The cameras identify when items are put in a shopping bag without first being scanned by a cashier, or at the self- service checkout. 

walmart told  used the technology in more than 1000 stores. The company said that it had made an investment to ensure the safety of our customers and associates.

The scheme called missed scan detection by walmart uses technology supplied by Irish company Everseen. The camaras track items rather than peaple. If an item is spotted being put in a shopping bag before it has been scanned at the checkout the system can call an employee to "help".

The retailer said shrinkage- the loss of products due to theft or error-  had decreased since the technology had been deployed.

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