TY - JOUR
T1 - Pre-Flight Calibration of the Mars 2020 Rover Mastcam Zoom (Mastcam-Z) Multispectral, Stereoscopic Imager
AU - Hayes, Alexander G.
AU - Corlies, P.
AU - Tate, C.
AU - Barrington, M.
AU - Bell, J. F.
AU - Maki, J. N.
AU - Caplinger, M.
AU - Ravine, M.
AU - Kinch, K. M.
AU - Herkenhoff, K.
AU - Horgan, B.
AU - Johnson, J.
AU - Lemmon, M.
AU - Paar, G.
AU - Rice, M. S.
AU - Jensen, E.
AU - Kubacki, T. M.
AU - Cloutis, E.
AU - Deen, R.
AU - Ehlmann, B. L.
AU - Lakdawalla, E.
AU - Sullivan, R.
AU - Winhold, A.
AU - Parkinson, A.
AU - Bailey, Z.
AU - van Beek, J.
AU - Caballo-Perucha, P.
AU - Cisneros, E.
AU - Dixon, D.
AU - Donaldson, C.
AU - Jensen, O. B.
AU - Kuik, J.
AU - Lapo, K.
AU - Magee, A.
AU - Merusi, M.
AU - Mollerup, J.
AU - Scudder, N.
AU - Seeger, C.
AU - Stanish, E.
AU - Starr, M.
AU - Thompson, M.
AU - Turenne, N.
AU - Winchell, K.
N1 - Funding Information:
The authors would like to thank two anonymous reviewers for detailed and well-thought out comments that substantially improved this manuscript during revision. This work was supported by funding from: the U.S. National Aeronautics and Space Administration (NASA), NASA’s Jet Propulsion Laboratory (JPL) at the California Institute of Technology, NASA’s Ames Research Center, the United States Geological Survey, the European Space Agency (ESA) PRODEX Programme, the Austrian Research Promotion Agency (FFG), the Canadian Space Agency, the United Kingdom Space Agency, the German Aerospace Center (DLR), the Free University of Berlin, the Danish Research Agency, the Carlsberg Foundation of Denmark, the Natural Sciences and Engineering Research Council of Canada (NSERC), the Canadian Space Agency (CSA), the Canada Foundation for Innovation (CFI), the Manitoba Research Innovation Fund (MRIF), and the University of Winnipeg. Danish participation in this work (Kinch and Jensen), and the broader Mars 2020 project, was supported by the Carlsberg Foundation grants CF16-0981, CF17-0979, and CF19-0023.
Publisher Copyright:
© 2021, The Author(s).
PY - 2021/3
Y1 - 2021/3
N2 - The NASA Perseverance rover Mast Camera Zoom (Mastcam-Z) system is a pair of zoomable, focusable, multi-spectral, and color charge-coupled device (CCD) cameras mounted on top of a 1.7 m Remote Sensing Mast, along with associated electronics and two calibration targets. The cameras contain identical optical assemblies that can range in focal length from 26 mm (25.5∘×19.1∘FOV) to 110 mm (6.2∘×4.2∘FOV) and will acquire data at pixel scales of 148-540 μm at a range of 2 m and 7.4-27 cm at 1 km. The cameras are mounted on the rover’s mast with a stereo baseline of 24.3 ± 0.1 cm and a toe-in angle of 1.17 ± 0.03 ∘ (per camera). Each camera uses a Kodak KAI-2020 CCD with 1600 × 1200 active pixels and an 8 position filter wheel that contains an IR-cutoff filter for color imaging through the detectors’ Bayer-pattern filters, a neutral density (ND) solar filter for imaging the sun, and 6 narrow-band geology filters (16 total filters). An associated Digital Electronics Assembly provides command data interfaces to the rover, 11-to-8 bit companding, and JPEG compression capabilities. Herein, we describe pre-flight calibration of the Mastcam-Z instrument and characterize its radiometric and geometric behavior. Between April 26th and May 9th, 2019, ∼45,000 images were acquired during stand-alone calibration at Malin Space Science Systems (MSSS) in San Diego, CA. Additional data were acquired during Assembly Test and Launch Operations (ATLO) at the Jet Propulsion Laboratory and Kennedy Space Center. Results of the radiometric calibration validate a 5% absolute radiometric accuracy when using camera state parameters investigated during testing. When observing using camera state parameters not interrogated during calibration (e.g., non-canonical zoom positions), we conservatively estimate the absolute uncertainty to be < 10 %. Image quality, measured via the amplitude of the Modulation Transfer Function (MTF) at Nyquist sampling (0.35 line pairs per pixel), shows MTF Nyquist= 0.26 − 0.50 across all zoom, focus, and filter positions, exceeding the > 0.2 design requirement. We discuss lessons learned from calibration and suggest tactical strategies that will optimize the quality of science data acquired during operation at Mars. While most results matched expectations, some surprises were discovered, such as a strong wavelength and temperature dependence on the radiometric coefficients and a scene-dependent dynamic component to the zero-exposure bias frames. Calibration results and derived accuracies were validated using a Geoboard target consisting of well-characterized geologic samples.
AB - The NASA Perseverance rover Mast Camera Zoom (Mastcam-Z) system is a pair of zoomable, focusable, multi-spectral, and color charge-coupled device (CCD) cameras mounted on top of a 1.7 m Remote Sensing Mast, along with associated electronics and two calibration targets. The cameras contain identical optical assemblies that can range in focal length from 26 mm (25.5∘×19.1∘FOV) to 110 mm (6.2∘×4.2∘FOV) and will acquire data at pixel scales of 148-540 μm at a range of 2 m and 7.4-27 cm at 1 km. The cameras are mounted on the rover’s mast with a stereo baseline of 24.3 ± 0.1 cm and a toe-in angle of 1.17 ± 0.03 ∘ (per camera). Each camera uses a Kodak KAI-2020 CCD with 1600 × 1200 active pixels and an 8 position filter wheel that contains an IR-cutoff filter for color imaging through the detectors’ Bayer-pattern filters, a neutral density (ND) solar filter for imaging the sun, and 6 narrow-band geology filters (16 total filters). An associated Digital Electronics Assembly provides command data interfaces to the rover, 11-to-8 bit companding, and JPEG compression capabilities. Herein, we describe pre-flight calibration of the Mastcam-Z instrument and characterize its radiometric and geometric behavior. Between April 26th and May 9th, 2019, ∼45,000 images were acquired during stand-alone calibration at Malin Space Science Systems (MSSS) in San Diego, CA. Additional data were acquired during Assembly Test and Launch Operations (ATLO) at the Jet Propulsion Laboratory and Kennedy Space Center. Results of the radiometric calibration validate a 5% absolute radiometric accuracy when using camera state parameters investigated during testing. When observing using camera state parameters not interrogated during calibration (e.g., non-canonical zoom positions), we conservatively estimate the absolute uncertainty to be < 10 %. Image quality, measured via the amplitude of the Modulation Transfer Function (MTF) at Nyquist sampling (0.35 line pairs per pixel), shows MTF Nyquist= 0.26 − 0.50 across all zoom, focus, and filter positions, exceeding the > 0.2 design requirement. We discuss lessons learned from calibration and suggest tactical strategies that will optimize the quality of science data acquired during operation at Mars. While most results matched expectations, some surprises were discovered, such as a strong wavelength and temperature dependence on the radiometric coefficients and a scene-dependent dynamic component to the zero-exposure bias frames. Calibration results and derived accuracies were validated using a Geoboard target consisting of well-characterized geologic samples.
KW - Calibration
KW - Camera
KW - Mars
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U2 - 10.1007/s11214-021-00795-x
DO - 10.1007/s11214-021-00795-x
M3 - Review article
AN - SCOPUS:85101264124
SN - 0038-6308
VL - 217
JO - Space Science Reviews
JF - Space Science Reviews
IS - 2
M1 - 29
ER -