分析樣板比對預測及其交疊區塊動態補償之應用

Abstract

樣板核對預測方法是利用目前編碼的區塊鄰近的點估計其動態向量。此種方法已經被證實有很好的編碼效率，在這篇論文中從理論以及實際統計資料展示了樣版核對的編碼效率，裡面提到了樣版核對的動態向量是跟那樣版區域的重心是有相關性的。樣版核對的效率比SKIP預測方法還要好，但是卻比傳統的區域動態補償的預測方式還要來的差，除非在動態向量以及圖片亮度值得亂度很小或亮度值是有很高的空間關係性時樣版核對的預測方法跟區域動態補償的編碼效率差不多。我們也示範了如何結合樣板核對和交疊區塊動態補償，以及達到了更好的時間軸上的預測效率。初步的結果與交疊區塊動態補償的比較下，顯示樣板核對和交疊區塊動態補償的結合減少了MSE 達2~16%。若與傳統動態補償的預測方法比較時，可以達到更高的18%的MSE減少量。

Abstract—Template matching prediction (TMP), which estimates the motion for a target block by using its surrounding pixels, has been observed to perform efficiently in inter-frame coding. In this paper, we expose, from a more theoretical viewpoint, the factors that determine the prediction efficiency of TMP. It is shown that the motion estimate found by template matching tends to be the motion associated with the template centroid and that TMP consistently outperforms SKIP prediction, but hardly competes with block motion compensation (BMC) unless both the motion and intensity fields are less random or have high spatial correlation. We also demonstrate how template and block motion estimates can jointly be applied in a parametric overlapped block motion compensation (OBMC) framework to further improve temporal prediction. Preliminary results show that combining TMP with OBMC can yield 2-16% reductions in mean-square prediction error, as compared with the single use of OBMC. The gain is even higher (18%) when the performance is compared with that of the standard BMC.