隨著醫學進步，斷層掃描圖已廣泛應用於疾病診斷中。因此，斷層掃描的骨頭重建已成為外科手術操作程序中所必須的步驟。這篇論文提出快速Active contour(Snake)演算法去更精確地擷取內外腿骨輪廓，接著以投影的概念利用動態規劃法降低腿骨重建的時間複雜度。根據對三張待測影像圖進行二十次實驗的結果顯示我們所提出的Snake演算法，對外圈輪廓的擷取時間有11.6%的改良率，內圈輪廓則有14.7%的進步。由此可見，我們所提出的Snake演算法及基於投射概念的動態規劃演算法，能對自動化斷層掃描影像重建有顯著的加速作用。

Computer tomography (CT) has extensively been used as a tool for diseases diagnosis. Therefore, the CT image reconstruction is an important requisite for navigated surgical procedures. This paper presents a fast active contour (Snake) algorithm to retrieve the outer and inner contours of leg bone precisely. Then, the authors present a dynamic programming method (DP) with project-based strategy using the contour of leg bone to narrow down the reconstruction complexity. Based on retrieving the contours of three testing images for twenty times, experimental results demonstrate that our proposed fast Snake algorithm has 11.6% execution–time improvement ratio in average for outer contour, and 14.7% for inner contour. Our proposed fast Snake algorithm and project-based DP strategy could be used to speed up the automatic 3-D reconstruction of CT images.

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