To look at that and claim to know that Oswald did not see Ruby, did not register on him, is totally unwarranted. If Oswald knew Ruby, then there is every reason to think that he synced on him. If he didn't know Ruby- if he didn't know him at all- then all bets are off.
There is a video on Youtube that has been around for a very long time. It's called "Who Does Oswald See". It has 176,000 hits.
This is what he wrote in the video description:
So, if Oswald knew Ruby, and if he made eye contact with him previously at the police station, then don't you think he saw him here?
So, what evidence is there that Oswald knew Ruby?
First, I'll point out something that John Armstrong emphasizes: that a woman who worked at a tailoring shop across the street from the Depository told police that her daughter and her daugher's friends saw Oswald talking to Jack Ruby outside after the shooting. They actually claimed that Ruby gave Oswald a pistol. It would have coincided to when Oswald left the building to go home.
Then, there is George Applin who was a witness in the Texas Theater who claimed to see Jack Ruby there sitting a few rows behind Oswald. George Applin died a mysterious and untimely death and is listed as such by Jim Marrs, Richard Belzer, Richard Charnin and others. The following article comes from the Weisberg Archive at Hood College.
So, was Jack Ruby the one who instructed Oswald to go to the Texas Theater? Somebody must have. Oswald certainly didn't go there because he had a hankering for a war movie. So, if Ruby didn't tell him, who did? He couldn't have been told to do it in advance because that would have tipped him off that something bizarre was going to happen. So, somebody must have told him to go there after the assassination. If it wasn't Ruby, who was it?
And, there are other claims of Oswald having known Ruby, including reports of Oswald being seen at the Carousel Club. But, it's complicated because there is the other Oswald, "Lee". So, maybe it was him. Still, there are sufficient grounds to suspect that the Oswald of fame "Harvey" knew Ruby, and if he did, it's reasonable to assume that he recognized him here.