## 4 Discussion  
Close-range photogrammetry is used in many engineering fields. Employing it for object dimensioning and assessing displacement values requires developing and testing an appropriate strategy. In the case of small pieces, more precise control points can be set out by founding and adjusting a three-dimensional linear network on the object. Our experiment shows that the adjusted positions of the control points are determined with high accuracy of about \(\pm 1\) mm. Furthermore, such a high accuracy refers to the entire 3D photogrammetric model derived from the control points deployed directly on the examined structure. Hence, it is possible to achieve desirable measurement uncertainty related to only two images taken with the non-metric camera Canon EOS 500D.  
The proposed approach is progressive and can be freely modified to be integrated with other surveying technologies. For example, it can be utilized while dimensioning indoor spaces for the area and volume calculations. Another possibility is to use it in displacement monitoring, control measurements, or finishing works on a construction site.  
In contemporary geomatics, one of the deciding factors when choosing a particular surveying method is its availability and time consumption. In the discussed case, both conditions are successfully fulfilled. Using a non-metric, commonly used camera makes the solution low-cost. Also, data processing is not time-consuming, and the algorithm can be run on a standard computer. The application is possible for each object, where a three-dimensional linear network can be established. Such a point deployment can be possible in different ways by selecting characteristic object points (for example, its vertices and edges) or projecting light spots using a common laser emitter. The network can be measured using a tape or hand-held laser distance meter as well as, in case of lesser object availability, a standard total station offering a reflectorless distance surveying option. In such a case, however, one should count with a final accuracy lower than 1 mm.  
The limitation in using the developed method may be poor lighting conditions on the site, insufficient resolution of the camera, and the inability to cover the object with a control network. It can be mentioned that the location of network points may refer to both characteristic ends of the measured object as well as points marked using available laser projectors. These items are the subject of further research conducted by the authors.  
Conceptualization, E.O.; methodology, K.K. and E.O.; validation, K.K. and E.O.; writing--original draft preparation, K.K. All authors have read and agreed to the published version of the manuscript.  
This research received no external funding.  
Not applicable.  
The data presented in this study is available on request from the co-author [PERSON]: [EMAIL_ADDRESS].  
The authors declare that they have no conflicts of interest.  
\begin{table}
\begin{tabular}{c c c c c} \hline
**From** & **To** & **Tape Measured** & **Photogrammetric** & **Residual Value** \\
**Point** & **Point** & **Distance [m]** & **Measured Distance [m]** & **\(\sigma\) [m]** \\ \hline A & B & 0.210 & 0.210 & 0.000 \\ C & D & 0.990 & 0.989 & 0.001 \\ \hline \end{tabular}
\end{table}
Table 2: The accuracy of the photogrammetric intersection expressed as the comparison between subsequent control points measured in different methods.