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Author Topic: A challenge - aligning two scanned and cropped images, no exif  (Read 7346 times)

tai_pinc

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A challenge - aligning two scanned and cropped images, no exif
« on: September 24, 2012, 06:35:22 PM »
Hi Everyone

Before I begin describing what I wish to do let me just say - I am aware that PhotoScan was not made for these uses. Still, it is the best service that I've checked and was also quite successful at the task.

So, I have a collection of Stereographic imagery (actually it's from the Congress Library) and I want to align them and create a Point Cloud. (just alignment, no model for now)

The pair images were scanned together, so there has to be some cropping made, and there's no exif of course.

Still, despite these difficulties, out of many pairs of images I tried, two came out very successfully.
This is why I still have some hope that there might be a way to make the rest work.

Good - Cave https://dl.dropbox.com/u/8354036/photoscan/cave.psz

For original images - http://www.loc.gov/pictures/collection/matpc/item/mpc2004001009/PP/

Good - Alley https://dl.dropbox.com/u/8354036/photoscan/alley.psz

For original images - http://www.loc.gov/pictures/collection/matpc/item/mpc2004000976/PP/

The problem is that usually PhotoScan confuses and switches between the left and right images. The alignment works great - it's just the opposite way. The geometry is kind of "mirrored" but also deformed. I'm uploading some examples so you can see for yourselves.

If only I could tell PhotoScan - "it's Ok, just switch the images locations"! that would be great.

Bad - Street https://dl.dropbox.com/u/8354036/photoscan/street1.psz

For original images - http://www.loc.gov/pictures/collection/matpc/item/mpc2004000999/PP/

I know that this is a strange use for the software, but still, it did a good job on two of the images, so why not?

Does anyone has any ideas? it would make me so happy if this works...

Thanks

Tai

olihar

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Re: A challenge - aligning two scanned and cropped images, no exif
« Reply #1 on: September 24, 2012, 11:04:32 PM »
For what you are doing I would much rather look into something in this direction.

http://www.ipol.im/pub/art/2011/m_qer/

Alexey Pasumansky

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Re: A challenge - aligning two scanned and cropped images, no exif
« Reply #2 on: September 25, 2012, 02:54:51 PM »
Hello Tai,

Looks like the problem is in the very small stereo base relatively to the distance to object/scene.

Maybe you should experiment with initial calibration parameters and particularly with cx.


Best regards,
Alexey Pasumansky,
Agisoft LLC

tai_pinc

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Re: A challenge - aligning two scanned and cropped images, no exif
« Reply #3 on: September 26, 2012, 02:04:38 AM »
Olihar - Thanks, that's seems very interesting. I would dig into it soon enough

Alexey - That's great! It requires a bit of work but I already manage better results
Thank you very much!

olihar

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Re: A challenge - aligning two scanned and cropped images, no exif
« Reply #4 on: September 26, 2012, 02:21:16 PM »
Olihar - Thanks, that's seems very interesting. I would dig into it soon enough

Alexey - That's great! It requires a bit of work but I already manage better results
Thank you very much!

I have it up and running on my machine I can try and process couple of images for you if you want.

tai_pinc

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Re: A challenge - aligning two scanned and cropped images, no exif
« Reply #5 on: September 27, 2012, 01:17:13 AM »
Hi Olihar

That would be great, thanks!

I put two pairs here:
https://dl.dropbox.com/u/8354036/photoscan/00992.zip
and here
https://dl.dropbox.com/u/8354036/photoscan/00994.zip.

Is there a way to get this software too?

Tai

olihar

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Re: A challenge - aligning two scanned and cropped images, no exif
« Reply #6 on: September 27, 2012, 02:11:41 AM »
So I gave it a quick try and I got this...


olihar

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Re: A challenge - aligning two scanned and cropped images, no exif
« Reply #7 on: September 27, 2012, 02:20:20 AM »
And the other one...


tai_pinc

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Re: A challenge - aligning two scanned and cropped images, no exif
« Reply #8 on: September 27, 2012, 09:39:44 AM »
Olihar - that's amazing! I'm speechless, really.

But how does it looks from the side?
Could you send me those files?
And is there any way I could make this too?

Thanks again

Tai