shape from shade, so i do not take over Bjorn's Options

[JohnVV]

So that i do not take over his nice thread i figured i would start a new one
I am just figuring it out so bear with me
Rhea
This is a example - very early example
http://www.shatters.net/forum/viewtopic.php?f=5&t=15847

one that i am going to redo .
the program i am using "Cyclops" has a few bugs

Enceladus
this is a good example a bit better than the above



the close ups are a 8k level 3 VT with and without a texture over it
then a 4k level2 vt

unfortunately i still have to figure out a bug .I need to run a highpass on it ( the 32 bit isis dem )
Cyclops exports to a 3d *.ply this is easy to export to a isis cub
and i get this ( this happens when i combine 16 smaller images into one big one )
and this example is at 1/2 size


Just a bit of a bug !!!

[Bjorn Jonsson]

Looks very promising despite the 'terraced' appearance in much of the image (a consequence of an 8 bit DEM?)

And big thanks for the information above. Thanks to it I identified an error late in my processing chain. After fixing it I'm getting very promising results but it is obvious that the best results are going to come from combining several approaches: Stereo, Cyclops and my primitive SFS software. I still haven't tried ISIS' pc2d. I may have to install CentOS to do so although I'm hoping to get ISIS to work under the version of Linux I'm running (Ubuntu).

Some interesting finds:

(1) I get *much* better results from Cyclops by visually estimating the light source direction instead of using the true direction. As an example, for image N1507742440_2.IMG of Dione the correct direction is (0.303693, -0.205793, 0.930279) but I get much better results using (0.5,0.2,0.6).

(2) Cyclops apparently doesn't like images with high solar elevation angles. This is not unexpected. The results are useful though but the quality is significantly worse than at lower solar elevation angles.

(3) Big craters are often too shallow in the resulting DEMs, requiring postprocessing in Photoshop (or combining the Cyclops DEM with a stereo DEM).

Two test renders:

The first one is a Cyclops DEM, the big craters are too shallow so it requires additional postprocessing but the really nice thing is that there are no visible artifacts like striping for example:


The second one is from my primitive SFS software after extensive postprocessing (mainly destriping). Small scale details are probably better than in the Cyclops DEM but the bad thing is that some striping is still visible: