適應性高動態範圍之色彩影像強化

近年來顯像設備的發展日益精進，在色彩影像的研究領域裡，顯示品質的重要性也隨之提升。本文提出一種優化顯像品質的色彩轉換方法，一般在高對比度的影像中有一個共同特點就是暗的陰影與明亮的影像的共存。在一般顯示裝置要將同時呈現出暗區和亮區的細節不易的。為了解決這個問題，提出利用雙向濾波器結合自適應色調映射方法的新方法，藉以提高影像品質。首先，雙邊濾波器是用來分解圖像分成兩層：粗略影像與細節影像。然後將粗略影像分為三個區域：明亮區域、中間色調和暗區域。最後，個別以其適和的色調映射方法是根據其個人財產來處理每一個區域。唯一的大型層圖像是通過使用自適應增強基調映射；因此，原始影像的細節、色彩得以被保留。此外，此方法也可避免使用直方圖均衡化所產生之過度飽和與色調分離。

關鍵字

雙向濾波器；高動態範圍；色調再現；色調分離

並列摘要

The field of imaging technology is currently growing and expanding rapidly. The importance of color image quality therefore is gradually increasing. The aims of this study are to develop a method to improve the color image quality for displays and to find a way to assess the image quality of the displays with high efficiency .One common characteristic of most high-contrast images is the coexistence of dark shadows and bright light source in one scene. It is very difficult to present details in both dark and bright areas simultaneously on most display devices. In order to resolve this problem, a new method utilizing bilateral filter combined with adaptive tone-mapping method is proposed to improve image quality. First of all, bilateral filter is used to decompose image into two layers: large-scale layer and detail layer. Then, the large scale layer image is divided into three regions: bright, mid-tone, and dark region. Finally, an appropriate tone-mapping method is chosen to process each region according to its individual property. Only large-scale layer image is enhanced by using adaptive tone mapping; therefore, the details of the original image can be preserved. The experiment results demonstrate the success of proposed method. Furthermore, the proposed method can also avoid posterization produced by methods using histogram equalization.

並列關鍵字

Bilateral Filter ； High Dynamic Range ； Tone Reproduction ； Posterization

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