I do not know anything about 3D printing, let me know if another place might be more appropriate for this post.
My friend about three months ago was in a catastrophic motorcycle accident. He was hit by a texting F150 truck driver. He lost his leg, an eye and has had pretty much full body reconstruction, including jaw and face. He was wondering if he could 3D scan in the helmet he was wearing with all the first responders/doctors (who helped save him that night) signatures then give each one a copy to thank them. He is in Ontario/Brampton area. He can pay for it.
Picture is not of actual helmet. Being sent down from up north right now.
You can create a full color 3d model of the helmet including signatures by using photogrammetry. A phone is enough to do it, there are even apps that do it for free. There are also desktop apps that are open source that can do it. Color 3d printing is also possible with technologies like HP (Multi) Jet fusion. Hobbyist are unlikely to have them but a maker space might.
I would like to point out that while this comment is technically correct, it’s far from the entire story. There’s a lot more that can go wrong when 3D scanning an object than can go right. There’s usually some surface prep needed, black objects can be difficult, you need a good background, and there will also inevitably be some cleanup of the model needed.
Going to look for local. He won’t be in any shape for DIY projects for a while IMO. I figure he will be more focused on designing a new leg for himself once he is.