# An Initial Dot Encoding Scheme with Significantly Improved Robustness and Numbers
## 4 Experiment and Result Analysis
### Comparative Experiment  
In order to compare the differences of the Schneider method, this paper has done some comparative experiments. The experiment will measure a three-dimensional surface of the wall of about 1000 mm \(\times\) 500 mm, using the wall scanned by the three-dimensional scanner as a real value, and simultaneously measuring the area using a 10-bit Schneider, a 12-bit Schneider and a 10-bit Initial Dot. According to the coding principle, the maximum number of codes that can be encoded by the 10-bit Schneider coding scheme is 107, and 104 kinds of experiments are used, which basically reach its maximum value. Similarly, the 12-bit Schneider uses 315 code points, which basically reaches its  
\begin{table}
\begin{tabular}{c c c} \hline
**Evaluation Parameters** & **Average Error** & **R-Square** \\ \hline  & 3.217 mm & 0.998 \\ \hline \end{tabular}
\end{table}
Table 4: The evaluation parameters of fitting result.  
Figure 9: The result of six times experiments.  
maximum value of 325. However, due to the large number of 10-bit Initial Dot encoding schemes, only 525 code points can be used in the same field of view, which is half of the maximum code value. Then, we use the following three types of marker points to perform the following steps:  
1. Paste the marker points and calibrate the parameters of the two cameras.
2. Shoot the encoding marks on the wall and decode mark points.
3. Move the camera and repeat the above two steps 4 times.
4. Complete splicing according to the repeated marks.  
Result Analysis  
After decoding and recognition of the encoding point, the results are shown in Table 5 and Figure 10. In the range of 1000 mm \(\times\) 500 mm field of view, the 10-bit Initial Dot encoding scheme can fill the entire field of view and only use 525 points, However, the 10-bit Schneider encoding scheme can only cover part of the field of view. In the same field of view, the number of 10-bit Initial Dot is the most, and the recognition is best. This experiment proves that the numbers of codes of Initial Dot are more than that of the Schneider of the same bit, and the decoding effect is better than that of the Schneider scheme under the same conditions. Then, the scatter is reconstructed in three dimensions and spliced into the same coordinate system.  
As shown in Figure 11, by fitting results of a three-dimensional scatter and scanning, the results are shown in Table 6. Since the result of the fitting is affected by the three-dimensional stitching, the more points between the coordinates, the better the fitting effect is obtained. Therefore, the number of Initial Dot encoding schemes is larger than that of the Schneider encoding scheme, the effect of three-dimensional coordinate stitching is better, and the average error is also lower. The fitting results show that the Initial Dot coding scheme is more effective than the Schneider scheme. Due to the limitations of the Schneider coded scheme, there will be duplicate points in the case of a larger field of view, which in turn will affect automatic matching. However, the Initial Dot coded scheme will hardly show a similar situation.  
Figure 10: Four experimental device diagrams.  
\begin{table}
\begin{tabular}{c c c c} \hline \hline
**Target** & **Number of Recognition** & **Total Number** & **Recognition Rate (\%)** \\ \hline
10-bit Schneider & 94 & 104 & 90.38\% \\
12-bit Schneider & 300 & 315 & 95.24\% \\
10-bit Initial Dot & 525 & 530 & 99.05\% \\ \hline \hline \end{tabular}
\end{table}
Table 5: Analysis of decoding results of 3 experiments.