## 3 Materials and Methods
### Acquisition and Data Processing  
Data acquisition was carried out during the first Scientific Expedition of the Lublin University of Technology to Central Asia in 2017 [41] and the University's fifth such expedition in 2021 [40] to museums in Uzbekistan where both objects were exhibited. The main problem of the 3D digitisation of objects was to build an appropriate place to scan using available furniture, providing access to power for the devices used, relatively good lighting for the artefacts and their safe extraction from showcases, which typically came from the end of the 20 th century and were not adapted to opening. Hand-held 3D scanners working with structured light technology were used to scan the objects. In the case of the jug, the Artec Spieder scanner was used, and for the digitisation of the mug, the Artec Eva. Both scanners allow for relatively fast execution of precise measurements in high resolution and, importantly, do not require sticking positioning markers on the digitised object, which is particularly important when scanning museum objects in in situ conditions. The used structured light is safe for the user and non-invasive for museum artefacts [10; 42]. The basic data of these scanners are presented in Table 1. \begin{table}
\begin{tabular}{c c c} \hline \hline
**Parameters** & **Artec Eva** & **Artec Spider** \\ \hline Texture capture capability & Yes & Yes \\ Scanning technology & Structured white light & Flashing light bulb, blue light (no laser) \\
3D resolution, max. & 0.5 mm & 0.1 mm \\
3D point accuracy, up to & 0.1 mm & 0.05 mm \\ Linear field of view & 214 \(\times\) 148 mm & 90 \(\times\) 70 mm \\ Height \(\times\) Width & Up to 536 \(\times\) 371 mm & up 180 \(\times\) 140 mm \\ Scanner distance from object & 0.4–1 m & 0.17–0.35 m \\ Video frames, up to & 16 fps & 7.5 fps \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Comparison of the basic parameters of scanners Artec Eva and Artec Spider. Figure 3: View of objects for digitisation: (**a**) mug; (**b**) jug; (**c**) work with the Artec Spider scanner. The scanning of the objects in Figure 3 was carried out in in situ conditions. For data acquisition during scanning, a software dedicated to the Artec Studio Professional scanner and a laptop with a 4-core Intel Core i5 processor and 16 GB of RAM were used. Eight scans were made for the jug-type object. This allowed for the precise acquisition of data about the facility. The data file in the form of a point cloud was approx. 5 GB in size. Six scans were taken for the mug and a 1.35 GB file was obtained. The processing of the obtained data was carried out according to the procedure presented in Figure 4. The same software as for data acquisition was used--Artec Studio Professional, as seen in Figure 4b-d. Processing was carried out using a desktop computer with an Intel Core i7 processor, 48 GB of RAM and an NVIDIA Quadro K2200 graphics card with built-in 4 GB GDDR5 memory. The use of equipment with high computing power allowed for efficient data processing activities. As a result, mesh digital 3D models with the texture applied were obtained (Figure 4c-f). The models were exported as files in the.obj format, and textures as.jpg files. The sizes of the obtained files after optimisation were as follows: for the mug model--9.65 MB, for the jug--12.7 MB. During the data processing, the following stages were followed:  
1. Registration 1--fine registration, introduction of single scans stored in local coordinate systems;