A New Edge-Enhancement Approach Delivers Higher-Quality, More Detailed 3D Scan Visualizations

Researchers from Ritsumeikan University, Tokai University, the University of Science and Technology Beijing, Indonesia's National Research and Innovation Agency (BRIN), and the Nara National Research Institute for Cultural Properties, working with the Indonesian Heritage Agency and Shrewd Design Co., have come up with a new edge-visualization process that, they say, delivers better clarity from 3D object scanning.

"Conventional methods for extracting and visualizing 3D edges mainly concentrate on sharp edges. However, many real-world objects contain numerous soft edges in addition to sharp edges, which are inadequately represented," explains project lead Satoshi Tanaka, a professor at Ritsumeikan University, of the team's work. "Our method introduces two key innovations: dual 3D edge extraction, which separately extracts both soft and sharp edges, and opacity–color gradation, which enhances the clarity of soft edges through variations in color and opacity."

The team's edge-highlighting system is designed to improve the clarity of three-dimensional objects, which have been digitized through scanning, making the shape and structure clearer — but current approaches, the researchers say, result in too much noise around the edges of high-complexity objects, harming clarity.

To solve this, the team developed a new approach that uses dual-edge 3D edge extraction and opacity-color gradation — the first processing the sharp and soft edges of a scanned object separately with distinct feature value thresholds, and the second treating soft edges to simultaneous gradation of opacity and color. The result: soft edges have sharper and thinner lines which better show off the complexity of the object, while a "halo effect" helps to obscure background edges in order to improve depth perception. The technique is also claimed to show a benefit for sharp edges, by highlighting their silhouettes with soft edges.

"Our 3D edge extraction approach is not merely an improvement but rather an extended technique that captures areas not covered by traditional methods," Tanaka claims. "For archaeologists and historians, this tool opens new possibilities for specialized visual analysis of cultural heritage objects. For the general public, it offers a deeper understanding of historical cultural sites, serving as a technology for enhancing exhibitions in museums and art galleries."

The team's work was tested on 3D point cloud data gathered from real-world scans, showing a clear improvement in the resulting visualization over state-of-the-art alternative approaches — yet, the researchers say, took no longer to compute than conventional binary statistical edge extraction, with the opacity-color gradation applied in real time.

The team's work has been published under open-access terms in the journal Remote Sensing.