用色溫估計法完成自動白平衡

Automatic White Balance with Color Temperature Estimation

王博民(Po-Min Wang)

指導教授 ： 傅楸善

國立臺灣大學/電機資訊學院/資訊工程學研究所/碩士(2006年)

https://doi.org/10.6342/NTU.2006.01448

摘要

自動白平衡的目的在於讓使用者只須按下相機快門就能拍出一張色彩鮮明不失真的照片。此步驟為數位相機中影像處理重要的項目之一。若無白平衡的處理，在高色溫的光源下，所拍攝的照片將會偏藍，低色溫光源下所拍攝出來的照片將會偏紅。因此，自動白平衡必須能夠自動地校正色彩偏差的情形。一個擁有良好自動白平衡演算法的相機，所拍攝出來的照片顏色較令人討喜，且擁有讓人滿意的影像品質。
本文一開始先介紹自動白平衡的概念及其重要性，並詳細介紹各種不同的自動白平衡演算法，分別比較其優劣,並進一步提出一個新穎及穩定的演算法，利用色溫估計的方式完成自動白平衡。最後分別利用客觀及主觀的方式評鑑各種演算法。實驗結果顯示我們的方法擁有出色的結果以及符合多數人的喜好。

關鍵字

白平衡 ； 色溫 ； 色彩恆定

並列摘要

This thesis discusses automatic white balance in digital camera. Auto white balance is the most important image processing step in the image pipeline of digital camera, since it controls the color appearance of the image. Without auto white balance adjustment, the photo will become bluish under high color temperature and have reddish color cast under low color temperature. Therefore, a camera with good auto white balance method produces accurate and satisfactory color appearance, and good image quality.
In the beginning, we introduce what automatic white balance is and its importance. Then, we describe several previous methods and indicate these methods’ main drawbacks. Furthermore, we propose a novel and robust automatic white balance method by using color temperature estimation. Finally, we use objective and subjective evaluations to evaluate these methods. By experimental results, we can find that our method has robust and satisfactory results and is popular for most users.

並列關鍵字

white balance ； color temperature ； color constancy ； awb

參考文獻

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