## 3 Results
### Verification of the Performance of the Improved Prototype Design
Figure 22: 3D mesh model obtained from the prototype device. (**a**) Before cropping, (**b**) after cropping. A detailed analysis of the geometric deviations between the test model and the reference model was subsequently conducted. Two surfaces were analyzed: the top surface of the calibration cube (the reference surface utilized for alignment) and the bottom surface of the reference pad (the secondary surface located outside the alignment area). The result of the deviation analysis is illustrated in Figure 23a. The deviations between the nominal and test data were quantified using statistical parameters. The analysis result, along with the displayed nominal reference model, is illustrated in Figure 23b. The range of deviations (Range) is defined as the difference between the maximum and minimum observed deviation from the nominal (reference) surface. A lower Range value means higher data consistency (lower scatter of values) and thus higher reliability and accuracy of the scanner. Conversely, a high Range value signifies the presence of more outliers or errors in the measurements, i.e., the 3D scanning is producing a wider range of values from the ideal surface. The arithmetic mean of the deviations, termed the \"mean\", can indicate a potential systematic error, given the accuracy of the nominal value and the precision of the alignment. A mean value that approaches 0 indicates that the scanner is not subject to significant systematic error, and therefore its measurements are, on average, correctly aligned and accurate. Conversely, a positive or negative mean value signifies a systematic upward (positive) or downward (negative) displacement of the scanner data, i.e., the presence of systematic error. Standard deviation (Sigma) is indicative of variability or random error in the data obtained from the device under test. A low sigma value suggests that the measured data are concentrated near the mean, which is an indicator of the accuracy and consistency of the scanner. Conversely, a high sigma value signifies greater variability in the data, suggesting higher noise or lower repeatability of the measurements. Such deviations may be indicative of technical issues, such as unstable calibration, sensor noise, or inadequate data processing. The analysis indicates that the prototype device exhibits precision, with a sigma of 0.41 mm on the bottom surface and 0.26 mm on the top surface. This finding suggests that the laser line was focused more intensely on the top surface compared to the bottom surface. It is important to note that the precision is particularly affected by the thickness of the laser line and its width of registration of the image points. It is evident that enhancing the precision of the prototype can be achieved through the utilization of a thinner laser line of superior quality, exhibiting greater consistency across varying distances. The accuracy of the device is evidenced by the measured mean values of \(-0.09\) mm on the top surface and +0.31 mm on the bottom surface. It is noteworthy that surface smoothing can enhance surface precision and reduce the sigma value. However, the systematic error of +0.31 mm  
Figure 23: Analysis of geometric deviations between the tested model and the reference model. (**a**) Result of the deviation analysis, (**b**) display of the analysis result together with the displayed nominal reference model. remains relatively low, particularly when considering the absence of external reference markers. This performance is noteworthy when benchmarked against other technologies in this category, such as ToF or Passive SfS. The values obtained through measurement and the quality of the data collected by the prototype device are significantly impacted by the selection of device parameter values. In the context of working with the prototype device, the authors have proposed default values for the measurements. However, in the context of changing the conditions of 3D digitizing, it is necessary to adjust these parameters of the digitizing process.