Browsing by Subject "Digital video"
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Item A study of very low bit rate video coding(Texas Tech University, 1997-08) Wang, NaxinThis work focuses on the low bit rate video coding used in video conferencing system. A simplified segmentation based coding approach is exponed to H 263 and MPEG-1 standards. This approach uses the motion information to separate the moving objects from the rest and segments the moving macroblocks into objects Based on the features of video conferencing sequence, the encoder is optimized so that more bits are spent on theses moving objects and the others are treated as background Therefore, it saves a lot of bits. The encoder can select the objects by their sizes or let the viewer select them. The quality of the output is fine by our observation.Item I give you my word : the ethics of oral history and digital video interpretation at Texas historic sites(2012-05) Cherian, Antony, 1974-; Roy, Loriene; Norkunas, Martha K.; Galloway, Patricia; Doty, Philip; Seriff, SuzanneThis dissertation examines the process of using oral history and digital video to revise interpretation and represent more inclusive histories at three rural Texas historic sites—-Washington-on-the-Brazos State Historic Site, the Lyndon Baines Johnson State Park, and Varner-Hogg Plantation—-21st century sites that, to varying degrees, have persisted to interpret a Texas master narrative that is no longer socially tolerable in its silencing of marginalized Texas voices. In particular, the dissertation focuses on complicated and rarely discussed ethical issues that surfaced during my work from 2001 to 2006 shooting, editing, and situating interpretive documentary videos at the each of the three sites. Historic sites in Texas, like others across the United States and worldwide, have been receiving increasing pressure from scholars and community groups to represent women, racial minorities, and other marginalized groups more prominently in the narratives they interpret. Oral history and digital media have played key roles in this ongoing movement. Oral history has widely been touted as a tool to democratize history, and advocates of digital video interpretation cite its affordability, relative ease of use, and its ability to “say so much in so little time.” These factors are all the more compelling for local, regional, and state-wide historic sites that are chronically under-funded, under-staffed, and that must often interpret multiple, complicated narratives with very little time or space in which to present them. However, little has been done to explore the unique and complicated ethical issues that arise from using oral history and digital video at historic sites. This dissertation takes a case study approach and uses as its intellectual framework ideas of reflective practice, part of the contemporary discourse among public history practitioners. Each case study introduces the site through a critical analysis of the images and texts produced by the site; presents the central historical silence at each site; describes the solution that oral history and digital video interpretation was expected to provide; and then uses the project’s process-generated video footage and records to examine key situations that led me to raise ethical questions about the individual projects and the overall enterprise.Item Negotiating documentary space(2012-05) Rudin, Daniel; Perzyński, Bogdan, 1954-; Lewis, RandolphThis essay attempts to propose an art practice based on an ethical and aesthetic relation of author, subject, and viewer. This relationship is productive of results that are seen as critical to a precise, useful, and ethical representation of social problems.Item Scene change detection in compressed video data(Texas Tech University, 1995-08) Ambady, Balagopalan MenonUse of digital video data is on the rise in applications like multimedia educational and training tools, multimedia mail, networked video conferencing systems and desktop entertainment systems. Due to the large amount of data associated with video applications, video data is compressed before storage or transmission. Therefore the problems of content based indexing and retrieval of compressed video data assume primary importance. Solutions to these problems require computationally efficient detection of scene changes. Previous research has shown that scene change techniques operating on compressed data are much faster than techniques requiring decompression of data before scene change detection. We have developed new scene change detection algorithms, based on block comparisons between adjacent frames of digital video data compressed in the spatial frequency domain.Item Software design and implementation of a video data acquisition and replay system(Texas Tech University, 2004-05) Helene, Sigi Jessica St.The objective of this paper involves using the waterfall approach model to design a bespoke product system to test video signals in a test lab. The thesis goes into depth describing the system requirements, design and implementation of a Video Data Acquisition and Replay (VIDAR). VIDAR allows video signals to be fed into a hardware system, downloaded onto a computer, and outputted onto a video system such as a television.Item Video compression in signal-dependent noise(Texas Tech University, 1996-12) Upadhya, Ashwin KumarThis work investigates the performance of video compression techniques in the presence of signal-dependent noise. The signal-dependent noise sources most commonly encountered are film-grain noise and speckle. Film-grain noise degradation occurs when a photographic film is scanned for the purpose of digitization [6]. All types of coherent imaging techniques, such as synthetic aperture radar (SAR) imagery, laser illuminated imagery, astronomical imagery and ultrasonic medical imagery are affected by speckle. Noise in the video not only affects the quality of the video, but also the compression scheme for the video. It is of utmost importance to improve the quality of video and also the achievable compression, for the sake of archiving, in applications such as medical imagery. This work aims to investigate techniques to improve the quality and achievable compression of moving pictures (video), keeping in mind such applications. There is no real consensus yet on the "best" quality measure to use for determining the quality of the output video, so we will use the standard mean square error, log mean square error, signal-to-noise ratio and perceptual mean square error (which is modeled on the human visual system) in this work.Item Video quality assessment based on motion models(2008-08) Seshadrinathan, Kalpana, 1980-; Bovik, Alan C. (Alan Conrad), 1958-A large amount of digital visual data is being distributed and communicated globally and the question of video quality control becomes a central concern. Unlike many signal processing applications, the intended receiver of video signals is nearly always the human eye. Video quality assessment algorithms must attempt to assess perceptual degradations in videos. My dissertation focuses on full reference methods of image and video quality assessment, where the availability of a perfect or pristine reference image/video is assumed. A large body of research on image quality assessment has focused on models of the human visual system. The premise behind such metrics is to process visual data by simulating the visual pathway of the eye-brain system. Recent approaches to image quality assessment, the structural similarity index and information theoretic models, avoid explicit modeling of visual mechanisms and use statistical properties derived from the images to formulate measurements of image quality. I show that the structure measurement in structural similarity is equivalent to contrast masking models that form a critical component of many vision based methods. I also show the equivalence of the structural and the information theoretic metrics under certain assumptions on the statistical distribution of the reference and distorted images. Videos contain many artifacts that are specific to motion and are largely temporal. Motion information plays a key role in visual perception of video signals. I develop a general, spatio-spectrally localized multi-scale framework for evaluating dynamic video fidelity that integrates both spatial and temporal aspects of distortion assessment. Video quality is evaluated in space and time by evaluating motion quality along computed motion trajectories. Using this framework, I develop a full-reference video quality assessment algorithm known as the MOtion-based Video Integrity Evaluation index, or MOVIE index. Lastly, and significantly, I conducted a large-scale subjective study on a database of videos distorted by present generation video processing and communication technology. The database contains 150 distorted videos obtained from 10 naturalistic reference videos and each video was evaluated by 38 human subjects in the study. I study the performance of leading, publicly available objective video quality assessment algorithms on this database.