- 學位論文
適用於液晶面板過壓驅動之邊緣感知圖像壓縮技術
An Edge Aware Image Compression Technique for LCD Overdrive Applications
摘要
過壓驅動技術廣泛的被應用來減少液晶顯示器灰階與灰階轉換之間的反應時間。利用比較前一個參考畫面的像素資料與目前畫面的像素資料，可以提供一個足夠高或低的電壓來驅動液晶分子使其及時扭轉。這些參考畫面的像素資料往往存放在外部記憶體，通常是動態隨機存取記憶體中，因此低失真的影像壓縮常被需要來降低記憶體頻寬的使用量。在本論文中，我們提出一個基於保存邊緣資訊之低失真且高壓縮率之影像壓縮技術，同時基於脈衝編碼調變的基礎，此壓縮技術僅需要0.5條線暫存器因此大幅降低硬體複雜度。效能評估顯示，利用所提出之邊緣感知圖像壓縮技術可以實現在壓縮率分別為4, 5, 6倍下PSNR分別為37.57 dB, 37.11 dB, 及36.71 dB的壓縮效果。
關鍵字
邊緣感知並列摘要
Overdrive technique is widely used to reduce the gray-to-gray level response time of liquid crystal display (LCD). To supply a high or low enough driving voltage for the liquid crystal cell to twist in time, the pixel data of the previous frame should be used as reference to be compared with the pixel data of the current frame. These pixel data are usually stored in the off-chip frame buffer, which is dynamic random access memory (DRAM) usually. Image compressions with low distortions, therefore, are used to apply overdrive technique with consuming a sufficient low DRAM bandwidth. In this thesis, we propose a new low distortion and high compress ratio image compression technique with preserving the edge information so as to avoid inducing artificial edges after overdrive technique is applied. Furthermore, the new DPCM based edge aware compression technique use only 0.5 line buffer so that the hardware complexity is reduced. Performance evaluations show that the PSNR of 37.57 dB, 37.11 dB, and 36.71 dB are achieved for the image compression of 4, 5, and 6, respectively.