本論文提出一個結合數位浮水印與興趣區域 (ROI) 位元率控制的車行視訊編碼機制。近年來道路監視器被大量地設立以增加對人車安全的保障，同時也使得交通監控相關應用更為廣泛。本研究將智慧型運輸系統 (ITS) 所蒐集的車輛相關訊息，利用數位浮水印技術嵌入於監控畫面中，以減少用來解讀畫面的資料量，便利資料的整理，並且增加資料的可讀性。本論文大致分成兩部分，第一部分為以區分車行畫面前景與背景物為基礎的數位浮水印嵌入與偵測機制。透過背景建立，我們將畫面中包含車輛的區塊擷取出來，並將其對應至ITS感測器所得到個別車輛資訊以進行浮水印嵌入，浮水印技術則與壓縮車行視訊所使用的H.264/AVC緊密結合以增加系統執行的效率，確保視訊畫質不受影響，維持壓縮視訊的長度，並確認隱藏訊息可被正確的偵測。論文的第二部份為建構於ROI之位元率控制機制，此機制利用車行畫面的特性，訓練相關模型以適用於各種交通監控場景，透過有效的預測，我們能夠準確的將較多的位元分配於ROI。因此，我們不僅可藉此告知解碼端關於數位浮水印的嵌入位置以利其偵測，並可協助系統提高整體視訊編碼表現，有效提升車輛部分的影像畫質。實驗結果顯示了此車行畫面編碼系統的優點與實用性。 A new application of information hiding by employing the digital watermarking techniques to facilitate the data annotation in traffic surveillance videos is proposed in this research. As there are more and more roadside surveillance cameras are deployed, the applications related to traffic surveillance systems become important. In the proposed schemes, the data collected from intelligent transportation systems (ITS) are embedded into the corresponding regions of traffic scenes to facilitate the data management. The scheme consists of two parts. The first part is the object-based watermarking, in which the information of each vehicle collected from other sensors/sources in the ITS will be conveyed/stored along with the visual data via information hiding. The traffic scene captured by a video camera will be analyzed and the individual vehicles are extracted as moving objects, which will be embedded with the associated information. The scheme is integrated with H.264/AVC, which is assumed to be adopted by the surveillance system, to achieve an efficient implementation. The second part is a Region Of Interest (ROI) rate control mechanism for encoding traffic surveillan videos, which helps to improve the overall performance. The quality of vehicles in the video is thus well preserved and a good rate-distortion performance can be attained. Experimental results show that this potential scheme works well in traffic surveillance videos.
