增強顯示器影像對比度及色彩飽和度

隨著時代的進步，顯示器在生活中漸漸變成一種不可或缺的消費性電子產品，以液晶顯示器是近年來備受矚目的研究主題之一，其中的發展不外乎趨於尺寸越來越大或是解析度越來越高，當尺寸變大解析度變高之後，伴隨而來的就是影像品質的提升或色彩受喜愛的程度，而針對這些研究的方向常常可以分為硬體材料或是訊號處理這兩大部分。本文針對訊號處理的部分提出一種應用在顯示器上增進影像對比度及色彩飽和度的方法。將輸入之畫面訊號進行色彩空間轉換至CIEL*a*b*色彩空間，在使用的色彩空間下進行影像對比度及色彩飽和度的提升，使畫面變得更清晰及更鮮豔。另外，此方法所建立在CIEL*a*b*色彩空間特性為亮度與彩度分離，能夠在個別處理亮度或色彩時不互相干擾，且為現階段所有色彩空間中包含最廣泛的色彩空間。最後將所研究的影像處理演算法實現於FPGA實驗板以及顯示器上，利用有限的硬體面積及記憶體來達成此方法之硬體架構實現，使其可以應用於動態影像顯示。

關鍵字

影像對比度；色彩飽和度；顯示器； FPGA ； CIEL*a*b*色彩空間

並列摘要

The consumer electronics with display becomes more and more important in life. Recent day, the liquid crystal display（LCD）has been one of technological research topic focusing on increasing size or enhancing resolution. Therefore, people focus on image quality and vivid color on the display. Hardware material and digital signal processing are two major parts of the direction of the LCD research. This thesis proposes digital signal processing which is application to enhance the quality of video display. Two main techniques are proposed in this thesis: To improve the chrominance and luminance of video frames on CIEL*a*b* color space. One, contrast enhancement method makes images bright and clear. Second, saturation enhancement method makes colors vivid and pleasant. Beside, the CIEL*a*b* color space separating chrominance and luminance is the widest color space nowadays. Finally, the experiment of these two methods are implemented successfully on FPGA board and LCD monitor. The FPGA board that are used limited hardware area can be applied to dynamic video.

並列關鍵字

image contrast ； color saturation ； monitor ； FPGA ； CIEL*a*b* color space

參考文獻

[1] C. C. Ku and T. M. Wang, "Luminance-based adaptive color saturation adjustment. Consumer Electronics", IEEE Transactions on Consumer Electronics, vol. 51, no. 3, pp. 939-946, Aug. 2005.

[2] Y. Huang, L. Hui and K. H. Goh, "Hue-based color saturation compensation," in Proc. IEEE International Symposium on Consumer Electronics, Sept. 2004, pp.160-164.

[3] Y. C. Zeng and H.Y. M. Liao, "Video enhancement based on saturation adjustment and contrast enhancement," in Proc. IEEE International Symposium on Circuits and Systems, May 2008, pp.3550-3553.

[4] C. C. Lai and C. C. Tsai, "Backlight power reduction and image contrast enhancement using adaptive dimming for global backlight applications," IEEE Transactions on Consumer Electronics, vol. 54, no. 2, pp. 669-674, May 2008.

[10] Wikimedia Commons http://commons.wikimedia.org/wiki/File:D_Sub_15pin.jpg May 2009

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增強顯示器影像對比度及色彩飽和度

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