Determine the finish of hardwood?

I removed the carpet in my home just recently and there is a huge difference from the living room hardwood which has been exposed since I lived here, and the hardwood that was underneath the carpet.

I wanted to screen and coat the floors since I've read online my floors can possibly get by with it instead of refinishing. I'm having difficulty identifying the type of finish on my floors and hope someone can give me a few pointers.