This figure shows a DEM of the northern half of the well-known tectonic fault
Rupes Recta. It has been generated based on two images acquired on
April 21, 2002 and
October 18, 2003 (a), yielding information about albedo and surface slope,
and on a further image taken on May 20, 2002 (b),
yielding shadow information. A quotient-based approach was followed to extract
an albedo map from the first two images. The scene was reconstructed by first
applying the quotient-based intensity error with smoothness and shadow constraints,
then using the resulting surface profile and albedo map as an initialization to
the shape from shading scheme that involves the integrability constraint. The
quotient image is shown in (c), the albedo map in (d), and the altitude profile
in (e). The height of Rupes Recta ranges from 200 to 350 m, which is well consistent
with the shadow length observed in (b). The albedo map (d) shows bright spots in
the lower part and especially in the upper right part of the image. The linear
structures in the albedo map along Rupes Recta are artifacts; presumably, the
surface gradients are not very accurate at places where the surface strongly bends
and the residual intensity error tends to be comparably large due to the
regularisation constraints.
