With the High Resolution Stereo Camera (HRSC) on ESA's Mars Express mission, planetary research has got, for the first time, a system capable of high-resolution 3D colour images of the planet's topography.
The unusual photographic capabilities makes it possible to calculate the altitude of each pixel - the camera uses its stereo capabilities for this.
The stereo production of the Digital Terrain Model by the HRSC uses some of the same techniques we do - the observation of the martian landscape with slightly different points of view uses the same principle with which two-eyed humans see their surroundings.
The camera is aligned by swivelling the spaceship perpendicularly to the Mars surface. The HRSC takes its images with nine photo-sensitive detectors, scanning the martian surface line by line with nine different viewing angles into and against the flight direction of the orbiter. These nine channels include four stereo and four colour channels, as well as the downward-looking nadir channel.
Credit: DLR, NASA/JPL.