Need to preserve color information on shiny object.

[TravisBarton]

Hey everyone,

I need to scan a shiny object and get the color data. The helmet attached is an example.

I know I can cover it in matting spray and scan the object successfully.

I have heard about a workflow where the object is scanned once for color, then again with the matting spray to get the accurate shape.

I am wondering if anyone knows how this is done or if it is even possible.

Thanks,

-TB

[Kiesel]

At first, I havn't  done such scans and so I can only share some ideas.

For such objects you need to shot 2 photo series from the exact same camera positions. It is probably perfect to use a camera rig for that, a camera robot or a motorized turntable are also thinkable. You get an idea how it could work here:

http://www.pi3dscan.com/index.php/instructions

And how to process in PhotoScan here:

http://www.pi3dscan.com/index.php/instructions/item/agisoft-how-to-process-a-scan-with-projection

In your case you need one photo series with matte object for geometry and one without matte for texture.

An additional possibility to avoid reflections is using cross polarisation, but only when you don't have metal surfaces, where you use polarisation filters in one direction on your light source and another polarisation filter rotated by 90 degrees to that on your light on your camera. I have also seen an electrical triggered polarisation light with two 90 degree directions (DIY project), which would make the process easier - one photo with and a second photo without cross polarisation.

I hope this is at least a starting point for you.

Regards and good luck.