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Author Topic: Scanning small objects  (Read 172 times)

tkalfaoglu

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Scanning small objects
« on: August 01, 2020, 08:39:20 PM »
I have two small objects about 5cm each, but I am unable to scan them properly..
I took dozens of pictures with a DSLR at F16 - 10 second exposures.

They are both plastic pieces that I would like to duplicate.
One is jet black and the other one is orange. Both somewhat shiny.
I overexposed the black one to get detail - and the photos do look good.

I tried putting them on a pedestal and walking around and taking photos.
Usually many of the photos were non aligned.

I also tried a rotating pedestal and the camera on a tripod, which is a lot easier, but I read that this was not recommended.
I also tried video - using ffmpeg to split it into a thousand images. Which mildly worked better.

What is the correct way to scan these &@*&$  things? My models are always crappy looking.
I even tried the mask method - to take pictures of the pedestal and marking them as masks.

Thanks! -t
« Last Edit: August 01, 2020, 08:42:17 PM by tkalfaoglu »

bestable

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Re: Scanning small objects
« Reply #1 on: August 02, 2020, 08:17:59 AM »
Hi
If You shared Your images we could try ourselves and see what problems arises, then give suggestions.

I have successfully scanned pinecones (Similar size to Your object, right ?)  on turntable with these camera settings:

James

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Re: Scanning small objects
« Reply #2 on: August 03, 2020, 05:45:14 PM »
i searched google for "5cm shiny orange plastic piece" and "5cm shiny jet black plastic piece" images, and the results were invariably things that would not be reconstructed well via photogrammetry due to the lack of surface texture.

have you had success with non shiny-small-plastic pieces? If not, then i suggest that's where you start, because shiny pieces are notoriously difficult and so are small pieces, so small shiny pieces are going to be even harder.

If you're sure that your photo quality is not the issue, and that you are getting sufficient detail, and that you are doing the masking things correctly, then i would suggest you increase the number of photos, maybe even hundreds as opposed to dozens, so that each one has a greater chance of matching with an adjacent similar looking one, which may have been why the video thing worked.

Other general things to try include adding a non small-shiny thing in the scene to help the software find matching points, such as a sheet of newspaper underneath. Make sure the frame is filled as much as possible with your object as opposed to the background. Also try adding more light or working outside rather than increasing exposure time.