## 2 Global Registration Method Based on the OBB Regional Area-Based Descriptor
### Principle Concept and Flow Chart Diagram of the Global Registration Method
\begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Models** & **Method** & **Translation Error (mm)** & **Rotation Error (rad)** & **Time (s)** \\ \hline \multirow{4}{*}{Brazo} & Spin Images (SI) & 5.893 & 0.074 & 6.762 \\  & Point Signatures (PS) & 3.642 & 0.056 & 103.433 \\  & PFH & 4.543 & 0.047 & 43.232 \\  & SHOT & 2.632 & 0.053 & 5.432 \\  & Proposed & 1.371 & 0.017 & 13.543 \\ \hline \multirow{4}{*}{Connector} & Spin Images (SI) & 7.443 & 0.093 & 8.342 \\  & Point Signatures (PS) & 5.378 & 0.053 & 123.533 \\  & PFH & 6.313 & 0.077 & 48.436 \\  & SHOT & 3.472 & 0.023 & 7.922 \\  & Proposed & 1.174 & 0.014 & 17.468 \\ \hline \multirow{4}{*}{Cylinder} & Spin Images (SI) & 6.421 & 1.235 & 9.672 \\  & Point Signatures (PS) & 8.432 & 2.348 & 103.573 \\  & PFH & 3.445 & 1.764 & 34.562 \\  & SHOT & 5.472 & 0.973 & 4.358 \\  & Proposed & 1.421 & 0.013 & 12.667 \\ \hline \multirow{4}{*}{Socket} & Spin Images (SI) & 9.243 & 2.645 & 9.457 \\  & Point Signatures (PS) & 9.831 & 2.569 & 103.376 \\ \cline{1-1}  & PFH & 5.219 & 1.323 & 52.436 \\ \cline{1-1}  & SHOT & 4.642 & 1.873 & 5.782 \\ \cline{1-1}  & Proposed & 1.684 & 0.015 & 13.578 \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Experimental results using synthetic data obtained by the proposed method and local feature descriptor methods. \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Points** & **Gaussian Noise (\(\sigma\))** & **Translation Error (mm)** & **Rotation Error (rad)** & **Time (s)** \\ \hline \multirow{4}{*}{6000} & 0.01 & 1.339 & 0.018 & 20.862 \\  & 0.02 & 1.481 & 0.019 & 20.277 \\ \cline{1-1}  & 0.03 & 1.585 & 0.021 & 20.839 \\ \hline \hline \end{tabular}
\end{table} 
Table 5: Experimental results using the connector model obtained by the proposed coarse registration method with different levels of Gaussian noise. The registration error can be controlled within a few tens of micrometers in one standard deviation for an object size reaching 100 millimeters. The authors would like to convey their appreciation for grant support from the Ministry of Science and Technology (MOST) of Taiwan under its grant with reference number MOST 103-2218-E-001-027-MY2. The appreciation is also conveyed to the Industrial Technology Research Institute (ITRI) for providing some testing samples. [PERSON] is the chief research project coordinator which is in charge of the research management and establishment as well as forming the concept of the methodology; [PERSON] is a PhD student responsible of the major development of the system and optimization of the method. [PERSON] assists the research and student supervision for the research project while [PERSON] contributes the method of the regional area-based surface descriptor to the development. The authors declare no conflict of interest. ## References

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