I doubt that a camera would be practical though, the slot for the pod would need to provide illumination and the camera lens would need to be positioned far eno

I doubt that a camera would be practical though, the slot for the pod would need to provide illumination and the camera lens would need to be positioned far enough away from the pod so that it could focus on the logo printed on top of it. The camera would need to be of a relatively high resolution, which would be expensive, otherwise competitors could print artwork which is not the trademarked logo but which does fool the machine into recognising it.