Add comments pinpointing polarizers' orientation uncertainty computation

This commit is contained in:
Thibault Barnouin
2022-01-30 15:44:42 +01:00
parent d03ae5ffc5
commit d133450b82
12 changed files with 36 additions and 285 deletions

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@@ -1,256 +0,0 @@
from pylab import *
import numpy as np
import matplotlib.pyplot as plt
from astropy.io import fits
from astropy.wcs import WCS
from aplpy import FITSFigure
import scipy.ndimage
import os as os
plt.close('all')
def bin_ndarray(ndarray, new_shape, operation='sum'):
"""
Bins an ndarray in all axes based on the target shape, by summing or
averaging.
Number of output dimensions must match number of input dimensions.
Example
-------
>>> m = np.arange(0,100,1).reshape((10,10))
>>> n = bin_ndarray(m, new_shape=(5,5), operation='sum')
>>> print(n)
[[ 22 30 38 46 54]
[102 110 118 126 134]
[182 190 198 206 214]
[262 270 278 286 294]
[342 350 358 366 374]]
"""
if not operation.lower() in ['sum', 'mean', 'average', 'avg']:
raise ValueError("Operation not supported.")
if ndarray.ndim != len(new_shape):
raise ValueError("Shape mismatch: {} -> {}".format(ndarray.shape,
new_shape))
compression_pairs = [(d, c//d) for d,c in zip(new_shape,
ndarray.shape)]
flattened = [l for p in compression_pairs for l in p]
ndarray = ndarray.reshape(flattened)
for i in range(len(new_shape)):
if operation.lower() == "sum":
ndarray = ndarray.sum(-1*(i+1))
elif operation.lower() in ["mean", "average", "avg"]:
ndarray = ndarray.mean(-1*(i+1))
return ndarray
def plots(ax,data,vmax,vmin):
ax.imshow(data,vmax=vmax,vmin=vmin,origin='lower')
### User input
infiles = ['x274020at.c0f.fits','x274020bt.c0f.fits','x274020ct.c0f.fits','x274020dt.c0f.fits',
'x274020et.c0f.fits','x274020ft.c0f.fits','x274020gt.c0f.fits','x274020ht.c0f.fits',
'x274020it.c0f.fits']
#Centroids
#The centroids should be estimated by cross-correlating the images.
#Here I used the position of the central source for each file as the reference pixel position.
ycen_0 = [304,306,303,296,295,295,294,305,304]
xcen_0 = [273,274,273,276,274,274,274,272,271]
#size, in pixels, of the FOV centered in x_cen_0,y_cen_0
Dx = 200
Dy = 200
#set the new image size (Dxy x Dxy pixels binning)
Dxy = 5
new_shape = (Dx//Dxy,Dy//Dxy)
#figures
#test alignment
vmin = 0
vmax = 6
font_size=40.0
label_size=20.
lw = 3.
#pol. map
SNRp_cut = 3 #P measumentes with SNR>3
SNRi_cut = 30 #I measuremntes with SNR>30, which implies an uncerrtainty in P of 4.7%.
scalevec = 0.05 #length of vectors in pol. map
step_vec = 1 #plot all vectors in the array. if step_vec = 2, then every other vector will be plotted
vec_legend = 10 #% pol for legend
figname = 'NGC1068_FOC.png'
### SCRIPT ###
### Step 1. Check input images before data reduction
#this step is very simplistic.
#Here I used the position of the central source for each file as the
#reference pixel position.
#The centroids should be estimated by cross-correlating the images,
#and compare with the simplistic approach of using the peak pixel of the
#object as the reference pixel.
fig,axs = plt.subplots(3,3,figsize=(30,30),dpi=200,sharex=True,sharey=True)
for jj, a in enumerate(axs.flatten()):
img = fits.open(infiles[jj])
ima = img[0].data
ima = ima[ycen_0[jj]-Dy:ycen_0[jj]+Dy,xcen_0[jj]-Dx:xcen_0[jj]+Dx]
ima = bin_ndarray(ima,new_shape=new_shape,operation='sum') #binning
exptime = img[0].header['EXPTIME']
fil = img[0].header['FILTNAM1']
ima = ima/exptime
globals()['ima_%s' % jj] = ima
#plots
plots(a,ima,vmax=vmax,vmin=vmin)
#position of centroid
a.plot([ima.shape[1]/2,ima.shape[1]/2],[0,ima.shape[0]-1],lw=1,color='black')
a.plot([0,ima.shape[1]-1],[ima.shape[1]/2,ima.shape[1]/2],lw=1,color='black')
a.text(2,2,infiles[jj][0:8],color='white',fontsize=10)
a.text(2,5,fil,color='white',fontsize=30)
a.text(ima.shape[1]-20,1,exptime,color='white',fontsize=20)
fig.subplots_adjust(hspace=0,wspace=0)
fig.savefig('test_alignment.png',dpi=300)
os.system('open test_alignment.png')
### Step 2. average of all images for a single polarizer to have them in the same units e/s.
pol0 = (ima_0 + ima_1 + ima_2)/3.
pol60 = (ima_3 + ima_4 + ima_5 + ima_6)/4.
pol120 = (ima_7 + ima_8)/2.
fig1,(ax1,ax2,ax3) = plt.subplots(1,3,figsize=(26,8),dpi=200)
CF = ax1.imshow(pol0,vmin=vmin,vmax=vmax,origin='lower')
cbar = plt.colorbar(CF,ax=ax1)
cbar.ax.tick_params(labelsize=20)
ax1.tick_params(axis='both', which='major', labelsize=20)
ax1.text(2,2,'POL0',color='white',fontsize=10)
CF = ax2.imshow(pol60,vmin=vmin,vmax=vmax,origin='lower')
cbar = plt.colorbar(CF,ax=ax2)
cbar.ax.tick_params(labelsize=20)
ax2.tick_params(axis='both', which='major', labelsize=20)
ax2.text(2,2,'POL60',color='white',fontsize=10)
CF = ax3.imshow(pol120,vmin=vmin,vmax=vmax,origin='lower')
cbar = plt.colorbar(CF,ax=ax3)
cbar.ax.tick_params(labelsize=20)
ax3.tick_params(axis='both', which='major', labelsize=20)
ax3.text(2,2,'POL120',color='white',fontsize=10)
fig1.savefig('test_combinePol.png',dpi=300)
os.system('open test_combinePol.png')
### Step 3. Compute Stokes IQU, P, PA, PI
#Stokes parameters
I_stokes = (2./3.)*(pol0 + pol60 + pol120)
Q_stokes = (2./3.)*(2*pol0 - pol60 - pol120)
U_stokes = (2./np.sqrt(3.))*(pol60 - pol120)
#Remove nan
I_stokes[np.isnan(I_stokes)]=0.
Q_stokes[np.isnan(Q_stokes)]=0.
U_stokes[np.isnan(U_stokes)]=0.
#Polarimetry
PI = np.sqrt(Q_stokes*Q_stokes + U_stokes*U_stokes)
P = PI/I_stokes*100
PA = 0.5*arctan2(U_stokes,Q_stokes)*180./np.pi+90
s_P = np.sqrt(2.)*(I_stokes)**(-0.5)
s_PA = s_P/(P/100.)*180./np.pi
fig2,((ax1,ax2,ax3),(ax4,ax5,ax6)) = plt.subplots(2,3,figsize=(40,20),dpi=200)
CF = ax1.imshow(I_stokes,origin='lower')
cbar = plt.colorbar(CF,ax=ax1)
cbar.ax.tick_params(labelsize=20)
ax1.tick_params(axis='both', which='major', labelsize=20)
ax1.text(2,2,'I',color='white',fontsize=10)
CF = ax2.imshow(Q_stokes,origin='lower')
cbar = plt.colorbar(CF,ax=ax2)
cbar.ax.tick_params(labelsize=20)
ax2.tick_params(axis='both', which='major', labelsize=20)
ax2.text(2,2,'Q',color='white',fontsize=10)
CF = ax3.imshow(U_stokes,origin='lower')
cbar = plt.colorbar(CF,ax=ax3)
cbar.ax.tick_params(labelsize=20)
ax3.tick_params(axis='both', which='major', labelsize=20)
ax3.text(2,2,'U',color='white',fontsize=10)
v = np.linspace(0,40,50)
CF = ax4.imshow(P,origin='lower',vmin=0,vmax=40)
cbar = plt.colorbar(CF,ax=ax4)
cbar.ax.tick_params(labelsize=20)
ax4.tick_params(axis='both', which='major', labelsize=20)
ax4.text(2,2,'P',color='white',fontsize=10)
CF = ax5.imshow(PA,origin='lower',vmin=0,vmax=180)
cbar = plt.colorbar(CF,ax=ax5)
cbar.ax.tick_params(labelsize=20)
ax5.tick_params(axis='both', which='major', labelsize=20)
ax5.text(2,2,'PA',color='white',fontsize=10)
CF = ax6.imshow(PI,origin='lower')
cbar = plt.colorbar(CF,ax=ax6)
cbar.ax.tick_params(labelsize=20)
ax6.tick_params(axis='both', which='major', labelsize=20)
ax6.text(2,2,'PI',color='white',fontsize=10)
fig2.savefig('test_Stokes.png',dpi=300)
os.system('open test_Stokes.png')
### Step 4. Binning and smoothing
#Images can be binned and smoothed to improve SNR. This step can also be done
#using the PolX images.
### Step 5. Roate images to have North up
#Images needs to be reprojected to have North up.
#this procedure implies to rotate the Stokes QU using a rotation matrix
### STEP 6. image to FITS with updated WCS
new_wcs = WCS(naxis=2)
new_wcs.wcs.crpix = [I_stokes.shape[0]/2, I_stokes.shape[1]/2]
new_wcs.wcs.crval = [img[0].header['CRVAL1'], img[0].header['CRVAL2']]
new_wcs.wcs.cunit = ["deg", "deg"]
new_wcs.wcs.ctype = ["RA---TAN", "DEC--TAN"]
new_wcs.wcs.cdelt = [img[0].header['CD1_1']*Dxy, img[0].header['CD1_2']*Dxy]
#hdu_ori = WCS(img[0])
stkI=fits.PrimaryHDU(data=I_stokes,header=new_wcs.to_header())
pol=fits.PrimaryHDU(data=P,header=new_wcs.to_header())
pang=fits.PrimaryHDU(data=PA,header=new_wcs.to_header())
pol_err=fits.PrimaryHDU(data=s_P,header=new_wcs.to_header())
pang_err=fits.PrimaryHDU(data=s_PA,header=new_wcs.to_header())
### STEP 7. polarization map
#quality cuts
pxscale = stkI.header['CDELT1']
#apply quality cuts
SNRp = pol.data/pol_err.data
pol.data[SNRp < SNRp_cut] = np.nan
SNRi = stkI.data/np.std(stkI.data[0:10,0:10])
pol.data[SNRi < SNRi_cut] = np.nan
fig = plt.figure(figsize=(11,10))
gc = FITSFigure(stkI,figure=fig)
gc.show_contour(np.log10(SNRi),levels=np.linspace(np.log10(SNRi_cut),np.max(np.log10(SNRi)),20),\
filled=True,cmap='magma')
gc.show_vectors(pol,pang,scale=scalevec,step=step_vec,color='white',linewidth=1.0)
fig.savefig(figname,dpi=300)
os.system('open '+figname)

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@@ -7,7 +7,7 @@ Main script where are progressively added the steps for the FOC pipeline reducti
#Project libraries
import sys
import numpy as np
import copy
from copy import deepcopy
import lib.fits as proj_fits #Functions to handle fits files
import lib.reduction as proj_red #Functions used in reduction pipeline
import lib.plots as proj_plots #Functions for plotting data
@@ -155,11 +155,10 @@ def main():
rectangle = [vertex[2], vertex[0], shape[1], shape[0], 0., 'w']
# Rotate data to have North up
ref_header = copy.deepcopy(headers[0])
ref_header = deepcopy(headers[0])
if rotate_data:
alpha = ref_header['orientat']
mrot = np.array([[np.cos(-alpha), -np.sin(-alpha)],
[np.sin(-alpha), np.cos(-alpha)]])
mrot = np.array([[np.cos(-alpha), -np.sin(-alpha)], [np.sin(-alpha), np.cos(-alpha)]])
rectangle[0:2] = np.dot(mrot, np.asarray(rectangle[0:2]))+np.array(data_array.shape[1:])/2
rectangle[4] = alpha
data_array, error_array, data_mask, headers = proj_red.rotate_data(data_array, error_array, data_mask, headers, -ref_header['orientat'])
@@ -180,7 +179,7 @@ def main():
## Step 3:
# Rotate images to have North up
ref_header = copy.deepcopy(headers[0])
ref_header = deepcopy(headers[0])
if rotate_stokes:
alpha = ref_header['orientat']
mrot = np.array([[np.cos(-alpha), -np.sin(-alpha)],
@@ -193,7 +192,7 @@ def main():
## Step 4:
# crop to desired region of interest (roi)
# stokescrop = proj_plots.crop_map(copy.deepcopy(stokes_test), copy.deepcopy(data_mask), snrp_cut=snrp_cut, snri_cut=snri_cut)
# stokescrop = proj_plots.crop_map(deepcopy(stokes_test), deepcopy(data_mask), snrp_cut=snrp_cut, snri_cut=snri_cut)
# stokescrop.run()
# stokes_crop, data_mask = stokescrop.crop()
@@ -202,13 +201,13 @@ def main():
Stokes_test = proj_fits.save_Stokes(I_stokes, Q_stokes, U_stokes, Stokes_cov, P, debiased_P, s_P, s_P_P, PA, s_PA, s_PA_P, headers, figname+figtype, data_folder=data_folder, return_hdul=True)
# Plot polarization map (Background is either total Flux, Polarization degree or Polarization degree error).
proj_plots.polarization_map(copy.deepcopy(Stokes_test), data_mask, rectangle=None, SNRp_cut=SNRp_cut, SNRi_cut=SNRi_cut, step_vec=step_vec, savename=figname+figtype, plots_folder=plots_folder, display=None)
proj_plots.polarization_map(copy.deepcopy(Stokes_test), data_mask, rectangle=None, SNRp_cut=SNRp_cut, SNRi_cut=SNRi_cut, step_vec=step_vec, savename=figname+figtype+"_P_flux", plots_folder=plots_folder, display='Pol_Flux')
proj_plots.polarization_map(copy.deepcopy(Stokes_test), data_mask, rectangle=None, SNRp_cut=SNRp_cut, SNRi_cut=SNRi_cut, step_vec=step_vec, savename=figname+figtype+"_P", plots_folder=plots_folder, display='Pol_deg')
proj_plots.polarization_map(copy.deepcopy(Stokes_test), data_mask, rectangle=None, SNRp_cut=SNRp_cut, SNRi_cut=SNRi_cut, step_vec=step_vec, savename=figname+figtype+"_I_err", plots_folder=plots_folder, display='I_err')
proj_plots.polarization_map(copy.deepcopy(Stokes_test), data_mask, rectangle=None, SNRp_cut=SNRp_cut, SNRi_cut=SNRi_cut, step_vec=step_vec, savename=figname+figtype+"_P_err", plots_folder=plots_folder, display='Pol_deg_err')
proj_plots.polarization_map(copy.deepcopy(Stokes_test), data_mask, rectangle=None, SNRp_cut=SNRp_cut, SNRi_cut=SNRi_cut, step_vec=step_vec, savename=figname+figtype+"_SNRi", plots_folder=plots_folder, display='SNRi')
proj_plots.polarization_map(copy.deepcopy(Stokes_test), data_mask, rectangle=None, SNRp_cut=SNRp_cut, SNRi_cut=SNRi_cut, step_vec=step_vec, savename=figname+figtype+"_SNRp", plots_folder=plots_folder, display='SNRp')
proj_plots.polarization_map(deepcopy(Stokes_test), data_mask, rectangle=None, SNRp_cut=SNRp_cut, SNRi_cut=SNRi_cut, step_vec=step_vec, savename=figname+figtype, plots_folder=plots_folder, display=None)
proj_plots.polarization_map(deepcopy(Stokes_test), data_mask, rectangle=None, SNRp_cut=SNRp_cut, SNRi_cut=SNRi_cut, step_vec=step_vec, savename=figname+figtype+"_P_flux", plots_folder=plots_folder, display='Pol_Flux')
proj_plots.polarization_map(deepcopy(Stokes_test), data_mask, rectangle=None, SNRp_cut=SNRp_cut, SNRi_cut=SNRi_cut, step_vec=step_vec, savename=figname+figtype+"_P", plots_folder=plots_folder, display='Pol_deg')
proj_plots.polarization_map(deepcopy(Stokes_test), data_mask, rectangle=None, SNRp_cut=SNRp_cut, SNRi_cut=SNRi_cut, step_vec=step_vec, savename=figname+figtype+"_I_err", plots_folder=plots_folder, display='I_err')
proj_plots.polarization_map(deepcopy(Stokes_test), data_mask, rectangle=None, SNRp_cut=SNRp_cut, SNRi_cut=SNRi_cut, step_vec=step_vec, savename=figname+figtype+"_P_err", plots_folder=plots_folder, display='Pol_deg_err')
proj_plots.polarization_map(deepcopy(Stokes_test), data_mask, rectangle=None, SNRp_cut=SNRp_cut, SNRi_cut=SNRi_cut, step_vec=step_vec, savename=figname+figtype+"_SNRi", plots_folder=plots_folder, display='SNRi')
proj_plots.polarization_map(deepcopy(Stokes_test), data_mask, rectangle=None, SNRp_cut=SNRp_cut, SNRi_cut=SNRi_cut, step_vec=step_vec, savename=figname+figtype+"_SNRp", plots_folder=plots_folder, display='SNRp')
return 0

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@@ -3,7 +3,7 @@ Library functions for graham algorithm implementation (find the convex hull
of a given list of points).
"""
import copy
from copy import deepcopy
import numpy as np
@@ -141,12 +141,12 @@ def partition(s, l, r, order):
for j in range(l, r):
if order(s[j], s[r]):
i = i + 1
temp = copy.deepcopy(s[i])
s[i] = copy.deepcopy(s[j])
s[j] = copy.deepcopy(temp)
temp = copy.deepcopy(s[i+1])
s[i+1] = copy.deepcopy(s[r])
s[r] = copy.deepcopy(temp)
temp = deepcopy(s[i])
s[i] = deepcopy(s[j])
s[j] = deepcopy(temp)
temp = deepcopy(s[i+1])
s[i+1] = deepcopy(s[r])
s[r] = deepcopy(temp)
return i + 1

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@@ -37,7 +37,7 @@ prototypes :
Rotate I, Q, U given an angle in degrees using scipy functions.
"""
import copy
from copy import deepcopy
import numpy as np
import matplotlib.pyplot as plt
import matplotlib.dates as mdates
@@ -222,15 +222,15 @@ def crop_array(data_array, headers, error_array=None, step=5, null_val=None,
null_val = [null_val,]*error_array.shape[0]
vertex = np.zeros((data_array.shape[0],4),dtype=int)
for i,image in enumerate(data_array):
for i,image in enumerate(data_array): # Get vertex of the rectangular convex hull of each image
vertex[i] = image_hull(image,step=step,null_val=null_val[i],inside=inside)
v_array = np.zeros(4,dtype=int)
if inside:
if inside: # Get vertex of the maximum convex hull for all images
v_array[0] = np.max(vertex[:,0]).astype(int)
v_array[1] = np.min(vertex[:,1]).astype(int)
v_array[2] = np.max(vertex[:,2]).astype(int)
v_array[3] = np.min(vertex[:,3]).astype(int)
else:
else: # Get vertex of the minimum convex hull for all images
v_array[0] = np.min(vertex[:,0]).astype(int)
v_array[1] = np.max(vertex[:,1]).astype(int)
v_array[2] = np.min(vertex[:,2]).astype(int)
@@ -279,7 +279,7 @@ def crop_array(data_array, headers, error_array=None, step=5, null_val=None,
crop_array = np.zeros((data_array.shape[0],new_shape[0],new_shape[1]))
crop_error_array = np.zeros((data_array.shape[0],new_shape[0],new_shape[1]))
for i,image in enumerate(data_array):
for i,image in enumerate(data_array): #Put the image data in the cropped array
crop_array[i] = image[v_array[0]:v_array[1],v_array[2]:v_array[3]]
crop_error_array[i] = error_array[i][v_array[0]:v_array[1],v_array[2]:v_array[3]]
@@ -732,9 +732,9 @@ def align_data(data_array, headers, error_array=None, upsample_factor=1.,
center = np.fix(ref_center-shift).astype(int)
res_shift = res_center-ref_center
rescaled_image[i,res_shift[0]:res_shift[0]+shape[1],
res_shift[1]:res_shift[1]+shape[2]] = copy.deepcopy(image)
res_shift[1]:res_shift[1]+shape[2]] = deepcopy(image)
rescaled_error[i,res_shift[0]:res_shift[0]+shape[1],
res_shift[1]:res_shift[1]+shape[2]] = copy.deepcopy(error_array[i])
res_shift[1]:res_shift[1]+shape[2]] = deepcopy(error_array[i])
rescaled_mask[i,res_shift[0]:res_shift[0]+shape[1],
res_shift[1]:res_shift[1]+shape[2]] = False
# Shift images to align
@@ -1106,14 +1106,19 @@ def compute_Stokes(data_array, error_array, data_mask, headers,
pol_eff[1] = pol_efficiency['pol60']
pol_eff[2] = pol_efficiency['pol120']
# Orientation and error for each polarizer ## THIS IS WHERE WE IMPLEMENT THE ERROR THAT IS GOING WRONG
# POL0 = 0deg, POL60 = 60deg, POL120=120deg
theta = np.array([180.*np.pi/180., 60.*np.pi/180., 120.*np.pi/180.])
# Uncertainties on the orientation of the polarizers' axes taken to be 3deg (see Nota et. al 1996, p36; Robinson & Thomson 1995)
sigma_theta = np.array([3.*np.pi/180., 3.*np.pi/180., 3.*np.pi/180.])
pol_flux = 2.*np.array([pol0/transmit[0], pol60/transmit[1], pol120/transmit[2]])
# Normalization parameter for Stokes parameters computation
A = pol_eff[1]*pol_eff[2]*np.sin(-2.*theta[1]+2.*theta[2]) \
+ pol_eff[2]*pol_eff[0]*np.sin(-2.*theta[2]+2.*theta[0]) \
+ pol_eff[0]*pol_eff[1]*np.sin(-2.*theta[0]+2.*theta[1])
coeff_stokes = np.zeros((3,3))
# Coefficients linking each polarizer flux to each Stokes parameter
for i in range(3):
coeff_stokes[0,i] = pol_eff[(i+1)%3]*pol_eff[(i+2)%3]*np.sin(-2.*theta[(i+1)%3]+2.*theta[(i+2)%3])/A
coeff_stokes[1,i] = (-pol_eff[(i+1)%3]*np.sin(2.*theta[(i+1)%3]) + pol_eff[(i+2)%3]*np.sin(2.*theta[(i+2)%3]))/A
@@ -1143,6 +1148,7 @@ def compute_Stokes(data_array, error_array, data_mask, headers,
Stokes_cov[0,2] = Stokes_cov[2,0] = coeff_stokes[0,0]*coeff_stokes[2,0]*pol_cov[0,0]+coeff_stokes[0,1]*coeff_stokes[2,1]*pol_cov[1,1]+coeff_stokes[0,2]*coeff_stokes[2,2]*pol_cov[2,2]+(coeff_stokes[0,0]*coeff_stokes[2,1]+coeff_stokes[2,0]*coeff_stokes[0,1])*pol_cov[0,1]+(coeff_stokes[0,0]*coeff_stokes[2,2]+coeff_stokes[2,0]*coeff_stokes[0,2])*pol_cov[0,2]+(coeff_stokes[0,1]*coeff_stokes[2,2]+coeff_stokes[2,1]*coeff_stokes[0,2])*pol_cov[1,2]
Stokes_cov[1,2] = Stokes_cov[2,1] = coeff_stokes[1,0]*coeff_stokes[2,0]*pol_cov[0,0]+coeff_stokes[1,1]*coeff_stokes[2,1]*pol_cov[1,1]+coeff_stokes[1,2]*coeff_stokes[2,2]*pol_cov[2,2]+(coeff_stokes[1,0]*coeff_stokes[2,1]+coeff_stokes[2,0]*coeff_stokes[1,1])*pol_cov[0,1]+(coeff_stokes[1,0]*coeff_stokes[2,2]+coeff_stokes[2,0]*coeff_stokes[1,2])*pol_cov[0,2]+(coeff_stokes[1,1]*coeff_stokes[2,2]+coeff_stokes[2,1]*coeff_stokes[1,2])*pol_cov[1,2]
# Compute the derivative of each Stokes parameter with respect to the polarizer orientation
dI_dtheta1 = 2.*pol_eff[0]/A*(pol_eff[2]*np.cos(-2.*theta[2]+2.*theta[0])*(pol_flux[1]-I_stokes) - pol_eff[1]*np.cos(-2.*theta[0]+2.*theta[1])*(pol_flux[2]-I_stokes))
dI_dtheta2 = 2.*pol_eff[1]/A*(pol_eff[0]*np.cos(-2.*theta[0]+2.*theta[1])*(pol_flux[2]-I_stokes) - pol_eff[2]*np.cos(-2.*theta[1]+2.*theta[2])*(pol_flux[0]-I_stokes))
dI_dtheta3 = 2.*pol_eff[2]/A*(pol_eff[1]*np.cos(-2.*theta[1]+2.*theta[2])*(pol_flux[0]-I_stokes) - pol_eff[0]*np.cos(-2.*theta[2]+2.*theta[0])*(pol_flux[1]-I_stokes))
@@ -1153,10 +1159,12 @@ def compute_Stokes(data_array, error_array, data_mask, headers,
dU_dtheta2 = 2.*pol_eff[1]/A*(np.sin(2.*theta[1])*(pol_flux[2]-pol_flux[0]) - (pol_eff[0]*np.cos(-2.*theta[0]+2.*theta[1]) - pol_eff[2]*np.cos(-2.*theta[1]+2.*theta[2]))*U_stokes)
dU_dtheta3 = 2.*pol_eff[2]/A*(np.sin(2.*theta[2])*(pol_flux[0]-pol_flux[1]) - (pol_eff[1]*np.cos(-2.*theta[1]+2.*theta[2]) - pol_eff[0]*np.cos(-2.*theta[2]+2.*theta[0]))*U_stokes)
# Compute the uncertainty associated with the polarizers' orientation (see Kishimoto 1999)
s_I2_axis = (dI_dtheta1**2*sigma_theta[0]**2 + dI_dtheta2**2*sigma_theta[1]**2 + dI_dtheta3**2*sigma_theta[2]**2)
s_Q2_axis = (dQ_dtheta1**2*sigma_theta[0]**2 + dQ_dtheta2**2*sigma_theta[1]**2 + dQ_dtheta3**2*sigma_theta[2]**2)
s_U2_axis = (dU_dtheta1**2*sigma_theta[0]**2 + dU_dtheta2**2*sigma_theta[1]**2 + dU_dtheta3**2*sigma_theta[2]**2)
# Add quadratically the uncertainty to the Stokes covariance matrix ## THIS IS WHERE THE PROBLEMATIC UNCERTAINTY IS ADDED TO THE PIPELINE
Stokes_cov[0,0] += s_I2_axis
Stokes_cov[1,1] += s_Q2_axis
Stokes_cov[2,2] += s_U2_axis
@@ -1361,7 +1369,7 @@ def rotate_Stokes(I_stokes, Q_stokes, U_stokes, Stokes_cov, data_mask, headers,
#Compute new covariance matrix on rotated parameters
new_Stokes_cov = copy.deepcopy(Stokes_cov)
new_Stokes_cov = deepcopy(Stokes_cov)
new_Stokes_cov[1,1] = np.cos(2.*alpha)**2*Stokes_cov[1,1] + np.sin(2.*alpha)**2*Stokes_cov[2,2] + 2.*np.cos(2.*alpha)*np.sin(2.*alpha)*Stokes_cov[1,2]
new_Stokes_cov[2,2] = np.sin(2.*alpha)**2*Stokes_cov[1,1] + np.cos(2.*alpha)**2*Stokes_cov[2,2] - 2.*np.cos(2.*alpha)*np.sin(2.*alpha)*Stokes_cov[1,2]
new_Stokes_cov[0,1] = new_Stokes_cov[1,0] = np.cos(2.*alpha)*Stokes_cov[0,1] + np.sin(2.*alpha)*Stokes_cov[0,2]
@@ -1383,7 +1391,7 @@ def rotate_Stokes(I_stokes, Q_stokes, U_stokes, Stokes_cov, data_mask, headers,
mrot = np.array([[np.cos(-alpha), -np.sin(-alpha)],
[np.sin(-alpha), np.cos(-alpha)]])
for header in headers:
new_header = copy.deepcopy(header)
new_header = deepcopy(header)
new_header['orientat'] = header['orientat'] + ang
new_wcs = WCS(header).deepcopy()