## 4 Results and Discussion
### Results of Camera's Positioning Accuracy and Precision in the X and Y Directions  
The results of the experiment to discuss the accuracy of the two approaches for producing pictures resembling the reference picture regarding the X and Y directions are presented in Table 1 and are explained as follows:  
**Accuracy in the X direction** The results of the experiment regarding accuracy (i.e., producing pictures resembling the reference picture) showed that when the images were captured with the assistance of positioning sensors, they more accurately resembled the reference picture. In other words, when the participants did not use the sensors during the first task, the average error, in terms of accuracy in the X direction, was (30 cm), but when they used the sensors during the second task, the average error decreased to (0.3 cm). **Accuracy in the Y direction** The same situation occurred in the Y direction. In the Y direction, which reflected scaling, the average accuracy error decreased from (33 cm) to (6.8 cm) when the participants used a positioning sensor during the second task. So far, this sensor-based approach could produce more accurate results than the non-sensor-based approach by reducing image transformation in both X and Y directions. The results of the experiment to discuss the precision of two approaches in producing pictures resembling each other regarding the X and Y directions are explained as follows: \begin{table}
\begin{tabular}{c c c c c} \hline \hline \multirow{2}{*}{**Type of Image**} & \multicolumn{2}{c}{**The Distance between the**} & \multirow{2}{*}{**In the X Direction**} & \multirow{2}{*}{**In the Y Direction**} & \multirow{2}{*}{**In the Z Direction**} \\  & **Center of Lens and Center of the** & & **(cm)** & **(cm)** & **(cm)** \\ \cline{2-5}  & **Fixed Point on Scene** & & & \\ \hline Reference & & 44.71 & 330.5 & N/A \\ image & Avg. & 14.7 & 297 & N/A \\  & Min. & 0 & 154 & N/A \\ Group 1 & Max. & 77 & 582 & N/A \\ (without sensor) & Precision Error (SD) & 15.5 & 112 & N/A \\  & Accuracy Error & 30 & 33 & N/A \\  & Range & 77 & 428 & N/A \\  & Avg. & 45 & 337 & N/A \\  & Min. & 11 & 312 & N/A \\ Group 2 & Max. & 101 & 366 & N/A \\ (with sensor) & Precision Error (SD) & 21 & 13.3 & N/A \\  & Accuracy Error & 0.3 & 6.8 & N/A \\  & Range & 90 & 54 & N/A \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Comparison between accuracy and precision of the two approaches regarding linear transformation. Figure 18: How to measure the length of horizontal sides. (**a**) If horizontal sides are parallel; (**b**) If horizontal sides are not parallel. Precision in the X directionThe results regarding precision (i.e., producing pictures resembling each other) in the X direction showed an exciting result. In this direction, precision decreased when the participants used the sensor-based approach. In other words, the pictures captured during the first task without sensors had less standard deviation (15.5 cm) as compared with those that were captured during the second task (21 cm). This result indicates that when the participants wanted to take pictures from the scene without sensors, based on their common sense, they selected locations in the X direction that better resembled the reference image (the X direction was parallel to the scene). Therefore, the degree of repeatability increased. In contrast, since the sensors inherently generated error, the participants were navigated to the locations in the X direction that were less close to each other. The results are shown in Table 1.  
Precision in the Y directionThe results of the experiment regarding precision determined when the images were captured with the assistance of positioning sensors showed that they were more precise in the Y direction. In other words, when participants used the sensors during the second task, the standard deviation in the Y direction decreased (from 112 cm to 13.3 cm).