本文選題：局部模型 + 無網(wǎng)格伽遼金法��； 參考：《哈爾濱工程大學(xué)》2012年博士論文

【摘要】：傳統(tǒng)手術(shù)訓(xùn)練使用人類的尸體、動物或橡膠人體模型作為訓(xùn)練對象，存在著尸源短缺、成本昂貴、與真實人體組織特性差別較大及迫害動物等諸多局限和問題，計算機技術(shù)的迅速發(fā)展使得數(shù)值模擬技術(shù)逐漸成為解決此類問題的重要手段，研究人員開始探索將虛擬現(xiàn)實技術(shù)應(yīng)用于醫(yī)護人員的外科手術(shù)培訓(xùn)中，通過建立集成有視覺顯示、力覺再現(xiàn)、聽覺、嗅覺等多感知的虛擬手術(shù)環(huán)境，給予醫(yī)生逼真的手術(shù)場景，實現(xiàn)手術(shù)培訓(xùn)教學(xué)、術(shù)前規(guī)劃、術(shù)中輔助支持、術(shù)后分析、復(fù)雜手術(shù)的反復(fù)演練等全面訓(xùn)練醫(yī)護人員的目的。虛擬現(xiàn)實技術(shù)與現(xiàn)代醫(yī)學(xué)的結(jié)合為高科技醫(yī)學(xué)技術(shù)的發(fā)展提供了廣闊的空間，也使得虛擬現(xiàn)實技術(shù)面臨一個嶄新而艱巨的挑戰(zhàn)。 在實際手術(shù)中，醫(yī)生主要依靠視覺與觸覺反饋信息進行手術(shù)操作，因此虛擬手術(shù)系統(tǒng)大都是針對視覺與觸覺兩大方面的仿真研究，通過視覺反饋直觀地呈現(xiàn)出逼真的虛擬手術(shù)場景及操作對象，利用觸覺反饋感受虛擬環(huán)境中力的作用并對操作作出及時、正確的判斷。本文也是從視覺與觸覺反饋兩方面出發(fā)，選擇典型的且難度較大的人體軟組織器官作為研究對象，緊緊圍繞虛擬手術(shù)中具有代表性的形變與切割兩項關(guān)鍵技術(shù)展開深入的研究，主要工作如下： 首先，針對圖像的手動分割工作量大及自動分割精度不高的問題，提出了將手動分割與自動分割相結(jié)合的醫(yī)學(xué)圖像分割方式，重建了具有人體解剖結(jié)構(gòu)特征的胃組織及肝臟組織的幾何模型，并對其進行視覺渲染與紋理映射，從而得到了真實度較高的人體軟組織模型；對力反饋技術(shù)及反饋力的計算與測試方法進行了研究，提出了基于PVDF（Polyvinylidene Fluoride，聚偏二氟乙烯）壓電薄膜傳感器的反饋力測試方法，并應(yīng)用于軟組織形變與切割模擬中反饋力的測試上。 其次，針對醫(yī)學(xué)觸診的特點及現(xiàn)有形變仿真建模方法的不足，提出了可變區(qū)域的局部質(zhì)點-彈簧/阻尼器（ALMSDM）模型，該模型具有位置可變及區(qū)域可擴展的優(yōu)點，改善了以往文獻中局部建模方法區(qū)域限定及全局的面模型形變恢復(fù)能力差的問題，并在虛擬軟組織面模型與體模型中得到了較好的應(yīng)用。從系統(tǒng)實時性的角度，針對ALMSDM在面模型與體模型中的應(yīng)用，分別提出了頂點法向量的局部更新思想與預(yù)計算策略，使系統(tǒng)的實時性得到了較大的改善。從形變恢復(fù)能力、反饋力分析及實時性評測三方面對面模型與體模型的ALMSDM進行了評價，進而驗證所提算法的可行性與通用性。 再次，創(chuàng)新性地將無網(wǎng)格法理論應(yīng)用于虛擬手術(shù)的形變建模中，在對質(zhì)點積分無網(wǎng)格伽遼金法進行深入研究的基礎(chǔ)上，針對虛擬軟組織形變多為大變形的特點，提出了一種改進的質(zhì)點積分無網(wǎng)格伽遼金法，并采用二維梁理論對所建模型進行了理論驗證；然后基于改進算法建立了虛擬軟組織形變仿真的靜態(tài)模型與動態(tài)模型，在靜態(tài)模型仿真中采用靜態(tài)位移累加的方式實現(xiàn)了動態(tài)形變過程的模擬，與動態(tài)模型相比，其速度很快，但由于缺少中間連續(xù)變化的過程使得該模型計算精度不高；動態(tài)模型的形變仿真計算量相對較大，，本文綜合考慮了動態(tài)模型的特點及虛擬手術(shù)實時性能的要求對模型進行了近似求解。仿真實驗與對比分析表明，無網(wǎng)格法在軟組織形變仿真中表現(xiàn)出良好的穩(wěn)定性和可靠性，避免了基于網(wǎng)格建模方法在模擬大形變時容易出現(xiàn)網(wǎng)格扭曲、鎖死等問題，解決了虛擬軟組織大變形時誤差大的問題；最后采用PVDF傳感器對動態(tài)模型的實際反饋力進行測試，并與反饋力模型計算得到的數(shù)據(jù)進行對比分析。 本文最后對虛擬手術(shù)切割算法進行了研究，針對現(xiàn)有切割算法存在的問題，提出了切口邊界獨立繪制的方案，即切口邊界的繪制不再依賴于網(wǎng)格破裂后的拓?fù)渲亟M；結(jié)合切口的特點及樣條方法的優(yōu)越性質(zhì)，提出新穎的基于Bézier曲線的切口再現(xiàn)算法，解決了切口繪制不光滑的問題；通過在區(qū)域邊界點與Bézier曲線之間直接添加彈簧約束的方式，使模型能夠靈活、真實地控制切口的張裂度，實現(xiàn)了切口彈性張開的逼真效果；對切割操作中含摩擦力與不含摩擦力的計算模型進行了理論與實測的對比分析，并設(shè)計了手術(shù)切割后摘除異物的仿真實驗。
[Abstract]:The traditional surgical training uses human body, animal or rubber body model as the training object. There is a shortage of corpse sources, high cost, large difference with the real human tissue characteristics and the persecution of animals and other limitations and problems. The rapid development of computer technology makes the numerical simulation technology gradually become an important means to solve such problems. The researchers began to explore the application of virtual reality to the training of medical and nursing personnel. By establishing a virtual operating environment integrated with visual display, reappearance of force, hearing, smell and so on, a realistic operation scene was given to the doctor, the training teaching, pre operation planning, auxiliary support, postoperative analysis, and complex hands were carried out. With repeated drills and other comprehensive training medical personnel. Combined with virtual reality technology and modern medicine has provided a broad space for the development of high-tech medical technology, virtual reality technology has faced a new challenge.
In the actual operation, the doctor mainly relies on the visual and tactile feedback information to operate the operation, so the virtual operation system is mostly aimed at the two aspects of the visual and tactile simulation. The virtual operation scene and the operating object are presented intuitively through the visual feedback, and the effect of the force in the virtual environment is felt by the tactile feedback. From the two aspects of visual and tactile feedback, this paper also selects typical and difficult human soft tissue organs as the research object, and focuses on two key technologies of representative deformation and cutting in virtual surgery. The main work is as follows:
First, in view of the problem of manual segmentation and low automatic segmentation accuracy, a medical image segmentation method, which combines manual segmentation and automatic segmentation, is proposed. The geometric model of gastric tissue and liver tissue with human anatomical features is reconstructed, and the visual rendering and texture mapping are carried out. The human soft tissue model with high authenticity is studied and the calculation and test method of force feedback technology and feedback force are studied. The feedback force testing method based on PVDF (Polyvinylidene Fluoride, polyvinylidene fluoride) piezoelectric thin film sensor is put forward and applied to the test of feedback force in soft tissue shape change and cutting simulation.
Secondly, in view of the characteristics of medical palpation and the shortage of existing deformation simulation modeling methods, a local particle spring / damper (ALMSDM) model with variable regions has been proposed. The model has the advantages of variable location and region extensibility, which improves the poor recovery ability of regional model and the global surface model in the previous literature. The problem is better applied in the virtual soft tissue surface model and the body model. From the point of view of the real time of the system, in view of the application of ALMSDM in the surface model and the body model, the local updating idea and the Precalculation strategy of the vertex normal vector are put forward respectively, so that the real-time performance of the system has been greatly improved. From the deformation recovery ability and feedback, the feedback of the system is greatly improved. The three aspects of force analysis and real-time evaluation are evaluated on the ALMSDM of the face model and the body model, and the feasibility and versatility of the algorithm are verified.
Thirdly, the theory of meshless method is applied to the deformation modeling of virtual surgery. On the basis of the deep study of the meshless Galerkin method, a modified particle integral meshless Galerkin method is proposed in view of the characteristics of the large deformation of virtual soft tissue, and the two dimensional beam theory is used to build the model. The static model and dynamic model of the virtual soft tissue deformation simulation are established based on the improved algorithm, and the dynamic deformation process is simulated by the static displacement accumulation in the static model simulation. Compared with the dynamic model, the speed is very fast, but the process of lack of continuous change in the middle is very fast. The accuracy of the model calculation is not high, and the calculation of the dynamic model is relatively large. In this paper, the characteristics of the dynamic model and the requirements of the real time performance of the virtual operation are considered. The simulation experiment and the comparison analysis show that the meshless method shows good stability and reliability in the soft tissue deformation simulation. It avoids the problem of grid distortion and locking, which can solve the problem of large error in the large deformation of virtual soft tissue. Finally, the PVDF sensor is used to test the actual feedback force of the dynamic model, and the data obtained by the feedback force model are compared and analyzed.
At the end of this paper, the virtual surgical cutting algorithm is studied. In view of the existing problems of the existing cutting algorithms, a scheme for the independent rendering of the incision boundary is proposed. That is, the drawing of the incision boundary is no longer dependent on the topology reorganization after the mesh breaking, and a novel B e zier curve based on the characteristics of the incision and the superiority of the spline method is proposed. The algorithm of incision reappearance solves the problem of unsmoothness in cutting the cut. By adding a spring constraint directly between the boundary point of the region and the B e zier curve, the model can be flexibly and truly control the crack extension of the incision, and the realistic effect of the elastic opening of the incision is realized, and the calculation of the friction and non friction force in the cutting operation is made. The model is compared with theoretical analysis and field measurement, and the simulation experiment of removing foreign body after surgical incision is designed.
【學(xué)位授予單位】：哈爾濱工程大學(xué)
【學(xué)位級別】：博士
【學(xué)位授予年份】：2012
【分類號】：R318.6;TP391.9

【參考文獻】

相關(guān)期刊論文 前10條

1 高宏建;吳水才;任新穎;劉有軍;;利用Amira進行肝臟及其管道系統(tǒng)的三維重建[J];北京生物醫(yī)學(xué)工程;2006年05期

2 吳涓,宋愛國,李建清;一種基于物理意義的快速力反饋形變模型及實時力覺響應(yīng)算法[J];傳感技術(shù)學(xué)報;2005年01期

3 付宜利;樸明波;王樹國;;微創(chuàng)膽囊手術(shù)中膽囊管路松弛狀態(tài)的仿真研究[J];大連海事大學(xué)學(xué)報;2009年01期

4 張小瑞;宋愛國;孫偉;李建清;;支持力/觸覺反饋的虛擬肝臟手術(shù)仿真系統(tǒng)[J];東南大學(xué)學(xué)報(自然科學(xué)版);2009年03期

5 張紹祥,王平安,劉正津,譚立文,邱明國,李七渝,李愷,崔高宇,郭燕麗,劉光久,單錦露,劉繼軍,張偉國,陳金華,王健,陳偉,陸明,游箭,龐學(xué)利,肖紅,謝永明,許忠信,王欲u&,鄧俊輝,唐澤圣;首套中國男、女?dāng)?shù)字化可視人體結(jié)構(gòu)數(shù)據(jù)的可視化研究[J];第三軍醫(yī)大學(xué)學(xué)報;2003年07期

6 郭燕麗,張紹祥,劉正津,譚立文,邱明國,李七渝,崔高宇,李愷,楊曉萍,張偉國,陳現(xiàn)紅,陳偉,陸明,王欲u&,鄧俊輝,唐澤圣;首例中國可視化人體心臟三維重建及臨床意義[J];第三軍醫(yī)大學(xué)學(xué)報;2003年07期

7 邱明國,張紹祥,劉正津,譚立文,王欲u&,鄧俊輝,唐澤圣;耳三維重建及虛擬內(nèi)窺鏡[J];第三軍醫(yī)大學(xué)學(xué)報;2003年07期

8 周小平,周瑞忠;無單元法研究現(xiàn)狀及展望[J];工程力學(xué);2005年01期

9 溫維亮;郭新宇;陸聲鏈;趙春江;;隱式曲面在三維植物建模中的應(yīng)用研究綜述[J];工程圖學(xué)學(xué)報;2010年03期

10 熊岳山;徐凱;王彥臻;譚珂;郭光友;;虛擬膝關(guān)節(jié)鏡手術(shù)仿真系統(tǒng)的關(guān)鍵技術(shù)研究[J];國防科技大學(xué)學(xué)報;2007年01期

相關(guān)重要報紙文章 前1條

1 通訊員 高翔　黃偉;[N];長江日報;2010年

相關(guān)博士學(xué)位論文 前10條

1 徐少平;虛擬手術(shù)仿真中軟組織實時形變模型的研究[D];南昌大學(xué);2010年

2 王征;虛擬手術(shù)中的軟組織形變仿真算法研究[D];東南大學(xué);2006年

3 楊文珍;虛擬手交互真實力覺生成研究[D];浙江大學(xué);2007年

4 謝杰鎮(zhèn);國人虛擬眼角膜建模與仿真研究[D];廈門大學(xué);2007年

5 宋超;基于物理的彈性變形模擬技術(shù)研究[D];浙江大學(xué);2008年

6 廖勝輝;醫(yī)學(xué)三維模型重建和體網(wǎng)格生成與變形研究[D];浙江大學(xué);2008年

7 鮑春波;生物軟組織建模仿真方法研究[D];大連理工大學(xué);2008年

8 林科燦;肝臟三維重建及虛擬肝臟手術(shù)規(guī)劃臨床應(yīng)用的研究[D];福建醫(yī)科大學(xué);2008年

9 戴培山;虛擬眼組織三維建模與仿真關(guān)鍵技術(shù)研究[D];中南大學(xué);2007年

10 趙云亮;無網(wǎng)格法基函數(shù)的改進與應(yīng)用[D];吉林大學(xué);2008年

相關(guān)碩士學(xué)位論文 前3條

1 黃朝琴;無網(wǎng)格法理論與應(yīng)用研究[D];中國石油大學(xué);2007年

2 石玉穎;基于力反饋的形變建模及虛擬柔體變形技術(shù)[D];天津大學(xué);2007年

3 黃雷;虛擬手術(shù)訓(xùn)練系統(tǒng)中手術(shù)場景的模擬及系統(tǒng)集成[D];上海交通大學(xué);2010年

本文編號：2045498