Add error calculation in radiometric cal. procedure

metis_rad_cal.pro

-function metis_rad_cal, data, header, cal_pack, polarimetric = polarimetric, history = history
+function metis_rad_cal, data, header, cal_pack, polarimetric = polarimetric, norad = norad, error = error, quality_matrix = quality_matrix, history = history
 
 	if header.filter.contains('VL', /fold) then begin
+		channel = cal_pack.vl_channel
+		radiometry = channel.radiometry
 
-		; NOTE - this is to take into account that calibration of polarimetric images or their combination, must not include the pmp efficiency (0.5) since this is included in the demodulation formulae
+		unit_factor = radiometry.msb.value
+		unit_error = radiometry.msb.error
 
-		if keyword_set(polarimetric) then pmp_factor = 2.D0 else pmp_factor = 1.D0
+		; NOTE - this is to take into account that calibration of polarimetric images or their combination, must not include the pmp efficiency (0.5) since this is already included in the demodulation
+
+		if keyword_set(polarimetric) then pmp_factor = 2. else pmp_factor = 1.
 
-		angular_pixel = cal_pack.vl_channel.angular_pixel.value * header.nbin
-		rad_info = cal_pack.vl_channel.radiometry[0]
-		units = cal_pack.vl_channel.cal_units
-		unit_factor = rad_info.msb.value
 		ndit = header.ndit
 	end
 
 	if header.filter.contains('UV', /fold) then begin
-		angular_pixel = cal_pack.uv_channel.angular_pixel.value * header.nbin
-		rad_info = cal_pack.uv_channel.radiometry[0]
-		units = cal_pack.uv_channel.cal_units
-		unit_factor = 1.D0
-		pmp_factor = 1.D0
+		channel = cal_pack.uv_channel
+		radiometry = channel.radiometry
+
+		unit_factor = 1.
+		unit_error = 0.
+
+		; the pmp factor does not apply to the uv channel
+		
+		pmp_factor = 1.
+
 		ndit = header.ndit1 * header.ndit2
-	endif
 
-	rad_factor = rad_info.rad_response.value * pmp_factor * $
-		cal_pack.instrument.pupil_area.value * $
-		angular_pixel * $
-		unit_factor
+		; read the uv/vl ratio of the door retro-illumination, to be used as correction for the optical efficiency
 
-	xposure = header.dit/1000.D0 * ndit
-	cal_factor = 1./rad_factor/xposure
+		efficiency_file = radiometry.opt_efficiency.file_name
+		efficiency = float(readfits(cal_pack.path + efficiency_file, /silent))
 		
-	data = data * cal_factor
+		eff_nobin = efficiency
+		efficiency = rebin(efficiency, header.naxis1, header.naxis2)
+
+		eff_error_file = radiometry.opt_efficiency.error
+		eff_error = float(readfits(cal_pack.path + eff_error_file, /silent))
+		eff_error = efficiency * sqrt(rebin((eff_error/eff_nobin)^2, header.naxis1, header.naxis2)/header.nbin)
+		
+		s = where(efficiency le 0., count)
+		quality_matrix[s] = 0
+
+		; WARN - temporary patch to bypass efficiency correction of the uv channel
+		; efficiency_file = 'not applied'
+		; efficiency = 1.
+	endif
+
+	angular_pixel = channel.angular_pixel.value * header.nbin
+	units = channel.cal_units
 
 	if ~ isa(history) then history = !null
-	history = [history, 'Radiometric calibration:', '  cal. factor = ' + string(cal_factor, format = '(E8.2)') + ' ' + units + '/DN']
+	history = [history, 'Radiometric calibration:']
 
 	journal, 'Radiometric calibration:'
-	journal, '  rad. response = ' + string(rad_info.rad_response.value, format = '(F0)') + ' DN/phot.'
+	journal, '  rad. response = ' + string(radiometry.rad_response.value, format = '(F0)') + ' DN/phot.'
 	journal, '  pupil area = ' + string(cal_pack.instrument.pupil_area.value, format = '(F0)') + ' cm²'
 	journal, '  pixel solid angle = ' + string(angular_pixel, format = '(E8.2)') + ' sr'
+	
+	; exposure normalisation
+
+	xposure = header.dit/1000.D0 * ndit
+	cal_factor = 1./xposure
+	cal_error = 0.
+	
 	journal, '  exposure time = ' + string(xposure, format = '(F0)') + ' s'
 	journal, '  pmp corr. factor = ' + string(pmp_factor, format = '(F0)')
+	
+	if keyword_set(norad) then begin
+		history = [history, '  exposure normalisation only']
+
+		journal, '  total cal. factor = exposure normalisation only'
+	endif else begin
+		; radiometric factor
+
+		rad_factor = radiometry.rad_response.value * $
+		cal_pack.instrument.pupil_area.value * $
+		angular_pixel * $
+		unit_factor * $
+		pmp_factor
+		
+		cal_factor = cal_factor/rad_factor
+		
+		cal_error = sqrt((radiometry.rad_response.error/radiometry.rad_response.value)^2 + (cal_pack.instrument.pupil_area.error/cal_pack.instrument.pupil_area.value)^2 + (channel.angular_pixel.error/channel.angular_pixel.value)^2 + (unit_error/unit_factor)^2)
+		
+		history = [history, '  cal. factor = ' + string(cal_factor, format = '(E8.2)') + ' ' + units + '/DN']
+
 		journal, '  total cal. factor = ' + string(cal_factor, format = '(E8.2)') + ' ' + units + '/DN'
+		journal, '  cal. factor error = ' + string(cal_error, format = '(E8.2)') + ' ' + units + '/DN'
+	endelse
+		
+	; radiometric calibration
+
+	data = data * cal_factor
+
+	if isa(error) then error += cal_error^2
+	
+	if header.filter.contains('UV', /fold) then begin
+	
+		; efficiency correction
+
+		data = data/abs(efficiency)
+
+		if isa(error) then error += (eff_error/efficiency)^2
+
+		history = [history, '  efficiency corr. map = ' + efficiency_file]
+		
+		journal, '  UV efficiency corr. map = ' + efficiency_file
+	endif
 	
 	return, data
 end
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