An Instrument Anomaly in the Mars Exploration Rover Pancam 1,009-nm Filter (R7): Characterization, Simulation, Correction, and Preliminary Verification
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An Instrument Anomaly in the Mars Exploration Rover Pancam 1,009-nm Filter (R7) : Characterization, Simulation, Correction, and Preliminary Verification. / Jakobsen, Simone J.; Kinch, Kjartan M.; Madsen, Morten Bo; Bell, James F.; Wellington, Danika; Dajose, Lorinda; Alizai, Khaled.
I: Earth and Space Science, Bind 6, Nr. 1, 01.01.2019, s. 96-115.Publikation: Bidrag til tidsskrift › Tidsskriftartikel › Forskning › fagfællebedømt
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TY - JOUR
T1 - An Instrument Anomaly in the Mars Exploration Rover Pancam 1,009-nm Filter (R7)
T2 - Characterization, Simulation, Correction, and Preliminary Verification
AU - Jakobsen, Simone J.
AU - Kinch, Kjartan M.
AU - Madsen, Morten Bo
AU - Bell, James F.
AU - Wellington, Danika
AU - Dajose, Lorinda
AU - Alizai, Khaled
PY - 2019/1/1
Y1 - 2019/1/1
N2 - During pre-flight calibration of the panoramic camera (Pancam) instrument on board the Mars Exploration Rovers MER A (Spirit) and MER B (Opportunity), a discrepancy was noted between 11-band spectra extracted from Pancam images of the camera's radiometric calibration target and reflectance spectra obtained with a spectrometer. This discrepancy was observed in the longest-wavelength filter of the camera (the longpass R7 filter with system λ eff = 1,009 nm) and consisted of a reduction in contrast between bright and dark regions. Here we describe and characterize this effect. We propose that the effect arises because long-wavelength photons close to the silicon band-gap at 1,100 nm are allowed through the R7 filter, pass through the bulk charge-coupled device, scatter from the backside, pass through the charge-coupled device again, and are registered in a pixel other than the pixel through which they originally entered. Based on this hypothesis we develop a model capable of accurately simulating the effect, and correct for it. We present preliminary results from testing this correction on preflight, as well as in-flight, images. The effect is small, but in some specific cases in small regions of high contrast, the effect is significant. In in-flight images of Martian terrain we observed the signal in dark shadows to be artificially inflated by up to ∼ 33% and analysis of early-mission calibration target images indicated that the reduced contrast due to the artifact is equivalent to >100 DN (full well = 4095 DN) for a hypothetical perfectly dark pixel.
AB - During pre-flight calibration of the panoramic camera (Pancam) instrument on board the Mars Exploration Rovers MER A (Spirit) and MER B (Opportunity), a discrepancy was noted between 11-band spectra extracted from Pancam images of the camera's radiometric calibration target and reflectance spectra obtained with a spectrometer. This discrepancy was observed in the longest-wavelength filter of the camera (the longpass R7 filter with system λ eff = 1,009 nm) and consisted of a reduction in contrast between bright and dark regions. Here we describe and characterize this effect. We propose that the effect arises because long-wavelength photons close to the silicon band-gap at 1,100 nm are allowed through the R7 filter, pass through the bulk charge-coupled device, scatter from the backside, pass through the charge-coupled device again, and are registered in a pixel other than the pixel through which they originally entered. Based on this hypothesis we develop a model capable of accurately simulating the effect, and correct for it. We present preliminary results from testing this correction on preflight, as well as in-flight, images. The effect is small, but in some specific cases in small regions of high contrast, the effect is significant. In in-flight images of Martian terrain we observed the signal in dark shadows to be artificially inflated by up to ∼ 33% and analysis of early-mission calibration target images indicated that the reduced contrast due to the artifact is equivalent to >100 DN (full well = 4095 DN) for a hypothetical perfectly dark pixel.
KW - calibration
KW - CCD
KW - Mars
KW - MER
KW - multispectral
KW - Pancam
U2 - 10.1029/2018EA000473
DO - 10.1029/2018EA000473
M3 - Journal article
AN - SCOPUS:85060625943
VL - 6
SP - 96
EP - 115
JO - Earth and Space Science
JF - Earth and Space Science
SN - 2333-5084
IS - 1
ER -
ID: 214515638