Digital surveys record relics, boost restoration

Against the backdrop of Spring Festival fireworks, the Taiheyan Pailou, a Qing-era glazed archway in Jiexiu's Yi'an town in North China's Shanxi province, stands serenely, its distinctive blue-glazed components drawing tourists from across the country.

Although the ancient architectural gem, tucked away in the countryside, bears the indelible marks of time, its high-precision digital record has been fully archived in the database of the Shanxi Cultural Relics and Museum Industry Group.

"Cultural relics are bound to perish, and all we can do is extend their lifespan as much as possible," said Zhang Zhihua, head of the group's digital conservation department. Immovable cultural relics in Shanxi face threats from irreversible natural aging, including surface fading and paint flaking.

According to the Shanxi Culture Relics Bureau, the province has more than 53,000 registered immovable cultural relics, including 531 national key cultural relic protection units — the highest number in China. Notably, it is home to more than 80 percent of the country's wooden-structured buildings built before the Yuan Dynasty (1271-1368).

However, their wide geographic distribution and sheer number pose practical conservation challenges. "Many relics are in remote mountain villages, making access difficult for professional teams. In recent years, climate change has accelerated deterioration and greatly increased conservation challenges," Zhang said.

In 2014, the local government founded the Shanxi Cultural Relics and Museum Industry Group to conduct emergency documentation of endangered relics using digital technology and to compile precise digital archives.

In a race against time, the group's data collection teams carry high-precision cameras and laser scanners as they survey ancient temples and halls, witnessing rapid advances in digitization technology.

"Ten years ago, we used industrial equipment originally designed for automotive manufacturing and parts processing. Scanning a single building took five to 10 days and required specific positions and lighting conditions to complete data collection," Zhang recalled.

"Today's customized laser scanners are lighter and more precise. A high-precision scan of a building can be completed in a single day, and digitizing some movable artifacts can take as little as half an hour. There has been a qualitative leap in both the efficiency and accuracy of recording," he added.

Over the past decade, the group has created millimeter-level precision digital archives covering nearly 1,500 ancient buildings, 1,200 colored sculptures, 15,000 square meters of murals and 1,200 stone tablets, forming a data pool of 2 petabytes. These records account for 85 percent of Shanxi's total digital collection of cultural relics.

The archives not only record the relics' current condition but also shift restoration from experience-based judgment to a scientific, data-driven model.

"The mechanical structure of ancient buildings is complex and cannot be measured accurately by the naked eye, experience or a ruler," Zhang said. "This technology can provide a wealth of data for relic restoration and use digital models to analyze potential risks during disassembly and reconstruction."

The group launched a digital rescue and conservation project in 2023, expanding the scope from national key cultural relics to lower-level sites and even some as yet unclassified relics.

"We held an exhibition at the Shanxi Bronze Museum in 2025, where many previously overlooked relics were displayed for the first time through this project," Zhang said. He added that presenting the relics in a digital form can attract greater public interest and more resources for cultural heritage conservation.

With an influx of young talent, the team remains energized. Li Yongxin, 26, was inspired by his older brother, who works in mural restoration, and joined the group's mural data collection team in 2023.

"An inscription at the Sanguan Temple in Yuncheng's Xinjiang county states that it is already difficult for future generations to inherit the endeavors of the past, and even harder to continue and pass them on," Li said.

His wish for the new year echoes that sentiment. Li hopes the meaningful work of relic digitization will carry forward that spirit, and that he can contribute his skills to the long-term preservation of cultural heritage.