As we prepare to return to the moon and explore Mars in the coming years, join in the search for extraterrestrial artifacts using SFSX – a Mac OS X app for lunar and planetary image visualization.

Shape from shading is a technique for generating 3D (actually 2.5D) terrain models from a single image. The method originally developed in the early days of the Space Age was employed in an independent investigation of the Face on Mars in the the 1980s. It is currently being used to assess a number of anomalous surface features on the Moon.

SFSX computes a 3D surface from a single image and generates computer generated images and movies from different look directions. The method works best for images of the moon and planets like Mars where the surface is lit at low sun angles producing strong shading and shadows. 

Some early 3D visualizations of the Face on Mars generated using shape from shading are mentioned in an episode of Carl Sagan’s Cosmos series.

How to Use the App

First load an image into the app from your computer:

SFSX relies on you to specify the direction of the sun using the top circular slider. After a short processing delay (which depends on the size of the image) the computed height map is displayed to the right.

Views at other look angles can be generated by changing the depression and azimuth angle sliders. The amount of relief can be adjusted with the vertical exaggeration slider.

3D views can be saved one frame at a time, or as a movie.

Here are some sample images to get you started:

Click here to buy SFSX on the App Store.

Feature image at the top of the article is a simulated ground level view of a pyramidal feature on the surface of Mars created using SFSX.