Stabbins, Roger Blue;
(2022)
Spectral Imaging Simulations for Planetary Surface Exploration: Preparing for PanCam on the ExoMars Rover.
Doctoral thesis (Ph.D), UCL (University College London).
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Abstract
When the ExoMars rover Rosalind Franklin lands on the surface of Mars, the images from the Wide Angle Cameras (WACs) and High Resolution Camera (HRC) of the PanCam instrument will provide human-perspective views of the landing site, in panoramic, multispectral, and stereo detail. The images will be interpreted qualitatively and quantitatively to characterise the potential of the environment as an ancient habitat, towards the mission objective of life detection. In this thesis a new model of PanCam has been formulated that can be evaluated with information available from component datasheets, that has three unique properties: a representation of the directional dependence of the spectral transmission of the multispectral WACs, an analytical model of the nonlinear charge-voltage conversion function of the Star-1000 CMOS detector (used by the WACs and HRC), and a model of the thermal dependence of the analog-digital convertor of the Star-1000. This model has been used to derive a new inverse model for PanCam, capable of correcting for non-linearities and thermal dependencies in order to calibrate an image from raw digital numbers to units of radiance. Two methods for rendering synthetic environments have been implemented, for simulating synthetic calibration scenes and physically realistic natural environments. These methods have been used to investigate the response of PanCam to the expected conditions of the surface of Mars, predicting exposure times in the range of 50 – 300 ms for capturing optimal images of typical rocky surfaces under Mars illumination and thermal conditions, and direct images of the Sun. Quantitatively, through application of the calibration model, surface reflectance and atmospheric transmission retrieval has been predicted to yield a signal-to-noise ratio of ∼150, and qualitative predictions have been presented of the image quality of PanCam, through visualisations of the colour reproduction capabilities of the WACs and HRC.
| Type: | Thesis (Doctoral) |
|---|---|
| Qualification: | Ph.D |
| Title: | Spectral Imaging Simulations for Planetary Surface Exploration: Preparing for PanCam on the ExoMars Rover |
| Event: | UCL (University College London) |
| Open access status: | An open access version is available from UCL Discovery |
| Language: | English |
| Additional information: | Copyright © The Author 2021. Original content in this thesis is licensed under the terms of the Creative Commons Attribution-NonCommercial 4.0 International (CC BY-NC 4.0) Licence (https://creativecommons.org/licenses/by-nc/4.0/). Any third-party copyright material present remains the property of its respective owner(s) and is licensed under its existing terms. Access may initially be restricted at the author’s request. |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > Dept of Space and Climate Physics |
| URI: | https://discovery.ucl.ac.uk/id/eprint/10141998 |
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