最大輸入編碼色彩重現之四原色色域最佳化設計

Abstract

為擴大顯示器色域以呈現更生動且自然的色彩，近年來已吸引許多顯示器專家及廠商投入多原色技術的發展。相較於傳統顯示器之設計，多原色顯示器保有色域設計的彈性。然而，惟有透過適切的色域轉換之影像編碼，消費者才有機會享受大色域顯示器所呈現的豐富鮮豔色彩。本論文提出重現最大輸入編碼色彩之(四原色)色域最佳化設計的方法。基於最大色域體積重疊的條件，此方法可達到高傳真的色彩重現目的。 為實際比較並驗證基於不同演算法所獲得之最佳化色域，本研究設計一組背光模組（暨驅動電路）作為驗證平台，並採用四原色發光二極體為光源，令該背光模組具備呈現不同色域之彈性。本研究以兩種主要編碼色域－“標準RGB”及“真實表面色域”作為輸入色域，分別依循兩種常用演算法則－最大白點亮度與最大設計色域體積要求，以及本論文所建議之最大輸入色域體積重疊要求進行計算，並依據所得結果進行交差比對。結果顯示使用本方法可重現最大輸入色域。此外，若應用於最新發展的大色域輸入編碼訊號，將可以使多原色顯示器顯示出更接近人眼視覺系統的色域表現範圍。

In order to widen the display color gamut for providing more vivid and natural color perception, many of researchers and manufacturers were attracted to invest in the development of multi-primary technology in recent years. Comparing to the conventional displays, multi-primary displays (MPDs) offer the flexibility to adjust and exhibit possible color gamut volume (CGV). However, only through proper encoding gamut conversion, consumers could have the chance to enjoy the vivid color image on the large gamut display. This thesis presents a method to design the optimal (four-primary) color gamut for reproducing maximum number of input encoded color. Based on the maximum color gamut volume intersection requirement, the high-fidelity color reproduction can be achieved. For actually comparing and evaluating the optimum color gamut based on different algorithms, a backlight module (and the driving circuit) was constructed as a platform for verification. A set of four four-primary LEDs were adopted as the light sources, which offer the flexibility to have the different color gamut on the backlight module. Two major encoding color gamuts, “sRGB” and “real surface color gamut,” are chosen as input gamuts. Calculations are performed under two commonly-adopted criteria, maximum white point luminance and maximum designed CGV, and the proposed one, maximum intersectional CGV, respectively. Result shows the proposed method, compared to others, is demonstrated to reproduce maximum input color gamut. Moreover, if applying the method to the new developed large color gamut input encoding signal, the MPDs will display the color gamut toward the gamut range of human visual system.