自動白平衡是在數位相機中一個很重要的影像處理過程。它是利用來修正在不同色溫下出現不同顏色的現象，使結果看來像是在正常光源下的影像。傳統的自動白平衡方法在某些情況下無法正確地修正色偏。在本論文中，我們提出了一個基於直方圖匹配的自動白平衡演算法。
本演算法分為三個部分。首先，計算出輸入影像相關的直方圖；接著，將相關的直方圖依照演算法進行匹配；最後，再判斷是否有顏色雜訊產生的可能，有則處理後輸出影像，否則直接輸出。
實驗結果顯示，我們的演算法在色偏的修正上有比傳統演算法更好的表現，並且在CIELAB色彩空間中的實驗數據也都較為優異。

Automatic white balance plays an important role in the image processing of digital camera. It is used to correct the color cast under different illumination and make the image looks like under canonical illumination. The traditional automatic white balance methods cannot correct color cast in some cases. In this thesis, an automatic white balance algorithm based on histogram matching is proposed.
The proposed algorithm is composed of three main parts: First of all, the corresponding histogram of the image is calculated. Secondly, the histogram is matched to a specific one. Last but not the least, the determination of whether the color artifact occurs or not is applied. If so, the elimination of color artifact is processed and get the output image. Otherwise, the image after histogram matching is adopted directly.

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