Turntable workflow
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I've had mixed results on my tests so far.
Is it recommended to do background masking on the images for use for RC?
What about green screen background?
How many images would you take per 360 degree rotation? I have been doing 36, but perhaps that is too much?
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Hello matmoeb.
Masking - yes, but if you have uniform background you can skip this. RC for this moment support only Image+Alpha masks, so you will need tiff or PNG with alpha as mask. Or you just can fill masked area with color.
How many images? Every 10 degree step will hive good overlap. But remember, this is only one loop.
For full 360 degree 3D scan you need about 18 loops, that required for the same overlap between loops from 4 to 36 images (from top or bottom loop to equator loop).
Something like this (synthetic dataset):
this is about 244 images
result you can see here: https://sketchfab.com/models/b014299cbc ... 2a0c82ea6d
You can choose 15 degree step, in this case it will be about 160 images for full 360 coverage, but you can lost details if you have complicated topology in your object. -
For best results you want a solid background, preferrably a color that provides a strong contrast. So most likely either black or white.
You also want uniform, diffuse lighting.
For small objects a decent light tent should more than suffice.
The more detailed or complex the object is, the more photos you should take.
Here is a real world example:
https://dl.dropboxusercontent.com/u/255 ... uirrel.rar (project file is for the demo version only, photos are included) -
Hoping someone can help...
I'm hoping to capture similar sized objects to the image attached using the turntable method. Obviously this image does not have sufficient lighting which i'm currently in the processing of sourcing, nor does it have an effective 'featureless' background required for the Photogrammetry process.
I'm in the process of sourcing a green screen but as far as I can work out I need a huge screen. The object is 6ft away from the back wall (a specified minimum distance to stop green spill onto the model) and the camera (Pi cam V2) is at a sufficient distance away from the object to ensure I get the full object in frame.
However as you can see these distances leave a huge amount of background space needing to be filled with the green screen, I calculate a screen size of 16ft x 16ft . My questions is this, if I used a green screen the same size as the grey wall on the image (which would obviously create a green floor too!) could I just crop each and all of my images to get rid of the unwanted background to the sides of the image? I've read that cropping the images pre-processing is a big no no but doesn't explain why... As far as I can work out, as long as all images are cropped to the same size I don't see why this would effect processing? Might be an extremely obvious reason why so apologies if it is!
I would just test it, but I don't really want to buy a green screen if it turns out not to be big enough!
Thanks in advance!
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Greetings.
It is possible to mask out parts of input images in order to exclude them from being used in the reconstruction process. Alpha channel is used for this purpose if present. Use full value to include and zero to exclude the pixel. E.g. tiff format works well.
You can also check the mask within RC in 2d view. After selecting a 2d view with an input image activate the Mask option in Ribbon -> IMAGE -> Input Layer.
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Hi there,
Thanks for your response, I am aware that I can use alpha channels during the reconstruction process, which I fully intend to do. However I believe masking cannot be used during the alignment process? It's at this point (the alignment step) that I cannot get a decent output. I'm just not convinced that having a green screen with lighting will make a drastic difference, however i'd like to be proved wrong!
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Hi,
I am a fresher and started learning 3d scanning process these days. I captured around 62 images of object on turntable rotation process.
But while importing them all together it divides in 3 to 4 components and do not compile a 3d model.
Is there any particular process or setting while compiling turntable images in RC?
Please help
Regards,
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Hi,
I am a fresher and started learning 3d scanning process these days. I captured around 62 images of object on turntable rotation process.
But while importing them all together it divides in 3 to 4 components and do not compile a 3d model.
Is there any particular process or setting while compiling turntable images in RC?
Please help
Regards,
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Hi Mobin,
I think you may need a lot more inputs. It's more likely your issue is due to inputs rather than the settings in the software. ssh4's comment at the top of this thread is still a pretty good guide. Also your goal for capturing is sharp, well lit, low noise images.
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