中文摘要

最近幾年來，許多的可攜式影音產品越來越受到人們的歡迎，不但功能越來越強大、體積更是越來越小，但是這些以電池為供電來源的產品也都面臨到電源消耗的問題，因此低功率產品的設計概念逐漸受到重視。而在許多的影音壓縮標準中，取樣訊號都必須先經過一道離散餘弦轉換（DCT）的處理，所以低功率的DCT設計有其必要性，同時也變的越來越重要。
本論文首先針對幾種常見的DCT架構進行效能分析，並依照分析的結果提出了Hybrid DCT架構的設計概念，該架構結合了Loeffler DCT的低失真度特性以及binDCT的低功率消耗特性，具有良好功率/效能比。
本論文使用TSMC 0.25-μm technology library進行DCT架構的合成，並且使用Synopsys PrimePower軟體分析功率的消耗情形，此外還採用了一套以結構化失真為基礎的影像品質評估法，代替傳統的PSNR和MSE值。最後，經由模擬的結果發現，本論文所提出的Hybrid DCT架構不但能提供良好的影像品質，而且和Loeffler DCT架構相比，最多還能省下約24.8%的功率消耗以及27.2%的面積。

Abstract

In recent years, the demand for multimedia mobile battery-operated devices has created a need for low power implementation of video compression. Many compression standards require the discrete cosine transform (DCT) function to perform image/video compression. For this reason, low power DCT design has become more and more important in today's image/video processing.
In this paper, we first compare several popular DCT architectures in VLSI. Then we propose a new power-efficient Hybrid DCT architecture which combines Loeffler DCT and binDCT in terms of special property on distortion and power consumption difference.
We use Synopsys PrimePower to estimate the power consumption in a TSMC 0.25-μm technology. Besides, we also adopt a novel quality assessment method based on structural distortion measurement to measure the quality instead of peak signal to noise rations (PSNR) and mean squared error (MSE). It is concluded that our Hybrid DCT offers similar quality performance to the Loeffler DCT, and leads to 24.8% power consumption and 27.2% chip area savings.

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