基於鄰近像素方向資訊之數位相機CFA內插演算法設計

Design of a CFA Demosaicing Based on Directional Information of Neighboring Pixels for Digital Still Cameras

林啟銘(Chi-Ming Lin)

指導教授 ： 蘇崇彥

國立臺灣師範大學/科技學院/工業教育學系/碩士(2007年)

摘要

為了減少硬體的成本，目前大部分消費型的數位相機都僅使用單一感光元件覆蓋一層色彩濾波陣列去記錄場景中的顏色。色彩內插演算法則是一種用於單一感光元件數位相機的影像處理程序，藉由內插缺少顏色的像素值來重建出全彩的影像。本論文提出一種低複雜度且有效抑制人工錯色的色彩內插演算法。在第一個步驟中，使用鄰近像素的邊緣方向資訊去判斷缺少綠色像素之內插方向；接著使用色彩差值的內插演算法去估測缺少的紅色與藍色像素。在第二個步驟中，本文提出一種新的優化內插演算法，使用色彩差值空間的中值濾波去更新綠色像素；接著使用一種改良的中值濾波方法去提升紅色與藍色像素的品質。實驗結果顯示，本論文所提出來的色彩內插演算法，在主觀的視覺品質與客觀的峰值訊號雜訊比與S-CIELab的評估上，都比近期內所提出來的方法有明顯的改善與提升。

關鍵字

色彩內插 ； 解馬賽克 ； 貝爾圖形 ； 數位相機

並列摘要

In order to reduce the hardware cost, most digital still cameras（DSCs） use only single-sensor equipped with a color filter array（CFA） to capture the color of the scene presently. Demosaicing algorithm is a process of estimating the missing color values for full-images from incomplete color samples acquired by single-sensor digital still cameras. This paper presents a low-complexity and effective demosaicing algorithm to suppress the color artifacts. In the first step, the directional information of neighboring pixels is used to determine the interpolated directions of missing green pixels; a color-difference algorithm is next used to handle red and blue ones. In the second step, a new refinement algorithm is proposed to update green pixels by a median filter in color-difference space and a modified median filter to refine the other two. Experimental results show that the proposed method is better than the state-of-the-art methods on visually quality subjectively and peak signal-to-noise ratio and S-CIELab metric objectively.

並列關鍵字

Color interpolation ； Demosaicing ； Bayer pattern ； Digital still camera

參考文獻

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