More of a error-correcting feedback loop rather than a filter, really. Which is very much what we do as humans, apparently. One recent theory of neuroscience that is becoming influential is Predictive Processing --https://en.wikipedia.org/wiki/Predictive_coding -- this postulates that we also constantly generate a "mental model" of our environment (a literal "prediction") and use sensory inputs to correct and update it.
So the only real difference between "perception" and a "hallucination" is whether it is supported by physical reality.