3D Documentation of Cultural Heritage Obtained by the Use of Point Clouds: The Case Study of Molla Hüsrev Mosque

Abstract. The correct documentation of the structure of cultural heritage is necessary for its conservation, restoration, and 3D analysis. This paper explores the use of professional Terrestrial Laser Scanning (TLS) and iPad Pro LiDAR sensors to create accurate three-dimensional models for documenting cultural heritage sites. The case study was conducted on the Molla Hüsrev Mosque in Istanbul, which dates back to the 15th century and is an Ottoman structure. The TLS scans were performed using the Leica P40 scanner, while the iPad Pro LiDAR scans were conducted using the SiteScape app. The two datasets were registered using the Iterative Closest Point (ICP) algorithm, which achieved an accuracy of 0.007 m. The ICP algorithm was also used to determine registration accuracy in complex buildings, and recommendations for improving accuracy in such buildings are discussed in the paper. The results showed that the TLS system achieved high geometric accuracy and high resolution (0.029 m RMS). The iPad Pro LiDAR system improved the completeness of surface reconstruction on complex surfaces. The fusion of the two datasets produced a denser, more complete dataset of the mosque. The paper's results show that while the iPad Pro LiDAR system is less accurate than the TLS system, its portability and high frame rate make it an ideal supporting tool for multi-sensor approaches. The fusion of the two datasets saves time and operational costs in the field while preserving spatial consistency. The paper demonstrates the growing use of consumer-grade LiDAR sensors in digital heritage documentation and presents an approach that scales up support for both consumer and professional sensors.