Generating Side Information Research Articles

Side information hybrid generation based on improved motion vector field

The quality of side information has an important impact on the performance of a distributed video coding system. At present, the generation of side information is mainly based on the translational motion model using the inter-frame correlation for motion estimation. Considering that the generated side information is prone to block effect and ghosting, as well as the situation that the nonlinear motion is not fully considered and the intra-frame correlation is not fully utilized, a side information hybrid generation algorithm based on an improvement model for the motion vector field is proposed. The side information frame to be generated for the current Wyner-Ziv frame is divided into easy-to-estimate and difficult-to-estimate macroblocks. For difficult-to-estimate macroblocks, the Horn and Schunck dense optical flow method is used to generate reliable motion vectors, for easy-to-estimate macroblocks, the block matching method is used to generate unreliable motion vectors which are modified by the proposed scheme, and then, the improved motion vectors are used for motion compensation to produce the final side information frame. Experiment results show that the quality of side information obtained by using the improved motion vector field for motion compensation has been significantly improved, thus the overall performance of the distributed video coding system has been effectively improved.

Side Information Generation Scheme Based on Coefficient Matrix Improvement Model in Transform Domain Distributed Video Coding.

In order to effectively improve the quality of side information in distributed video coding, we propose a side information generation scheme based on a coefficient matrix improvement model. The discrete cosine transform coefficient bands of the Wyner–Ziv frame at the encoder side are divided into entropy coding coefficient bands and distributed video coding coefficient bands, and then the coefficients of entropy coding coefficient bands are sampled, which are divided into sampled coefficients and unsampled coefficients. For sampled coefficients, an adaptive arithmetic encoder is used for lossless compression. For unsampled coefficients and the coefficients of distributed video coding coefficient bands, the low density parity check accumulate encoder is used to calculate the parity bits, which are stored in the buffer and transmitted in small amount upon decoder request. At the decoder side, the optical flow method is used to generate the initial side information, and the initial side information is improved according to the sampled coefficients by using the coefficient matrix improvement model. The experimental results demonstrate that the proposed side information generation scheme based on the coefficient matrix improvement model can effectively improve the quality of side information, and the quality of the generated side information is improved by about 0.2–0.4 dB, thereby improving the overall performance of the distributed video coding system.

Text Mining Using Metadata for Generation of Side Information

Text Mining is knowledge discovery process from large database to find out unknown patterns. In many metadata based text mining applications, side information also known as metadata which is associated with the text document. There are different types side information containing large amount of data i.e. metadata, weblogs and non-textual data (image, video, etc.). The side information is difficult to estimate when it contains noisy data. To achieve this, there is scope of improvement in generating side information i.e. selecting efficient classification and clustering algorithms, providing security for clustered side information, document organization, exploring filtering approaches. In future, there is a scope to design an extended approach for clustering using classical partitioning and probabilistic model.

Distributed Coding Scheme for Multi-view Video through Efficient Side Information Generation

In this paper, a distributed image coding scheme for multi-view video through an efficient generation of side information is proposed. A distributed video coding technique corrects the errors in the side information, which is generated with the original image, by using the channel coding technique at the decoder. Therefore, the more correct the generated side information is, the better the performance of distributed video coding. The proposed technique is to apply the distributed video coding schemes to the image coding for multi-view video. It generates side information by selectively and efficiently using both 3-dimensional warping based on the depth map with spatially adjacent frames and motion-compensated temporal interpolation with temporally adjacent frames. In this scheme the difference between the adjacent frames, the sizes of the motion vectors for the adjacent blocks, and the edge information are used as the selection criteria. From the experiments, it was observed that the quality of the side information generated by the proposed technique was improved by the average peak signal-to-noise ratio of 0.97dB than the one by motion-compensated temporal interpolation or 3-dimensional warping. The result from analyzing the rate-distortion curves revealed that the proposed scheme could reduce the bit-rate by 8.01% on average at the same peak signal-tonoise ratio value, compared to previous work.

적응적 가중치 기반의 움직임 보상 보간에 기초한 채널 분리형 분산 비디오 부호화기법

Recently, lots of research works have been actively focused on the DVC (Distributed Video Coding) techniques which provide a theoretical basis for the implementation of light video encoder. However, most of these studies have showed poorer performances than the conventional standard video coding schemes such as MPEG-1/2, MPEG-4, H.264 etc. In order to overcome the performance limits of the conventional approaches, several channel-divided distributed video coding schemes have been designed in such a way that some information are obtained while generating side information at decoder side and then these are provided to the encoder side, resulting in channel-divided video coding scheme. In this paper, the interpolation scheme by weighted sum of multiple motion-compensated interpolation frames is introduced and a new channel-divided DVC scheme is designed to effectively describe noisy channels based on the motion vector and its matching characteristics. Through several simulations, it is shown that the proposed method performs better than the conventional methods at low bit-rate and keeps the reconstructed visual quality constantly.

LineCast: Line-Based Distributed Coding and Transmission for Broadcasting Satellite Images

In this paper, we propose a novel coding and transmission scheme, called LineCast, for broadcasting satellite images to a large number of receivers. The proposed LineCast matches perfectly with the line scanning cameras that are widely adopted in orbit satellites to capture high-resolution images. On the sender side, each captured line is immediately compressed by a transform-domain scalar modulo quantization. Without syndrome coding, the transmission power is directly allocated to quantized coefficients by scaling the coefficients according to their distributions. Finally, the scaled coefficients are transmitted over a dense constellation. This line-based distributed scheme features low delay, low memory cost, and low complexity. On the receiver side, our proposed line-based prediction is used to generate side information from previously decoded lines, which fully utilizes the correlation among lines. The quantized coefficients are decoded by the linear least square estimator from the received data. The image line is then reconstructed by the scalar modulo dequantization using the generated side information. Since there is neither syndrome coding nor channel coding, the proposed LineCast can make a large number of receivers reach the qualities matching their channel conditions. Our theoretical analysis shows that the proposed LineCast can achieve Shannon's optimum performance by using a high-dimensional modulo-lattice quantization. Experiments on satellite images demonstrate that it achieves up to 1.9-dB gain over the state-of-the-art 2D broadcasting scheme and a gain of more than 5 dB over JPEG 2000 with forward error correction.

Block boundary matching algorithm for generating side information in distributed video codec

Distributed video codec (DVC) has been developed to construct a simple encoder that utilizes information theory for distributed sources in the circumstance of mobile multimedia communication. In the DVC codec, an efficient algorithm to generate side information (SI) is one of the most important techniques to improve the coding performance. We propose a scheme to increase the quality of SI frame, where the proposed scheme consists of three steps. In the first step, SI frame is constructed by motion estimation and motion compensation in the DVC decoder. Then, in the second step, the blocks in the temporary SI frame are classified into reli- able or unreliable ones. The unreliable blocks are updated by block boun- dary matching algorithm in the third step. Simulation results show that the proposed algorithm outperforms the conventional methods significantly. In addition, the proposed scheme can be combined with the conventional schemes generating SI frame to increase the coding performance of the DVC codec. © The Authors. Published by SPIE under a Creative Commons Attribution 3.0 Unported License. Distribution or reproduction of this work in whole or in part requires full attribution of the original publication, including its DOI. (DOI: 10.1117/1.OE.52 .10.103111)

Side Information Refinement for Transform domain Distributed Video Coding

A new side information refinement method for transform domain distributed video coding (DVC) is proposed. In DVC, side information is the frame constructed from key frames which are intra coded. It is utilized as the initial estimate of source symbols of Wyner-Ziv coded frame which is not transmitted to the decoder. Errors in the estimated frames are to be corrected by the decoder using the parity bits which are the only information received from the encoder. Quality of decoder generated side information is one of the most important factors deciding the overall performance of the decoder. A new refinement method of improving the quality of side information of the DVC decoder is proposed. The side information frame is refined at the end of each transform band decoding stage followed by a conventional bi-directional motion estimation and compensation technique. Proposed side information refinement technique consequently improves the quality of final reconstructed pictures.

패리티 비트 요구량 모델링에 의한 분산 비디오의 고속 복호화 기법

Recently, as one of low complexity video encoding methods, DVC (Distributed Video Coding) scheme has been actively studied. Most of DVC schemes exploit feedback channel to achieve better coding performances, however, this causes these schemes to have high decoding delay. In order to overcome these, this paper proposes a new fast DVC decoding method using parity-bit request model, which can be obtained by using bit-error rate, sent by encoder with motion vector, which is transmitted through feedback channel by decoder after generating side information. Through several simulations, it is shown that the proposed method improves greatly the decoding speed, compared to the conventional schemes.

Sprite-based generation of side information for multi-view Distributed Video Coding

Generation of side information for multi-view Distributed Video Coding in multi-camera environments (e.g., video surveillance) poses challenges in scenarios with temporary non-overlapping among views and consequently, no resources for generating the side information at some time instants. In this paper we extend our previous work (Ciobanu and Corte-Real, Multimed Tools Appl 48(3):411---436, 2010) (for scenarios with permanent complete-overlapping among views) and propose a solution to this problem by exploiting the past visual data associated with each view, gathered over time as a panoramic image (sprite). The entire collection of temporal data from all the cameras is subsequently used for generating the side information. We tackle several topics related to these scenarios and propose solutions for the encountered issues. Optimization techniques are also discussed, e.g., temporal tags and block alternatives associated with the sprite contents for an improved generation of side information. This paper also presents a post-processing technique for additional refinement of generated side information. Practical results show an overall significant enhancement of side information by over 2 dB.

분산 동영상 부호화 시스템을 위한 부가정보 생성 기법의 성능 평가

단순한 구조의 부호기를 사용할 수 있는 분산 동영상 부호화 시스템에서는 복호기에서 움직임 보상 보간 기법을 이용하여 부가정보를 생성한다. 생성된 부가정보의 정확성이 Wyner-Ziv 프레임을 복원하기 위한 패리티 정보량에 큰 영향을 미치기 때문에 부가정보의 정확한 생성이 분산 동영상 부호화 시스템의 성능에 큰 영향을 미친다. 본 논문에서는 다양한 부가정보 생성 기법의 성능을 분석하고 효율적인 부가정보 생성 기법을 제안하였고 하드웨어 구현 관점에서 각 부가정보 생성 기법을 비교하였다. 또한 분산 동영상 부호화 시스템에서 사용되는 터보 부호의 부호회율 제어 방법이 전체 성능에 미치는 영향과 부가정보 생성 기법이 전체 분산 동영상 부호화 시스템의 성능에 미치는 영향을 비교 분석하였다. The side information in the distributed video coding system is generated using motion compensated interpolation methods. Since the accuracy of the generated side information affects the amount of parity bits for the reconstruction of Wyner-Ziv frame, it is important to produce an accurate side information. In this paper, we analyze the informance of various side information generation methods and propose an effective side information generation technique. Also, we compare each side information generation methods from the hardware point of view and analyze the performance of distributed video coding system using various side information generation methods.

Wyner–Ziv Video Coding With Classified Correlation Noise Estimation and Key Frame Coding Mode Selection

We improve the overall rate-distortion performance of distributed video coding by efficient techniques of correlation noise estimation and key frame encoding. In existing transform-domain Wyner-Ziv video coding methods, blocks within a frame are treated uniformly to estimate the correlation noise even though the success of generating side information is different for each block. We propose a method to estimate the correlation noise by differentiating blocks within a frame based on the accuracy of the side information. Simulation results show up to 2 dB improvement over conventional methods without increasing encoder complexity. Also, in traditional Wyner-Ziv video coding, the intercorrelation of key frames is not exploited since they are simply intracoded. In this paper, we propose a frequency band coding mode selection for key frames to exploit similarities between adjacent key frames at the decoder. Simulation results show significant improvement especially for low-motion and high frame rate sequences. Furthermore, the advantage of applying both schemes in a hierarchical order is investigated. This method achieves additional improvement.

율-왜곡 기반 선택적 분산 비디오 부호화 기법

분산 비디오 부호화(Distributed Video Coding: DVC)는 계산 성능 및 전력이 제한된 환경에 적합한 초경량 비디오 부호화 기법으로 주목 받고 있으며, 부호화 성능을 개선하기 위한 많은 연구가 진행되고 있다. 본 논문에서는 DVC의 부호화 성능 개선을 위한 율-왜곡(Rate-Distortion) 기반의 영역별 선택적 블록 부호화 기법을 제안한다. 제안 기법은 복호기에서 보조정보를 얻는 과정에서 얻어지는 움직임 벡터가 부호기로 피드백 되는 경우, 이를 이용하여 움직임 보상 예측 신호를 구하고 율-왜곡 기반으로 블록 단위로 선택적 블록 부호화를 수행한다. 모의실험을 통하여 본 논문에서 제안한 움직임 정보 피드백을 이용한 율-왜곡 기반의 선택적 블록 부호화 기법이 기존의 DVC 부호화 기법에 비해 시퀀스에 따라 최대 약 2.2 dB의 PSNR 성능 향상을 확인하였다. 또한 율-왜곡을 고려하여 일부 영역만 부호화함으로써 기존 방식에 비해 부호화 복잡도를 줄일 수 있음을 보인다. Recently, DVC (Distributed Video Coding) is receiving a lot of attention as one of the low complexity video encoding techniques suitable for various applications with computation-limited and/or power-limited environment, and is being actively studied for improving the coding efficiency. This paper proposes a rate-distortion based selective block encoding scheme. First, the motion information is obtained in the process of generating side information at decoder and received through the feedback channel, and then, based on this information, the proposed method performs a selective block encoding based on rate-distortion optimization. Experimental results show that the performance of the proposed scheme reaches up to 2.2 dB PSNR gain over the existing scheme. Moreover, it is shown that the complexity can be reduced by encoding parts of region considering rate-distortion cost.

Apparatus And Method For Processing Multi-Channel Audio Signal Using Space Information

An apparatus for and a method of processing a multi-channel audio signal using space information. The apparatus includes: a main coding unit down mixing a multi-channel audio signal by applying space information to surround components included in the multi-channel audio signal, generating side information using the multi-channel audio signal or a stereo signal of a down-mixed result, coding the stereo signal and the side information, and transmitting the coded result as a coding signal; and a main decoding unit receiving the coding signal, decoding the stereo signal and the side information using the received coding signal, up mixing the decoded stereo signal using the decoded side information, and restoring the multi-channel audio signal.

Capacity of a synchronous BFSK frequency-hopped multiple access system with RTT erasure decision

The capacity of binary frequency shift keying (BFSK) frequency-hopped multiple access (FHMA) systems with side information is derived. The use of erasure decision with ratio-threshold test (RTT) for generating side information in fading and non-fading channels is investigated. The authors demonstrate the benefits of using erasure decision, achievable maximum capacity, optimum threshold setting and the optimal number of users in order to maximise the capacity.