北京工业大学电视原理英文论文.doc

北京工业大学电视原理论文论文题目 The principle of 3D TV姓名： 吕祎 学号： 12021027专业： 电子信息工程指导教师：毛征 中国北京 二一五年四月 The principle of 3D TVThesis submitted to the faculty of School of Foreign Languages Beijing University of technology in partial fulfillment ofthe requirements for the degree ofBachelor of EngineeringBy:LvYi Electronic and control engineering, BJUT, April 2015 AcknowledgmentsFor this thesis, grateful acknowledgment goes first to my girlfriend, who never appear so that I can focus on my course. Without her contribution,I will not so successful.Besides, I would like to avail myself with this opportunity to thank all teachers and professors in School , whose devoted teaching and enlightening lectures have benefited me a lot.Moreover, I grateful acknowledge all my classmates and friends who have been supporting me throughout the four years, making my college life colorful and meaningful.Last but not least, my sincere gratitude also extends to my family, especially my dear parents, who have been working hard all day, supporting, encouraging and caring for me all of my life. AbstractIn 2009, there is a great movie changing the history of the development of 3D. The movie is Avatar(阿凡达). From this movie , people know the power of 3D technology. Sir Charles Wheatstone is widely considered to be the father of stereoscopy. In1838, he published paper describing how each eye sees a sightly different version of the same scene. It seems unlikely that Wheatstone was the first person in history to notice this effect. Wheatstone himself provides a first person in 1838 paper, which suggest that Leonardo Da Vinci woould probably have been aware of the effects of binocular vision.However, Wheatstone is the first to described stereoscopy explicitly and in detail. One of the inherent problems with many 3D display technology is that they require the viewer to wear special glasses. Before considering the technologies and approaches for 3D video capture,we should review the scene representation formats and consider what kind of data is required for each format. The video streams captured by rig of cameras should be processed prior to encoding and transmission, in order to balance to optical differences between different cameras, align them by transforming their coordinate systems and adapt the video streams to the external capturing conditions, such as color distribution and exposure parameters. Transmission of raw video signal requires high band widths and excessive storage capacities which are unrealistic and costly. Therefore,video coding is required to compress the video while allowing the reversible conversion of data, requiring fewer bits and more efficient transmission.Video coding targets exploiting the redundancies in the video sequence together with considering the Human Visual System in order to achieve compression. Multimedia transmissions over communication networks are prone to transmission errors in the form of packet losses, bit errors, or bust errors. Therefore, the reconstructed video frames at the receiving end may differ from the original transmitted video content. A binary scene model contains objects with a particular data structure.4 Table of contentsAcknowledgments.iAbstract.ii1.Introduction.22. Capture and Processing（捕获和处理）.43.Compression (压缩).64 Transmission(传输).75 Rendering, Adaptation and 3D Displays（渲染适应和三维显示）.96 Quality Assessment(品质评估).12参考文献.131.IntroductionIn 2009, there is a great movie changing the history of the development of 3D. The movie is Avatar(阿凡达). From this movie , people know the power of 3D technology.Figure I examining the current state-of-the-art in 3D visual related technology, it is instructive to examine the way in which 3d technology has developed, and the reasons for previous failures. In this way it is possible to assess the durability of the current 3D boom, and to consider which of the remaining challenges the most important to solve.1.1.1 3D in the 19th centurySir Charles Wheatstone is widely considered to be the father of stereoscopy. In1838, he published paper describing how each eye sees a sightly different version of the same scene. It seems unlikely that Wheatstone was the first person in history to notice this effect. Wheatstone himself provides a first person in 1838 paper, which suggest that Leonardo Da Vinci woould probably have been aware of the effects of binocular vision.However, Wheatstone is the first to described stereoscopy explicitly and in detail.Wheatstones mirror stereosocope, taken from his 1838 paper, which allows viewing of a stereo pair of drawings.1.1.2 Early 20th centuryThe early 20th century saw the arrival of a number of key technologies, the basic principles of which are still used in many of todays 3D technologies, Shutter glasses, and polarized stereoscopic viewing technologies were all initially developed during this period. Shutter glasses and polarized lenses of course from the basis of the stereoscopic systems in use today.1.1.3 1950s-the golden period of 3DAlthough there was considerable interest by scientists and researchers in developing 3Dmovie technology, it was not until the early 1950s that the movie studios started to take a serious interest in the process. Movie studio executives were becoming increasingly concerned about the impact of television on cinema audiences. Between 1946-1952, weekly attendance figures in US cinemas had fallen from 82.4 million to 46 million. In addition to this, the House Un-America activities Committee had blacked talented scriptwriters, and directors. The US movie industry was in crisis and needed to find something to attract people back into the cinema. This dire situation led to experimentation with new technology, so that cinemas could provide an experience far superior to television.According to Lipton, the first American movie to be made in color and 3D was Bwana Devil,which was first screened on November 27, 1952. The movie was a hit, and grossed $100,000 in its first week. This woke the industry up to the potential of 3D.1.1.4 The 1980s Revival and the Arrival of IMAXAlthough the first 3D boom proved to be disappointingly short-lived, this was not the end of interest in 3D from the public or the movie industry. Certainly by the late 1970s, the movie industry was again concerned about new technology making home viewing more attractive than visiting a cinema. Mass market Video Cassette Recorders had arrived, which allowed the public to watch movies at home ,and at a time of their choosing.This was perceived as a clear threat to movie industry revenues. However, it was clear from the problems described in Section 1.1.3 that more development work was required to make 3d technology commoner sally viable. Researchers continued to improve the technology, focusing on techniques that would provide solution to problems such as view synchronization.1.1.5 The 21s century RevivalThe twenty-first century has seen a significant revival in 3D technology. Once again , the movie industry has taken the lead by reintroducing 3D into cinemas.Although thanks to IMAX-3D technology has never really gone away, the twenty-first century has seen more widespread adoption of the technology by main stream cinemas . New threats are being faced by the new movies to be shared, and freely downloaded. This can sometimes occur before the official release data.In addition, whereas pirate copies used to be low quality, modern pirate movies can often be obtained in HD. Therefore, providing high quality,modern pirate movies cant be experienced at home. It also acts as an effective method of preventing illegal recordings taking place by bootleggers who take hidden cameras into the cinema.1.1.6 Auto-StereoscopicOne of the inherent problems with many 3D display technology is that they require the viewer to wear special glasses. Some viewers find such glasses off-putting, and therefore researchers have put considerable efforts into developing display technologies that do not require glasses.Such displays usually fall into the auto-stereoscopic category which is described in this subsection.1.2 3D Video Formats1.2.1 Fame Compatible and Service Compatible Stereoscopic VideoThe first formats to be used in modern 3DTV systems will be stereoscopic, as this type of video does not require excessive transmission bit-rates, and is easier to capture than the other formats described in this section. All stereoscopic formats suffer from a lack of flexibility in terms of rendering.It is very difficult to change the users viewpoint,and to change the disparity between the views presented to the user. This prevents users from adjusting the presentation of the 3D video for comfortable viewing.1.3 3D Video Application Scenarios1.3.1 3DTV Broadcast SystemsBroadcast remains the most efficient way of delivering high quality video content to large numbers of people. In Europe, the digital television standards are being revised to enable support for 3DTV channels. Frame compatible format video is already supported by the various Digital Video Broadcasting standards, while work is under way to enable support for service compatible video. On 1October 2010, British Sky Broadcasting launched a 3D channel that could be decoded using their standard High Definition DVB-S2 set-top box. Compatibility with the existing technology is made possible by the use of frame compatible 3D, where the two views are down sampled in the horizontal direction, so that they can both be placed within one HD frame.2.Capture and Processing（捕获和处理）2.1 Scene Representation Formats and TechniquesBefore considering the technologies and approaches for 3D video capture,we should review the scene representation formats and consider what kind of data is required for each format.Figure2.1 depicts the increasing 3D resolution from simpler formats.The two most common types of information needed are color video and depth information.2.2 3D Video Capturing TechniquesIn this section, we consider methods of producing the 3D video data. The camera technologies used in 3D capture systems are described,and methods for acquiring both stereoscopic ad multi-view video are examined. The discussions also include examples of 3D video capturing, drawing on experience from work on EU-funded research projects, MUSCADE and DIOMEDES. These projects were funded by the European Union, and involved the acquisition of multi-view video as part of the overall research programme.2.3 3D Video processing The video streams captured by rig of cameras should be processed prior to encoding and transmission, in order to balance to optical differences between different cameras, align them by transforming their coordinate systems and adapt the video streams to the external capturing conditions, such as color distribution and exposure parameters. Most 3D video processing frameworks start with the calibration of the individual cameras within the multi-camera capture rig. In other words,each camera is calibrated separately first. Figure 2.12 depicts the extracted parameters in both calibration processes, and the corresponding flow diagram of the calibration process. The point positions on the test pattern, which is shown in Figure 2.12, are known beforehand and the goal of this manipulation is to find the intrinsic and extrinsic parameters, so that it is possible to obtain the best correspondence between the control point and their projection. Once all the parameters are computed, it is possible to eliminate distortions in the image captured.3.Compression (压缩)3.1 Video Coding PrinciplesTransmission of raw video signal requires high band widths and excessive storage capacities which are unrealistic and costly. Therefore,video coding is required to compress the video while allowing the reversible conversion of data, requiring fewer bits and more efficient transmission.Video coding targets exploiting the redundancies in the video sequence together with considering the Human Visual System in order to achieve compression. The redundancies within a video sequence can be basically identified as spatial and temporal correlations. In the context of 3D video, the dimension of similarity is further extended to inter-camera statistical correspondences.3.2 Overview of Traditional Video Coding Standards (传统编码)The first attempts at video coding systems date back to the 1960s when an analogue video phone system was designed. Organized groups of experts focused on video coding, thus the International Telecommunication Union and the Joint Photographic Experts Group(JPEG) had made attempts at standardization in the late 1980s. 3.3 3D Video CodingL-R stereoscopic video, the simplest form of 3Dvideo, requires more storage capacity and higher bandwidth for transmission compared to 2D video. Therefore, 3D video coding is crucial to make the immersive video applications available for the mass consumer market in the near future . The coding approaches for 3D video may be diverse depending on the representation of 3D video. 3Dvideo coding approaches aim to exploit inter-view statistical dependencies in addition to the conventional 2D video coding approach, which removes the redundancies in the temporal and spatial dimensions. The prediction of views utilizing the neighbouring views and the images from the same image sequence are shown in Figure 3.5The efficiencies of the prediction methods shown vary depending on the frame rate, the inter-camera baseline distances and the complexity of the content.4 Transmission(传输)4.1 Challenges of 3D Video Transmission Multimedia transmissions over communication networks are prone to transmission errors in the form of packet losses, bit errors, or bust errors. Therefore, the reconstructed video frames at the receiving end may differ from the original transmitted video content. Furthermore, these errors on reconstructed video propagate from one frame to another due to the prediction mechanism used in conventional video compression algorithms.This in turn degrades the perceived quality of the reconstructed video at the receiver. Similarly, the emerging immersive video communication applications will be affected by channel error conditions.Transmission of 3D video is more difficult compared to 2Dvideo transmission, both 2D video and depth are needed to be transmitted. This means if one sequence is corrupted, the final quality will be disrupted. Therefore, when designing 3D video transmission system, efficient resource allocation between 2D video and depth needs to be carefully considered since the overall bit allocation is a limited resource.4.2 Error Resilience and Concealment TechniquesWith the growth in the range of multimedia services being used for everyday activities such as teleconferencing, mobile television and peer-to-peer video sharing , the reception of video with high quality is of prime importance to users, as well as to service providers.New video coding bastardizations, such as H.264, scalable video coding, wavelet coding and distributed video coding , were introduced to accomplish these requirements. Some of these techniques concentrate on video transmission between the servers and clients in heterogeneous networks, such as scalable extension of H.264/Advanced Video Coding, while others such as distributed video coding are more applicable to video uplink applications.4.2.1 Background Due to the dynamic nature and the unpredictability of the transmission channels, the bit stream transmitted through communication networks always undergoes either burst errors or bit errors. However, at the decoding end, the packets with bit errors will be dropped, resulting in corrupted pictures and deterioration in the quality of the output bit steam. Therefore, research on error recovery, concealment and error propagation prevention methods is an important aspect of multimedia communications. In current practice there are several methods to mitigate these adverse effects, such as forward error correction, feedback-related algorithms, error concealment and error resilience mechanisms. However, the introduction of these error control and recovery mechanisms heavily degrades the coding efficiency. In general, there are four types of data losses associated with bit errors which occur in wireless video transmission systems: 1.Least significant data loss-These are the type of errors which occur at less important portions of the encoded segments. For example ,errors in the texture data of the video will not propagate in the temporal domain, so they will only deteriorate the quality of the picture which they belong to. Also , abit error in texture data will not propagate spatially. Hence, this is a localized error which cause the least significant data loss. 2. Prediction data loss-If bit errors take place in motion vectors, they will result in prediction errors. There is a higher tendency for these prediction errors to propagate in th