Abstract: | 數位視訊服務在未來的通訊領域裡變得非常重要;特別地,數位視訊廣播(DVB),依市場的需求提供新的服務,這些服務包括資料搜尋,聊天,與娛樂. HDTV,被稱為下一代的視訊系統.在電視節目廣播中可同時傳送數個SD數位或一個HD數位的節目載波信號;在影像解析度SD數位信號大略與現行的信號相同,HD數位則數倍於現行的信號,兩者皆採16:9的畫面比率. 在DTV的傳送通道可以提供數種服務分享.在信號廣播傳送前MPEG-2的壓縮技術提供了良好的視訊品質與傳輸效率;MPEG-2壓縮技術適合各種 視訊的內容,一個視頻影像是由一張接著一張的靜態影像所組成,MPEG-2取之前影像圖框識別的優點來做為下一個影像圖框的識別基礎.每一次取代全部的視頻信號來傳送,每一次僅用8~15張圖框來傳送整個影像信號,利用傳送影像圖框間的差異來節省有限頻寬的容量.當影像信號變得複雜時才提高所對應的壓縮率來符合影像信號. 在本文針對不同的數位資料採不同壓縮轉換的方法做研究探討,其所需要的識別是有其各種不同的壓縮程序;傳統的壓縮策略是比較無效率的;最後設計一完整的HDTV信號廣播系統並做信號估測以驗證信號已達到我們所要求的系統設計. Digital video services are becoming an very important part of future communication systems. Especially digital video broadcasting (DVB), As the market matures from the new services will be demanded.These demands including Internet access for browsing, chatting, and gaming. In addition, entertainment HDTV,is called as next generation television system, Several simultaneous Standard Definition Television (SDTV) image streams or a single High Definition Television (HDTV) image will make up the television programming broadcasts. SDTV is considered roughly the same quality level as today's television broadcasts and HDTV relates to a number of higher definition video standards. In any case, a television image in SDTV or HDTV will be transmitted in 16:9 aspect ratio. A single DTV channel may include a variety of data services sharing the channel space. The compression scheme for broadcast is called MPEG-2 which can take the data required to create a video image and pack it more efficiently before it is broadcast. The MPEG-2 compression scheme has the ability to adapt to picture content. A video image is broadcast as a series of still frames, one after the other. MPEG-2 takes advantage of the fact that much of a video frame is usually identical to the previous frame as well as the following frame. Instead of transmitting an entire video frame every time, the MPEG-2 transmission scheme only needs to transmit a complete image every 8 to 15 frames. The rest of the frames are created by transmitting only what is different between the frames. very little data needs to be transmitted to keep that scene in motion. As the image becomes more complex, the MPEG-2 data rate will rise to accommodate the additional data needed to complete the frames. In this paper an experimental study of different compression methodologies for digital angiogram data is performed. The need for compression is identified, and various aspects of the compression converter is studying. Traditional motion compensation strategies are considered, and their level of effectiveness with angiogram video is assessed.Finally, we design and implementation the HDTV system and used SONY prefessional product and test by Tetronix equipment. It could be reaches to transmit signal in real time and prove the quantity of system fit our system design. |