def estimate_arc_reflection_model_params(wavelength, reflectance, porosity=0.1,
wavelength_min=450,
wavelength_max=1000):
# Smooth.
# N = 5
# reflectance = np.convolve(reflectance, np.ones((N,)), mode='same') / N
cax = np.logical_and(wavelength > wavelength_min,
wavelength < wavelength_max)
idx_min_reflection = np.argmin(reflectance[cax])
reflection_min = reflectance[cax][idx_min_reflection]
wavelength_min_reflection = wavelength[cax][idx_min_reflection]
n = refractive_index_porous_silica(wavelength_min_reflection, porosity=0.5)
thickness_estimate = 0.25 * wavelength_min_reflection / n
# thickness_estimate = 120
reflection_from_arc = float(
arc_reflection_model(np.array([wavelength_min_reflection]),
thickness_estimate,
fraction_abraded=0,
fraction_dust=0,
porosity=porosity))
reflection_from_glass = float(
arc_reflection_model(np.array([wavelength_min_reflection]),
thickness_estimate,
fraction_abraded=1,
fraction_dust=0,
porosity=porosity))
# print('Reflection from glass: {}'.format(reflection_from_glass))
# print('Reflection from arc: {}'.format(reflection_from_arc))
# print('Reflection from sample: {}'.format(reflection_min))
fraction_abraded = (reflection_min - reflection_from_arc) / (
reflection_from_glass - reflection_from_arc)
# if thickness_estimate < 135:
# thickness_estimate = 135
return {'thickness': thickness_estimate,
'fraction_abraded': float(fraction_abraded),
'fraction_dust': 0.001,
'porosity': porosity
}
def arc_model_to_rgb(thickness, porosity, aoi=8):
# Wavelength axis
wavelength = np.arange(360, 801, 5).astype('float')
# Choice of illuminant makes a very small change to the calculated RGB color.
illuminant = 'LED-B3'
# # Scan thickness and porosity.
# thickness = np.arange(0, 196, 5).astype('float')
# porosity = np.arange(0, 0.51, 0.1).astype('float')
# col = np.zeros((3, len(thickness), len(porosity)))
# col_hex = np.empty((len(thickness), len(porosity)), dtype='object')
# xyY = np.zeros((3, len(thickness), len(porosity)))
index_film = refractive_index_porous_silica(wavelength, porosity)
index_substrate = refractive_index_glass(wavelength)
# Calculate reflectance
reflectance = thin_film_reflectance(index_film=index_film,
index_substrate=index_substrate,
film_thickness=thickness,
aoi=aoi,
wavelength=wavelength)
reflectance_ref = thin_film_reflectance(index_film=index_film,
index_substrate=index_substrate,
film_thickness=0,
aoi=aoi,
wavelength=wavelength)
rgb = spectrum_to_rgb(wavelength, reflectance, illuminant=illuminant)
rgb_ref = spectrum_to_rgb(wavelength,
reflectance_ref,
illuminant=illuminant)
# White balance
rgb_wb = rgb / rgb_ref
# Clamp
rgb_wb[rgb_wb >= 1] = 1
rgb_wb[rgb_wb < 0] = 0
return rgb_wb
def arc_model_c(wavelength, thickness, fraction_abraded, fraction_dust,
porosity):
index_film = refractive_index_porous_silica(wavelength=wavelength,
porosity=porosity)
index_substrate = refractive_index_glass(wavelength=wavelength)
thin_film_R = thin_film_reflectance(
index_film=index_film,
index_substrate=index_substrate,
film_thickness=thickness,
wavelength=wavelength,
aoi=aoi
)
#
# thin_film_R = thin_film_reflection_fast(
# wavelength=wavelength,
# thickness=thickness,
# aoi=aoi,
# porosity=porosity)
#
# index_film = index_porous_silica(wavelength=wavelength,
# porosity=porosity)
# thin_film_reflectance = thin_film_reflection(
# polarization='mixed',
# wavelength=wavelength,
# d_list=[np.inf, thickness, np.inf],
# index_film=index_film,
# index_substrate=index_glass,
# aoi=aoi)
glass_reflectance = np.interp(wavelength, wavelength_calc,
glass_reflectance_calc)
reflectance = (1 - fraction_dust) * (
fraction_abraded * glass_reflectance + (
1 - fraction_abraded) * thin_film_R) + fraction_dust
return 100 * reflectance
reflectance.
toddkarin
09/10/2020
"""
import numpy as np
from time import time
from pvarc.materials import refractive_index_glass, refractive_index_porous_silica
from pvarc.tmm import thin_film_reflectance_tmm
from pvarc import thin_film_reflectance
wavelength = np.linspace(200, 1250, 2000)
index_substrate = refractive_index_glass(wavelength)
index_film = refractive_index_porous_silica(wavelength)
aoi = 8
film_thickness = 120
polarization = 'mixed'
start_time = time()
R_tmm = thin_film_reflectance_tmm(index_film=index_film,
index_substrate=index_substrate,
film_thickness=film_thickness,
aoi=aoi,
wavelength=wavelength,
polarization=polarization)
time_tmm = time() - start_time
print('Elapsed time for TMM method: {:.5f} s'.format(time_tmm))
start_time = time()
R_explicit = thin_film_reflectance(index_film=index_film,
refractive_index_glass
from pvarc.metrics import solar_weighted_photon_reflectance
# Set thickness and porosity values.
thickness = np.arange(0, 196, 5).astype('float')
porosity = np.arange(0, 0.51, 0.025).astype('float')
swpr = np.zeros((len(thickness), len(porosity)))
wavelength = np.linspace(200, 1250, 200)
# Integration limits for SWPR
swpr_wavelength_min = 400
swpr_wavelength_max = 1100
for k in tqdm(range(len(porosity))):
index_film = refractive_index_porous_silica(wavelength, porosity[k])
index_substrate = refractive_index_glass(wavelength)
for j in range(len(thickness)):
# Calculate reflectance at rough.
reflectance = thin_film_reflectance(index_film=index_film,
index_substrate=index_substrate,
film_thickness=thickness[j],
aoi=8,
wavelength=wavelength)
swpr[j, k] = solar_weighted_photon_reflectance(
wavelength,
reflectance,
wavelength_min=swpr_wavelength_min,
wavelength_max=swpr_wavelength_max)
def arc_reflection_model(wavelength,
thickness=125,
fraction_abraded=0,
porosity=0.3,
fraction_dust=0,
aoi=8,
n0=1.0003):
"""
Return the reflection values for a model of an aged ARC. The reflection
is a linear combination of reflection from a thin film of a variable
thickness and the reflection from BK7 glass.
Parameters
----------
wavelength : ndarray
wavelength in nm
thickness
thickness of ARC in nm.
fraction_abraded
fraction of coating loss. 1 corresponds to 100% of the coating area
removed and only underlying glass is present, 0 corresponds to the
coating covering the entire sample.
fraction_dust
fraction of module area covered by dust with reflectivity of 1. A
value of 0 corresponds to no dust (clean sample), 1 to full dust
coverage (reflectivity of 1).
aoi
angle of incidence in degrees.
Returns
-------
reflectance : ndarray
Reflectance of sample at the values of wavelength specified.
"""
index_substrate = refractive_index_glass(wavelength)
index_film = refractive_index_porous_silica(wavelength, porosity=porosity)
glass_reflectance = single_interface_reflectance(
n0=n0,
n1=index_substrate,
polarization='mixed',
aoi=aoi)
thin_film_R = thin_film_reflectance(index_film=index_film,
index_substrate=index_substrate,
film_thickness=thickness,
aoi=aoi,
wavelength=wavelength)
reflectance = (1 - fraction_dust) * (
fraction_abraded * glass_reflectance + (
1 - fraction_abraded) * thin_film_R) + fraction_dust
return reflectance
def calculate_rgb_vs_thickness_porosity(
camera='Ximea-MC050cg_combined_labeled.csv',
light_source='LEDW7E_A01_intensity.csv',
optical_system='MVL23M23.csv',
thickness_max=186,
thickness_step=0.4,
porosity_max=0.5,
porosity_step=0.01,
aoi=0):
# Wavelength axis
wavelength = np.arange(300, 755, 5).astype('float')
dwavelength = wavelength[1] - wavelength[0]
# Scan thickness and porosity.
thickness = np.arange(0, thickness_max, thickness_step).astype('float')
porosity = np.arange(0, porosity_max, porosity_step).astype('float')
# Initialize arrays.
swpr = np.zeros((len(thickness), len(porosity)))
rgb_wb = np.zeros((len(thickness), len(porosity), 3))
# Load Camera QE
qe_fpath = os.path.join(os.path.dirname(__file__), 'cameras',
camera)
df = pd.read_csv(qe_fpath, skiprows=2)
dfi = pd.DataFrame({'Wavelength': wavelength})
for k in ['Red', 'Green', 'Blue']:
dfi[k] = np.interp(wavelength, df['Wavelength'], df[k],
left=0, right=0)
# Load Illuminant spectrum
illum_fpath = os.path.join(os.path.dirname(__file__), 'sources',
light_source)
df_illum = pd.read_csv(illum_fpath, skiprows=2)
# illuminant_sd = ILLUMINANTS_SDS[sources[s]]
# illuminant_conv = ILLUMINANTS['CIE 1931 2 Degree Standard Observer'][illuminant_name]
illuminant_spectrum = np.interp(wavelength, df_illum['Wavelength'],
df_illum['Intensity'], left=0, right=0)
illuminant_spectrum_photon = illuminant_spectrum * wavelength
# Load optical system
optical_system_fpath = os.path.join(os.path.dirname(__file__), 'cameras',
optical_system)
df_optical_system = pd.read_csv(optical_system_fpath, skiprows=2)
optical_system_transmission = 0.01 * np.interp(
wavelength,
df_optical_system['Wavelength'],
df_optical_system['Transmission'],
left=0, right=0)
# Calculate RGB colors
for k in tqdm(range(len(porosity))):
index_film = refractive_index_porous_silica(wavelength, porosity[k])
index_substrate = refractive_index_glass(wavelength)
for j in range(len(thickness)):
# Calculate reflectance
reflectance = thin_film_reflectance(index_film=index_film,
index_substrate=index_substrate,
film_thickness=thickness[j],
aoi=aoi,
wavelength=wavelength)
# for c in ['Blue', 'Green', 'Red']:
# np.sum(reflectance * illuminant_spectrum_photon * dfi[c] / 100) * dwavelength
rgb = np.sum(
reflectance[:, np.newaxis] * \
optical_system_transmission[:, np.newaxis] * \
illuminant_spectrum_photon[:, np.newaxis] * \
np.array(dfi.iloc[:, 1:]) / 100,
axis=0) * dwavelength
swpr[j, k] = solar_weighted_photon_reflectance(wavelength,
reflectance)
# Use first run through, with 0 nm thickness, (i.e. low-iron glass)
# as a reference for white balance.
if thickness[j] == 0:
rgb_ref = rgb.copy()
# White balance
rgb_wb[j, k, :] = rgb / rgb_ref
# x = rgb_wb[0, :, :] / np.sum(rgb_wb, axis=0)
# y = rgb_wb[1, :, :] / np.sum(rgb_wb, axis=0)
# z = rgb_wb[2, :, :] / np.sum(rgb_wb, axis=0)
# t_grid, P_grid = np.meshgrid(thickness, porosity, indexing='ij')
return thickness, porosity, rgb_wb, swpr
# Coating thickness to plot.
thickness_scan = np.array([0, 20, 40, 60, 80, 100, 120, 140, 160])
# aoi_scan = np.arange(70,-1,-10)
# aoi_scan = np.array([0,10,20,30,40,50,60,70])
for porosity in [0.15, 0.3]:
plt.figure(0, figsize=(3.7, 3))
plt.clf()
ax = plt.axes()
rect = ax.patch
rect.set_facecolor('k')
Rmat = np.zeros((len(wavelength), len(thickness_scan)))
index_film = refractive_index_porous_silica(wavelength, porosity)
index_film_smooth = refractive_index_porous_silica(wavelength_smooth,
porosity)
index_substrate = refractive_index_glass(wavelength)
index_substrate_smooth = refractive_index_glass(wavelength_smooth)
def smoothit(y, N=10):
return np.convolve(y, np.ones((N, )) / N, mode='valid')
plt.plot(smoothit(source['wavelength'][1:-200]),
smoothit(source['value'][1:-200]) / source['value'][1:-5].max() *
5,
'w--',
label='LED')
for j in range(len(thickness_scan)):