When you say you want to scan faces, I am guessing that you want to make a 3D model scan of the face. Is that correct, please?
If you need to make a rapid head scan of the face without having to do additional editing processes afterwards, the R200 model is actually likely to be the best choice. This is because:
1. It is well-supported by commercial 3D model scanning software
2. The 'RealSense SDK 2016 R2' SDK that is compatible with the R200 comes with a free sample program called 3DScan that can scan heads and then output the scan as an .obj format 3D model file.
3. It is especially suited to scanning large objects and the human body, unlike the SR300 which is suited to scanning small objects.
Whilst is is possible to make 3D scans with the 400 Series cameras, it is currently a slower process because you have to first take a 'point cloud' scan made up of dots and then use another software package such as MeshLab to convert the point cloud into a solid model.
The R200 is also a retired model, but is still available from Intel's online store in a heavily discounted bundle deal with a single-board computer, the Up Board.
If the D415 is a preferable option, you could minimize the time needed for people to be seated by taking the initial point cloud scan and then converting the saved point cloud file to a solid model later on at your convenience. The RealSense Viewer software that comes with the D415's RealSense SDK 2.0 can create point cloud files quickly.
Thanks for the quick reply.
Sorry, I was not clear enough. I indeed meant on creating a 3D model, with and without texture.
Regarding the R200, does'nt it greatly compromise on accuracy?
Also, the point cloud, received from the D415 does only export from one angle, does'nt it? It does not support tracking yet?
I did find 3D-scanning software that recently supports the D400 series: RecFusion. (€99, but evaluation version is free).
About the SR300, it is also supported for the Easy3DScan app, I recall. So it would be a better choice? (If I could get a unit)
The old RealSense models like the R200 have an error range of around +- 5% and the 400 Series have an error range of 1% or less. I wouldn't say that the R200 is bad at scanning, though I have sometimes seen reports where the dimensions of a scan are off by a few centimeters compared to the original.
It is true of any 3D scan with a single camera that you are going to either have to rotate the camera or the person if you want to get a 360 degree scan of the head instead of just a frontal scan.
If you are interested in skeletal tracking for the 400 Series cameras, I recommend checking out the Nuitrack software.
If you cannot get an Intel SR300, the next best choice is the Creative BlasterX Senz3D. This is fully compatible with the RealSense SDK 2016 R2 and 2016 R3, and should work with the new SDK 2.0 that the D415 / D435 use (as SDK 2.0 supports SR300 too). This is because Creative manufactured the official RealSense SR300 camera for Intel, so the BlasterX is virtually identical. Another choice f BlasterX is unavailable is the Razer Stargazer, another SR300-compatible camera.