使用圓柱形標誌之體內光學追蹤應用於微創手術

Abstract

目標：本論文致力於建立一套使用圓柱形標誌的體內光學追蹤系統，用於微創手術。目標是對於待追蹤物進行空間中的定位、追蹤，得知其空間位置後，可用於其他應用，像是擴增實境與危險警告。 方法：基於在2013年提出的體內光學追蹤系統下，改變標誌的形狀，由方形改為圓柱形。因原本的系統需將一個長方形的模具固定於待追蹤物上，再將方形標誌黏貼於模具上，然而，在手術中，此長方形模具接觸到組織時，模具上的銳角可能會對組織造成不必要的傷害。而本論文提出的圓柱形標記是黏貼於圓柱形的模具上，因此不會有銳角對組織造成傷害的疑慮。由於使用圓柱形標誌進行定位是一個新穎的想法，本論文也提出一個特定的演算法對圓柱形標誌進行標誌偵測。 結果：實驗證明，在75到150毫米的觀察距離內，此系統的平均定位誤差為2.7毫米，小於在微創手術中最大的安全距離上限：20毫米。 結論：在本論文中提出的使用圓柱形標誌之光學追蹤系統可以完成在微創手術中的定位任務。此系統有三項優點：減少對組織不必要的傷害、可以進入更小的套孔，並且保留了體內光學定位系統的優點，包括較短的量測距離及更簡單的座標系統以減少座標轉換的誤差。

Objectives: The aim of this thesis is to create an intracorporeal optical tracking system using cylindrical marker for minimally invasive surgery. The main function is to localize and to track the tracked objects, providing positions of the tracked objects, which can be used in other applications, like augmented reality and risk warning. Methods: Based on the intracorporeal optical tracking system proposed in 2013, shape of marker is improved from square to cylinder. In original system, it’s necessary to attach a rectangular module rigidly to the tracked object. And the square marker can be affixed to the rectangular module. However, sharp edges of the rectangular module may give rise to unnecessary damages to tissues when it touches tissues in surgery. The cylindrical marker is affixed to a cylindrical module with no sharp edges. Hence, it can reduce unnecessary damages to tissues. Because using cylindrical marker to achieve tracking work is a novel idea, a specific algorithm to detect cylindrical marker is proposed in this thesis. Results: The experiments shows that the mean error of tracking accuracy of the proposed system is 2.7 mm in observation distance from 75 to 150 mm, which is less than the maximal safe distance: 20 mm in minimally invasive surgery. Conclusions: The novel optical tracking system proposed in this thesis using cylindrical marker can achieve tracking work for minimally invasive surgery. The system has three advantages: reducing unnecessary damages to tissues, feasibility to penetrate smaller trocar, and preserving advantages of intracorporeal optical tracking system, including shorter observation distance and simpler coordinate system to reduce errors caused by coordinate transformation.