M.Eng. René Schwarz DEVELOPMENT OF AN ILLUMINATION SIMULATION SOFTWARE FOR THE MOON’S SURFACE An approach to illumination direction estimation on pictures of solid planetary surfaces with a significant number of craters. BASED UPON THE ORIGINAL EXAMINATION VERSION Cover Images – Moon photograph: S103-E-5037 (December 21, 1999) — Astronauts aboard the Space Shule Discovery recorded this rarely seen phenomenon of the full Moon partially obscured by the atmosphere of Earth. e image was recorded with an electronic still camera at 15:15:15 GMT, Dec. 21, 1999. © NASA, available at http://spaceflight. nasa.gov/gallery/images/shuttle/sts-103/html/s103e5037.html. – Moon surface tile: Simulated map of safe landing areas around a large lunar crater. © NASA/Goddard Scientific Visualization Studio, available at http://www.nasa.gov/images/content/271355main_safeonly_print_jpg.jpg. Meinen Großeltern, Rosa Maria und Konrad Siermann, Gerda Schwarz & meinen Eltern, Angela und Sven Schwarz, die mich mein Leben lang nach Kräen in meinen Bestrebungen unterstützt haben. DEVELOPMENT OF AN ILLUMINATION SIMULATION SOFTWARE FOR THE MOON’S SURFACE An approach to illumination direction estimation on pictures of solid planetary surfaces with a significant number of craters. — Master’s esis — BY Mr. B.Eng. René Schwarz (Matriculation Number 17288) né Siermann, born on April 15th, 1987 in Merseburg, Germany SUBMITTED TO THE DEPARTMENT OF COMPUTER SCIENCE AND COMMUNICATION SYSTEMS AND THE INSTITUTE OF SPACE SYSTEMS (GERMAN AEROSPACE CENTER, DLR) IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF ENGINEERING (M.ENG.) IN COMPUTER SCIENCE/ARTIFICIAL INTELLIGENCE AT THE MERSEBURG UNIVERSITY OF APPLIED SCIENCES ON THIS 9TH DAY OF APRIL, 2012. SUPERVISORS GERMAN AEROSPACE CENTER (DLR) MERSEBURG UNIVERSITY OF APPLIED SCIENCES Institute of Space Systems Department of Computer Science and Communication Systems Dipl. Math.-Techn. Bolko Maass Prof. Dr. rer. nat. Hartmut Kröner ENTWICKLUNG EINER SOFTWARE ZUR SIMULATION DER OBERFLÄCHENBELEUCHTUNG DES MONDES Ein Zugangsweg zur Schätzung der Beleuchtungsrichtung auf Bildern planetarer Oberflächen mit einer signifikanten Anzahl von Kratern. — Masterthesis — VON Herrn B.Eng. René Schwarz (Matr.-Nr. 17288) geb. Siermann, geboren am 15. April 1987 in Merseburg VORGELEGT DEM FACHBEREICH INFORMATIK UND KOMMUNIKATIONSSYSTEME UND DEM INSTITUT FÜR RAUMFAHRTSYSTEME (DEUTSCHES ZENTRUM FÜR LUFT- UND RAUMFAHRT, DLR) ZUR ERLANGUNG DES AKADEMISCHEN GRADES EINES MASTER OF ENGINEERING (M.ENG.) IN INFORMATIK/KÜNSTLICHE INTELLIGENZ AN DER HOCHSCHULE MERSEBURG AM 09. APRIL 2012. MENTOREN DEUTSCHES ZENTRUM HOCHSCHULE MERSEBURG FÜR LUFT- UND RAUMFAHRT (DLR) Fachbereich Informatik und Kommunikationssysteme Institut ür Raumfahrtsysteme Dipl. Math.-Techn. Bolko Maass Prof. Dr. rer. nat. Hartmut Kröner M.Eng. René Schwarz Merseburg University of Applied Sciences German Aerospace Center (DLR), Institute of Space Systems, Bremen e-mail: [email protected] · web: http://www.rene-schwarz.com Citation Proposal Schwarz, René: Development of an illumination simulation soware for the Moon’s surface: An approach to illumination direction estimation on pictures of solid planetary surfaces with a significant number of craters. Master’s esis, Merse- burg University of Applied Sciences, German Aerospace Center (DLR). Books on Demand, Norderstedt, Germany, 2012. ISBN 978-3-8482-1628-4. BibTeX entry: 1 @book{schwarz-rene-2012-illumination, 2 author = {Schwarz, Ren\’e}, 3 title = {Development of an illumination simulation software for the Moon’s surface: 4 An approach to illumination direction estimation on pictures of solid planetary 5 surfaces with a significant number of craters}, 6 publisher = {Books on Demand, Norderstedt, Germany}, 7 note = {Master’s Thesis, Merseburg University of Applied Sciences, 8 German Aerospace Center (DLR)}, 9 year = {2012}, 10 isbn = {978-3-8482-1628-4}, 11 url = {http://go.rene-schwarz.com/masters-thesis} 12 } Bibliografische Information der Deutschen Nationalbibliothek Die Deutsche Nationalbibliothek verzeichnet diese Publikation in der Deutschen Nationalbibliografie; detaillierte bib- liografische Daten sind im Internet über http://dnb.d-nb.de abruar. Copyright ©2012 M.Eng. René Schwarz (rene-schwarz.com), unless otherwise stated. is book is subject to the conditions of the Creative Commons Aribution-NonCommercial 3.0 Unported License (CC BY-NC 3.0); it can be obtained in a digital version (free of charge) as well as in form of a printed paperback copy. Please aribute/cite this work in the way specified above. If you want to use this book or parts of it for commercial purposes, please contact the author via e-mail. Any trademarks, service marks, product names or named features are assumed to be the property of their respective owners; they are used throughout this book in an editorial fashion only. ere is no implied endorsement/relationship. Although the author has used his best efforts in preparing this book, he assumes no responsibility for errors or omis- sions, especially the information is represented here without any warranty; without even the implied warranty of merchantability or fitness for a particular purpose. Other licenses can apply for some contents; especially source code wrien by the author is released subject to the conditions of the GNU General Public License (GPL), version 2 or later, unless otherwise stated. Document Preparation and Layout: M.Eng. René Schwarz Illustrations and Artwork: Mahias Kopsch (unless otherwise stated) Printing and Publishing: BoD — Books on Demand GmbH, Norderstedt. Printed in Germany. Typeset using XƎLATEX as part of the MiKTEXTEX distribution. Digital version (PDF): http://go.rene-schwarz.com/masters-thesis Paperback copy ISBN: 978-3-8482-1628-4 Abstract e exploration of the solar system over the last decades has broadened our knowledge and understanding of the universe and our place in it. Great scientific and technological achieve- ments have been made, allowing us to study faraway places in the solar system. e world’s space agencies are now facing a new era of continuing space exploration in the 21st century, expanding permanent human presence beyond low Earth orbit for the first time. To pursue this goal, the development of advanced technologies is more urgent than ever before. One key technology for future human and robotic missions to places distant from Earth will be a system for autonomous navigation and landing of spacecra, since nowadays naviga- tion systems rely on Earth-based navigation techniques (tracking, trajectory modeling, com- manding). A promising approach involves optical navigation technologies, which can operate completely independently of Earth-based support, allowing a surface-relative navigation and landing on celestial bodies without human intervention. e German Aerospace Center (DLR) is developing a new, holistic optical navigation system for all stages of an approach and landing procedure within the ATON project (Autonomous Terrain-based Optical Navigation). e central feature of this new navigation system is its landmark-based navigation. Commonly, craters are used as landmarks, as they exhibit very characteristic shapes and they are stable over the long term with respect to shape, structure and positioning. However, the flawless perception of these surface features by computers is a non-trivial task. A new edge-free, scale-, pose- and illumination-invariant crater detection algorithm is de- veloped for ATON, which will do away with the limitations of current algorithms. To promote further development, the possibility of generating realistic surface images of celestial bodies with a significant number of craters and with well-known local illumination conditions is es- sential, as well as a technique for estimating the local illumination direction on these images. To date, no soware exists to generate artificial renderings of realistically illuminated planetary surfaces while determining the local solar illumination direction. Having said this, the objective of this thesis is the development of a surface illumination sim- ulation soware for solid planetary surfaces with a significant number of craters, whereas all work has been done in the context of the Moon. e thesis work has led to the development of the Moon Surface Illumination Simulation Framework (MSISF), which is the first soware known to produce realistic renderings of the entire Moon’s surface from virtually every view- point, while simultaneously generating machine-readable information regarding the exactly known parameters for the environmental conditions, such as the local solar illumination angle for every pixel of a rendering showing a point on the Moon’s surface. To produce its renderings, the MSISF maintains a global digital elevation model (DEM) of the Moon, using the latest data sets from the ongoing NASA Lunar Reconnaissance Orbiter (LRO) mission. e MSISF has also demonstrated its ability to not only produce single renderings, but also whole series of renderings corresponding to a virtual flight trajectory or landing on the Moon. is thesis shows how these renderings will be produced and how they will be suitable for the development and testing of new optical navigation algorithms. e MSISF can also be modified for the rendering of other celestial bodies. With the MSISF, a basis has been established for the further development of the new DLR crater detection algorithm as well as for the illuminance flow estimation on pictures of solid planetary surfaces. Keywords: Moon, 3D Model,