f8's profile - activity

Hello everyone, I'm doing my student project and I have problem to solve. I tried few methods but its not that simple, so I would be nice if someone experienced show me which way to go. My target is to find small white rectangle on center of 1st picture, and center-bottom 2nd one. Problem is sometimes, like on 1st pic its brighter, sometimes its darker, but always it is almost-white rectangle and have very similar size.

Does anyone want to help me?