It is demonstrated how the Hermite transform can be used for image coding and analysis. hierarchical coding structures based on increasingly specified basic patterns, i.e. general 2-D patterns, general 1-D patterns, a...
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It is demonstrated how the Hermite transform can be used for image coding and analysis. hierarchical coding structures based on increasingly specified basic patterns, i.e. general 2-D patterns, general 1-D patterns, and specific 1-D patterns such as edges and corners, are presented. In the image coding application, the relation with existing pyramid coders is described. A new coding scheme, based on local one-dimensional image approximations, is introduced. In the image analysis application, the relation between the Hermite transform and existing line/edge detection schemes is described. It is shown that, by concentrating on more specific patterns, the coding efficiency can be increased since fewer coefficients have to be coded. Meanwhile, sufficient descriptive power can be maintained for approximating the most interesting features in natural images.
In distributed computing systems slow working nodes, known as stragglers, can greatly extend finishing times. Coded computing is a technique that enables straggler-resistant computation. Most coded computing technique...
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In distributed computing systems slow working nodes, known as stragglers, can greatly extend finishing times. Coded computing is a technique that enables straggler-resistant computation. Most coded computing techniques presented to date provide robustness by ensuring that the time to finish depends only on a set of the fastest nodes. However, while stragglers do compute less work than non-stragglers, in real-world commercial cloud computing systems (e.g., Amazon's Elastic Compute Cloud (EC2)) the distinction is often a soft one. In this paper, we develop hierarchical coded computing that exploits the work completed by all nodes, both fast and slow, automatically integrating the potential contribution of each. We first present a conceptual framework to represent the division of work amongst nodes in coded matrix multiplication as a cuboid partitioning problem. This framework allows us to unify existing methods and motivates new techniques. We then develop three methods of hierarchical coded computing that we term bit-interleaved coded computation (BICC), multilevel coded computation (MLCC), and hybrid hierarchical coded computation (HHCC). In this paradigm, each worker is tasked with completing a sequence (a hierarchy) of ordered subtasks. The sequence of subtasks, and the complexity of each, is designed so that partial work completed by stragglers can be used, rather than ignored. We note that our methods can be used in conjunction with any coded computing method. We illustrate this by showing how we can use our methods to accelerate all previously developed coded computing techniques by enabling them to exploit stragglers. Under a widely studied statistical model of completion time, our approach realizes a 66% improvement in the expected finishing time. On Amazon EC2, the gain was 27% when stragglers are simulated.
A low delay coder for speech and music signals sampled at 32 kHz is described. Its algorithmic delay does not exceed 25 ms which enables audio conferencing applications without echo cancellation. Its bot rate is scala...
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A low delay coder for speech and music signals sampled at 32 kHz is described. Its algorithmic delay does not exceed 25 ms which enables audio conferencing applications without echo cancellation. Its bot rate is scalable between 64 and 32 kbits/s by steps of 8 kbits/s. The transmitter issues the binary code at 64 kbits/s with lower bit rate codes embedded in it. The receiver may operate at lower bit rates with gradual loss of quality. The proposed coder is based on a mixed scheme: the adopted solution contains elements from the CELP speech coder and frequency domain where bit allocation is calculated and transform coefficients are quantized. A first solution based on the DFT is discussed, then a second solution based on a MDCT with small overlap is applied. The quantization of these coefficients is done in the following way. First, a prediction of the whole spectrum is applied. Then, a mean-removed gain-shape split VQ is used for amplitude spectrum quantization and a hierarchical 2-dimensional VQ is used for phase spectrum quantization stage, each codeword describing the selected vector index is split into parts corresponding to different bit rates. Due to the hierarchical codebook structure, truncated indices may be used, without much affecting the signal quality. Simulation results are presented and the robustness of the proposed coder is examined.
In this paper, we present JPEG-based scalable image compression algorithms for storage and transmission applications. The JPEG standard for still image compression provides the framework for reconstructing images in d...
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In this paper, we present JPEG-based scalable image compression algorithms for storage and transmission applications. The JPEG standard for still image compression provides the framework for reconstructing images in different sizes and picture qualities. These features are generally referred to as spatial and SNR scalability, respectively, and are extremely important in a variety of applications. A review of the different modes of the JPEG standard followed by the implementation and performance evaluation of the progressive and hierarchical coding modes which provide SNR and spatial scalability, respectively, are detailed. We then present a highperformance technique based on Wavelet filter downsampling for achieving spatial scalability within the framework of the hierarchical mode of the JPEG standard. This technique provides substantial improvement in performance while maintaining the compatibility with existing JPEG decoders.
Intending to contribute to constructing better multimedia network systems, we propose a new concept of image database system of which form of storage is featuring exponential or graceful oblivion and abrupt recollecti...
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Intending to contribute to constructing better multimedia network systems, we propose a new concept of image database system of which form of storage is featuring exponential or graceful oblivion and abrupt recollection like the human memory property. By virtue of this property of database storages that is realized by employing hierarchical or pyramidal image coding, the database memory and transmission costs can be significantly reduced. In this paper we will describe the details of the concept, the results of theoretical analysis based on a simplified model which reveals the effectiveness of the proposed system, the structure of an experimental prototype system and the result of an experimental image retrieval service carried out by implementing it over ATM high speed channels.
We examine the design of space-time codes that allow simple encoding and decoding of high and low-priority streams of data. This paper comprises two parts. In the first part we introduce the system model, establish pe...
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We examine the design of space-time codes that allow simple encoding and decoding of high and low-priority streams of data. This paper comprises two parts. In the first part we introduce the system model, establish performance and complexity criteria, and introduce "direct-sum" codes that combine existing space-time codes with hierarchical modulation. In this second part, we show that the direct-sum codes of the first part can be greatly improved upon by non-direct-sum designs. We demonstrate unitary-transform codes for two and four antennas. In particular, one such code performs 4 dB better than the direct-sum Alamouti code, with per-bit decoding complexity on one stream that is a bounded function of the rate of the other stream.
Video adaptation has been considered as a promising technique to tackle challenging problems in pervasive media applications. However, the style of video representation and description in current framework is too simp...
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Video adaptation has been considered as a promising technique to tackle challenging problems in pervasive media applications. However, the style of video representation and description in current framework is too simple to accommodate diversified usages, especially for real-time application environment. In this paper, an intermediate video description termed Intermedia is proposed, which is generated by off-line pre-processing the original video signal and includes abundant information of video content. On the basis of Intermedia, a novel framework for video adaptation can be implemented to handle multiple video applications. The framework has low complexity operations not only in signal level, but also in structural level, and in joint level. Texture, motion and structural characteristic are included in Intermedia, so that the framework call tackle a number of different adaptation applications, e.g., bit-rate conversion, temporal resolution reduction, video summarization browsing, and multi-dimensional adaptation. Experimental results demonstrate that Intermedia can support multiple video adaptations rapidly while maintaining coding efficiency(1).
Filters are determined which achieve optimal pyramidal decomposition of vector signals by minimising the variance of the errors between successive pyramid levels. Further, the filters are also determined which minimiz...
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Filters are determined which achieve optimal pyramidal decomposition of vector signals by minimising the variance of the errors between successive pyramid levels. Further, the filters are also determined which minimize the error produced when only one of the channels is retained from a multi-channel. perfect reconstruction filter bank. The effect of either decomposition is to ensure that the lower-resolution image produced by the pyramid or the primary subband, bears maximum resemblance to the input image. This property is needed in applications requiring hierarchical (scalable, progressive) coding of vector fields. The noiseless case is examined first. Given arbitrary filters in one of the analysis or synthesis stages of the pyramid or the filter bank, the optimal corresponding synthesis, respectively analysis filters, are determined. Further, the globally optimal pairs of analysis and synthesis filters are determined. It is seen that under noiseless or lossless transmission conditions, the two above decomposition methods are optimised by identical families of analysis and synthesis filters. This is not the case if it is assumed that additive transmission noise corrupts the downsampled signal prior to the synthesis stage. This noise may represent transmission noise or the effect of quantisation between the analysis and synthesis stages. Given arbitrary analysis filters and arbitrary noise characteristics, the optimal synthesis filters are then determined for each decomposition method. The results are initially presented for the binary case and subsequently generalized to the case of M-factor pyramids and M-channel filter banks. (C) 1998 Elsevier Science B.V. All rights reserved.
Most indexing systems are based on global image descriptors. Nowadays, new representations are used. They try to describe images more precisely without exploiting any semantic description. They use local statistics an...
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Most indexing systems are based on global image descriptors. Nowadays, new representations are used. They try to describe images more precisely without exploiting any semantic description. They use local statistics and their relationships in the image. In this paper we present these approaches and introduce a new representation system based on a pyramidal graph. First results are also presented which show that the proposed structure is very promising for both partial and global requests.
Audio-visual and other multimedia services are seen as important source of traffic for ATM networks. Due to the statistical multiplexing schemes used by ATM networks, cells are exposed to delays, jitters and losses. T...
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Audio-visual and other multimedia services are seen as important source of traffic for ATM networks. Due to the statistical multiplexing schemes used by ATM networks, cells are exposed to delays, jitters and losses. These phenomena affect the quality of the service provided to the video-based applications, In this paper, we introduce a set of control mechanisms at different levels of the protocol architecture. These mechanisms have been particularly tailored to better support MPEG-2-based video communications applications using ATM networks as their underlying transmission mechanism. We show that the use of errorconcealment mechanisms prove more effective when supplemented by a structural set of protocol mechanisms. We study the impact of cell losses on the quality of MPEG-2 video sequences and provide an evaluation of the quality of the decoded video as perceived by the end user. Our results demonstrate the effectiveness of the proposed protocol architecture in improving the quality of service provided to the video application.
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