I want to take photos of coins rolling through a coin slot.
I started with a ArduCam global shutter camera, which worked, but the minimum focusing distance is 1m, which gives me a very tiny coin image. I want the image to be at least close to full frame, and mostly not distorted around the edges. The image will be fed to a NN for processing.
I want to be able to identify mint marks, if possible. Mint marks are around 1mm. I recognize I may have to do a separate photo of that specific area for this. This is a secondary goal.
I started with the global shutter, since the coin will likely be in motion. I’d prefer not to have to stop the coin to photograph it, that complicates the design, but it’s not a deal breaker.
What camera / lens would you suggest for this application?
Oh, I’m planning on doing this on a raspberry pi. Currently testing on pi 3, but planing to move to a pi 5.
Hi @_tom, if your Arducam camera has a M12 lens mount, would one of the lenses listed at this page help? It shows a variety of lenses with a MOD (minimum object distance?) of 0.3m or 0.2m.
I don’t think the lens is removable. At least, the description doesn’t say anything about that, and I’m hesitant to try to remove the lens for fear of breaking something.
The product description you linked to does show that it has an M12 lens mount, which suggests that the lens on your camera should be removable by carefully unscrewing the lens out from the lens mount.
I can’t promise you it will work though, as I am just a random dude on the internet. But if it does, that means you can consider more suitable lenses for your application.