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Topic: Detailed technical information?

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aridolan (Over 1 year ago)
Where can I find detailed information describing how Photosynth works, so that I can better understand how to create new synths. In particular, I want to understand the effect of the order of the uploaded pictures on the final Synth, the usefulness of the point cloud display and the trade-ofs related to the number of pictures in a Synth.
Nathanael (Over 1 year ago)
A) I don't know if you've seen the Photosynth Photography Guide or the "How to synth" video. I'll grant you that the video is basic, not detailed technical info for the most part, but the Photography Guide begins to delve deeper into how things work. Both available here: http://photosynth.net/howtosynth.aspx

B) The order that the images are uploaded in has virtually no effect on the final synth. The synther solves the reconstruction problem non-linearly and so small fluctuations in synth output can occur even when the same images are processed when fed to the synther in the same order (at least that has been my experience). I'll look for links to quotes from Photosynth team members supporting that statement, but before the synth is finished every photo has been compared to every other photo so if the full set remains unchanged, the order that the photos are placed into the synther should not generate any real difference.
Nathanael (Over 1 year ago)
For links to video interviews with Photosynth team members, lectures by Photosynth's architect, Blaise, and links to the original 'Photo Tourism' project see my spreadsheet, available from the following link: 
( http://cid-0ef7a30c1e7b926c.skydrive.live.com/browse.aspx/Photosynth )

You'll need either Excel 2007 or Excel 2010 Beta to open it. If you don't have either yet, you can freely acquire 2010 from this site: http://office.com/beta
Nathanael (Over 1 year ago)
Here are two brief discussions which touch on your question of order. 

http://getsatisfaction.com/livelabs/topics/two_synths_with_different_results

http://photosynth.net/discussion.aspx?cat=a6bad539-de7d-4a16-8c4d-b143f7d5f984&dis=38772776-3f6f-4f5e-b34a-0e9771d6f10e

Watching Blaise's lectures will also inform you greatly as to the finer details. Also any interview with Drew Steedly is very useful as he and David Nister were two of the main guys responsible for building the synther.
aridolan (Over 1 year ago)
Thank you, Nathanael, for your answers and links. I am still downloading the Office 2010 beta (it is taking hours), but in the meantime I found an interview with Blaise about the technology behind Photosynth: http://channel9.msdn.com/posts/Dan/Blaise-Aguera-y-Arcas-The-technology-behind-Photosynth/

I followed the discussion links you added, and thinking about the somewhat non-deterministic process of Photosynth, I wonder if the optimization algorithm beg used is based on a bottom-up artificial life technique, such as genetic algorithms (an area I played with many years ago).
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