Forum : Advice & Critiques

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Topic: Not able to rotate my image.

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Photojo (Over 1 year ago)
First of all let me thank the Photosynth Team for all the hard work you've done inorder to make this site possible. So... Thank You!
     I have just uploaded my first photosynth image. All appears to be working normally except that I cannot rotate my sculpture. 63 pics, 92% synthy. Camera is mounted on a small tripod and sculpture is on a lazy susan. Followed the Photosynth guide concerning the use of a turntable or lazy susan. I rotated the sculpture on the lazy susan in small increments and took my snapshots. The "double arrows" however, did not appear on my image and I can't rotate it. What may I have done wrong? I'm a newbee so bare with me. The URL for the image is: http://photosynth.net/view.aspx?cid=6db806b5-c361-4792-be68-36d897aba71f   
Thank you, Joe
Nathanael (Over 1 year ago)
Greetings, Photojo!

I'm not on the Photosynth team, but I can tell you what is causing you to not get the results that you wanted.

The white backdrop which you are using behind the sculpture actually has detail in it that Photosynth is able to identify because of the lighting. The wood grain of the floor or table (I'm not sure which) that the turntable is on top of is also a small problem. Because neither this white backdrop nor the highly identifiable wood grain under the turntable move, while the sculpture does move, Photosynth becomes slightly confused.

I'm positive that if you set that turntable (or even the sculpture without the turntable) in a place where you can walk all the way around it (where all of the objects in the scene are stationary in relation to each other), you'll see an immediate improvement.
Nathanael (Over 1 year ago)
The other solution is to make sure that the background can't be tracked (I realise that this is what you were trying to do) or, alternately, to build a different sort of turntable like the one that Jim Cseke had linked to in this topic: http://photosynth.net/discussion.aspx?cat=6b63cb81-8b57-4d5d-a978-41d5509bf59a&dis=d9c62550-52cc-4f60-a614-9046dfda1cde

Unfortunately, Jim deleted the synth that showed his turntable, but the idea was that the part that actually turned was to set the camera on and in the centre of the table was a stationary platform for the subject to sit on. This meant that the background moved correctly with the subject as would naturally happen if you simply walked around the subject, but with stability and an ability to keep the camera an exact distance from the subject that shooting handheld shots doesn't generally afford.
Photojo (Over 1 year ago)
great, Great, GREAT! Thank you Nathanael for your prompt answers. Since I am very interested in building a turntable to work with Photosynth you've helped me tremendously. If I understand you correctly the main idea is to have the object stationary and have the camera rotate. CAPITAL idea!! I'm going to get to work on a design for just that immediately. (I did see the old post about the turntable and was disappointed that it was deleted.) By the way that "wood" part that the sculpture is sitting on is part of a bamboo lazy susan. I was doing the opposite of what Jim Cseke was doing (I had my camera stationary and the sculpture rotating).

Thanks again, you've been a great help to me.
Joe
Nathanael (Over 1 year ago)
Sounds like you're right on track to me, amigo. 

Apologies for not recognizing the bamboo when I see it. I've no excuse, except that I was viewing the synth on an old standard definition CRT TV.

Aside from the background issue, your first set of photos was actually ideal. I could see good definition in the point cloud. Looking at it again, I'd like to see an orbit added in that's using your flash. I think that there's potential for the pine cone, but only if we can blow the shadows off of its surfaces. That said, your current exposure is doing well to pick up the texture on the light stone. Sharp focus + exposure on surfaces is key.

I'd also be interested in seeing you raise the camera up a bit so that it looks down on the scene from more like 45 degrees. You might need one more orbit between the moreorless eye-level shots you've taken and the 45 degree downward orbit to get them to link, but with a subject like this, you can always take more photos if necessary.
Photojo (Over 1 year ago)
Nathanael: I want to clarify that I do realize that the problem is that Photosynth picked up on the detail on the white background (texture), and the wood that did not move (desk in this case, (more texture)) is the cause of the real problem.  I plan on revising my lazy susan stage area to minimise texture problems and I also plan to build something like what Jim C did. I will probably make use of both types of turntables.

Joe
Photojo (Over 1 year ago)
Thanks again Nathanael. I've seen some of your other posts and you are a huge credit to Photosynth.

Joe
Nathanael (11 months ago)
@waybetter, 

The sort of rotation that PhotoJo was describing is like what you see in this synth: 
http://bit.ly/dougsynthd3d | http://bit.ly/dougsynth

where you have taken photos in an orbit around an object and Photosynth gives you the circular handle to click and drag to rotate the object.
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