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Author Topic: Alignment problem with 360 panorama from rotating camera on tripod  (Read 8149 times)

bmartin

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Hello,

I'm trying to reconstruct an indoor scene by taking a video with a rotating camera placed on a tripod at the center of the room.  With the video, I regularly sampled 142 tif images (640x480) to import in Agisoft Photoscan pro.  The problem is that I can't find a way to get them aligned properly (see snapshot).

Is there something special to do for this kind of tripod centered acquisition?

Thanks

Alexey Pasumansky

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Re: Alignment problem with 360 panorama from rotating camera on tripod
« Reply #1 on: January 05, 2016, 10:37:21 PM »
Hello bmartin,

If the images are taken from exactly the same position you should add the corresponding cameras to the single group in the Workspace pane and assign Camera Station type to the created folder (using the context menu option).

But please note that from the images taken from the same point you wouldn't be able to estimate the depth of scene.
Best regards,
Alexey Pasumansky,
Agisoft LLC

Dave Martin

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Re: Alignment problem with 360 panorama from rotating camera on tripod
« Reply #2 on: January 05, 2016, 10:57:42 PM »
bmartin,

You may find it useful to have a look at page 6 of the latest user guide as it has advice on taking that type of image set.

Dave
« Last Edit: January 05, 2016, 11:21:08 PM by Dave Martin »

bmartin

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Re: Alignment problem with 360 panorama from rotating camera on tripod
« Reply #3 on: January 05, 2016, 11:31:50 PM »
Hello Alexey,

Thanks for the tip about the groups.  See GoodPanoramicAlignment.JPG. 

Question: Could you explain a little more why I needed to make a group (I thought that by defaut all the images were part of a default group)?

Also, when I try to build a dense point cloud, I get a "Zero resolution error" as shown in the other screenshot.  Is is because of the impossibility to build depth information as you said?  Is there a way to fix an arbitrary resolution anyway so I later get the texture of the images projected on a cylinder (or sphere)?

Thanks
« Last Edit: January 06, 2016, 12:26:46 AM by bmartin »

bigben

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Re: Alignment problem with 360 panorama from rotating camera on tripod
« Reply #4 on: January 08, 2016, 03:47:04 PM »
You need to have the cameras in a folder so that you can set it as a camera station ... tells PS that all cameras in that folder have the same position.

Photogrammetry requires images from different positions... so while you have images of different parts of the room they're all shot from the same position so there is no way to calculate depth info.  The points you see in the pointcloud are all at the same distance from the camera location and actually indicate vectors from the camera position to the point.

You can use multiple camera stations, but this requires a large number of images as each camera station is only equivalent to a single camera regardless of how many images are in it.

You can export a panoramic image from a camera station. It will be a 360°x180° equirectangular panorama at the full resolution of the source images. There are no options for setting the resolution of the panorama AFAIK.

n@sk

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Re: Alignment problem with 360 panorama from rotating camera on tripod
« Reply #5 on: January 13, 2016, 09:18:26 PM »
Hi bmartin,

Not sure whether you are trying to create a panorama or a 3D model, but as Dave pointed out the answer is on the user manual page 6.

If you would like to make good use of the tripod in this scenario, you might want to have a look at
http://lib.tkk.fi/Diss/2005/isbn9512279665/  page 43,101

I hope this helps