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  本文關鍵詞：基于移動最小二乘的二維形狀變形和形狀插值控制　出處：《浙江工商大學》2014年碩士論文　論文類型：學位論文

  更多相關文章： 形狀變形 移動最小二乘 形狀插值 插值控制

【摘要】：計算機動畫是一種利用人眼視覺暫留效應原理,通過連續(xù)播放一系列靜止的圖畫,讓人在視覺上產(chǎn)生景物運動錯覺的技術。它是計算機圖形學與藝術相結合的產(chǎn)物,目前廣泛應用于影視特技制作、建筑裝潢設計、商業(yè)廣告等領域。 二維形狀變形和二維形狀插值是計算機動畫中的重要技術。在二維形狀變形技術中,研究人員最近提出了一種基于移動最小二乘的變形方法。該方法允許用戶通過點和線來實時操作二維角色,并且能夠生成光滑且視覺真實的角色變形結果。但是,該方法采用歐氏距離作為變形約束權值,而沒有考慮角色形狀的拓撲結構,導致可能產(chǎn)生扭曲的變形結果。在二維形狀插值技術中,保剛性插值算法能夠產(chǎn)生比較自然的形狀過渡效果。但是,在這類方法中,形狀的中間過渡序列一般完全由源和目標形狀決定,而缺乏有效手段讓用戶可以控制中間過渡序列的產(chǎn)生。 針對上述問題,分別提出了一種考慮拓撲結構的移動最小二乘卡通角色變形方法和一種基于移動最小二乘的形狀插值控制方法。主要內(nèi)容包括： (1)提出了一種考慮拓撲結構的移動最小二乘卡通角色變形方法。首先,基于用戶的交互約束配置,在角色形狀上最小化拉普拉斯能量函數(shù),得到一組權值,我們稱該組權值為“調(diào)和權值”。然后,以調(diào)和權值作為變形約束權值,對卡通角色進行移動最小二乘變形。由于“調(diào)和權值”考慮了形狀的拓撲結構并且以一種局部擴散的方式傳播了用戶交互約束的變形影響,最終有效避免了可能的變形扭曲。此外,設計了一種保面積的移動最小二乘變形方法,適用于不可壓縮角色物體的變形。實驗結果表明,新方法有效避免了可能的形狀扭曲,能夠?qū)崟r地產(chǎn)生光滑且視覺真實的卡通角色變形效果。 (2)提出了一種基于移動最小二乘的形狀插值控制方法。該方法允許用戶通過若干個控制點來控制形狀的插值過渡序列。首先,以保剛性插值算法為基礎,生成源和目標形狀之間的初始過渡序列。然后,為了控制形狀的過渡序列,用戶根據(jù)需要在源形狀上預放置若干個控制點。最后,在選定的中間幀上,用戶編輯這些控制點,算法基于移動最小二乘變形技術自動把用戶控制光滑地傳播到整個形狀以及相鄰幀上,最終實現(xiàn)用戶控制的形狀插值過渡。實驗結果表明,新方法允許用戶通過簡單直觀的交互獲得視覺自然的插值效果。
[Abstract]:Computer animation is a series of static pictures by using the principle of human visual temporary effect. It is a combination of computer graphics and art. It is widely used in the field of film and television stunts, architectural decoration design, commercial advertising and so on. Two-dimensional shape deformation and two-dimensional shape interpolation are important techniques in computer animation. Researchers have recently proposed a new method based on moving least squares, which allows users to use points and lines to manipulate two-dimensional roles in real time. And it can produce smooth and visual real character deformation results. However, the Euclidean distance is used as the weight of deformation constraints without considering the topological structure of role shape. In two-dimensional shape interpolation, the rigid-preserving interpolation algorithm can produce a more natural shape transition effect. However, in this kind of method. The intermediate transition sequence of shape is generally determined by the shape of source and target, and there is a lack of effective means for user to control the generation of intermediate transition sequence. In order to solve the above problems, a moving least square cartoon character deformation method and a shape interpolation control method based on moving least squares are proposed respectively. The main contents are as follows: Firstly, based on the user's interaction constraint configuration, the Laplace energy function is minimized in the shape of the character. We get a set of weights, which we call "harmonic weights". Then, we take harmonic weights as the weight of deformation constraints. Because the "harmonic weight" takes into account the topological structure of the shape and propagates the deformation effect of user interaction constraints in a local diffusion way. Finally, the possible distortion distortion is effectively avoided. In addition, a moving least square deformation method with conserved area is designed, which is suitable for the deformation of incompressible bodies. The experimental results show that the proposed method is suitable for the deformation of incompressible bodies. The new method can effectively avoid the possible shape distortion, and can produce smooth and visual real-time cartoon character distortion in real-time. (2) A shape interpolation control method based on moving least squares is proposed, which allows users to control shape interpolation transition sequences through several control points. Firstly, it is based on rigid preserving interpolation algorithm. An initial transition sequence between the source and the target shape is generated.; then, in order to control the transition sequence of the shape, the user prepositions several control points on the source shape as needed. Finally, on the selected intermediate frame. The user edits these control points and the algorithm automatically propagates the user control smoothly to the whole shape and adjacent frames based on the moving least square deformation technique. Finally, the user controlled shape interpolation transition is realized. Experimental results show that the new method allows users to obtain natural visual interpolation effects through simple and intuitive interaction.
【學位授予單位】：浙江工商大學
【學位級別】：碩士
【學位授予年份】：2014
【分類號】：TP391.41

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本文編號：1408367