Forum : Photosynth Lounge

Photogrammetric, Oblique Image Stitching, Pets Dressed in Clothes Photos… this is a place to chat and share stories with your fellow Photosynthers. Not all topics have to be about photography, this is a place to relax and chat about whatever you fancy.


Topic: 13% synthy

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Roadsternut (Over 1 year ago)
I’m having a problem. I’ve loaded 104 pictures of my subject and each time I’m only achieving a 13% syn. Roughly 4 pictures. Is there something I’m doing wrong? Thanks.
Nathanael (Over 1 year ago)
Hi there!

You've chosen a very difficult Photosynth subject: shiny cars. 

Shiny anything is difficult (not impossible!) for Photosynth to handle because of the reflections in the surface. Photosynth is likely to identify details of the things reflected in your perfectly polished paint job and try to track them along with everything else in the photos which will confuse it as the reflected objects move at a different speed than all the other details in the scene.

If you were to try again in a less reflective environment you may meet with more success. I'm sorry that I can't offer much more encouragement than that. A less reflective vehicle would synth much more easily. A 4x4 truck that's been tearing through the mud and has had a little time to dry would light up in Photosynth like crazy or a rusty old truck. Sadly the best looking cars pose the biggest challenge for synthers.

I'll leave links to your two biggest versions of your roadster synth in 2D mode
Nathanael (Over 1 year ago)
...so that others can easily see what's working for you and what's not.

http://photosynth.net/view.aspx?cid=75b209b1-387e-46fd-995d-234b65fc8814&m=true&i=0:20:1

http://photosynth.net/view.aspx?cid=ea3e976d-c66e-4a80-80ec-ecfe9ff92339&m=true&i=0:20:1

Looking at synths in Grid Mode can show you straight off which photos were matched to each other. The smallest ones at the very bottom are the ones that didn't match any others in the whole synth (or not strongly enough to hold together).

Other than the suggestion of a less reflective place to take photos, I might try to get my hands on a tripod if I were you. Some of your shots are a bit blurry which will work against Photosynth and several of them are overexposed as well. Try to speed up your camera's shutter until there's not so much white in your photos.

I hope you stick around to figure it out. Your ride is sweet!

Role Models:
http://photosynth.net/Search.aspx?keyword=roadster&sortby=Best Synth
Nathanael (Over 1 year ago)
That last link didn't post correctly. Copy the entire last line (including the space and the word 'Synth' at the end) and paste it into your address bar to see the synths that I meant to show you.
Roadsternut (Over 1 year ago)
That’s not just a shinny car.. That’s my new shinny car! lolz_ And yes I’ve even tried to sequence them myself then re-run but I get the same results. How about this, more pictures taken closer together? And Thanks Nathaneal for the feed back.
Nathanael (Over 1 year ago)
When it comes to shiny things in Photosynth more photos closer together is always a good idea. :)
Marvin (Over 1 year ago)
Hi Roadsternut.

In addition to Nathanael's good suggestions I would try the following:

1) Most of your pictures seem clumped together.  Instead, stand at a distance where you can get the entire car in one shot, and start taking pictures every 5-10 degrees, while keeping a constant distance from the car.

2) Try to take the pictures facing slightly down.  This will catpure some of the ground, and this is usually textured (and so has a lot of features that are easily synthed).

3) Take all the pictures in one location.  Having different backgrounds will confuse Photosynth.

4) Keep the roof down.  There's more features on the inside of the car.

5) For object like cars (singe point of interest), a reasonable rule of thumb is to keep moving while taking pictures.  Taking more than one pictures in the same place will stitch, but not help the general reconstruction that much.  Moving the camera gives parallax.
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