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Author: Manal Khalil Jalloul
Publisher:
ISBN:
Category :
Languages : en
Pages : 142
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Book Description
Distributed video coding (DVC) is a new video coding paradigm that allows low co mplexity encoding for emerging applications such as wireless video surveillance, multimedia sensor networks, and mobile camera phones. Side information (SI) generation is a key function in the DVC decoder, and plays a key-role in determining the performance of the codec. Current approaches to D VC rely on motion-compensated interpolation (MCTI) to generate at the decoder th e SI which is an estimation of the frame being decoded. This work presents a nov el MCTI algorithm to generate the SI. This algorithm can also be used for other purposes such as frame rate up-conversion (FRUC). In the proposed scheme, motion estimation utilizes only the low-frequency conten t of the key frames whereas motion compensation is performed using the entire fr equency range. The motivation behind this approach is that MCTI was found to pro vide better interpolation results in the low frequency range than in the high fr equency range. Thus, the proposed approach allows obtaining a better estimate of the high frequency component of the interpolated frame using the more accurate low frequency estimate. A variable-size block matching algorithm (VSBMA) is adop ted in our scheme where the dimensions of the block are allowed to adapt to the local activity within the image; by using larger blocks for large areas of stati onary background or uniform motion, and using smaller blocks where the movement is localized or complex. A 3-D recursive search algorithm (3DRS) is used for mot ion estimation with the resulting variable-size blocks. A novel motion-compensated enhancement (MCE) algorithm is also proposed in this thesis to refine and improve the quality of the interpolated frame generated by MCTI, which is considered as an initial SI (ISI) estimate. In MCE, another motio n-compensated interpolation is performed using the previous and following key fr ames, just like MCTI, plus an a priori knowledge about the interpolated frame ta ken from the ISI estimate. This was shown to generate a motion compensated estim ate of the SI more accurate than MCTI alone. Simulation results are presented to illustrate the performance of the proposed scheme.
Author: Manal Khalil Jalloul
Publisher:
ISBN:
Category :
Languages : en
Pages : 142
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Book Description
Distributed video coding (DVC) is a new video coding paradigm that allows low co mplexity encoding for emerging applications such as wireless video surveillance, multimedia sensor networks, and mobile camera phones. Side information (SI) generation is a key function in the DVC decoder, and plays a key-role in determining the performance of the codec. Current approaches to D VC rely on motion-compensated interpolation (MCTI) to generate at the decoder th e SI which is an estimation of the frame being decoded. This work presents a nov el MCTI algorithm to generate the SI. This algorithm can also be used for other purposes such as frame rate up-conversion (FRUC). In the proposed scheme, motion estimation utilizes only the low-frequency conten t of the key frames whereas motion compensation is performed using the entire fr equency range. The motivation behind this approach is that MCTI was found to pro vide better interpolation results in the low frequency range than in the high fr equency range. Thus, the proposed approach allows obtaining a better estimate of the high frequency component of the interpolated frame using the more accurate low frequency estimate. A variable-size block matching algorithm (VSBMA) is adop ted in our scheme where the dimensions of the block are allowed to adapt to the local activity within the image; by using larger blocks for large areas of stati onary background or uniform motion, and using smaller blocks where the movement is localized or complex. A 3-D recursive search algorithm (3DRS) is used for mot ion estimation with the resulting variable-size blocks. A novel motion-compensated enhancement (MCE) algorithm is also proposed in this thesis to refine and improve the quality of the interpolated frame generated by MCTI, which is considered as an initial SI (ISI) estimate. In MCE, another motio n-compensated interpolation is performed using the previous and following key fr ames, just like MCTI, plus an a priori knowledge about the interpolated frame ta ken from the ISI estimate. This was shown to generate a motion compensated estim ate of the SI more accurate than MCTI alone. Simulation results are presented to illustrate the performance of the proposed scheme.
Author: Jun Guo
Publisher:
ISBN:
Category :
Languages : en
Pages : 106
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Book Description
Author: Yaser Mohammad Taheri
Publisher:
ISBN:
Category :
Languages : en
Pages : 136
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Book Description
Distributed video coding is a coding paradigm, which allows encoding of video frames at a complexity that is substantially lower than that in conventional video coding schemes. This feature makes it suitable for some emerging applications such as wireless surveillance video and mobile camera phones. In distributed video coding, a subset of frames in the video sequence, known as the key frames, are encoded using a conventional intra-frame encoder, such as H264/AVC in the intra mode, and then transmitted to the decoder. The remaining frames, known as the Wyner-Ziv frames, are encoded based on the Wyner-Ziv principle by using the channel codes, such as LDPC codes. In the transform-domain distributed video coding, each Wyner-Ziv frame undergoes a 4x4 block DCT transform and the resulting DCT coefficients are grouped into DCT bands. The bitplaines corresponding to each DCT band are encoded by a channel encoder, for example an LDPCA encoder, one after another. The resulting error-correcting bits are retained in a buffer at the encoder and transmitted incrementally as needed by the decoder. At the decoder, the key frames are first decoded. The decoded key frames are then used to generate a side information frame as an initial estimate of the corresponding Wyner-Ziv frame, usually by employing an interpolation method. The difference between the DCT band in the side information frame and the corresponding one in the Wyner-Ziv frame, referred to as the correlation noise, is often modeled by Laplacian distribution. A soft-input information for each bit in the bitplane is obtained using this correlation noise model and the corresponding DCT band of the side information frame. The channel decoder then uses this soft-input information along with some error-correcting bits sent by the encoder to decode the bitplanes of each DCT band in each of the Wyner-Ziv frames. Hence, an accurate estimation of the correlation noise model parameter(s) and generation of high-quality side information are required for reliable soft-input information for the bitplanes in the decoder, which in turn leads to a more efficient decoding. Consequently, less error-correcting bits need to be transmitted from the encoder to the decoder to decode the bitplanes, leading to a better compression efficiency and rate-distortion performance. The correlation noise is not stationary and its statistics vary within each Wyner-Ziv frame and within its corresponding DCT bands. Hence, it is difficult to find an accurate model for the correlation noise and estimate its parameters precisely at the decoder. Moreover, in existing schemes the parameters of the correlation noise for each DCT band are estimated before the decoder starts to decode the bitplanes of that DCT band and they are not modified and kept unchanged during decoding process of the bitplanes. Another problem of concern is that, since side information frame is generated in the decoder using the temporal interpolation between the previously decoded frames, the quality of the side information frames is generally poor when the motions between the frames are non-linear. Hence, generating a high-quality side information is a challenging problem. This thesis is concerned with the study of accurate estimation of correlation noise model parameters and increasing in the quality of the side information from the standpoint of improving the rate-distortion performance in distributed video coding. A new scheme is proposed for the estimation of the correlation noise parameters wherein the decoder decodes simultaneously all the bitplanes of a DCT band in a Wyner-Ziv frame and then refines the parameters of the correlation noise model of the band in an iterative manner. This process is carried out on an augmented factor graph using a new recursive message passing algorithm, with the side information generated and kept unchanged during the decoding of the Wyner-Ziv frame. Extensive simulations are carried out showing that the proposed decoder leads to an improved rate-distortion performance in comparison to the original DISCOVER codec and in another DVC codec employing side information frame refinement, particularly for video sequences with high motion content. In the second part of this work, a new algorithm for the generation of the side information is proposed to refine the initial side information frame using the additional information obtained after decoding the previous DCT bands of a Wyner-Ziv frame. The simulations are carried out demonstrating that the proposed algorithm provides a performance superior to that of schemes employing the other side information refinement mechanisms. Finally, it is shown that incorporating the proposed algorithm for refining the side information into the decoder proposed in the first part of the thesis leads to a further improvement in the rate-distortion performance of the DVC codec.
Author: Huihui Bai
Publisher: Springer Science & Business Media
ISBN: 1447122488
Category : Computers
Languages : en
Pages : 183
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Book Description
This book examines distributed video coding (DVC) and multiple description coding (MDC), two novel techniques designed to address the problems of conventional image and video compression coding. Covering all fundamental concepts and core technologies, the chapters can also be read as independent and self-sufficient, describing each methodology in sufficient detail to enable readers to repeat the corresponding experiments easily. Topics and features: provides a broad overview of DVC and MDC, from the basic principles to the latest research; covers sub-sampling based MDC, quantization based MDC, transform based MDC, and FEC based MDC; discusses Sleplian-Wolf coding based on Turbo and LDPC respectively, and comparing relative performance; includes original algorithms of MDC and DVC; presents the basic frameworks and experimental results, to help readers improve the efficiency of MDC and DVC; introduces the classical DVC system for mobile communications, providing the developmental environment in detail.
Author: Ce Zhu
Publisher: CRC Press
ISBN: 143988000X
Category : Computers
Languages : en
Pages : 512
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Book Description
Wireless video communications encompass a broad range of issues and opportunities that serve as the catalyst for technical innovations. To disseminate the most recent advances in this challenging yet exciting field, Advanced Video Communications over Wireless Networks provides an in-depth look at the fundamentals, recent technical achievements, challenges, and emerging trends in mobile and wireless video communications. The editors have carefully selected a panel of researchers with expertise in diverse aspects of wireless video communication to cover a wide spectrum of topics, including the underlying theoretical fundamentals associated with wireless video communications, the transmission schemes tailored to mobile and wireless networks, quality metrics, the architectures of practical systems, as well as some novel directions. They address future directions, including Quality-of-Experience in wireless video communications, video communications over future networks, and 3D video communications. The book presents a collection of tutorials, surveys, and original contributions, providing an up-to-date, accessible reference for further development of research and applications in mobile and wireless video communication systems. The range of coverage and depth of expertise make this book the go-to resource for facing current and future challenges in this field.
Author: Akinola Mobolaji
Publisher: LAP Lambert Academic Publishing
ISBN: 9783659768804
Category :
Languages : en
Pages : 260
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Book Description
DVC is a new paradigm in video coding where the broadcast type codecs of high computational complexity at the encoder with low complexity at the decoder (using set top boxes) is flipped. Thus It enables video streaming from low complexity encoders which is a requirement for wireless mobile devices that is now widely available worldwide. DVC will leverage on the wide availability of mobile devices to enable video streaming from these low energy devices from remote locations.
Author: 羅際巧
Publisher:
ISBN:
Category :
Languages : en
Pages :
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Author: Sudhakar Radhakrishnan
Publisher: BoD – Books on Demand
ISBN: 953307177X
Category : Computers
Languages : en
Pages : 270
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Book Description
Information has become one of the most valuable assets in the modern era. Within the last 5-10 years, the demand for multimedia applications has increased enormously. Like many other recent developments, the materialization of image and video encoding is due to the contribution from major areas like good network access, good amount of fast processors e.t.c. Many standardization procedures were carrried out for the development of image and video coding. The advancement of computer storage technology continues at a rapid pace as a means of reducing storage requirements of an image and video as most situation warrants. Thus, the science of digital video compression/coding has emerged. This storage capacity seems to be more impressive when it is realized that the intent is to deliver very high quality video to the end user with as few visible artifacts as possible. Current methods of video compression such as Moving Pictures Experts Group (MPEG) standard provide good performance in terms of retaining video quality while reducing the storage requirements. Many books are available for video coding fundamentals.This book is the research outcome of various Researchers and Professors who have contributed a might in this field. This book suits researchers doing their research in the area of video coding.The understanding of fundamentals of video coding is essential for the reader before reading this book. The book revolves around three different challenges namely (i) Coding strategies (coding efficiency and computational complexity), (ii) Video compression and (iii) Error resilience. The complete efficient video system depends upon source coding, proper inter and intra frame coding, emerging newer transform, quantization techniques and proper error concealment.The book gives the solution of all the challenges and is available in different sections.
Author: Mobolaji Olukunle Akinola
Publisher:
ISBN:
Category : Digital video
Languages : en
Pages : 247
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Book Description
Author: 沈允中
Publisher:
ISBN:
Category :
Languages : en
Pages :
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