MacBook Pro Mid 2012 briefly displays static after waking from sleep

On my MacBook, whenever I wake it up from hibernation, it briefly displays static for about 2 seconds before showing the login screen, very like an untuned analog TV. The problem is purely cosmetic, because after that it functions perfectly. It doesn't seem to happen if I simply sleep it though.

The machine has gone through two OS upgrades, I believe starting from Mountain Lion, which I don't think had the problem, so it may have started with Mavericks, and continues with Yosemite. I currently have everything updated to the latest version.

It's not really a huge issue, but I'd like to fix it if possible. Any ideas?

I've had this issue many times over the years. It's kind of like the video ram gets clogged in a way. I've solved it with a PRAM reset. Restart and before the computer actually starts up hold down Option, Command (⌘), P, and R till you hear the second startup chime. Then release the keys. This should take care of that for a while. If you get it again you can look into a SMC Reset which is a bit more complicated