Stereophotoclinometry

Stereophotoclinometry is a technique used to generate ultra-high resolution digital elevation models (DEM) from images. This is typically used in NASA spacecraft missions to asteroids and comets. It has also been used for making DEMs of the Moon and the Earth.

It was created by Dr. Robert Gaskell who works at the Planetary Science Institute.


Wiki Link: https://spc.psi.edu/spc_wiki/

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A comparison of a Rosetta image and a SPC rendered model

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Contacts:

Dr. Eric Palmer – epalmer@psi.edu
Dr Gaskell – rgaskell@psi.edu
Dr. John Weirich – jweirich@psi.edu

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An SPC model of asteroid 67P/Churyumov–Gerasimenko

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Mathilde

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Stooke shape model (left). Near Image (center). SPC shape model (Right).

Topography of the lunar poles, constructed using stereophotoclinometry (SPC) and Clementine images, is compared with results from LOLA and LRO wide-angle camera analyses.

Publications

Digital Terrain Models of Mathilde and the Moon

Reference Citation: Weirich, J.~R., Palmer, E.~E., Domingue, D.~L.\ 2019.\ Digital Terrain Models of Mathilde and the Moon.\ Lunar and Planetary Science Conference 2681.

Abstracts

https://ui.adsabs.harvard.edu/abs/2011LPI….42.2535G/abstract 50th Lunar and Planetary Science Conference, held 18-22 March, 2019 at The Woodlands, Texas. LPI Contribution No. 2132, id.2681

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The Moon

A comparison of a LROC image to and SPC model of the lunar surface. A 5×5 km subsection of Karpinskiy regional DTM with grid overlay.

Topography of the lunar poles, constructed using stereophotoclinometry (SPC) and Clementine images, is compared with results from LOLA and LRO wide-angle camera analyses.

Publications

Digital Terrain Models of Mathilde and the Moon

Reference Citation: Weirich, J.~R., Palmer, E.~E., Domingue, D.~L.\ 2019.\ Digital Terrain Models of Mathilde and the Moon.\ Lunar and Planetary Science Conference 2681.

Abstracts

https://ui.adsabs.harvard.edu/abs/2011LPI….42.2535G/abstract 50th Lunar and Planetary Science Conference, held 18-22 March, 2019 at The Woodlands, Texas. LPI Contribution No. 2132, id.2681

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POST ARCHIVE

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Ryugu

Preview
An SPC model of Ryugus carbonaceous aster at a resolution of 3cm

This SPC model was generated during the JAXA Hayabusa 2 mission.

Data: https://www.darts.isas.jaxa.jp/pub/hayabusa2/paper/Watanabe_2019/README.html

Bennu

OSIRIS REx NASA Mission

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A SPC rendered shape model of Bennu

The accuracy of the global digital terrain model (GDTM) of Bennu obtained by the OSIRIS-REx mission to date has achieved global requirements earlier than anticipated. Additionally, a comparison between real images and synthetic images derived from the GDTM using normalized cross correlation show an exceptionally good match.

Data

101955 Bennu Shape Model PDS SBN OSIRIS-REx SPICE Data Archive

Publications:

Image Cross Correlation as a Measurement of Shape Model Quality

Reference Citation: Palmer, E.~E., Weirich, J.~R., Campbell, T., Barnouin, O.~S., Daly, M.~G., Lauretta, D.~S.\ 2018.\ Image Cross Correlation as a Measurement of Shape Model Quality.\ Lunar and Planetary Science Conference 1106.

Stereophotoclinometry Models in Support of the OSIRIS-REx Mission .

Reference Citation: Palmer, E.~E., and 11 colleagues 2019.\ Stereophotoclinometry Models in Support of the OSIRIS-REx Mission.\ Lunar and Planetary Science Conference 2588.

Evaluation of the Bennu Global Digital Terrain Model for OSIRIS-REx

Reference Citation: Palmer, E., and 7 colleagues 2019.\ Evaluation of the Bennu Global Digital Terrain Model for OSIRIS-REx.\ EPSC-DPS Joint Meeting 2019 2019, EPSC-DPS2019-387.

Abstracts:

Evaluation of the Bennu Global Digital Terrain Model for OSIRIS-REx EPSC AbstractsVol. 13, EPSC-DPS2019-387-1, 2019 EPSC-DPS Joint Meeting 2019

Stereophotoclinometry Models in Support of the OSIRIS-REx Mission 50th Lunar and Planetary Science Conference 2019 (LPI Contrib. No. 2132)

Image Cross Correlation as a Measurement of Shape Model Quality 49th Lunar and Planetary Science Conference 19-23 March, 2018, held at The Woodlands, Texas LPI Contribution No. 2083, id.1106

Evaluation of Topographic Error and Quality with Stereophotoclinometry 49th Lunar and Planetary Science Conference 2018 (LPI Contrib. No. 2083)

Error Analysis of Stereophotoclinometry in Support of the OSIRIS-REx Mission American Astronomical Society, DPS meeting #47, id.213.17

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A progression of the SPC process throughout the OSRIS-REx mission

2013 Nolan Model
The first shape model was done by Dr. Nolan and was based on radar imaging of Bennu (Nolan, 2013). This model was the basic reference for the mission planning of OSIRIS-REx. One can see that the basic shape of Bennu was well characterized. The comparison image was from early November 2018.
12 November Early Limb-based model
Altimetry Working Group used early Approach Phase rotation images, every 10°, to determine the limbs and construct a model with a 3m ground sample distance. It improved the accuracy of the shape model, and Navigation Team had exceptional success with its center-finding routines.
22 November Early SPC model
While SPC can be used earlier, we used the limb-based model until the imaging data was exceptional. This reduces artifacts and improves accuracy for following models. OSIRIS-REx approached the asteroid at a low phase, so there are limited shadows from the topography.
2nd December – End of approach
At the end of the Approach Phase, a 1.5m model was generated from the full suite of approach images. Limb, albedo and topography agreement was very good; however, the poles lacked imaging so there is only limb-based data there. Final imagery pixel size was 32cm near the equator.
End of PreSurvey Model
At the end of preliminary Survey, we generated a model with a 75cm ground sample distance. Both the topography and albedo representation were excellent and exceeded our expectations. Preliminary Survey data was 50-75 cm in pixel size.

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Here is a regional model at the end of Preliminary Survey, with 50 to 75 cm resolution. This is of DL15 aka Nightingale aka the Primary TAG site. Images below are the progression as we processed more images.
14 cm model resolution of the Primary TAG site.
5 to 6 cm resolution of the Primary TAG site.
State of the model after Natural Feature Tracking (NFT) landmarks have been generated. Some regions have high resolution (up to 1.7 cm) while others are the same as in the above image.
Animate GIF showing the comparison between spacecraft image and model for Primary TAG site. 6 second loop.

Ceres

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Ceres Shape model

Data

Ceres Shape model SBN PDS 2018

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67P/Churyumov–Gerasimenko

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An SPC rendered model of the comet 67P/Churyumov–Gerasimenko

During the last weeks of July, the ROSETTA spacecraft made its final approach to comet 67P/Churyumov-Gerasimenko, revealing a two lobed object that would be a challenge to model. The first real rotation “movies”, taken between August 1 and 4 and another set from August 8 allowed a group working at the Laboratoire d’Astrophysique de Marseille (LAM), to construct a first crude full-resolution shape model, building on earlier work on approach images also performed at LAM. During the next weeks and months, higher and higher resolution images became available at a variety of illuminations and viewing geometries, allowing the refinement of the shape and the construction of surface topography to sub-meter scale. We present a potpourri of preliminary results from this most intriguing object.

Data

Gaskell 2014 67P/Churyumov–Gerasimenko shape model data SBN PDS data archive

Publications

Comet 67P/CG: Preliminary Shape and Topography from SPC

Reference Citation: Gaskell, R.~W., and 6 colleagues 2014.\ Comet 67P/CG: Preliminary Shape and Topography from SPC.\ AAS/Division for Planetary Sciences Meeting Abstracts #46 209.04.

Abstracts

Comet 67P/CG: Preliminary Shape and Topography from SPC American Astronomical Society, DPS meeting #46, id.209.04

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Tethys

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Tethys Shape Model
September 2013

The shape model of Tethys derived by Robert Gaskell from Cassini Imaging Science Subsystem narrow and wide angle camera (ISSNA and ISSWA) images. The model is provided in the implicitly connected quadrilateral (ICQ) format. This version of the model was prepared on July 25, 2012.

Data

Gaskell Tethys shape Model PDS SBN data archive. September 2013

Publications

Gaskell Tethys Shape Model V1.0

Reference Citation: Gaskell, R.~W.\ 2013.\ Gaskell Tethys Shape Model V1.0.\ NASA Planetary Data System CO-SA-ISSNA-5-TETHYSSHAPE-V1.0.

Abstracts

PDS Gaskell Tethys Shape Model V1.0 NASA Planetary Data System, id. CO-SA-ISSNA-5-TETHYSSHAPE-V1.0Paragraph

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