Researchers at MIT's Computer Science and Artificial Intelligence Lab have developed software that uses variations in Wi-Fi signals to recognize human silhouettes through walls. The researchers built a device, called RF-Capture, that transmits wireless signals and then analyzes the reflections of those signals to piece together a human form, according to a study published this morning.

It can determine breathing patterns and heart rate

The technology is an extension of something the MIT team has been working on for a few years. In 2013, they used similar radio frequency technology to detect motion on the other side of a wall or obstruction, Gizmodo reports. Now, the RF-Capture is sophisticated enough to determine subtle differences in body shapes, and, with 90 percent accuracy, distinguish between 15 different people through a wall. It can even determine a person's breathing patterns and heart rate.

Here's how it works: The RF-Capture is placed in a room, and a person walks in a neighboring room on the other side of the wall. The device emits wireless signals, which travel through the wall, and reflect off different parts of the human body as it moves. As various part of the body are reflected in the wireless signal, the RF-Capture takes snapshots. Then, using an algorithm to identify body parts, it stitches the images together to create a silhouette of the moving figure. In some experiments, when the researchers focused the device on specific movement patterns they were able to trace a person's handwriting as he wrote in the air, Gizmodo reports.

While there's no real-world application for the RF-Capture yet, the MIT researchers say there are many possibilities. According to Gizmodo, the RF-Capture could be used to track the movements of an elderly person living alone, and be able to determine if they had fallen down. The technology could also potentially be used in smart homes, if certain gestures detected by the device were used to control appliances. The researchers expect the technology to get more accurate over time.

If this seems like an excellent way to spy on someone, you're not wrong. But the researchers told Gizmodo that in addition to necessary regulation that would need to be implemented, they're currently designing blockers that would only allow a person to be tracked by her own device.