A new report suggests that a future iPhone may come equipped with a laser system for depth sensing—and it’s nowhere near as crazy an idea as it might sound.

Fast Company claims that a source familiar with Apple’s forthcoming products says the phone maker is “working hard to add a rear-facing 3D laser system to the back of one of the new iPhones to be announced this fall.” That chimes with rumors reported by MacRumors earlier this year that a future device may include “fully-featured 3D sensing capabilities.”

These days, the term “laser sensors” brings to mind the lidar units many autonomous cars use to map the world in high resolution. But they needn’t be quite so advanced. Last year, researchers at MIT showed that a $10 laser and some simple circuitry could add low-power range-finding capabilities to a regular smartphone, with an accuracy to within millimeters.

Indeed, Fast Company’s source believes that the laser, lens, detector, and electronics for the depth sensor could cost Apple as little as $2 per phone. Clearly, that means that it’s not going to be mapping the world in the same level of detail as a driverless car. But it would be able to provide a means of measuring distances and mapping spaces. That’s more than any single-camera iPhone can achieve, and laser range-finding could be more accurate than the stereo camera system of the iPhone 7 Plus. And unlike the 7 Plus’s cameras, it would work in low light.

Its addition to the iPhone would fit with the direction that Apple seems taking its flagship product. At its developer conference in June, the firm made good on its long-standing desire to build augmented-reality products with the launch of new developer tools to help people build AR software for its devices. Early examples of software suggest that, even using a single camera, the resulting apps are impressive. But a laser sensor could provide more accurate ranging information and, in turn, more realistic AR. It could open up other applications as well, such as 3-D mapping of spaces or more intelligent camera focusing.

Whether a laser sensor appears on the next iPhone remains to be seen. But if it does, it will make a lot of sense.

(Read more: Fast Company, “Apple Is Getting Real About Augmented Reality,” “Self-Driving Cars’ Spinning-Laser Problem")