Kura creates a smarter dining experience with Coral

Kura Revolving Sushi Bar leverages local AI to serve better sushi

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Kura Revolving Sushi Bar in Japan has always been committed to the highest standards of health and safety for its customers. Known for their tech forward approach, Kura has dabbled in sushi making robots, an automated prize machine called Bikkura-pon, and a patented dome-shaped dish cover, aptly dubbed Mr. Fresh. But most recently, Kura has developed an AI powered system that not only facilitates efficiency for better customer experiences, but also enables better tracking to prevent foodborne illnesses.

In a world rocked by COVID-19, people are more conscious of good hygiene practices, as diners and restaurateurs alike are concerned about the spread of germs and bacteria. But, high-tech Kura Sushi was already addressing this concern with Japanese electronics integrator KSY by building an AI vision system that will ensure customers have a safe dining experience. The system is powered by Coral and is focused on reducing the points of contact between customers, staff and their food.

“Before the Coral system, we counted plates and monitored quality with an IR-and-RFID system whose accuracy was not that good,”
Naoyuki Sugiyama
Technology Development Manager, Kura Sushi

AI for restaurants

Engineers at Kura Sushi wanted an intelligent solution that could help track which diners ate what dishes at what price points, reduce wait staff interactions, and improve overall efficiency. Subscribing to the "fail fast" approach, they often turn to the Raspberry Pi for quick validation of early concepts. They knew they were on the right path when they discovered the Coral USB Accelerator, a quick and easy way to add on-device AI acceleration to any preferred prototyping device.

Their first prototype was duct taped to the conveyors,working with KSY, Kura was able to develop a viable path to production. KSY, like many distributors, also works with customers to help design AI-at-the-edge solutions. They designed the enclosure and power supply around the Coral USB Accelerator Kura Sushi wanted to use along with the Raspberry Pi computer.

“We have 80 percent of the Raspberry Pi sales in Japan,” explains Tosa Saito, head of Raspberry Pi integration at KSY. “One of the reasons customers come to us is because we have deep expertise in integration for mass production.”

The resulting system went from concept to prototype in only three months, starting in June 2019. Conceived before the COVID-19 pandemic as a way to help the restaurants run more efficiently and increase profit margins, the system has the added benefit of making their restaurants a little more hygienic.

A different dining experience

Diners at the 450-or-so Kura Sushi restaurants in Japan, Taiwan, and the United States have long been greeted by a touch screen that directs them to their tables. Plates of sushi under specially designed plastic shields sail past their tables on a conveyor belt. Taking a plate constitutes ordering one.

Previously, orders tallied up when patrons slid their empties into a slot at their table. Now, an AI-powered system provides an additional tallying system. The new system recognizes what’s on each plate, allowing for more robust info tracking, like across multiple price points, for example. But it doesn’t stop there, the ability to track consumption over time extends to the kitchen, where the chefs can plan around preparing the most popular dishes.

In addition to helping ensure that the hottest menu items are always on-hand, the tracking allows staff to monitor how long plates have been on the belt. The ability to quickly replace plates that have been out for too long ensures freshness, an element that factors into both food quality and safety.

And of course, there is the added bonus of reduced interactions between the dish and staff, as it makes its way from the kitchen to the table.

“One of the reasons customers come to us is because we have deep expertise in integration for mass production.”
Tosa Saito
Head of Raspberry Pi integration at KSY

The local AI advantage

A unit for each restaurant table combines a camera, a Coral USB Accelerator, and a Raspberry Pi processor to detect when a diner picks up a plate. A QR code on each plate lets the system register the item on the plate along with its expiration time. In the kitchen, chefs get a running tally of dishes selected by diners and those still circulating. The system maintains a database of menu items and specific plates in Google Cloud.

When designing the system, Kura had a set of challenging requirements. The new system would need to support multiple diners per table, scanning thousands of images across potentially dozens of tables in real time. Inference speeds would need to be fast enough to register that a diner had selected a plate, and capture what menu item was on that plate before it left the conveyor belt. They also needed to ensure that the data load would not overwhelm the network, which maintains many of the other systems integral to keeping the restaurant running.

From the beginning, Kura Sushi knew that using Cloud-based AI to process that much data would overwhelm their network capacity. That’s why they asked KSY to design and then facilitate production for an offline solution using the Coral USB Accelerator from the get go. “Kura Sushi asked us to provide a lot of USB accelerators,” Saito explains.

The completed system meets all the restaurant chain’s requirements, says Naoyuki Sugiyama, technology development manager at Kura Sushi. “Before the Coral system, we counted plates and monitored quality with an IR-and-RFID system whose accuracy was not that good,” he says, referring to infrared and radio frequency identification. “Sometimes, we missed capturing sushi taken by customers, and sometimes sushi spoiled.”

The Future of Dining?

Especially in an era of heightened vigilance around hygiene, restaurant automation may be the wave of the future. Kura Revolving Sushi Bar is ahead of the curve with AI-powered ordering, made possible with Coral.

Kura Sushi began rolling out its new order tracking system to select restaurants in April 2020 and plans to complete installation in all of its locations in 2021. That will require more than 10,000 Coral units. Fortunately, says KSY’s Saito, Coral’s plug-and-play architecture and ease of integration instill confidence that the KSY and Kura Sushi team can get the job done.

If you’re interested in how Coral can help you build your next product, please contact us.