Automatic Recognition and Digital Documentation of Cultural Heritage Hemispherical Domes using Images

TL;DR

This paper introduces a novel, fast, and reliable method for digitally documenting hemispherical domes in cultural heritage sites using only two images, significantly reducing processing time and maintaining high accuracy.

Contribution

The paper presents a new automatic framework based on closed-form relationships between spheres and ellipses, enabling efficient digital modeling from minimal image data.

Findings

Achieved 6mm modeling accuracy.

Reduced computation time by a factor of 7.

Validated effectiveness on both laboratory and real-world datasets.

Abstract

Advancements in optical metrology has enabled documentation of dense 3D point clouds of cultural heritage sites. For large scale and continuous digital documentation, processing of dense 3D point clouds becomes computationally cumbersome, and often requires additional hardware for data management, increasing the time cost, and complexity of projects. To this end, this manuscript presents an original approach to generate fast and reliable semantic digital models of heritage hemispherical domes using only two images. New closed formulations were derived to establish the relationships between spheres and their projected ellipses onto images, which fostered the development of a new automatic framework for as-built generation of spheres. The effectiveness of the proposed method was evaluated under both laboratory and real-world datasets. The results revealed that the proposed method achieved as-built modeling accuracy of around 6mm, while improving the computation time by a factor of 7, when compared to established point cloud processing methods.