Clarification of Photosynth capabilities please.

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  • Updated 12 years ago
I was at the Smithsonian Air and Space museum at Dulles yesterday. While I was there, I took my camera out for the first "heavy" use it's ever had. Over 550 high resolution pictures of the aircraft and area in one day. There were 66 of those of just the SR-71 Blackbird on the first floor. The SR-71 photos, I panned across every view, and took many multiple overlapping shots and detail shots from all sides and the top (from the catwalk).

I posted the SR-71 pictures only, which took about an hour. You can see these so we have a common reference by search for "SR71 Dulles" and look for the one posted by JWSmythe.

Now for my questions.

1) I attempted to synth the entire set. It ran for about an hour, never getting past the creating tile part on the task bar. Is there any way to add a huge collection? I'd like to add photos of landmarks that I've shot over the years, but most of them would be filler photos, as they don't overlap. For example, years ago I shot a panorama from under the the Hollywood sign at Griffith Park. I don't know that I still have the individual frames, but it would be nice if it would merge them. Other individual shots would be a couple dozen shot from the WTC just days before 9/11. None are overlapping, but I would hope they would overlap with community photos.

2) From the demos that I had seen, it would draw from the "community" pool to fill in gaps. On the real synths including mine, there are no community pictures shown. I found another set from the same place, except several feet over. They are not included. If I could upload the full 550+ set, there would be quite a bit of overlap, so I would think they would synth nicely between the sets. How do I make my synth use others photos to "fill in" the gaps or transit from my set to theirs?

3) On the SR71 set, I did shoot the entire perimeter, as I want to use them as reference for making some technical drawings. In the generated synth, there was no way to "walk around" the aircraft. I could only view one side at a time. I saw the instructions indicated that if shooting a room I should shoot from the perimeter in, and then from the center out. That wouldn't be feasible for a landmark such as this. Is there a better way to shoot something like this in the future, so I can "walk around" the whole subject?

Photo of JWSmythe


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  • concerned

Posted 12 years ago

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Photo of David Gedye

David Gedye, Principal Group Manager

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When you first see Photosynth you get a whole new idea about what COULD be done with photos. As people are discovering, this version of Photosynth is amazing, but has its limits. We recommend 300 photos max -- for two reasons.

1) There are several steps in the computer vision that require time and memory that scale approximately quadratically with the number of photos. You run out of a 32-bit address space pretty quickly. If you run on a 64-bit OS you can go further, but...

2) Our navigation -- as you've pointed out -- isn't as easy to use as we'd all like it to be, and the bigger the set the more a problem this becomes. This is a solvable problem, and you'll see a continued stream of improvements here over the coming months and years.

And yes -- we are VERY interested in allowing individuals, groups, and the community to create bigger and bigger experiences. The basic way we are going to acheive this is by linking synths together and allowing you to walk -- as seamlessly as possible -- from one synth to the next.

In summary, please use Photosynth for what it's good for right now: 20-300 photo experiences of a single room, object, or place. We'll get to the bigger experiences later.

IFinally, it's also not a tool for making technical drawings of a complex space. Some point clouds of highly textured objects COULD be used in that way, but I'm sorry to say that we're a long way away from being able to reconstruct complex shapes such a 10 planes hanging in the air in the Air and Space Museum. Please don't look to Photosynth to solve this problem anytime soon.
Photo of Sherwood Botsford

Sherwood Botsford

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To what extent could this be helped:
* Ordered pictures. For each picture if it has a known location, and direction. This should help reduce the quadratic checking to something smaller. Certain pictures can be ruled out because of geometry to not have any common view.
One easy way to add semi-ordering: Each set of pix from a given location is put into it's own folder. This would still scale quadratically, but there would be a smaller co-efficient at the front.

A second ordering principle would be that observation points circle the object in a specific direction. This would mean that the program would be able to eliminate certain pix from comparison. E.g. Once it knows that frame 3 from observation point 1 is not visible from observation point 2, it won't check that frame with ob point 3. This isn't fool proof.

* Land mark artifacts. Placing known objects in the view -- think 3d corner reflector targets, built so that the view of them gives information about the orientation of the picture, as well as the distance

* Knowing the zoom level of the image. This in effect gives you the angular view