Archaeology artifact scanning

Arch_tech · Newbie Joined: Mar 03, 2010 Posts: 2

Hello,

I am currently in the process of establishing a system of scanning in artifacts and rendering them in 3-d for both pdf publication and class/research uses.

What I have so far:

1. Konica-Minolta Vivid 9i non-contact 3-D digitizer
2. Geomagic Studio 11
3. Professional quality light tent
4. Adobe Acrobat 9 pro Extended (for pdf creation)
5. PC/laptop

The biggest problems I am facing is with image quality. Since the 9i has a very low resolution camera and the fact that we have not yet purchased the "turn-table" device, the quality is not where we would like it to be. I am certain that this is due to not having the rotation device and when I merge the individual scans together (say a pottery vessel--slightly larger than a basketball) there is a slight blur to the 3-d object where the merging overlapped. According to Geomagic, there is not a software solution to this and they suggest the rotation device, which will take months to aquire with a budget crisis going on. Does anyone have any suggestions to both improving overall quality and eliminating the blur with out using the rotation/turn table device? I have also tried the "project image" option, but that will not work with irregular shaped, 500 year old pottery vessels.---the image just doen't line-up correctly.

Thanks!

Joe · Newbie Joined: Mar 19, 2007 Posts: 4

Hi yeah the Minolta camera isn't much cop, my suggestion would be if you want to produce 3D PDFs with good colour / texture is to get a copy of 3d Studio Max or alike and map high quality photos to the model taken with a good camera, you can then import the Max scene in the 3D PDFs. I can't quite remember but I think it may take the lighting with it too.
I'd be interested to know how you go on as I've tried importing scanned models into 3d PDFs and it's always been a bit clunky.
Good Luck Joe

emstampa · Newbie Joined: May 25, 2011 Posts: 2

Hey Arch_tech

We have a vivid 9i with the rotary table and it is helpful in the initial alignment of the data but not required. If you are scanning with at least 30% overlap there should be no problem with manually aligning and merging the data. Even when using the turntable you still must do a "fine" alignment before merging. The turntable only gets things to a close alignment. They issue may be with the scanner itself and the quality of the scans.

A few questions for you. Has the scanner been calibrated recently? Are the lenses clean and in good condition, How do the individual scans look? Have you played with the settings in the PET scan software to remove the bad/curled edges after each scan? This will greatly improved the ability to get a good alignment.

If you want to send me a few scans in STL format I will look at them and see how they look and offer any advice. There are some other settings in the software that are key to getting good data Send to info@ems-usa.com

btam · Newbie Joined: May 29, 2011 Posts: 3

Hi Arch_tech,

If I read your post right you are having problems with the colour texture map.

A couple of things to try. Make sure you have enough images going around the object. If you scan at say 45 to 90 degrees between surfaces you will not get a good colour image in the areas that start facing away from the camera.

You can use the 'manual turntable' option with the Minolta. Just get a lazy susan / manual turntable and the software will prompt you to turn it at your specified rotation angle. I suggest something around 30 degrees to ensure you get good colour coverage.

Make sure you setup photography studio level lighting so that you get even ambient lighting on the object. If not you will get different lighting variations across your colour image which will not blend well.

Try doing the initial merging and texture blending in Minolta PET software if possible. A trick I've tried is to export the untextured mesh model into Geomagic, fix up the wholes, reimport to PET and then 'merge' with a tiny fragment of the original PET merged model. This will result in Minolta mapping the textures onto the healed mesh model.

Also ensure you are scanning as close as you can to the model. If need be, scan the model in segments eg. upper half and lower half to get increased resolution in both geometry and colour. If the surface is a bit uniform try using external reference objects eg. ping pong balls suspended on wire that don't touch your object to help align the scans without covering the object.