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Author Topic: Scanning my girlfriend  (Read 4990 times)

My3dScene

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Scanning my girlfriend
« on: May 09, 2015, 05:39:05 PM »
This is the situation,

Same girlfriend, same camera, illumination (CANON 6D, 50mm, sharp RAW images 20MP), Same amount of images, but 2 different positions.

In the first position (Lay down) I had 120 of 120 cameras perfectly aligned.

In the second position (Seated) I had 4 of 120 images aligned.
It is hard to understand what is wrong, considering if I align a few photos just  for testing (separated), they all align perfectly, for instance face photos, hands, etc, but If I select all together, Photoscan is only aligning 4 images of 120.

To work by Chunks is not really working due to even though I can get good areas scaned, if I select different regions I will generate big gaps in between.

any guessing what is going on?
Cheers.

James

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Re: Scanning my girlfriend
« Reply #1 on: May 09, 2015, 07:02:22 PM »
Laying down the subject is more likely to stay perfectly still, whereas seated there is more scope for slight movements.

If you have not yet tried masking your background out then try that.

If you don't fancy doing it the long/manual way, then try aligning subsets of your images (which you say does work) and build low res mesh from these subsets and then perform import mask -> from model for selected images.

If you have masked the background then it may just be that your subject moved relative to herself whilst seated, or that you did not fill the frame sufficiently.

My3dScene

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Re: Scanning my girlfriend
« Reply #2 on: May 10, 2015, 05:15:42 PM »
Thanks James,
I'm currently trying to apply your advices, but I was wondering if there is a way to make Agisoft Photoscan do this:

"Ok, I can't align the whole chunk of photos, but I can align this 11 images here , then this 6 images in a different region there, and so on..."
Then the user pick the separated but aligned regions and manually put them together.

I know you can work in chunks, but there is always images that belong "in between" so if Agisoft creates for you the different chunks I think the process with a bit of human helping  would be a lot better.

Might be there is an script or an advanced function for that?





JMR

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Re: Scanning my girlfriend
« Reply #3 on: May 11, 2015, 11:16:07 AM »
yes it somtetimes happen tha pscan fails to align some photos without evident reason. Try to select in small groups photos 5-10 that are connected to those that have aligned well, righ-click and select align photos in the context menu. Also try setting tiepoint limit to zero or to a number much higher than default value.
let us know if you are lucky and do not give up with this girlfriend... this is not that important! ;-)

Marcel

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Re: Scanning my girlfriend
« Reply #4 on: May 11, 2015, 11:32:58 AM »
The version where she is laying down probably has a background (carpet or fabric?) that contains more useful details Photoscan can use to align the photos.

James

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Re: Scanning my girlfriend
« Reply #5 on: May 11, 2015, 11:40:47 AM »
Try to select in small groups photos 5-10 that are connected to those that have aligned well, righ-click and select align photos in the context menu.

That would be my advice too! If you have the pro version then you can manually help photoscan align these unaligned photos by placing at least 3 markers in at least two aligned images and in one or more non-aligned image before trying the step above.

You can also use markers to 'manually' align chunks by placing 3 common markers in each 'pair' of chunks and aligning 'by markers'.

do not give up with this girlfriend... this is not that important! ;-)

If she will pose while you practice photoscanning she is a keeper.

My3dScene

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Re: Scanning my girlfriend
« Reply #6 on: May 11, 2015, 12:42:39 PM »
Thank you guys for your advices, I will put my hands on them and I'll be commenting my results. Of course I can try scanning again, but is a kind of challenge to use my current photo set.

The version where she is laying down probably has a background (carpet or fabric?) that contains more useful details Photoscan can use to align the photos.

Yes, I think the background could help a bit to align in the laying down position, considering I am using 50mm / F2  which is not much DOF to capture a sharp background in the seated position, and also in the seated version I took the photos slightly closer.

if nothing above works I might have to try with another girlfriend to scan in name of science of course.




Marcel

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Re: Scanning my girlfriend
« Reply #7 on: May 11, 2015, 01:39:29 PM »
Yes, I think the background could help a bit to align in the laying down position, considering I am using 50mm / F2  which is not much DOF to capture a sharp background in the seated position, and also in the seated version I took the photos slightly closer.

50mm F2 will give you about 7 centimeter / 0.2 feet depth of field, that won't work for Photoscan. The more sharpness in the picture the better.

Try F11 or F13 to maximize the depth of field, you probably will need a tripod to avoid blur from camera shake (if you photograph inside).