- 學位論文
運用H.264預測模式作畫面內的錯誤隱藏
Intra Frame Error Concealment Using Prediction Modes of H.264
摘要
在有限的網路頻寬與儲存空間下，為了應付龐大的視訊資料，H.264壓縮技術扮演非常重要的角色。有鑒於未來通訊朝無線化趨勢，如新一代的傳輸技術3.5G的行動電話和WiMax，使得H.264資料傳輸時發生錯誤或是遺失的問題越來越重要，其中錯誤隱藏是近年來頗受重視的解決之道。 本文提出了一個新的空間域錯誤隱藏法。此新方法運用Canny的邊緣偵測以及利用H.264的畫面內預測模式與邊緣的相關性作畫面內的錯誤隱藏，改善了當損壞的巨方塊有邊緣的資訊時，先前方法不能將它重建回來的缺失，亦可處理損壞的巨方塊內有一個以上邊緣的情況。實驗結果顯示，當巨方塊錯誤率在1%時，使用本論文提出的方法後，PSNR值可以高達53.77dB；在3%錯誤率發生時，在視覺或者是PSNR值上皆較H.264與其他人的方法為優；在20%錯誤率發生時，對於內容和緩變動的視訊能夠得到良好的錯誤隱藏的效果。
並列摘要
In the limited network bandwidth and storage space, H.264 compression technology plays a very important role in transmitting enormous video data. Wireless transmission technology of the next generation, such as 3.5 G mobile phone and WiMax, is the future trend of communications. Therefore, the problem of causing data in error or lost during the transmission of H.264 data is important. Using error concealment to solve this problem attracts much attention recently. This thesis proposes a new spatial domain error concealment method. The new method uses Canny edge detection and exploits the relation between edges in a macroblock (MB) and the intra prediction modes of H.264 to do error concealment. Using the proposed method can improve the fidelity of edge recovery in a corrupted MB, which is difficult to achieve when previously proposed methods are used. It also can recover a corrupted MB with more than one edge. The experimental results show that when the block error rate (BER) is 1%, a peak signal to noise ratio (PSNR) as high as 53.77 dB is achieved; for 3% BER the proposed method outperforms H.264 and other methods both visually and in PSNR criterion; for 20% BER, good error concealment performance can be achieved for the video with modest varying contents.