In a bid to cut down on theft and mistakes, Walmart is using artificial intelligence hooked up to cameras monitoring checkouts to ensure every item in your cart is scanned and paid for. This is already happening at over 1,000 Walmart stores.

As Business Insider reports, the system is known internally as Missed Scan Detection and uses computer vision to monitor both manned and self-checkout areas at each store. The system is able to detect when an item goes unscanned, or is mis-scanned, and reports the fault to a checkout attendant who can then approach and rectify the problem.

According to Walmart spokeswoman LeMia Jenkins, "Walmart is making a true investment to ensure the safety of our customers and associates ... Over the last three years, the company has invested over half a billion dollars in an effort to prevent, reduce and deter crime in our stores and parking lots. We are continuously investing in people, programs and technology to keep our stores and communities safe."

When store inventory disappears without being paid for it's known as "shrink." This can happen through theft or mistakes and retailers are obviously very keen to reduce it as much as possible. If Walmart experiences the average for US retailer shrink rates, then it's losing roughly $4 billion a year. With that in mind, you can see why heavy investment and embracing AI to reduce shrink is worthwhile for the company.

One of the companies supplying Walmart with the computer vision tech required to make checkout monitoring possible is Everseen. According to Everseen CEO Alan O'Herlihy, "People make mistakes ... In terms of shrinkage, or loss, that's the main source." And if you're wondering which item causes the most problems, it's milk. O'Herlihy explains, "People find it hard to scan milk ... Sometimes they get frustrated and they just don't scan it."

This article originally appeared on PCMag.com.