利用漸進式網格與紋理貼圖之三維物體瀏覽系統

Abstract

本論文目的在於設計一套適用於網路傳輸的漸進式物體瀏覽系統。使用者可以利用此瀏覽系統在短時間內得到粗略的物體網格與紋理，並隨著下載時間的增長而改善物體模型中網格及紋理的品質。 此系統結合了漸進式網格與漸進式紋理的觀念，可以將一個帶有紋理的物體網格轉換成漸進式的物體模型。在漸進式物體網格方面，本系統參考文獻中網格簡化的演算法來加以實作，並予以適當的修改，然後將其設計為漸進式的物體網格；而在漸進式物體紋理方面，我們參考了JPEG格式中漸進模式的觀念，並利用DCT的係數設計漸進式紋理的儲存。在本論文中也提出了在物體簡化過程中重新對應紋理的方法，並利用此方式結合漸進式網格與漸進式紋理。本論文中除了對整個系統的理論與實作加以描述外，也透過低頻寬網路的模擬來展示瀏覽的過程。

The primary objective of this thesis is to design a browsing system, which is applicable to network transmission. The users can get a rough but recognizable mesh with texture in a short time, then the refinement of the mesh and texture can be retrieved while browsing time increases. Our browsing system integrates the concept of the progressive mesh and the progressive texture, and converts a mesh with texture into the format of progressive object model. In the implement of the progressive mesh, we adopt and modify one of the well-known algorithms of the mesh simplification, and take this algorithm to generate progressive meshes. In the implement of progressive texture, we take the "progressive mode" of the JPEG standard for reference, and use the DCT coefficients to encode the data of progressive texture. In this thesis, we also introduce an algorithm, which re-map the texture in multi-resolution meshes. We use this algorithm to combine the progressive mesh with the progressive texture. This thesis not only describes the theory of our browsing system, but also demonstrates the result of simulation on the low-bandwidth network.