多重色彩轉移：以範例為基礎之照片美化系統

在編輯相片時，編輯者通常會想像相片編輯完成後的樣子。這個想像，經常是受到其他相片的影響，也許是在同一本相簿中的相片或是之前瀏覽過的相片。但一般使用者時常會遇到想要某種效果，卻不知道如何達成的問題。基於這樣的觀察，我們發展出了一套易學易用的相片編輯系統，讓使用者將喜愛且相似主題的相片當做範例，借用範例照片的顏色來修改照片的顏色。使用者只要用畫筆在兩張照片相對映的區域做簡單的標記，系統就可以自動的完成編輯的動作。發展這套系統的目的是希望編輯者能簡單的藉由參考另一張滿意的照片來修改不滿意的照片。我們設計的使用者介面能讓使用者在兩張照片相對映的區域畫上標記來轉移想要的顏色。此外，大部份的情況，使用者只對於一張照片的一部份不滿意。因此，相同的使用流程，我們的系統也支援局部的修改一張照片，而且我們的演算法能成功的保存令人滿意部份或是先前修改的區域。在這篇論文中，我們利用了使用圖分割做最佳化的演算法來找出使用者希望編輯的區域，也設計了一個新的能量函式，能在計算中同時考量一個圖素的顏色與位置資訊。另外，我們發展了多重色彩轉移的方法，用來估計一組轉移函數中各項對一個圖素的影響，並且將這些影響加總來修改這個圖素。而影像導向的最佳化被用來增加結果中各區域的一致性，並且消除在邊界上的修改痕跡。在這篇論文中，我們也展示了我們工具多樣化的應用，並且系統能產生正確符合使用者期待的結果。更重要的，這套系統非常容易學習，不需具備要任何攝影或是影像編輯的知識，使用者也不需要改變照相的習慣。

關鍵字

色彩轉移；影像增強；互動式影像編輯；範例為基礎；圖分割；計算攝影學；影像處理

並列摘要

One of the most common situations in photo editing is that users want some specific effects but don’t know how to achieve them. Nevertheless, they have an image in their mind about how the photo should be, which is derived from a better photo on similar subjects, or from their imagination. With this user motivation in mind, this thesis proposes a method for altering a photo’s color based on the coloring of another exemplary photo. Users simply set the requirement by drawing some pairs of brush strokes in corresponding regions and then the tool will perform the editing automatically. The goal of our tool is to enable the photo editor to easily alter the dissatisfied photo by referring the other acceptable photo. A suitable user interface have designed for drawing the corresponding regions between a source and one or more targets to transfer the desired color. Besides, in most general cases, users are just dissatisfied with a part of the photo, so our system allow users to edit their photo completely or partially by the same work flow, and our algorithm can preserve the satisfying or ex-editing region successfully. In this thesis, we find the region the user expect to edit by a graph cut optimization algorithm, and we have designed a new energy function which can consider the color and positional information simultaneously in this process. Additionally, a multiple color transfer method is developed to estimate the different influence of a set of transfer functions on a pixel and accumulate the influences to alter the pixel. Moreover, a image-guide optimization is used to increase the coherence in regions and eliminate the artifacts near edges in the result. We also display a variety application of our tool in this thesis, and Our system can produce accurate results that match users’ expectations. More importantly, the tool is very easy to learn; no photography or photo editing knowledge is required, and users don’t need to change their habit of taking photos.

並列關鍵字

Color transfer ； Image Enhancement ； Interactive image editing ； Exsample-based ； Graph cuts ； Computational photography ； Image processing

參考文獻

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[6] Y. Chang, S. Saito, and M. Nakajima. Example-Based Color Transformation of Image and Video Using Basic Color Categories. Image Processing, IEEE Transactions on, 16(2):329–336, 2007.

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多重色彩轉移：以範例為基礎之照片美化系統

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