在山巒連綿不斷的台灣，為方便互通往來，隧道是不可或缺的基礎建設，其穩固與否與人民安全息息相關，隧道的定期檢測時，隧道襯砌的狀況必須被評估，以維護其安全性與功能性，而雷射掃描取得隧道點雲是得以快速探討完整襯砌變形之有效方法。
由於單次雷射掃描無法覆蓋整個隧道場景，必須進行多次分段地掃描並將不同測站掃描之點雲套合至同坐標系，從而得出完整的隧道點雲以進行後續的分析應用。傳統隧道雷射掃描會在隧道中佈設共軛球或控制點，以方便點雲的套合。然而，佈設控制點是耗工費時的任務。
本研究經文獻回顧與實作評估多個套合方法，以期能在無控制點的情況下完成隧道雷射掃描之點雲套合。透過模擬點雲資料對套合方法進行測試及評估，挑選出最適合用於隧道點雲套合的方法，並分析不同的隧道場景和參數對點雲套合的影響。在本研究中，我們成功省去尋找控制點步驟，實現無控制點的點雲套合。

In the continuous mountainous terrain of Taiwan, tunnels are indispensable infrastructure for facilitating mutual transportation. Their stability is closely tied to public safety. During regular inspections, the condition of tunnel linings must be assessed to maintain their safety and functionality. Laser scanning has proven to be a rapid and effective method for acquiring tunnel point clouds, enabling a comprehensive exploration of lining deformations..
Since a single laser scan is unable to cover the entire tunnel scene, it is necessary to perform multiple segmented scans. The point clouds obtained from different stations must then be registered to the same coordinate system to generate a complete tunnel point cloud for subsequent analytical applications. Traditional tunnel laser scanning involves deploying conjugate spheres or control points within the tunnel to facilitate point cloud registration. However, the placement of control points is a labor-intensive and time-consuming task.
This study conducts a literature review and practical evaluations of various registration methods, aiming to achieve point cloud registration in tunnel laser scanning without the need for control points. Through simulations using point cloud data, different registration methods are tested and assessed to identify the most suitable approach for tunnel point cloud registration. The research also analyzes the impact of different tunnel scenarios and parameters on point cloud registration. In this study, we successfully eliminate the step of searching for control points, achieving point cloud registration without the use of control points.

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