Enceladus 3d Options

[malgar]

Hi,
I'm always been a lurker here. This is a great forum! Thanx to all!
I've written a small script in Python that extract the elevation map from an image with lights and shadows. It's a technic called "shape from shading" or photoclinometry. I've applied a simplified algorythm that works only with particular conditions. For example light must come exactly from left to right. It works well only with no patterned images and output images are affected by a boring striped pattern.
Btw, I've worked on an Enceladus crater an this is the result.
3D rendering is by GRASS software.
In attachments there are the image of the crater, the 3D image and a map with profiles.

ale

[JRehling]

Hi,
I'm always been a lurker here. This is a great forum! Thanx to all! 
I've written a small script in Python that extract the elevation map from an image with lights and shadows. It's a technic called "shape from shading" or photoclinometry. I've applied a simplified algorythm that works only with particular conditions. For example light must come exactly from left to right. It works well only with no patterned images and output images are affected by a boring striped pattern. 
Btw, I've worked on an Enceladus crater an this is the result.
3D rendering is by GRASS software.
In attachments there are the image of the crater and the 3D image.

ale

Fantastic stuff -- is it possible to rotate the highest resolution image (with boulders) and run the script on that? Any such product could be downsampled and still have great resolution -- could be used to produce a synthetic image of a horizon-looking panorama as seen from the surface. What could be cooler than that?

[malgar]

produce a synthetic image of a horizon-looking panorama as seen from the surface. What could be cooler than that?

Like these?
(Terragen power!!)

[Bjorn Jonsson]

This is absolutely fantastic, I'm especially impressed by the fact that (horizontal) stripes are not obvious. Is a description of the algorithm you are using available somewhere ? Also it would be very interesting to see a 16 bit grayscale version of the DEM instead of the color version in enceladus_profiles.png so I could try rendering this myself ;-).

I have from time to time been experimenting with something similar:

http://www.mmedia.is/bjj/data/mimas/mimas.html (this is a Voyager-based map with no Cassini data).

However, horizontal stripes have been an extremely annoying problem.

[malgar]

This is absolutely fantastic, I'm especially impressed by the fact that (horizontal) stripes are not obvious. Is a description of the algorithm you are using available somewhere ?

Hi, in the next days I'll release the whole script (it is only few rows of code), now it is too raw.. I have to "polish" it a bit.
Clearly this is not a my idea. I've caught this page in french http://www.astrosurf.com/rondi/lune3d.htm, and I've tried to reproduce the algorithm. In truth, it is a "simple" integration row by row of brightness.
How is your algorithm?

Also it would be very interesting to see a 16 bit grayscale version of the DEM instead of the color version in enceladus_profiles.png so I could try rendering this myself ;-).

For sure!
Look at here:

I have from time to time been experimenting with something similar:
http://www.mmedia.is/bjj/data/mimas/mimas.html (this is a Voyager-based ma with no Cassini data).

Wooow! great job!

However, horizontal stripes have been an extremely annoying problem.

I think that horizontal stripes come from a bad alignament of sunlight. If it is, with a great precision, from left to right, stripes are minimal.
When you integrate the row and you "sum" a bright pixel, there will be a string of pixel with high values, untill you reach a dark pixel that subtract values. If light is not well aligned, the integration will never find the dark pixel, and it will become a bright horizontal stripe.