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The Global ETD Search service is a free service for researchers
to find electronic theses and dissertations. This service is
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Networked Digital Library of Theses and Dissertations.
Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
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Showing 1 to 8 of 8 (0.036 seconds)Spelling suggestions: "subject:"multiview video"" "subject:"multi_view video""
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3D Video Capture of a Moving Object in a Wide Area Using Active Cameras / 能動カメラ群を用いた広域移動対象の3次元ビデオ撮影Yamaguchi, Tatsuhisa 24 September 2013 (has links)
京都大学 / 0048 / 新制・課程博士 / 博士(情報学) / 甲第17919号 / 情博第501号 / 新制||情||89(附属図書館) / 30739 / 京都大学大学院情報学研究科知能情報学専攻 / (主査)教授 松山 隆司, 教授 美濃 導彦, 教授 中村 裕一 / 学位規則第4条第1項該当 / Doctor of Informatics / Kyoto University / DFAM
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End-to-end 3D video communication over heterogeneous networksMohib, Hamdullah January 2014 (has links)
Three-dimensional technology, more commonly referred to as 3D technology, has revolutionised many fields including entertainment, medicine, and communications to name a few. In addition to 3D films, games, and sports channels, 3D perception has made tele-medicine a reality. By the year 2015, 30% of the all HD panels at home will be 3D enabled, predicted by consumer electronics manufacturers. Stereoscopic cameras, a comparatively mature technology compared to other 3D systems, are now being used by ordinary citizens to produce 3D content and share at a click of a button just like they do with the 2D counterparts via sites like YouTube. But technical challenges still exist, including with autostereoscopic multiview displays. 3D content requires many complex considerations--including how to represent it, and deciphering what is the best compression format--when considering transmission or storage, because of its increased amount of data. Any decision must be taken in the light of the available bandwidth or storage capacity, quality and user expectations. Free viewpoint navigation also remains partly unsolved. The most pressing issue getting in the way of widespread uptake of consumer 3D systems is the ability to deliver 3D content to heterogeneous consumer displays over the heterogeneous networks. Optimising 3D video communication solutions must consider the entire pipeline, starting with optimisation at the video source to the end display and transmission optimisation. Multi-view offers the most compelling solution for 3D videos with motion parallax and freedom from wearing headgear for 3D video perception. Optimising multi-view video for delivery and display could increase the demand for true 3D in the consumer market. This thesis focuses on an end-to-end quality optimisation in 3D video communication/transmission, offering solutions for optimisation at the compression, transmission, and decoder levels.
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Single and Multi-view Video Super-resolutionNajafi, Seyedreza 10 1900 (has links)
<p>Video super-resolution for dual-mode cameras in single-view and mono-view scenarios is studied in this thesis. Dual-mode cameras are capable of generating high-resolution still images while shooting video sequences at low-resolution. High-resolution still images are used to form a regularization function for solving the inverse problem of super-resolution. Exploiting proposed regularization function in this thesis obviates the need for classic regularization function. Experimental results show that using proposed regularization function instead of classic regularization functions for super-resolution of single-view video leads to improved results. In this thesis, super-resolution problem is divided into low-resolution frame fusion and de-blurring. A frame fusion scheme for multi-view video is proposed and performance improvement when exploiting multi-view sequence instead of single-view for frame fusion is studied. Experimental results show that information taken by a set of cameras instead of a single camera can improve super-resolution process, especially when video contains fast motions. As a side work, we applied our low-resolution multi-view frame fusion algorithm to 3D frame-compatible format resolution enhancement. Multi-view video super-resolution using high-resolution still images is performed at the decoder to prevent increasing computation complexity of the encoder. Experimental results show that this method delivers comparable compression efficiency for lower bit-rates.</p> / Master of Applied Science (MASc)
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Multi-view Video Coding Via Dense Depth FieldOzkalayci, Burak Oguz 01 September 2006 (has links) (PDF)
Emerging 3-D applications and 3-D display technologies raise
some transmission problems of the next-generation multimedia data.
Multi-view Video Coding (MVC) is one of the challenging topics in
this area, that is on its road for standardization via ISO MPEG. In
this thesis, a 3-D geometry-based MVC approach is proposed and
analyzed in terms of its compression performance. For this purpose,
the overall study is partitioned into three preceding parts. The
first step is dense depth estimation of a view from a fully
calibrated multi-view set. The calibration information and
smoothness assumptions are utilized for determining dense
correspondences via a Markov Random Field (MRF) model, which is
solved by Belief Propagation (BP) method. In the second part, the
estimated dense depth maps are utilized for generating (predicting)
arbitrary (other camera) views of a scene, that is known as novel
view generation. A 3-D warping algorithm, which is followed by an
occlusion-compatible hole-filling process, is implemented for this
aim. In order to suppress the occlusion artifacts, an intermediate
novel view generation method, which fuses two novel views generated
from different source views, is developed. Finally, for the last
part, dense depth estimation and intermediate novel view generation
tools are utilized in the proposed H.264-based MVC scheme for the
removal of the spatial redundancies between different views. The
performance of the proposed approach is compared against the
simulcast coding and a recent MVC proposal, which is expected to be
the standard recommendation for MPEG in the near future. These
results show that the geometric approaches in MVC can still be
utilized, especially in certain 3-D applications, in addition to
conventional temporal motion compensation techniques, although the
rate-distortion performances of geometry-free approaches are quite
superior.
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Dense Depth Map Estimation For Object Segmentation In Multi-view VideoCigla, Cevahir 01 August 2007 (has links) (PDF)
In this thesis, novel approaches for dense depth field estimation and object segmentation from mono, stereo and multiple views are presented. In the first stage, a novel graph-theoretic color segmentation algorithm is proposed, in which the popular Normalized Cuts 59H[6] segmentation algorithm is improved with some modifications on its graph structure. Segmentation is obtained by the recursive partitioning of the weighted graph. The simulation results for the comparison of the proposed segmentation scheme with some well-known segmentation methods, such as Recursive Shortest Spanning Tree 60H[3] and Mean-Shift 61H[4] and the conventional Normalized Cuts, show clear improvements over these traditional methods.
The proposed region-based approach is also utilized during the dense depth map estimation step, based on a novel modified plane- and angle-sweeping strategy. In the proposed dense depth estimation technique, the whole scene is assumed to be region-wise planar and 3D models of these plane patches are estimated by a greedy-search algorithm that also considers visibility constraint. In order to refine the depth maps and relax the planarity assumption of the scene, at the final step, two refinement techniques that are based on region splitting and pixel-based optimization via Belief Propagation 62H[32] are also applied.
Finally, the image segmentation algorithm is extended to object segmentation in multi-view video with the additional depth and optical flow information. Optical flow estimation is obtained via two different methods, KLT tracker and region-based block matching and the comparisons between these methods are performed. The experimental results indicate an improvement for the segmentation performance by the usage of depth and motion information.
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Integral Video CodingYang, Fan January 2014 (has links)
In recent years, 3D camera products and prototypes based on Integral imaging (II) technique have gradually emerged and gained broad attention. II is a method that spatially samples the natural light (light field) of a scene, usually using a microlens array or a camera array and records the light field using a high resolution 2D image sensor. The large amount of data generated by II and the redundancy it contains together lead to the need for an efficient compression scheme. During recent years, the compression of 3D integral images has been widely researched. Nevertheless, there have not been many approaches proposed regarding the compression of integral videos (IVs). The objective of the thesis is to investigate efficient coding methods for integral videos. The integral video frames used are captured by the first consumer used light field camera Lytro. One of the coding methods is to encode the video data directly by an H.265/HEVC encoder. In other coding schemes the integral video is first converted to an array of sub-videos with different view perspectives. The sub-videos are then encoded either independently or following a specific reference picture pattern which uses a MVHEVC encoder. In this way the redundancy between the multi-view videos is utilized instead of the original elemental images. Moreover, by varying the pattern of the subvideo input array and the number of inter-layer reference pictures, the coding performance can be further improved. Considering the intrinsic properties of the input video sequences, a QP-per-layer scheme is also proposed in this thesis. Though more studies would be required regarding time and complexity constraints for real-time applications as well as dramatic increase of number of views, the methods proposed inthis thesis prove to be an efficient compression for integral videos.
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A platform for multi-video learning content in emergency-related educational scenariosLozano-Prieto, David January 2021 (has links)
Utilizing multiple videos is an upcoming approach for developing learning material. It consists of recording scenes from different perspectives using diverse recording approaches, for example, 360-degrees camera, a drone camera, and body cameras. Up until now, there is a lack of efficient ways to present such recordings and extract the benefits of applying this type of media in learning contexts. To close this gap, this thesis explores suitable manners for presenting this specific type of media, aiming to be helpful for the further training of emergency-related learners. To achieve this goal, we performed a study structured in three major blocks: design of the solution, development of the designed system, and assessment of the suitability of the presented solution. The design was informed by a literature review, a qualitative expert interview, and a preferences questionnaire. After the design process, the system named Theia was developed using web-based technologies. Finally, to validate the system’s suitability within the context of this project, an expert evaluation was carried out. It consisted of a mixed assessment combining qualitative methods, based on task performance and qualitative interview assessment, and the usage of a Technology Acceptance Model (TAM) questionnaire, aiming for the usability and the ease of use of the developed tool. After the evaluation, the proposed system was concluded to incorporate a suitable layout, navigation, functionalities, and interactive mechanisms for an adequate video presentation of media footage from simultaneous recordings within an educational context for emergency-related students. Additionally, valuable insights were extracted from the analysis of the results for the future of the area of research, including recommendations for an optimal footage recording and the starting point for future work in the research community.
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3D Video Playback : A modular cross-platform GPU-based approach for flexible multi-view 3D video renderingAndersson, Håkan January 2010 (has links)
The evolution of depth‐perception visualization technologies, emerging format standardization work and research within the field of multi‐view 3D video and imagery addresses the need for flexible 3D video visualization. The wide variety of available 3D‐display types and visualization techniques for multi‐view video, as well as the high throughput requirements for high definition video, addresses the need for a real‐time 3D video playback solution that takes advantage of hardware accelerated graphics, while providing a high degree of flexibility through format configuration and cross‐platform interoperability. A modular component based software solution based on FFmpeg for video demultiplexing and video decoding is proposed,using OpenGL and GLUT for hardware accelerated graphics and POSIX threads for increased CPU utilization. The solution has been verified to have sufficient throughput in order to display 1080p video at the native video frame rate on the experimental system, which is considered as a standard high‐end desktop PC only using commercial hardware. In order to evaluate the performance of the proposed solution a number of throughput evaluation metrics have been introduced measuring average frame rate as a function of: video bit rate, video resolution and number of views. The results obtained have indicated that the GPU constitutes the primary bottleneck in a multi‐view lenticular rendering system and that multi‐view rendering performance is degraded as the number of views is increased. This is a result of the current GPU square matrix texture cache architectures, resulting in texture lookup access times according to random memory access patterns when the number of views is high. The proposed solution has been identified in order to provide low CPU efficiency, i.e. low CPU hardware utilization and it is recommended to increase performance by investigating the gains of scalable multithreading techniques. It is also recommended to investigate the gains of introducing video frame buffering in video memory or to move more calculations to the CPU in order to increase GPU performance.
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