cA * A
a = ca * a
b = cb * b
# calculate colorfullness like signal M:
M = cM * ((a**2.0 + b**2.0)**0.5)
# calculate brightness Q:
Q = A + cHK[0] * M**cHK[
1] # last term is contribution of Helmholtz-Kohlrausch effect on brightness
# calculate saturation, s:
s = M / Q
# calculate amount of white, W:
W = 100.0 / (1.0 + cW[0] * (s**cW[1]))
# adjust Q for size (fov) of stimulus (matter of debate whether to do this before or after calculation of s or W, there was no data on s, M or W for different sized stimuli: after)
Q = Q * (fov / 10.0)**cfov
# calculate hue, h and Hue quadrature, H:
h = hue_angle(a, b, htype='deg')
if 'H' in outin:
H = hue_quadrature(h, unique_hue_data=unique_hue_data)
else:
H = None
# calculate cart. co.:
if 'aM' in outin:
aM = M * np.cos(h * np.pi / 180.0)
bM = M * np.sin(h * np.pi / 180.0)
if 'aS' in outin:
aS = s * np.cos(h * np.pi / 180.0)
bS = s * np.sin(h * np.pi / 180.0)
if 'aW' in outin:
aW = W * np.cos(h * np.pi / 180.0)
bW = W * np.sin(h * np.pi / 180.0)
if (outin != ['Q', 'aW', 'bW']):
camout[i] = eval('ajoin((' + ','.join(outin) + '))')
else:
camout[i] = ajoin((Q, aW, bW))
elif direction == 'inverse':
# get Q, M and a, b depending on input type:
if 'aW' in outin:
Q, a, b = asplit(data[i])
Q = Q / (
(fov / 10.0)**cfov
) #adjust Q for size (fov) of stimulus back to that 10° ref
W = (a**2.0 + b**2.0)**0.5
s = (((100 / W) - 1.0) / cW[0])**(1.0 / cW[1])
M = s * Q
if 'aM' in outin:
Q, a, b = asplit(data[i])
Q = Q / (
(fov / 10.0)**cfov
) #adjust Q for size (fov) of stimulus back to that 10° ref
M = (a**2.0 + b**2.0)**0.5
if 'aS' in outin:
Q, a, b = asplit(data[i])
Q = Q / (
(fov / 10.0)**cfov
) #adjust Q for size (fov) of stimulus back to that 10° ref
s = (a**2.0 + b**2.0)**0.5
M = s * Q
if 'h' in outin:
Q, WsM, h = asplit(data[i])
Q = Q / (
(fov / 10.0)**cfov
) #adjust Q for size (fov) of stimulus back to that 10° ref
if 'W' in outin:
s = (((100.0 / WsM) - 1.0) / cW[0])**(1.0 / cW[1])
M = s * Q
elif 's' in outin:
M = WsM * Q
elif 'M' in outin:
M = WsM
# calculate achromatic signal, A from Q and M:
A = Q - cHK[0] * M**cHK[1]
A = A / cA
# calculate hue angle:
h = hue_angle(a, b, htype='rad')
# calculate a,b from M and h:
a = (M / cM) * np.cos(h)
b = (M / cM) * np.sin(h)
a = a / ca
b = b / cb
# create Aab:
Aab = ajoin((A, a, b))
# calculate rgbc:
rgbc = np.dot(invMAab, Aab.T).T
# decompress rgbc to rgb:
rgb = rgbc**(1 / cp)
# convert rgb to xyz:
xyz = np.dot(invMxyz2rgb, rgb.T).T
camout[i] = xyz
if flipaxis0and1 == True: # loop over shortest dim.
camout = np.transpose(camout, axes=(1, 0, 2))
if camout.shape[0] == 1:
camout = np.squeeze(camout, axis=0)
return camout
def fit_ellipse(xy, center_on_mean_xy=False):
"""
Fit an ellipse to supplied data points.
Args:
:xy:
| coordinates of points to fit (Nx2 array)
:center_on_mean_xy:
| False, optional
| Center ellipse on mean of xy
| (otherwise it might be offset due to solving
| the contrained minization problem: aT*S*a, see ref below.)
Returns:
:v:
| vector with ellipse parameters [Rmax,Rmin, xc,yc, theta]
Reference:
1. Fitzgibbon, A.W., Pilu, M., and Fischer R.B.,
Direct least squares fitting of ellipsees,
Proc. of the 13th Internation Conference on Pattern Recognition,
pp 253–257, Vienna, 1996.
"""
# remove centroid:
# center = xy.mean(axis=0)
# xy = xy - center
# Fit ellipse:
x, y = xy[:, 0:1], xy[:, 1:2]
D = np.hstack((x * x, x * y, y * y, x, y, np.ones_like(x)))
S, C = np.dot(D.T, D), np.zeros([6, 6])
C[0, 2], C[2, 0], C[1, 1] = 2, 2, -1
U, s, V = np.linalg.svd(np.dot(np.linalg.inv(S), C))
e = U[:, 0]
# E, V = np.linalg.eig(np.dot(np.linalg.inv(S), C))
# n = np.argmax(np.abs(E))
# e = V[:,n]
# get ellipse axis lengths, center and orientation:
b, c, d, f, g, a = e[1] / 2, e[2], e[3] / 2, e[4] / 2, e[5], e[0]
# get ellipse center:
num = b * b - a * c
if num == 0:
xc = 0
yc = 0
else:
xc = ((c * d - b * f) / num)
yc = ((a * f - b * d) / num)
# get ellipse orientation:
theta = np.arctan2(np.array(2 * b), np.array((a - c))) / 2
# if b == 0:
# if a > c:
# theta = 0
# else:
# theta = np.pi/2
# else:
# if a > c:
# theta = np.arctan2(2*b,(a-c))/2
# else:
# theta = np.arctan2(2*b,(a-c))/2 + np.pi/2
# axis lengths:
up = 2 * (a * f * f + c * d * d + g * b * b - 2 * b * d * f - a * c * g)
down1 = (b * b - a * c) * ((c - a) * np.sqrt(1 + 4 * b * b / ((a - c) *
(a - c))) -
(c + a))
down2 = (b * b - a * c) * ((a - c) * np.sqrt(1 + 4 * b * b / ((a - c) *
(a - c))) -
(c + a))
a, b = np.sqrt((up / down1)), np.sqrt((up / down2))
# assert that a is the major axis (otherwise swap and correct angle)
if (b > a):
b, a = a, b
# ensure the angle is betwen 0 and 2*pi
theta = fmod(theta, 2.0 * np.pi)
if center_on_mean_xy == True:
xc, yc = xy.mean(axis=0)
return np.hstack((a, b, xc, yc, theta))
def run(data, xyzw, out = 'J,aM,bM', conditions = None, forward = True):
"""
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
: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()?
:forward:
| True, optional
| If True: run in CAM in forward mode, else: inverse mode.
:out:
| '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)
Returns:
:camout:
| ndarray with Jab coordinates or whatever correlates requested in out.
Note:
* This is a simplified, less flexible, but faster version than the main ciecam02().
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 = out.split(',') if isinstance(out,str) else out
#--------------------------------------------
# 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)
if not forward: mcat_x_invmhpe = np.dot(mcat,np.linalg.inv(mhpe))
#--------------------------------------------
# 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))
#===================================================================
# WHITE POINT transformations (common to forward and inverse modes):
#--------------------------------------------
# transform from xyzw to cat sensor space:
rgbw = mcat @ xyzw.T
#--------------------------------------------
# apply von Kries cat:
rgbwc = ((D*Yw/rgbw) + (1 - D))*rgbw # factor 100 from ciecam02 is replaced with Yw[i] in cam16, but see 'note' in Fairchild's "Color Appearance Models" (p291 ni 3ed.)
#--------------------------------------------
# convert from cat02 sensor space to cone sensors (hpe):
rgbwp = (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)
rgbwpa = NK(FL*rgbwp/100.0, True)
pw = np.where(rgbwp<0)
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:
if data.ndim == 2: data = data[:,None]
#===================================================================
# STIMULUS transformations
if forward:
#--------------------------------------------
# transform from xyz to cat sensor space:
rgb = math.dot23(mcat, data.T)
#--------------------------------------------
# apply von Kries cat:
rgbc = ((D*Yw/rgbw)[...,None] + (1 - D))*rgb # factor 100 from ciecam02 is replaced with Yw[i] in cam16, 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:
rgbpa = NK(FL*rgbp/100.0, forward)
p = np.where(rgbp<0)
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 = 'ciecam02')
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* (A / Aw)**(c*z)
#--------------------------------------------
# calculate brightness, Q:
if ('Q' in outin) | ('s' in outin) | ('aS' in outin):
Q = (4.0/c)* ((J/100.0)**0.5) * (Aw + 4.0)*(FL**0.25)
#--------------------------------------------
# calculate chroma, C:
if ('C' in outin) | ('M' in outin) | ('s' in outin) | ('aS' in outin) | ('aC' in outin) | ('aM' in outin):
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:
if ('M' in outin) | ('s' in outin) | ('aM' in outin) | ('aS' in outin):
M = 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:
camout = camout[:,0,:]
return camout
elif forward == False:
#--------------------------------------------
# Get Lightness J from data:
if ('J' in outin):
J = data[...,0].copy()
elif ('Q' in outin):
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!')
#--------------------------------------------
# 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
if ('aS' in outin):
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 ('aM' in outin): # convert M to C:
C = MCs/(FL**0.25)
if ('aC' in outin):
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)
#--------------------------------------------
# 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).T
return xyz
def cam18sl(data, datab = None, Lb = [100], fov = 10.0, inputtype = 'xyz', direction = 'forward', outin = 'Q,aW,bW', parameters = None):
"""
Convert between CIE 2006 10° XYZ tristimulus values (or spectral data)
and CAM18sl color appearance correlates.
Args:
:data:
| ndarray of CIE 2006 10° absolute XYZ tristimulus values or spectral data
or color appearance attributes of stimulus
:datab:
| ndarray of CIE 2006 10° absolute XYZ tristimulus values or spectral data
of stimulus background
:Lb:
| [100], optional
| Luminance (cd/m²) value(s) of background(s) calculated using the CIE 2006 10° CMFs
| (only used in case datab == None and the background is assumed to be an Equal-Energy-White)
:fov:
| 10.0, optional
| Field-of-view of stimulus (for size effect on brightness)
:inputtpe:
| '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 -> cam18sl
| -'inverse': cam18sl -> xyz
:outin:
| 'Q,aW,bW' or str, optional
| 'Q,aW,bW' (brightness and opponent signals for amount-of-neutral)
| other options: 'Q,aM,bM' (colorfulness) and 'Q,aS,bS' (saturation)
| Str specifying the type of
| input (:direction: == 'inverse') and
| output (:direction: == 'forward')
:parameters:
| None or dict, optional
| Set of model parameters.
| - None: defaults to luxpy.cam._CAM18SL_PARAMETERS
| (see references below)
Returns:
:returns:
| ndarray with color appearance correlates (:direction: == 'forward')
| or
| XYZ tristimulus values (:direction: == 'inverse')
Notes:
| * Instead of using the CIE 1964 10° CMFs in some places of the model,
| the CIE 2006 10° CMFs are used througout, making it more self_consistent.
| This has an effect on the k scaling factors (now different those in CAM15u)
| and the illuminant E normalization for use in the chromatic adaptation transform.
| (see future erratum to Hermans et al., 2018)
| * The paper also used an equation for the amount of white W, which is
| based on a Q value not expressed in 'bright' ('cA' = 0.937 instead of 123).
| This has been corrected for in the luxpy version of the model, i.e.
| _CAM18SL_PARAMETERS['cW'][0] has been changed from 2.29 to 1/11672.
| (see future erratum to Hermans et al., 2018)
References:
1. `Hermans, S., Smet, K. A. G., & Hanselaer, P. (2018).
"Color appearance model for self-luminous stimuli."
Journal of the Optical Society of America A, 35(12), 2000–2009.
<https://doi.org/10.1364/JOSAA.35.002000>`_
"""
if parameters is None:
parameters = _CAM18SL_PARAMETERS
outin = outin.split(',')
#unpack model parameters:
cA, cAlms, cHK, cM, cW, ca, calms, cb, cblms, cfov, k, naka, unique_hue_data = [parameters[x] for x in sorted(parameters.keys())]
# precomputations:
Mlms2xyz = np.linalg.inv(_CMF['2006_10']['M'])
MAab = np.array([cAlms,calms,cblms])
invMAab = np.linalg.inv(MAab)
#-------------------------------------------------
# setup EEW reference field and default background field (Lr should be equal to Lb):
# Get Lb values:
if datab is not None:
if inputtype != 'xyz':
Lb = spd_to_xyz(datab, cieobs = '2006_10', relative = False)[...,1:2]
else:
Lb = datab[...,1:2]
else:
if isinstance(Lb,list):
Lb = np2dT(Lb)
# Setup EEW ref of same luminance as datab:
if inputtype == 'xyz':
wlr = getwlr(_CAM18SL_WL3)
else:
if datab is None:
wlr = data[0] # use wlr of stimulus data
else:
wlr = datab[0] # use wlr of background data
datar = np.vstack((wlr,np.ones((Lb.shape[0], wlr.shape[0])))) # create eew
xyzr = spd_to_xyz(datar, cieobs = '2006_10', relative = False) # get abs. tristimulus values
datar[1:] = datar[1:]/xyzr[...,1:2]*Lb
# Create datab if None:
if (datab is None):
if inputtype != 'xyz':
datab = datar.copy()
else:
datab = spd_to_xyz(datar, cieobs = '2006_10', relative = False)
datar = datab.copy()
# prepare data and datab for loop over backgrounds:
# make axis 1 of datab 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 datab.shape[0] == 1: #make datab and datar have same lights source dimension (used to store different backgrounds) size as data
datab = np.repeat(datab,data.shape[1],axis=0)
datar = np.repeat(datar,data.shape[1],axis=0)
else:
if datab.shape[0] == 2:
datab = np.vstack((datab[0],np.repeat(datab[1:], data.shape[1], axis = 0)))
if datar.shape[0] == 2:
datar = np.vstack((datar[0],np.repeat(datar[1:], data.shape[1], axis = 0)))
# Flip light source/ background dim to axis 0:
data = np.transpose(data, axes = (1,0,2))
#-------------------------------------------------
#initialize camout:
dshape = list(data.shape)
dshape[-1] = len(outin) # requested number of correlates
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.nan*np.ones(dshape)
for i in range(data.shape[0]):
# get rho, gamma, beta of background and reference white:
if (inputtype != 'xyz'):
xyzb = spd_to_xyz(np.vstack((datab[0], datab[i+1:i+2,:])), cieobs = '2006_10', relative = False)
xyzr = spd_to_xyz(np.vstack((datar[0], datar[i+1:i+2,:])), cieobs = '2006_10', relative = False)
else:
xyzb = datab[i:i+1,:]
xyzr = datar[i:i+1,:]
lmsb = np.dot(_CMF['2006_10']['M'],xyzb.T).T # convert to l,m,s
rgbb = (lmsb / _CMF['2006_10']['K']) * k # convert to rho, gamma, beta
#lmsr = np.dot(_CMF['2006_10']['M'],xyzr.T).T # convert to l,m,s
#rgbr = (lmsr / _CMF['2006_10']['K']) * k # convert to rho, gamma, beta
#rgbr = rgbr/rgbr[...,1:2]*Lb[i] # calculated EEW cone excitations at same luminance values as background
rgbr = np.ones(xyzr.shape)*Lb[i] # explicitely equal EEW cone excitations at same luminance values as background
if direction == 'forward':
# get rho, gamma, beta of stimulus:
if (inputtype != 'xyz'):
xyz = spd_to_xyz(data[i], cieobs = '2006_10', relative = False)
elif (inputtype == 'xyz'):
xyz = data[i]
lms = np.dot(_CMF['2006_10']['M'],xyz.T).T # convert to l,m,s
rgb = (lms / _CMF['2006_10']['K']) * k # convert to rho, gamma, beta
# apply von-kries cat with D = 1:
if (rgbb == 0).any():
Mcat = np.eye(3)
else:
Mcat = np.diag((rgbr/rgbb)[0])
rgba = np.dot(Mcat,rgb.T).T
# apply naka-rushton compression:
rgbc = naka_rushton(rgba, n = naka['n'], sig = naka['sig'](rgbr.mean()), noise = naka['noise'], scaling = naka['scaling'])
#rgbc = np.ones(rgbc.shape)*rgbc.mean() # test if eew ends up at origin
# calculate achromatic and color difference signals, A, a, b:
Aab = np.dot(MAab, rgbc.T).T
A,a,b = asplit(Aab)
a = ca*a
b = cb*b
# calculate colorfullness like signal M:
M = cM*((a**2.0 + b**2.0)**0.5)
# calculate brightness Q:
Q = cA*(A + cHK[0]*M**cHK[1]) # last term is contribution of Helmholtz-Kohlrausch effect on brightness
# calculate saturation, s:
s = M / Q
# calculate amount of white, W:
W = 1 / (1.0 + cW[0]*(s**cW[1]))
# adjust Q for size (fov) of stimulus (matter of debate whether to do this before or after calculation of s or W, there was no data on s, M or W for different sized stimuli: after)
Q = Q*(fov/10.0)**cfov
# calculate hue, h and Hue quadrature, H:
h = hue_angle(a,b, htype = 'deg')
if 'H' in outin:
H = hue_quadrature(h, unique_hue_data = unique_hue_data)
else:
H = None
# calculate cart. co.:
if 'aM' in outin:
aM = M*np.cos(h*np.pi/180.0)
bM = M*np.sin(h*np.pi/180.0)
if 'aS' in outin:
aS = s*np.cos(h*np.pi/180.0)
bS = s*np.sin(h*np.pi/180.0)
if 'aW' in outin:
aW = W*np.cos(h*np.pi/180.0)
bW = W*np.sin(h*np.pi/180.0)
if (outin != ['Q','aW','bW']):
camout[i] = eval('ajoin(('+','.join(outin)+'))')
else:
camout[i] = ajoin((Q,aW,bW))
elif direction == 'inverse':
# get Q, M and a, b depending on input type:
if 'aW' in outin:
Q,a,b = asplit(data[i])
Q = Q / ((fov/10.0)**cfov) #adjust Q for size (fov) of stimulus back to that 10° ref
W = (a**2.0 + b**2.0)**0.5
s = (((1.0 / W) - 1.0)/cW[0])**(1.0/cW[1])
M = s*Q
if 'aM' in outin:
Q,a,b = asplit(data[i])
Q = Q / ((fov/10.0)**cfov) #adjust Q for size (fov) of stimulus back to that 10° ref
M = (a**2.0 + b**2.0)**0.5
if 'aS' in outin:
Q,a,b = asplit(data[i])
Q = Q / ((fov/10.0)**cfov) #adjust Q for size (fov) of stimulus back to that 10° ref
s = (a**2.0 + b**2.0)**0.5
M = s*Q
if 'h' in outin:
Q, WsM, h = asplit(data[i])
Q = Q / ((fov/10.0)**cfov) #adjust Q for size (fov) of stimulus back to that 10° ref
if 'W' in outin:
s = (((1.0 / WsM) - 1.0)/cW[0])**(1.0/cW[1])
M = s*Q
elif 's' in outin:
M = WsM*Q
elif 'M' in outin:
M = WsM
# calculate achromatic signal, A from Q and M:
A = Q/cA - cHK[0]*M**cHK[1]
# calculate hue angle:
h = hue_angle(a,b, htype = 'rad')
# calculate a,b from M and h:
a = (M/cM)*np.cos(h)
b = (M/cM)*np.sin(h)
a = a/ca
b = b/cb
# create Aab:
Aab = ajoin((A,a,b))
# calculate rgbc:
rgbc = np.dot(invMAab, Aab.T).T
# decompress rgbc to (adapted) rgba :
rgba = naka_rushton(rgbc, n = naka['n'], sig = naka['sig'](rgbr.mean()), noise = naka['noise'], scaling = naka['scaling'], direction = 'inverse')
# apply inverse von-kries cat with D = 1:
rgb = np.dot(np.diag((rgbb/rgbr)[0]),rgba.T).T
# convert rgb to lms to xyz:
lms = rgb/k*_CMF['2006_10']['K']
xyz = np.dot(Mlms2xyz,lms.T).T
camout[i] = xyz
if camout.shape[0] == 1:
camout = np.squeeze(camout,axis = 0)
return camout
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.nan*np.ones(dshape)
# 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
