變形影像(Anamorphosis)是一種透視投影藝術，藝術家利用扭曲變形過後的影像創作成不同於原始影像的畫作，而觀察者可以透過特定角度或是特殊裝置欣賞到原始的影像。

變形影像藝術主要可以分成兩大類：第一類為透視法(perspective)，觀察者需要從某一個角度或視點才能得到原始影像；第二類為反射法(mirror)，畫作上會放置一個鏡面物體(如圓柱體或球體)，觀察者得以從鏡面物體上得到反射過後的原始影像。

本論文主要專注在第二類的方法，建立一個系統利用三維建築物模型之間的相互遮蔽形成以三維都市為主題的立體變形藝術。使用者可以指定想要呈現在圓柱上的原始圖樣，將原始圖案調整對比度及扭曲後作為參考遮罩得到各種色塊資訊和邊緣特徵。我們將邊緣特徵化為城市景觀中的道路，將各種色塊按照不同對比度放上不同建築物模型形成初步的城市景觀，再調整各個建築物的高度及材質。最後提出一套量化的標準判斷結果好壞，再使用最佳化方法在有限時間內得到最好的結果。我們希望題目達到下面三個目標：一、讓觀察者不易察覺隱藏影像資訊；二、不影響圓柱鏡面上的渲染結果；三、合理的城市景觀。

Anamorphic art is also called "anamorphosis", the artists usually create an distorted image which appear confusing at the first glance. The viewer needs to shift position or use a typical device to recover the distorted image.

There are two types of anamorphosis: perspective and mirror. In the case of perspective anamorphosis, the viewer the image must be viewed from a typical angle and position. In the case of mirror anamorphosis, the image must be seen reflected in a distorting mirror like cylindrical or conical mirror.

In this paper we focus on the mirror anamorphosis. We present novel a system to make a 3D anamophosis by using the occlusion between 3D buildings. Users can choose a original image which they want to see at the cylinder, then we distort the image and get the edge feature as the road growing feature of the city, we also put the different building models according to quantization. Finally, we adjust the height and material of each building by the reflected rays and our optimization method. We believe the proposed system can help user to create their own 3D mirror anamorphosis and keep the cityscape more nature.

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