Please help finding a movie, going insane!

Hello all,

I have very little details I'm afraid but pretty sure someone will know.

I can't really remember the plot exactly, I'm pretty sure it was along the lines of some force or aliens taking over people's bodies. Anyway, the one scene I remember distinctly is where someone, the main woman possibly, is wearing a kind of biological protective suit and in the helmet it has a heads up display that tells the wearer if a being is benign or not. I'm confident that it's somewhere between late 70's to mid 80's. If you can help I may not go crazy!