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Correlation Noise Modeling (CNM) is a key factor to influence the performance of Distributed Video Coding (DVC). In most current CNM solutions, the distribution parameter is estimated based on the motion compensated residual frames and kept constant during the decoding process. A progressive correlation noise refinement method is proposed in this paper for transform domain Wyner-Ziv video coding to...
During the past decade, Distributed Video Coding (DVC) has emerged as a new video coding paradigm, shifting the complexity from the encoder - to the decoder-side. This paper addresses a problem of current DVC architectures that has not been studied in the literature so far, that is, the mismatch between the intra and Wyner-Ziv (WZ) quantization processes. Due to this mismatch, WZ rate is spent even...
The compression efficiency of coding noisy image sequences is highly dependent on the noise itself and on the used quantization parameter. For very high quality near lossless compression a promising approach to save bitrate is to introduce an in-loop denoising filter in the codec. In this paper, we enhance our in-loop denoising scheme by a low complexity noise variance estimation algorithm. Additionally,...
To solve the problem of the low speech signal quality on the FH channels with wideband rejective interference, the performance optimization of CVSD coding in the digital FH system was studied. A new CVSD demodulation arithmetic was designed based on the principle of traditional CVSD system. Then the rule for measuring the quality of speech signal was offered and presented the simulation method of...
We consider an information theoretic model that describes parallel reception of a common signal by many receivers. The signal is distorted by noise and independently decoded by each receiver. Receivers cooperate in the sense that the outcome is conveyed to a decision center, which makes the final decision on the received signal by a majority vote. A potential scenario which could be described by this...
This paper introduces a new Level-Crossing ADC (LCADC) architecture which employs the novel use of a clocked comparator. The proposed LCADC can measure a timing noise spectrum with wide dynamic range and wide frequency range. An extension of the underlying theory of the performance measurement of an LCADC is also included.
In video communication systems, due to quantization and transmission errors, mismatches between the transmitter - and receiver-side information may occur, severely impacting the reconstructed video. Theoretical understanding of the quality degradation ensuing from such mismatches is essential when targeting quality-of-service for video communications. In this paper, by viewing the mismatches in the...
JPEG coding leaves characteristic footprints that can be leveraged to reveal doctored images, e.g. providing the evidence for local tampering, copy-move forgery, etc. Recently, it has been shown that a knowledgeable attacker might attempt to remove such footprints by adding a suitable anti-forensic dithering signal to the image in the DCT domain. Such noise-like signal restores the distribution of...
Since current coding standards rely on block based processing, reconstructed images include horizontal and vertical grid noise along the block boundaries. This image degradation, called blocking artifacts, is mainly caused due to the quantization process of discrete cosine transform (DCT) coefficients. In this paper, we present a novel post processing framework for blocking artifact reduction, which...
We propose a tracking-aware system that removes video components of low tracking interest and optimizes the quantization during compression of frequency coefficients, particularly those that most influence trackers, significantly reducing bitrate while maintaining comparable tracking accuracy. We utilize tracking accuracy as our compression criterion in lieu of mean squared error metrics. The process...
This paper proposes a compact mathematical model for predicting and analyzing Delta-Sigma modulator's spurious tones. The model is based on frequency modulation and it outputs an accurate quantization noise estimate array for an arbitrary modulator stimulus: dc, ramp, sinusoid, two-tone, etc. For predicting the pattern noise or limit cycles, the proposed estimation model was found very precise. The...
Increasingly, software defined radio receivers adopting band sampling are widely applied in space mission. In such systems, particularly in spread-spectrum ranging systems, the influence of sampling noise can not be neglected. The paper analyzes the sampling noise, presents its influence on the carrier noise ratio, and derives the ranging error by calculating the synchronization error of the delay...
This paper presents a discrete time ΔΣ modulator operating under 1V power supply. To achieve high precision under low voltage while preserve low power consumption, techniques from systematic level to circuits' level are used. On the systematic level, modulator with 4-bit quantizer is employed. The advantage is its excellent stability performance which extends input signal range near to the reference...
Super-resolution (SR) reconstruction technique is mainly a task of reconstructing high resolution images from a sequence of low resolution images. The super-resolution technique for H.264 compressed video has been focused by many researchers recently. This paper briefly analyzes the narrow quantization constraint set method (NQCS), and then, in consideration of motion characteristic information of...
Application of the ΣΔ modulation technique to the on-chip spectral test for high-speed A/D converters is presented. The harmonic HD2/HD3 and intermodulation IM2/IM3 test is obtained with one-bit ΣΔ sequence stored in a cyclic memory or generated on line, and applied to an ADC under test through a driving buffer and a simple reconstruction filter. To achieve a dynamic range (DR) suitable for high-performance...
The motes in a wireless sensor network observe the environment, make estimates based on their observations, and then send these estimates to a Cluster-Head (CH). A novel scheme based on dithered quantization and channel compensation is used to ensure that each mote's local estimate received by the CH is unbiased. Then the CH fuses these unbiased local estimates into a global one using a Best Linear...
The goal of this paper is to propose a bio-inspired algorithm for decentralized dynamic access in cognitive radio systems. We study an improved social foraging swarm model that lets every node allocate its resources (power/bits) in the frequency regions where the interference is minimum while avoiding collisions with other nodes. The proposed approach adapts its behavior with respect to the interference...
A Phase-based Delta-Sigma (ΔΣ) Analog-to-Digital Converter (ADC) adopting a Delay-Locked-Loop (DLL) mechanism is presented. It is realized by a modification of a DLL using a Voltage-Controlled Delay Line (VCDL) based quantizer and a charge pump in the feedback path. The proposed architecture offers both reference jitter shaping and quantization noise shaping. Simulation results show that the proposed...
Decoding of real BCH DFT (RBDFT) codes is considered in this paper. RBDFT codes find applications in several areas. Though the generator matrix of RBDFT codes is real, the parity check matrix is still complex, because of which complex arithmetic operations are necessary at the decoder. But for a real message vector, the syndromes of RBDFT code preserve Hermitian symmetry. This Hermitian symmetric...
In this article, the design and analysis of sophisticated multi-band quadrature ΣΔ modulators (QΣΔM) are addressed, offering a high-performance and easily-reconfigurable solution for the analog-to-digital (A/D) interface of cognitive radio receivers. Based on spectrum sensing information, the multi-band principle stemming from multi-stage converter implementation enables multiple reconfigurable noise...
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