Rapid and Accurate Production of 3D Point Cloud via Latest-Generation Sensors in the Field of Cultural Heritage: A Comparison between SLAM and Spherical Videogrammetry

The manuscript intends to describe different methodologies for the acquisition, data processing, and identification of strategies aimed at improving the quality of 3D point cloud production using latest-generation sensors in the field of cultural heritage surveying. The point clouds taken into consideration were acquired by passive and active sensors on the Buzias site, an important historical and architectural structure in Romania. In particular, a spherical camera (Ricoh Theta Z1) was used in order to obtain a video; subsequently, starting from the video, more datasets were extracted and processed in a photogrammetric software based on Structure from Motion and Multi View Stereo algorithms. In addition, a Simultaneous Localization And Mapping (SLAM) sensor (ZEB Revo RT) was used in order to generate a point cloud. The different point clouds produced were compared with the data obtained through a Terrestrial Laser Scanner (TLS) survey. Statistical analyses were carried out to check and validate the results obtained from the comparison between the different techniques and data acquisition methods. The statistical analysis showed that the model obtained with the GeoSLAM was metrically more accurate and detailed than the point cloud generated by the videogrammetric processing highlighted in this study. The paper also analyzes the performance of the three different sensors used, including parameters such as acquisition (timing and ease of use), processing (timing and ease of use), results (accuracy, resolution, and chromatic quality), and costs (instrumental and operator).