實用的灰階影像彩色化系統

灰階影像彩色化（Colorization）是一門重要且有趣的研究領域。其主要議題就是如何讓電腦將具有一維的亮度資訊的灰階影像，轉換成具有三維資訊，如紅、綠、藍（RGB）的彩色影像。目前已存在的方法不是藉由使用者提供簡單的顏色資訊，就是參考一張彩色影像的顏色資訊，配合灰階影像的亮度來進行彩色化的工作。在本論文我們提出一個便利且具彈性的以使用者為導向之彩色化系統，參考邊緣資訊，對使用者在灰階影像上給定的幾筆塗筆（Scribbles）進行塗筆範圍擴張，以決定每個像素的色差；對未擴張到的部份的每個像素，定義並計算其與每個塗筆顏色之距離，來決定其色差。除此，為了增加效能與使用的便利性，本系統提供多樣的強化模組，讓使用者能以簡易的操作方式得到滿意的彩色化結果。實驗結果顯示本論文所提的彩色化系統，確實能讓使用者簡單且快速地塗色，並得到令人滿意的彩色化結果。

關鍵字

彩色化； RGB顏色空間； YUV顏色空間；擴散；線性內插

並列摘要

This paper presents a flexible and effective colorization system that carries out colorization by performing two stages of chrominance determination for pixels in a gray-scale image, including scribble region expansion and chrominance blending. The region corresponding to each scribble color is determined by expanding the scribbles in parallel associated with the edge map of the given image. Usually a few pixels remain unassigned to a color region after this stage. For those pixels we define and compute the transportation distance between each pixel and each scribble color. Then the reciprocals of the distances are used as weights to assign each of those pixels a weighted sum of the scribble colors. To promote practicability and effectiveness of the system several modules are provided that make the system more user-friendly and enhance the colorization results. The experimental results show that the proposed system is not only flexible and easy to use, but it also provides natural and satisfactory colorization results.

並列關鍵字

Colorization ； RGB color space ； YUV color space ； Region expansion ； Linear interpolation

參考文獻

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[6] Y. Xiang, B. Zou, and H. Li, “Selective color transfer with multi-source images,” Pattern Recognition Letters, vol. 30, no. 7, pp. 682-689, 2009.

[7] A. Levin, D. Lischinski, and Y. Weiss, “Colorization using optimization,” ACM Transactions on Graphics, vol. 23, pp. 689-694, 2004.

[9] D. Nie, Q. Ma, L. Ma, and S. Xiao, “Optimization based grayscale image colorization,” Pattern Recognition Letters, vol. 28, no. 12, pp. 1445-1451, 2007.

國際替代計量

實用的灰階影像彩色化系統

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