This work proposes a change-based segmentation method for applications to cultural heritage (CH) imaging to perform monitoring and assess changes at each surface point. It can be used as a support or component of the 3D sensors to analyze surface geometry changes. In this research, we proposed a new method to identify surface changes employing segmentation based on 3D geometrical data acquired at different time intervals. The geometrical comparison was performed by calculating point-to-point Euclidean distances for each pair of surface points between the target and source geometry models. Four other methods for local distance measurement were proposed and tested. In the segmentation method, we analyze the local histograms of the distances between the measuring points of the source and target models. Then the parameters of these histograms are determined, and predefined classes are assigned to target surface points. The proposed methodology was evaluated by considering two different case studies of restoration issues on CH surfaces and monitoring them over time. The results were presented with a colormap visualization for each category of the detected change in the analysis. The proposed segmentation method will help in the field of conservation and restoration for the documentation and quantification of geometrical surface change information. This analysis can help in decision-making for the assessment of damage and potential prevention of further damage, and the interpretation of measurement results.

The three-dimensional digitization of the cultural heritage objects during different stages of the conservation process is an important tool for objective documentation. Further data analysis is also important to monitor, estimate and understand any possible change as accurately as possible. In this work, the cultural heritage (CH) objects were selected for 3D scanning, analysis and visualisation of the change or degradation on their surface over time. The main goal of this work is to develop analysis, and visualization methods for CH object to assess local change in their surface geometry to support conservation processes documentation. The analysis was based on geometrical analysis of change in global distance between before and after chemical cleaning for a chosen object. The new local neighborhood distance histogram has been proposed as a local measure of surface change based on optimized k-neighborhood search algorithm to assess the local geometry change of a focus point.

Augmented reality is a field of presenting and visualizing the real-world problem enhanced by computergenerated algorithms. The computer-generated perceptual information becomes a premier research topic to solve various 3D problems. In this present age, it is very important to digitize the process of work and store it to keep track of the changes over time. This work is focused on storing digital documentation of the restoration of cultural heritage objects concerning the parameter of occurrences of surface geometry change on the surface of the objects. The paper shows the application of structured light techniques to the analysis of a cultural heritage object during restoration. In order to detect and visualize changes a global geometry analysis was applied and presented the outcome through a global distance histogram. The study also includes the discussion of facing possible challenges during the development of the algorithms for the change analysis.

Samples of historical terrazzo floor from the Jewish Historical Institute in Warsaw, dated back to the thirties of the twentieth century, have been analysed. Investigations by polarised optical microscopy, scanning microscopy, powder X-ray diffraction and simultaneous thermal analysis were preformed. Based on the results obtained, it was concluded that terrazzo tiles were prepared on the basis of ordinary Portland cement and aggregate, dominated with crushed stone (marble, serpentinite, limestone and marl), accompanied by sparse quartz sand grains. The binding mass was colourised with the use of pigments containing iron ions. The occurrence of altered serpentinite and marble grains, the latter clouded and partly replaced with micrite, the presence of portlandite, indicate the terrazzo tiles were subjected to thermal impact. This is related to the fire that took place at the beginning of World War II. Based on this study, repair mortars were formulated, on one hand compatible with the authentic ones, on the other retaining traces of fire.

In this paper, we propose a method for creating a ceramic Venus figurine replica from a mold in the Museum of Ceramic Techniques collection in Koło, Poland stored at the museum for many years. Moreover, none of the Venus figurines in this collection have been preserved to the present day. Our process starts with partially degraded mold fragments and ends with an actual copy of the Venus figurine in three forms: faience kilned to bisque, porcelain, and glazed faience. The entire process involves understanding old manufacturing technology, conservation supervision, and state-of-the-art 3D scanning, data processing, and 3D printing technologies. We began with a preservation state evaluation that included a technical analysis of the degradation state of the mold. Then, we applied 3D scanning technology using the structured light method. Later, we integrated all mold fragments into front and back 3D models. These 3D models were optimized for 3D printing technology and were used to manufacture the mold. Finally, the printed fragments were corrected using traditional techniques performed by art conservators. This process took comparatively less time and produced a more realistic result than would have been observed if only 3D software had been used. This process also enabled us to create educational materials for the Koło museum about old manufacturing technologies. From the point of view of museum visitors, the copies are made with sufficient detail that they are indistinguishable from handmade artifacts. Our estimates show that combining both techniques (traditional and digital) saved approximately 25% of the time that would have been used if the individual techniques had been used separately. We also believe that our use case could be transferred to a broader group of objects that use molding in their production processes.