TOKYO -- A big opportunity is presenting itself as major patents owned by a maker of surgical robots have begun to expire -- and companies in Japan and elsewhere are already pouncing on it.

The patents are held by Intuitive Surgical of the U.S., which makes the da Vinci surgical system and has so far dominated the market.

Japan's medical equipment market amounted to 3 trillion yen ($27.4 billion) in 2017, according to the Ministry of Health, Labor and Welfare.

In Japan, Olympus and Kawasaki Heavy Industries are working on surgical assistant robots, while Sony is also looking to move into the field with technologies from its image sensors and Aibo pet robot. Overseas, Alphabet, the parent of Google, is accelerating its research and development of automated surgical equipment, as are a host of startups.

In an automated surgery, artificial intelligence and robots enhance an operation's safety by replicating surgeons' judgments, making use of their experiences and by being more precise than humans.

Olympus has begun developing a surgical assistant that utilizes its endoscope technology. The National Cancer Center and other parties are involved. The partners hope to market the robot, which is meant to eliminate the need for "scopists," doctors who manipulate endoscopes, in 2024.

"We will produce an unprecedented surgical assistant system that has the brains of surgeons," said Masaaki Ito, head of the Department of Colorectal Surgery and Surgical Technology at the National Cancer Center Hospital East.

The system will be made of robot arms attached to an endoscope. Equipped with AI, it is to offer optimal visualization for each procedure of colorectal and stomach cancer operations. The AI will recognize hidden blood vessels and find tiny amounts of bleeding from images provided by the endoscope. The AI also is to indicate the optimal amount of pressure that should be applied to an electric scalpel and other surgical equipment.

In cooperation with medical institutions across Japan, the NCC has stored videos of 1,000 surgical cases showing how equipment moves and where internal organs are located. The library is one of the world's largest labeled visual databases.

With the help of this database, the AI will be able to make the judgments that are now the domain of surgeons. For example, the AI will accurately recognize the size of a tumor and instantaneously determine how to safely remove it.

Furthermore, instructed by AI, surgical robots will be able to reproduce experienced surgeons' advanced skills. And since they are capable of more accurate hand movements than humans, robots may be able to reduce bleeding and other risks.

The development of surgical assistant robots and related AI is progressing at an accelerating pace.

Alphabet is developing a robot jointly with Johnson & Johnson, a leading American developer of medical devices. Their joint venture has completed the operation verification of a prototype robot that is to be released next year. Although details of the envisioned robot have yet to be announced, it is expected to assist in the operation of surgical equipment.

At present, the global market is mostly dominated by the da Vinci system that Intuitive Surgical released in 1999. Some 54 million units of the system have been shipped. In 2018, they were used in about 10 million surgeries.

But the da Vinci is expensive, between 150 million yen ($1.37 million) and 300 million yen. Including the cost of disposables, tens of millions of yen are needed per year to operate a unit.

The system has aroused strong demand because of its easy operability and advanced remote-controlled robotic arms. But key patents on the designs and movements that enable these features began to expire in 2019.

Medicaroid, set up in Kobe, Hyogo Prefecture, by Kawasaki and health care company Sysmex, is to release Japan's first surgical assistant robot before April. In cooperation with Optim, a Tokyo-based information technology company, Medicaroid is developing AI-assisted support functions that can be added to the robot; they are expected to debut during the first half of the 2020s.

Sony hopes to bring its image sensor and Aibo technologies into surgery rooms. In September, the company released a system capable of centrally managing images on machines in an operating room. Sony hopes this will pave the way for the images to be analyzed by AI for use in surgeries.

Hitachi in 2020 is to release a "smart operating room" that links information from various kinds of medical equipment. The Tokyo Women's Medical University and other parties are involved in the project.

In the future, the system is to be equipped with AI-based support functions.

The da Vinci system does well at assisting surgeons' arm and hand movements but has yet to be equipped with "brains" to support their judgment. Olympus and other companies are thus developing AI for surgical robots.

There are two other trends taking shape in the surgical robot market. In one, leading medical equipment makers are acquiring startups in the field.

In April, Johnson & Johnson spent $3.4 billion purchasing Auris Health, an American developer of robots that assist endoscopic surgeries for lung cancer and other diseases. In October, Siemens Healthcare, a leading German maker of diagnostic imaging apparatuses, paid $1.1 billion to acquire an American company that provides robots to assist catheter-based cardiac operations.

Elsewhere, Medtronic, one of the world's largest medical equipment manufacturers, is stepping up its merger and acquisition strategy as are other players in the field.

The other trend has more to do with telecommunications technology, specifically 5G. As the next-generation wireless technology comes into widespread use, new surgical equipment will ride the wave.

Already, the Japan Surgical Society has begun working on telesurgery guidelines, and in a test last month NTT Docomo succeeded in exchanging a huge amount of surgical data between a treatment room and a remote place over 5G technology.