Even with robust vision-based surveillance capabilities at all points of entry, U.S. border patrol and homeland security have to contend with a much bigger threat. “The United States does a pretty good job checking people coming in, but we do a really poor job knowing if they ever leave,” Dr. Lee says. “We know how to solve that problem using technology, but that creates its own problems.
“The best place to do this is at the x-ray machines in the TSA line, where you can have a mechanism to record everybody,” Dr. Lee continues. “But that is going to be expensive because you have to do this at every airport in the United States. Monitoring and recording slows things down, and TSA is under a lot of pressure to speed things up.