As Amazon launches its shop without tills, how does ‘Just Walk Out’ technology actually work?

The shops are notable not for what is inside them but what is not: there are no tills, and shoppers can just walk out with whatever they want to buy.

Amazon is able to do so because of a complicated network of cameras, sensors and artificial intelligence that is as much like a driverless car as it is a corner shop.

The company refers to the system as “Just Walk Out” technology – which is precisely what is intended to do.

As a customer, the technology works very simply, despite the complexities that underpin it. Customers head to the shop, scan the Amazon app so that it knows who you are and where to charge you, pick items from the shelves, and then walk out.

Everything else is handled automatically, down to the receipt that will pop up on the phone for checking. Amazon is so confident that it says you should not need to check, and that it will not ask you to pay for anything that it missed.

That is despite the fact you can browse and shop in the same way you normally would. You can pick items up and put them back on the shelf, for instance, and do not need to make any effort to show the cameras the thing you bought.

That simplicity is underpinned by overwhelming complexity, however. While you are doing your normal shop, a whole suite of cameras mounted in the ceiling are watching what you are doing and adding anything relevant to your bill.

Amazon is fairly reticent about describing how exactly all of this technology works. Even though it sells the “Just Walk Out” tools to other retailers, it is cagey about what those tools actually are.

Its website details only the fact that it uses “computer vision, sensor fusion, and deep learning”, and that it relies on “a combination of sophisticated technologies to determine ‘who took what’ from the store”.

Some details have been revealed in patent filings that showed the company was using a system of cameras and sensors to track them, but it is not clear how exactly the final iteration is put together.

The mysterious nature of what it is doing, and the uncanny accuracy with which it is able to track shoppers, has led to concerns that the technology could also be used for profiling or tracking.

Amazon has stressed that it does not use facial recognition to work, and encourages retailers who buy the Just Walk Out technology to encourage customers to think of it in a similar way to the security cameras that are used just about everywhere in the UK.