在本論文的研究中，我們提出體積守恆的變形模塑(volume-preserving free-from deformation modeling) 技術應用於腹腔鏡手術模擬系統中。我們所提出的系統包括下列五個部份: 即時的物理變形模塑、體積守恆的變形、力回饋、快速的碰撞偵測、及手術動作。為了使器官快速地變形，我們提出了混合式物理變形模塑 (hybrid physical-based deformation modeling)。雖然混合式物理變形模塑提供了快速和物理的變形，但變形後的體積並不守恆。因此我們結合了體積守恆變形模塑技術到混合式變形模塑中，使得變形後的體積能夠守恆，而有更逼真的視覺效果。為了在不同效能的電腦上都能有即時的變形效果，使用者可以藉由調整體積守恆的參數來達到即時的變形效果。

In this paper, we propose a volume-preserving free-form deformation modeling technology for a laparoscopic surgery simulation system. The proposed system consists of five components: (i) real-time deformation, (ii) volume-preserving deformation, (iii) efficient collision detection, (iv) force feedback, and (v) surgical operations. In real-time deformation, the proposed hybrid physical-based deformation modeling technique (HPDM) was used to simulate the deformation of human organs. The HPDM exhibits high speed and physical deformation without preserving the volume of a model. The volume-preserving free-form deformation modeling technique was associated with the HPDM to preserve the volume of the deformed model for realistic visualization. To fit a real-time deformation on different-performance computation platforms, a user can adjust the parameters of volume-preserving free-form deformation.

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