RECONSTRUCT MARS AUTOMATICALLY IN MINUTES

A computer system is under development that can automatically combine images of the Martian surface, captured by landers or rovers, in order to reproduce a three dimensional view of the red planet. The resulting model can be viewed from any angle, giving astronomers a realistic and immersive impression of the landscape. This important new development has been presented at the European Planetary Science Congress in Potsdam by Dr Michal Havlena.

“The feeling of ‘being right there’ will give scientists a much better understanding of the images. The only input we need are the captured raw images and the internal camera calibration. After minutes of computation on a standard PC, a three dimensional model of the captured scene is obtained,” said Dr Havlena.

The growing amount of available imagery from Mars makes the manual image processing techniques used so far nearly impossible to handle. The new automated method which allows fast high quality image processing, was developed at the Center for Machine Perception of the Technical University of Prague, under the supervision of Tomas Pajdla, as a part of the EU FP7 Project PRoVisG.

From the technical point of view, the image processing consists of three stages: the first step is determining the image order. If the input images are unordered, i.e. they do not form a sequence but still are somehow connected, a state-of-the-art image indexing technique is able to find images of cameras observing the same part of the scene. To start with, up to a thousand features on each image are detected and “translated” into visual words, according to a visual vocabulary trained on images from Mars. Then, starting from an arbitrary image, the following image is selected as such if it shares the highest number of visual words with the previous image.

The second step of the pipeline, the so-called “structure-from-motion computation”, helps scientists determine the accurate camera positions and rotations in three dimensional space. To do this for each image pair representing neighboring frames, it is enough to find 5 corresponding features to obtain a relative camera pose between the two images.

The last and most important step is the so-called “dense 3D model generation” of the captured scene, which essentially creates and fuses the Martian surface depth maps. To do, this the model uses the intensity disparities (parallaxes) present in images taken at two distinct camera positions, which were identified in the second step.

“The pipeline has already been used successfully to reconstruct a three dimensional model from nine images captured by the Phoenix Mars Lander, which were obtained just after performing some digging operation on the Mars surface,” said Dr Havlena.

“The challenge is now to reconstruct larger parts of the surface of the red planet, captured by the Mars Exploration Rovers Spirit and Opportunity,” concluded Dr Havlena.

IMAGES
This is a visualization of combining two digital elevation models (DEMs) from the ESTEC Planetary Test Bed (PTB). Two hand-held stereo views were used for DEM reconstruction, and automatically combined. Image courtesy of Joanneum Research, Graz, Austria.

ExoMars Rover simulation in 3D Reconstruction of CNES Marsyard SEROM. This frame from an animation has been generated from 33 stereo image pairs taken at the CNES SEROM Marsyard in Toulouse. Processing was performed using the ExoMars PanCam 3D Vision Software by Joanneum Research, Graz, Austria. The camera equipment (PanCam Analogue Camera – PAC) was provided by Aberystwyth University, UK (Prof. Dave Barnes). The images were acquired by ESA (Luc Joudrier). The ExoMars Rover model (status: Early 2008) was compiled by EADS Astrium Space, Stevenage, UK.

This is a frame from an animation generated from 33 stereo image pairs taken at the CNES SEROM Marsyard in Toulouse. Processing was performed using the ExoMars PanCam 3D Vision Software by Joanneum Research, Graz, Austria. The camera equipment (PanCam Analogue Camera – PAC) was provided by Aberystwyth University, UK (Prof. Dave Barnes). The images were acquired by ESA (Luc Joudrier). The ExoMars Rover model (status: Early 2008) was compiled by EADS Astrium Space, Stevenage, UK.

This frame from an animation has been generated from 33 stereo image pairs taken at the CNES SEROM Marsyard in Toulouse. Processing was performed using the ExoMars PanCam 3D Vision Software by Joanneum Research, Graz, Austria. The camera equipment (PanCam Analogue Camera – PAC) was provided by Aberystwyth University, UK (Prof. Dave Barnes). The images were acquired by ESA (Luc Joudrier). The ExoMars Rover model (status: Early 2008) was compiled by EADS Astrium Space, Stevenage, UK.

FURTHER INFORMATION

European Planetary Science Congress (EPSC) 2009
EPSC 2009 is organised by Europlanet, a Research Infrastructure funded under the European Commission’s Framework 7 Programme, in association with the European Geosciences Union. It is the major meeting in Europe for planetary scientists. The programme comprises 37 sessions and workshops covering a wide range of planetary topics.
EPSC 2009 is taking place at the Kongresshotel am Templiner See, Potsdam, Germany from Sunday 13 September to Friday 18 September 2009.
For further details, see the meeting website:
http://meetings.copernicus.org/epsc2009/

Europlanet Research Infrastructure (RI)
Europlanet RI is a major (€6 million) programme co-funded by the European Union under the Seventh Framework Programme of the European Commission.
Europlanet RI brings together the European planetary science community through a range of Networking Activities, aimed at fostering a culture of cooperation in the field of planetary sciences, Transnational Access Activities, providing European researchers with access to a range of laboratory and field site facilities tailored to the needs of planetary research, as well as on-line access to the available planetary science data, information and software tools, through the Integrated and Distributed Information Service.   These programmes are underpinned by Joint Research Activities, which are developing and improving the facilities, models, software tools and services offered by Europlanet.
Europlanet Project website: http://www.europlanet-ri.eu/
Europlanet Outreach and Media website: http://www.europlanet-eu.org//