X-ray vision is one of those superpowers that seems like it would be creepy more often than useful. Now we're going to find out for sure in 2017. That's when MIT is projecting to have its X-ray tech ready for sale.
Before you go worrying about radiation, however, rest assured that the system doesn't actually use X-rays, unlike law enforcement's X-ray vans. Instead, the unit fires off low-powered radio signals into a room and then looks at the reflections to make sense of what is there. In other words, it's very precise radar.
MIT has been working on the technology since 2012, and in 2013 was at the point it could detect where a person was in a room, and even large arm movements to control lights and appliances. You can watch the original demo video here.
Since then, MIT has refined it further so it can detect multiple people and body positions, as shown in the video at the top of the page. It's so precise it can measure a person's breathing pattern and heart rate. It can also potentially identify a person based on their body mass, although it doesn't provide a true image of someone at the skin level (tough luck to the perverts out there).
MIT is thinking it would be great for health monitoring. You can keep an eye on a baby from another room, or monitor an aging family member to see if they've fallen down or are in distress. Naturally, there are also law enforcement possibilities, such as seeing where hostages and bad guys are before storming a building.
To market the units, MIT is creating a company called Emerald. It's projecting to have the first units on the market in 2017, and is estimating prices of $250 to $300. It will be a small enclosed unit, and it will have a smartphone app for easier setup and monitoring.
MIT says it will be easy for home setup, but somehow will be much harder to use if you want to spy on someone. There aren't many details on how that might be, but hopefully the team will have the safeguards figured out before it ships.