Rei Kawakami was on a train to the airport after a conference in Seoul in October when she heard about the fire engulfing Shuri Castle in Okinawa.

“I’ve been to Shuri Castle and I knew that for the people of Okinawa, it was part of life,” said the 39-year-old associate professor. After reading news reports that students were so shocked by the castle’s destruction they were unable to go to school, Kawakami felt compelled to act.

“I have children and I imagined how overwhelming it would be if they were the ones who experienced this,” the computer vision specialist and University of Tokyo graduate student said. “I could not bear to do nothing.”

In fact, it was a paper on the virtual reconstruction of Rome which won an award at the International Conference on Computer Vision in Seoul that inspired Kawakami to launch the Our Shurijo: Shuri Castle Digital Reconstruction project. The undertaking will build a digital 3D model of the castle using photographs and video footage contributed online.

The Oct. 31 blaze, suspected to have been caused by an electrical fault, torched seven wooden buildings occupying over 4,000 sq. meters of a hill overlooking the prefectural capital Naha.

Shuri Castle was the center of politics, foreign affairs and culture in the Ryukyu Kingdom from 1429 until Okinawa was annexed by Japan in 1879. It burned down several times, including during World War II. The castle’s ruins, excluding restored buildings, were registered as a UNESCO World Heritage site in 2000.

The central government is aiming to compile a reconstruction schedule by March 2020 based on a plan that was decided earlier this month. It took around 30 years to complete its previous reconstruction push, which ended in February 2019.

“I’ve heard that it will take a long time to rebuild the castle,” Kawakami said. “I hope our project encourages the local people and gives them the energy to move forward.”

Kawakami and her team are aiming to collect a million photographic and video images, which will be sorted and combined with specially written algorithms. The data will culminate in a precise 3D model of the castle complex that will allow visitors to virtually explore the buildings and magnify objects.

“We set 1 million images as our goal because the more we use for the 3D castle, the higher the quality,” Kawakami said.

The project team comprises over 20 volunteers including students, professors and engineers from countries including Spain and France.

Among them are people from Paris-based startup Iconem, which has joined a project with Microsoft Corp. using 3D technology to rebuild Notre Dame Cathedral, which was heavily damaged by fire in April and reportedly may not recover. Kawakami contacted Iconem through a research acquaintance who is working with the company.

“It fitted our aim … to digitize endangered heritage sites,” said Jonathan Chemla, Iconem’s chief technical officer.

Iconem specializes in processing large volumes of images, Chemla, 27, said, adding he intends to use techniques similar to those being applied to Notre Dame. “International cooperation is always important to find solutions,” he said.

Since the launch of the project’s website on Dec. 20, the team has received about 28,981 images from around 2,709 people. About 40 percent of them came from outside Japan.

Kawakami also hopes that in the future, residents and visitors to Okinawa will be able to explore the digital model of Shuri Castle using virtual reality goggles or smartphones at the site.

“The digital castle could be used to teach high school students in Okinawa, as well as to attract tourists until the castle is rebuilt,” Kawakami said.

“There are issues such as cost, but I will continue to do this project until we make local people happy,” Kawakami said.

Among the project’s supporters are her former mentor Katsushi Ikeuchi, a professor emeritus at the University of Tokyo who has pledged to contribute ¥1 million ($9,140).

Several companies are also participating, including Sakura Internet Inc., which provided a computer server, and Capturing Reality s.r.o., which is allowing the team to use its software for combining images.

The project team is collecting photos and videos of Shuri Castle on its website at www.our-shurijo.org, which is available in Japanese, English, Korean and Chinese.