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Author Topic: align photos - sequential matching  (Read 5064 times)

someDude

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align photos - sequential matching
« on: February 18, 2014, 03:15:31 AM »
Hello,
I'm having a few struggles with chunks aligning perfectly at first attempt, but when i add some more photos to fill the missing gaps, suddenly many others won't align anymore and new holes pop up. weird.

As far as I learned about the photo alignment, it is looking at all possible pairs of a chunk. Is this correct?

Well, at least for my case, when scanning small objects, I have the option to deliberately create a large overlap from one photo to the next (which I'm already doing, still not good enough it seems  :'( ).

In case I understood this right, it might reduce the computational time significantly, if one could select some sort of "sequential alignment", where PS only looks at the overlap of two successive images in the list of the chunk.
Also, this might reduce alignment errors, where PS might (not sure if this is the case) be unsure where a certain image belongs.

Thank you for your consideration
« Last Edit: February 18, 2014, 03:27:59 AM by someDude »

Marcel

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Re: align photos - sequential matching
« Reply #1 on: February 20, 2014, 06:32:30 PM »
If you use "Pair Selection->Generic" then Photoscan will do a pre-selection of photo pairs (basically figuring our which photos overlap). This can help making the alignment faster.

Looking at only the overlap in two successive images wouldn't work, unless your photo set consists of photos taken in a straight line.

Could you show some example photos? Personally I hardly ever have alignment errors (but we photograph subjects with a lot of fine detail).

someDude

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Re: align photos - sequential matching
« Reply #2 on: February 20, 2014, 08:46:04 PM »
You are right, my alignment errors came from somewhere else:

improper lighting and no decent background. since i don't have endless space inside my flat to walk around my object with a camera, i tried to bring diffuse softbox-lighting on the object and turn it in front of a white canvas. But PS would keep misplacing similar parts of the objects, leaving nothing but a huge explosion of features.

But: 


 
everything worked perfectly when i took the pictures outside, on a cloudy day and let the object stay in one place, walking around it.

I guess I should practise some more, before asking for stuff ;)