U.S. grocers are playing catch-up.

Held back by razor-thin profit margins, which have made investing difficult, grocery retailers lagged behind their peers in Europe and parts of Asia in making strides with technology that reduces the time shoppers spend navigating aisles, ringing up purchase and bagging items.

Then Amazon showed up and acquired Whole Foods. Now, there's more pressure to roll out projects that may have been in a pilot phase — or try new things entirely.

"The technology is more mature now, and these things are becoming easier to do," Mike McNamara, the executive vice president, chief information and digital officer for Target, told CNBC.

He said retailers have complained that the technology for such innovations as speeding up checkout has been bulky and visually unpleasant. "You have to design something that's practical," he said.

The future of America's grocery stores will include more scanning devices, smart shelves with digital displays and self-driving shopping carts. The Innovation Lab at The National Retail Federation's Big Show this year featured a slew of companies showing off their ideas that would revamp the grocery shopping experience.

Start-up SwiftGo was previewing a device to weigh an item as it's placed into a cart, ensuring everything is accounted for as a shopper scans food and drinks, and checks out from a mobile app. As more companies look to add "scan and go" options inside their stores, theft remains a major issue of concern, but weight scales in carts offer one way to mitigate that challenge. SwiftGo had also added red lights to grocery carts that would light up to notify employees when it appeared a customer hadn't scanned an item to pay for it.



Focal Systems showed off grocery carts equipped with a tablet to help a shopper navigate the store, locate relevant promotional offers and automatically pay without a cashier. Anheuser-Busch InBev and other food brands are also working with Focal Systems to monitor out-of-stock items, by accessing the images taken from cameras on the sides of shopping carts.

Target's partnership with Zebra, which sells scanning devices and label printers, among other items, was highlighted at the Big Show. The big-box retailer is also working with payment platform Verifone, which can help a retailer "save the sale" on the floor of a store with portable credit card readers.

"All around the world people want to save money and they want to save time," Walmart CEO Doug McMillon said during a keynote speech at the event. "We want to foster a culture that supports change and helps us go along the journey we're all on, which will lead to even more change in the future."