It is a little off topic but I thought many of the forum goers might find the Photosynth to 3D process I've been working on useful for creating 3D models from aerial photos. The process is pretty simple and FREE:
· Gather images with a lot of overlap (like most of our aerial shots)
· Upload the files to http://www.photosynth.net (or use the open source Bundler app http://phototour.cs.washington.edu/bundler/ )
· Use this exporter to extract the point cloud http://pspcexporter.codeplex.com/
· Use a product like Meshlab http://www.meshlab.net/ (hard to get good results) or VrMesh Studio ( http://www.vrmesh.com/products/overview.asp ) to generate a mesh surface from the point cloud.
Here are two examples from my work in Ecuador and West Texas:
https://www.youtube.com/user/mdwillis01#p/a/u/0/2-oK5lnNA-I
and
https://www.youtube.com/user/mdwillis01#p/u/6/nJgvLll57f0 (only part of this one was done with Photoysnth).
The images were captured from kite and balloon platforms but the same workflow should work for any series of photographs.
Also, here is a Google Earth file with some of the same data http://70.114.146.89/~mwillis/Puchara_Grande.kmz (~10 Mb). My linux box connection is slow. It'll take a bit to download.
-Mark
Replies
Thanks for the sharing. Good info :-D
I realize there has not been a lot of activity on this forum post for a while, but I would like to share some research with you regarding the attainable accuracies of Mark's Photosynth workflow. Please refer to a presentation I have given at a GIS conference
Hello to all of you!
Great job Mark! I want to ask a question.
I' m interested in making DEM and orthophotos with a small RC plane on the cheap. I will use it for morphotectonic studies, coastal and wetland monitoring.
I want to use a cheap rc plane and mount a pocket camera in order to take nadir photos. Any suggestions?
A great free (open source) software for orthorectification is ILWIS. You can download it from 52 North site. ILWIS is a windows program, with a great gui and an extensive help file.
GRASS GIS is one of the best software for ortho but you it has a very steep learning curve especially for hobbyists.
@Bohumil Michalik: ERDAS is also a very powerfull but quite expensive software.
I wish I only had a part-time job like you....
Ad
If you poke around on my youtube channel you can see the process used on several rock art sites (non-aerial) and get an idea of some of the other possibilities.
As for types of images that are acceptable, as far as I know, all standard image formats are supported except for RAW. My images were JPEG with minimum compression.
@Nicholas Budd The downside is that you need a large number of photographs to get a dense mesh. My example used 410 photographs. I haven't tested my UAV yet but I'm guessing the number of photos taken for a similar area are much fewer using a UAV. Great thing about a kite, you can fly it as long as the wind is blowing and get a lot of photos.
Thanks everyone for the kind compliments. I believe this technique, or some new variation on it, has a lot of potential.
-Mark