Hi,
I’m new to RC and am amazed by the speed of it. However i’m trying to replicate a workflow i had in another scanning software, which is to capture an object for photogrammetry in a turntable in a given position, and then capture it again rotating it sideways, so i have full coverage of it.
Default alignment doesn’t work well at all with both scans.
Tried only importing the 1st turntable, aligned it as best as i could, and exported as xmp info with “exact” method.
Did the same on the 2nd turntable, there were some errors (i dunno why, it’s a turntable with around 8º-10º increment), tried to do some manual control points, fixed it a bit, and exported as xmp again.
Did a new project, imported all the images with XMP, and i got the 2nd component, tried to flip the ground plane 90º and align again, but nothing… I can’t “trick” the software to think that i was the camera that rotated (which it didn’t) and not the object.
Could someone help me out with this issue?
Here are 2 images, one from each turntable, so you can better understand what i mean.
1 - http://i.imgur.com/VSXGPc0.jpg
2 - http://i.imgur.com/MvUd945.jpg
I haven’t done anything with turntables yet.
but since photogrammetry works based on moving camera, you will need to trick it to use turntable.
looking at the photos, it looks like there is too much information in the background, and it’s used that to help align cameras.
you might need to do something about lighting the background to over expose it and make it all solid white. or do the opposite and make it all black.
other way to go would be to mask all the background out.
you could also try setting the alignment to high image overlap. so it only try’s to get image features in the center of the photo.
Thanks for the tips! I’ve also been shooting in RAW, then converting to JPG, would it be better for RC to input RAWs directly?
Also, how do you mask the background in RC?
its best to do raw conversion before rc.
if you can over expose the background to white from the raw files it might be enough.
otherwise using tif’s or png’s with alpha channels should work. I don’t use it this way since i haven’t found a good way to make those while keeping the gps info in the metadata.
I’d work with masks: open the enhanced JPGs in Photoshop, and using “actions” build a custom alpha mask for each image, then save as PNG (PNG can have alpha channel, which RC will use as masks).
Your actions could include: big “rectangular” mask, masking everything except the center of the image (since your cashew nut is always right in the center of the image) and adding to this mask by masking everything in the orange colour range (the putty on which your cashew rests) - I think in Photoshop this is “selection” -> colour range. By making a custom action for this particular dataset, you can build masks in this manner for all your images automatically.
Hey Glimps,
since nobody has said it yet:
Your object covers way too little of the image - it should about 80% with as little background as possible.
In this context, I think RAW is overdoing it a bit… 
I only ever use jpegs and it works just fine.
I recommend zooming in and doing the shots again - probably much less trouble than masking (if you haven’t already done that).
Also I find that there is quite some noise in the images - what ISO did you use?
I would try to use 100 or 200 max which schouldn’t be a problem on a turntable with easy lighting options.
Just curious: how do you deal with the orange bits in the model?
