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Compressed sensing (CS) provides a new method to encode depth videos, which utilizes the sparsity of depth maps to improve the coding efficiency. In this paper, we design a novel CS-based depth video codec. The codec adaptively decomposes blocks from 64 χ 64 to 8 χ 8 sub-blocks via wavelet transforming. The decomposition divides smooth regions and complex boundaries by frequencies, and minimizes the...
Modern video compression standards rely on motion-compensated prediction from multiple reference pictures. In past standardisation efforts following the introduction of bidirectional prediction, reference pictures were typically signalled in two independent lists, used for forward- and backward-prediction. Modern video coding standards, such as H.264/MPEG-4 Advanced Video Coding or High Efficiency...
To improve the intra lossless video coding efficiency by introducing frequency domain compression, this paper presents a new intra coding scheme for lossless mode in HEVC. The proposed method utilizes reversible lifting DWT and DC level shifting to transform one frame into four sub-bands of frequency coefficients for the original coding tools to process. To recover the transformed frequency coefficients...
Adaptive transform learning schemes have been extensively studied in the literature with a goal to achieve better compression efficiency compared to extensively used Discrete Cosine Transforms (DCT) inside a video codec. These transforms are learned offline on a large training set and are tested either in competition with or in place of the core transforms i.e. DCT. In our previous work, we proposed...
In this paper, we present precise time and energy models for an intra-only HEVC video encoder. These models are a step forward to understand and estimate the computational complexity and energy demands of an HEVC encoder, which in turn opens the path to finely tuning the computational resources that are dedicated to this purpose. Our models estimate the complexity and energy consumed by the HEVC encoder,...
Motion vectors of depth-maps in multiview and free-viewpoint videos exhibit strong spatial as well as inter-component clustering tendency. This paper presents a novel coding technique that first compresses the multidimensional bitmaps of macroblock mode and then encodes only the non-zero components of motion vectors. The bitmaps are partitioned into disjoint cuboids using binary tree based decomposition...
In order to improve the compression ratio, most of improved compression methods require more memory and CPU time. But these improvements are not suitable for embedded system with limited-resource, especially for vehicle communications system. In order to communicate realtimely by lower costs, the huge and short data are compressed before transmitting. This paper discusses several original lossless...
Abstract-The capacity of the intensity-modulation directdetection (IM-DD) optical broadcast channel (OBC) is investigated. The OBC is modeled as a Gaussian channel with input-independent noise and both average and peak input constraints. Outer and inner bounds on the capacity region are derived. The outer bounds are based on Bergmans' approach. The inner bounds are based on superposition coding with...
Shadow removal from color images is considered as a challenging task during last decades. Several approaches have been introduced to address and improve this task. A major breakthrough in this area is projecting the correct direction that minimizes the entropy to get rid of the lighting effect. In this work, we reduce the computational time of entropy minimization up to 52% and decrease the number...
In this paper, we investigate how to adapt a composite decode-forward (DF) two-way relaying scheme to fading links. We develop a maximum entropy (ME) quantization algorithm to feed back the link magnitudes such that the transmitters are able to perform link adaptation. The ME algorithm outperforms that of Lloyd-Max in mid and high range SNR, and performs comparably at low SNR. With just one bit of...
In this paper, the secrecy rate region of independent parallel multiple-carrier two-way secure communications with secure feedback is investigated. The legitimate user securely feeds back the secret key to the other legitimate user via secure feedback link in the presence of a passive eavesdropper, and the latter legitimate user encrypts confidential message with the received secret key. It is first...
This paper decouples the complex Rate-Distortion (R-D) analysis problem by inspecting the respective influence of source distribution and quantizer design on R-D performance. First, a universal R-D property is theoretically revealed that, for any source distribution can be expressed as the product of a Scaling Factor (SF) and its remaining part, SF does not affect its derivative R-D function. Second,...
This paper discusses a possible program for improving the outer (converse) bounds on the finite-blocklength performance of multiple-access codes. The program is based on a certain conjecture involving Rényi entropy of a sum of two independent binary vectors. Some partial results towards showing the conjecture are presented. The problem of bounding the joint Rényi entropy in terms of the marginal entropies...
We consider a distributed parameter estimation problem, in which multiple terminals send messages related to their local observations using limited rates to a fusion center who will obtain an estimate of a parameter related to observations of all terminals. It is well known that if the transmission rates are in the Slepian-Wolf region, the fusion center can fully recover all observations and hence...
Consider a remote estimation system formed by a channel and an encoder that assesses a continuous random variable denoted as source. The internal structure of the channel has a finite state machine (FSM) whose state dictates the transmission characteristics. Each state of the FSM corresponds to a discrete memoryless channel (DMC). At each channel use, information is transmitted from the encoder to...
In the communication of source-coded messages, certain dependency structures often exist among the messages, where a source model is proposed to model arbitrary dependency structure of such kind. Under a message-dependency model, the problem of communicating dependent messages subject to certain delay constraint is formulated as the problem of maximizing the average utility at the receiver. In this...
We revisit a fundamental open problem in quantum information theory, namely whether it is possible to transmit quantum information at a rate exceeding the channel capacity if we allow for a non-vanishing probability of decoding error. Here we establish that the Rains information of any quantum channel is a strong converse rate for quantum communication: For any code with a rate exceeding the Rains...
Content delivery networks often employ caching to reduce transmission rates from the central server to the end users. Recently, the technique of coded caching was introduced whereby coding in the caches and coded transmission signals from the central server are considered. Prior results in this area demonstrate that (a) carefully designing placement of content in the caches and (b) designing appropriate...
Guesswork forms the mathematical framework for quantifying computational security subject to brute-force determination by query. In this paper, we consider guesswork subject to a per-symbol Shannon entropy budget. We introduce inscrutability rate as the asymptotic rate of increase in the exponential number of guesses required of an adversary to determine one or more secret strings. We prove that the...
English words and the outputs of many other natural processes are well-known to follow a Zipf distribution. Yet this thoroughly-established property has never been shown to help compress or predict these important processes. We show that the expected redundancy of Zipf distributions of order α > 1 is roughly the 1/α power of the expected redundancy of unrestricted distributions. Hence for these...
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