Double Slit Exp: What Really Happened?

[pb23me]

My question is about the double slit experiment..I was just listening to a guy explain this experiment on youtube and I got skeptical at one point in his explanation. He said that when the photons went through the double slits the detectors were turned" on" then the observers viewed the results, seeing which slit each photon went through then observing the wall they hit. The results in this case were that they hit 2 spots on the wall. Then with the detectors still" on" they took the data then erased the data before "looking" at it then looked at the spots on the wall and it resembled a wave pattern? Is this the way the experiment happened or is this guy distorting it somewhat?

 

[tom.stoer]

I think the description is correct; you may check
http://en.wikipedia.org/wiki/Quantum_eraser_experiment
http://en.wikipedia.org/wiki/Delayed_choice_quantum_eraser