隨著科技日益的進步，影像已經邁向數位化與高品質的年代。為因應未來人們對於高品質與鮮豔色彩的需求，色彩調整的方式將會愈來愈被重視。調整色彩主要的因素為: 1.消費者的需求；2.人眼視覺特性；3.色彩模型特性。因為其調整後的色彩是由人眼所觀看，所以色
彩調整不僅要符合理論也要符合人眼所觀察的結果。傳統的色彩調整
方式大部份只是調整或增強色彩的對比度與飽和度以達到更鮮豔的色彩與更清晰的影像，但是在過程中往往會發生過飽和的情況。其過飽和會使得飽和度增加，同時也使影像觀看起來不太自然。再加上為了顯示色彩須要對過飽和做再修正的動作，會使得色彩的資訊量流失，使得預期達到的結果將會產生變化。所以本論文提出了一飽和度調整模型來解決此問題。

本文提出一飽和度調整模型基於人眼視覺配合YCbCr色彩模型特性與亮度變化。過去大多數人在做色彩調整時，大都是以分別將亮度與飽和度調整到最好為主要方法，但是經常會發生過飽和的情形發生，使得影像變得較不自然。本文利用曝光補償來模擬當明亮度變化時亮度、飽和度與色相三者之間的關係。根據模擬發現飽和度會隨著亮度變化所改變，也發現其色彩移動模式與YCbCr模型有相呼應的關係。最後，再加上人眼視覺特性來做修正，以達到更好的效果。根據實驗結果可以發現影像色彩的明亮度、對比度與鮮豔度都有所提升，且不會有過飽和的情況發生，影像也較為自然。

This thesis proposes a saturation adjustment method based on human vision with YCbCr color model characteristics and luminance changes. In the traditional color adjustment approach, people tried to separately adjust the luminance and saturation. However, this approach makes the color over-saturate very easily and makes the image look unnatural. In this work we try to use the concept of exposure compensation to simulate the brightness changes and to find the relationship among luminance, saturation, and hue. The simulation indicates that saturation changes with the change of luminance and the simulation also shows there are certain relationships between color variation model and YCbCr color model. Together with all these symptoms, we also include the human vision characteristics to propose a new saturation method to enhance the vision effect of an image. The experimental results show that the proposed approach can make the image have better vivid and contrast. Most important of all, unlike the over-saturation caused by the conventional approach, our approach prevents over-saturation and further makes the adjusted image look natural.

中文摘
要........................... I
英文摘
要................................... II
內文目錄.............................III
圖表目錄...............................V

第一章   緒論	                         1
   1.1   研究背景與動機	                 1
   1.2   研究主題與目標	                 4
   1.3   論文架構	                 5

第二章  人眼視覺與色彩模型	         6
   2.1  人眼視覺	                 6
     2.1.1  人眼特性	                 6
     2.1.2  色彩體系	                 11
       2.1.2.1  孟塞爾色彩體系	         11
       2.1.2.2  NCS色彩體系	         14
       2.1.2.3  PCCS色彩體系	         16
   2.2  色彩模型	                 17
     2.2.1  HSV	                         18
     2.2.2  YUV	                         20
     2.2.3  YCbCr	                 22
第三章  利用曝光補償模擬明亮度變化	 26
第四章  飽和度調整模型	                 31
   4.1 建立色彩調整模型	                 31
   4.2 根據人眼視覺特性修正切面三角形模型37
   4.3 利用切面三角形做飽和度調整	 40
第五章  實驗結果	                 43
第六章  結論	                         56
參考文獻	                         57














圖目錄

圖1.1過飽合範例	2
圖2.1人眼構造	7
圖2.2錐狀體(Cone)與桿狀體(Rod)	8
圖2.3錐狀體與桿狀體對於亮度強度相對感光反應的特性曲線圖	10
圖2.4亮度與色彩對比度在空間中的敏感度特性曲線圖	10
圖2.5 孟塞爾色立體	12
圖2.6孟塞爾色相環、明度軸與彩度軸	13
圖2.7 NCS色立體	15
圖2.8 NCS色相環	15
圖2.9 PCCS色立體	17
圖2.10 HSV色彩空間	19
圖2.11 YUV色彩空間	21
圖2.12 YCbCr色彩空間	23
圖2.13 Cb-Cr投影平面	25
圖2.14 Cb-Cr平面	25
圖4.1對YCbCr色彩模型根據色相做切割之示意圖	32
圖4.2演算法範例圖	41
圖5.1實驗結果A	46
圖5.2實驗結果B	48
圖5.3實驗結果C	50
圖5.4細微觀察圖5.1	53
圖5.5細微觀察圖5.2	55



表目錄

表3.1 曝光補償模擬結果	29
表4.1六個特徵三角形及其頂點位址	36
表4.2 修正後的特徵三角形及其頂點位址	39

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