## 6 Results and Discussion
This suggests that the method used to measure these surface specimens demonstrated good repeatability and reproducibility across different configurations of defects. * Configuration C1 (CVr: 1.84%, CVR: 1.43%): This defect configuration exhibited very low variability, both for measurements repeated by the same operator (CVr) and for measurements between different operators (CVR). The CVr and CVR values were close and low, indicating high consistency and repeatability, as well as reproducibility of measurements. The CVr and CVR values below 5% for this configuration indicate that the measurement method was highly precise and consistent [53; 54; 55], suggesting an accurate defect volume assessment for a defect configuration with a relatively larger volume. The measurement method proved to be reliable for assessing a relatively larger defect volume with consistent results. * Configuration C2 (CVr: 4.36%, CVR: 3.40%): Measurements repeated by the same operator (CVr) displayed slightly higher variability than in Configuration C1. However, the variability between different operators (CVR) was also slightly higher but still acceptable. Although slightly higher than for Configuration C1, the CVr and CVR values were still below 5%, indicating good precision and satisfactory repeatability and reproducibility. Consequentially, despite the smaller defect volume, the method's consistency suggests that it can reliably capture smaller defect sizes. * Configuration C3 (CVr: 3.69%, CVR: 3.84%): The results were similar to those of Configuration C2, with slightly higher variability values for measurements repeated by the same operator (CVr) and between different operators (CVR). Similarly to the previous configurations, the CVr and CVR values below 5% point to a method with high precision. The consistency of the measurements across the moderate defect volume indicate reliable performance regardless of defect size. * Configuration C4 (CVr: 1.57%, CVR: 1.06%): This configuration demonstrated variability values similar to those of Configuration C1, with high consistency in measurements  
Figure 10: (**a**) Variations in SDr and SDR; (**b**) variations in SVr and SVR as affected by various defect configurations, repeated measurements, and operators. repeated by the same operator (CVr) and between different operators (CVR). Configuration C4 stood out for its exceptional precision and consistency in measurements, showcasing CVr and CVR values that were among the lowest. The stability in the measurements suggests that the method could accurately capture larger defect volumes as well. Despite the larger defect volume, the CVr and CVR values remaining below 5% indicate a method that can handle different defect scales. In our study, all four defect configurations of the specimen surfaces exhibited very low variability in measurements. The coefficient of variation of repeatability (CVr) and the coefficient of variation of reproducibility (CVR) for each configuration were both below 5%. The small variability indicates that our measurements were consistently close to the mean value for each configuration. This indicates a high level of consistency, repeatability, and reproducibility in our measurements. The relationship between the CVr and CVR values and the theoretical defect volume showcases the robustness and adaptability of our measurement method. The fact that the CVr and CVR values were consistently below 5% across different defect volumes implies that the SDI method is not significantly influenced by the specific defect size. This consistency enhances the credibility of our results and suggests that the method can reliably assess defect volumes across a range of sizes. The combination of low CVr and CVR values with consistent measurements for various defect configurations and volumes underscores the accuracy, reliability, and versatility of our measurement method in assessing the volume of surface defects in concrete surfaces.