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arXiv 2021年

作者： Fang, Zhigao Zhang, Jiaqi Yu, Lu Zhao, Yin Zhejiang Provincial Key Laboratory of Information Processing Communication and Networking Hangzhou China Huawei Technologies Co. Ltd. Hangzhou China

We conduct a subjective experiment to compare the performance of traditional image coding methods and learning-based image coding methods. HEVC and VVC, the state-of-the-art traditional coding methods, are used as the representative traditional methods. The learning-based methods used contain not only CNN-based methods, but also a GAN-based method, all of which are advanced or typical. Single Stimuli (SS), which is also called Absolute Category Rating (ACR), is adopted as the methodology of the experiment to obtain perceptual quality of images. Additionally, we utilize some typical and frequently used objective quality metrics to evaluate the coding methods in the experiment as comparison. The experiment shows that CNN-based and GAN-based methods can perform better than traditional methods in low bit-rates. In high bit-rates, however, it is hard to verify whether CNN-based methods are superior to traditional methods. Because the GAN method doesn't provide models with high target bit-rates, we can't exactly tell the performance of the GAN method in high bit-rates. Furthermore, some popular objective quality metrics have not shown the ability well to measure quality of images generated by learning-based coding methods, especially the GAN-based one. Copyright © 2021, The Authors. All rights reserved.

关键词： Image coding

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Fundamental Limits of Multiple-Access Integrated Sensing and communication Systems

arXiv

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arXiv 2022年

作者： Liu, Yao Li, Min Liu, An Ong, Lawrence Yener, Aylin The College of Information Science and Electronic Engineering The Zhejiang Provincial Key Laboratory of Information Processing Communication and Networking Zhejiang University Hangzhou310027 China The School of Engineering University of Newcastle CallaghanNSW2308 Australia The Department of Electrical and Computer Engineering The Ohio State University ColumbusOH43210 United States

A memoryless state-dependent multiple access channel is considered to model an integrated sensing and communication system, where two transmitters wish to convey messages to a receiver while simultaneously estimating the sensing state sequences through echo signals. In particular, the sensing states are assumed to be correlated with the channel state, and the receiver has imperfect channel state information. In this setup, improved inner and outer bounds for capacity-distortion region are derived. The inner bound is based on an achievable scheme that combines message cooperation and joint compression via distributed Wyner-Ziv coding at each transmitter, resulting in unified cooperative communication and sensing. The outer bound is based on the ideas of dependence balance for communication rate and rate-limited constraints on sensing distortion. The proposed inner and outer bounds are proved to improve the state-of-the-art bounds. Finally, numerical examples are provided to demonstrate that our new inner and outer bounds strictly improve the existing results. © 2022, CC BY.

关键词： Transmitters

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Improved Incremental Freezing HARQ Schemes Using Polar Codes over Degraded Compound Channels 14th

Improved Incremental Freezing HARQ Schemes Using Polar Codes...

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14th EAI International Conference on communications and networking in China, ChinaCom 2019

作者： Hu, Tianze Xie, Lei Chen, Huifang Duan, Hongda Wang, Kuang College of Information Science and Electronic Engineering Zhejiang University Hangzhou310027 China Zhejiang Provincial Key Laboratory of Information Processing Communication and Networking Hangzhou310027 China Zhoushan Ocean Research Center Zhoushan316021 China

ISBN: (纸本)9783030411138

The error propagation problem in incremental freezing (IF) hybrid automatic repeat request (HARQ) scheme using Polar codes is studied. We propose two IF HARQ schemes using polar codes, namely the cyclic redundancy check (CRC)-aided IF HARQ scheme and the cumulative-path-metrics-based IF HARQ scheme. In the CRC-aided IF HARQ scheme, several CRC bits are added to each transmitted block. Using these CRC bits, the proposed IF HARQ scheme and the Chase Combining HARQ scheme can be combined to achieve a better error correction performance in the cost of a larger decoding delay. In the cumulative-path-metrics-based IF HARQ scheme, the successive joint decoder maintains multiple possible paths simultaneously, and the cumulative path metrics is used to represent the reliability of each surviving path in the decoding process. Moreover, a modified path splitting reduced successive cancellation list (SCL) decoding algorithm is presented to reduce the computational complexity and the memory requirement of cumulative-path-metrics-based IF HARQ scheme. Simulation results show that, using the Polar code constructed under long block length and high block error rate, the CRC-aided IF HARQ scheme has a higher system throughput. With the Polar code constructed under short block length and low block error rate, the cumulative-path-metrics-based IF HARQ scheme has a higher system throughput. In both situations, the system block error rate of the CRC-aided IF HARQ scheme performs well. © 2020, ICST Institute for Computer Sciences, Social Informatics and Telecommunications Engineering.

关键词： Freezing

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Performance Analysis of Consensus-Based Distributed System Under False Data Injection Attacks 14th

Performance Analysis of Consensus-Based Distributed System U...

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14th EAI International Conference on communications and networking in China, ChinaCom 2019

作者： Zheng, Xiaoyan Xie, Lei Chen, Huifang Song, Chao College of Information Science and Electronic Engineering Zhejiang University Hangzhou310027 China Zhejiang Provincial Key Laboratory of Information Processing Communication and Networking Hangzhou310027 China Zhoushan Ocean Research Center Zhoushan316021 China

ISBN: (纸本)9783030411138

This paper investigates the security problem of consensus-based distributed system under false data injection attacks (FDIAs). Since the injected false data will spread to the whole network through data exchange between neighbor nodes, and result in continuing effect on the system performance, it is significant to study the impact of the attack. In this paper, we consider two attack models according to the property of the injection data, the deterministic attack and the stochastic attack. Then, the necessary and sufficient condition for the convergence of distributed system under the attack are derived, and the attack feature making the system unable to converge is provided. Moreover, the convergence result under resource-limited attack is deviated. On the other hand, the statistical properties of the convergence performance under zero-mean and non-zero-mean stochastic attacks are analyzed, respectively. Simulation results illustrate the effects caused by FDIAs on the convergence performance of distributed system. © 2020, ICST Institute for Computer Sciences, Social Informatics and Telecommunications Engineering.

关键词： Electronic data interchange

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Affine Deformation Model Based Intra Block Copy for Intra Frame Coding

Affine Deformation Model Based Intra Block Copy for Intra Fr...

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IEEE International Symposium on Circuits and Systems (ISCAS)

作者： Daowen Li Zhihao Zhang Kaitian Qiu Yaqing Pan Yingming Li Haoji Roland Hu Lu Yu Institute of Information and Communication Engineering Zhejiang University Zhejiang Provincial Key Laboratory of Information Processing Communication and Networking

ISBN: (数字)9781728133201

ISBN: (纸本)9781728133218

In intra frame coding, many methods are proposed to reduce spatial redundancy, including angular intra prediction and intra block copy. However, these two methods cannot deal with complex structure redundancy, such as scaling and rotation relationship where spatial structures are the same but sizes and orientations are different, leading to limited coding efficiency. In this paper, we first mathematically prove that 4-parameter affine deformation model can describe this complex relationship. Then we propose an affine deformation model based intra block copy (ADMIBC) scheme. In the scheme, we focus on several problems, including a fast displacement vector validity judgement algorithm to reduce encoding time, a padding method for unavailable reference pixels during sub-pixel interpolation to improve prediction accuracy and candidate list building methods of control point displacement vector predictor to reduce coding bits. Experimental results show that ADMIBC achieves up to −2.16% BD-rate reduction and −0.99% on average in all intra configuration, compared to the latest video coding standard Versatile Video Coding (VVC).

关键词： Encoding Strain Deformable models Buildings Voltage control Interpolation Mathematical model

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Assessment of Perceptual Depth Intensity on Source Stereoscopic Images

Assessment of Perceptual Depth Intensity on Source Stereosco...

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IEEE International Symposium on Circuits and Systems (ISCAS)

作者： Jiaqi Zhang Minxia Yang Lu Yu Rende Shui Institute of Information and Communication Engineering Zhejiang University Zhejiang Provincial Key Laboratory of Information Processing Communication and Networking

ISBN: (数字)9781728133201

ISBN: (纸本)9781728133218

Accurate and efficient objective assessment methods for multidimensional quality of experience (QoE) of stereoscopic 3D content are in urgent demand. Especially, depth perception quantization for source 3D content is necessary to optimize the comprehensive QoE. A few studies evaluate the depth quality degradation due to compression or transmission, while the objective assessment of perceptual depth intensity has not been deeply investigated. In this paper, we propose a depth intensity metric (DIM) to simulate subjective evaluation on uncompressed source 3D images. Considering the multi-cue aggregation mechanism in depth perception as well as visual characteristic of binocular fusion, perceptual features are extracted from binocular and monocular cues to generate the depth intensity perception score. The effectiveness of DIM is verified by conducting subjective experiment on publicly available stereoscopic image databases. Experimental results demonstrate that DIM can achieve higher accuracy compared to the state-of-the-art depth intensity metric.

关键词： Three-dimensional displays Measurement Entropy Visualization Image color analysis Stereo image processing Feature extraction

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Structured feature enhanced deep visual relocalization

Structured feature enhanced deep visual relocalization

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IEEE International Conference on Unmanned Systems (ICUS)

作者： Qihao Peng Zhiyu Xiang Tianle Wang Zhejiang Provincial Key Laboratory of Information Processing Communication and Networking Zhejiang University Hangzhou China

ISBN: (数字)9781728180250

ISBN: (纸本)9781728180267

Relocalization is a mandatary task for robots or unmanned vehicles which need to work under changing environments over the long term. Recently, deep learning has been successfully applied to visual relocalization, where the absolute camera pose can be regressed from monocular RGB images. However, the resulting accuracy is still sub-optimal. In this paper, we propose a deep relocalization network which regresses the global poses of the images in the scenario. Our model takes in tuples of images and enforces constraints between pose predictions for pairs as an additional loss term in training. The features coded from convolutional layers are further enhanced by two bidirectional LSTM in a structured way to boost the features' inner correlation, which is the main contribution of the work. Then the we use unlabeled data to further fine-tune the network and during inference we perform pose graph optimization (PGO) to get smoother and globally consistent pose predictions. Experiments on public indoor and outdoor dataset demonstrate that our model achieved better relocalization performance than the baseline and is more robust to illumination changes, texture-less areas and repetitive structures in the scenario.

关键词： information processing Zirconium Training Optimization Image retrieval Deep learning Cameras

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Multi-stereo 3D reconstruction with a single-camera multi-mirror catadioptric system

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Measurement Science and Technology 2020年第1期31卷 015102-015102页

作者： Chen, Shuya Xiang, Zhiyu Zou, Nan Chen, Yiman Qiao, Chengyu College of Information and Electronic Engineering Zhejiang University Hangzhou China Zhejiang Provincial Key Laboratory of Information Processing Communication and Networking Zhejiang University Hangzhou China

Omnidirectional catadioptric systems are popular in many fields, such as robotics, surveillance, telepresence and virtual reality, thanks to their large field of view. For 3D scene reconstruction in a single shot, usually two different catadioptric cameras are needed. More cameras may contribute to better reconstruction while a larger mounting space and higher power cost are required. In this paper, a single camera multi-mirror catadioptric system with a vertical and horizontal baseline structure is proposed. It features the realization of multiple central or non-central omnidirectional stereo pairs in a compact manner. To make the 3D reconstruction process general and adaptive to various types of system configurations, a flexible calibration and reconstruction algorithm pipeline is presented. The algorithm features the approximation of the system into multiple central sub-cameras and carries out stereo matching in a spherical representation. In addition, an effective 3D point cloud fusion algorithm is proposed to optimize the reconstruction results from multiple stereo pairs. Experiments carried out with synthetic and real data verified the feasibility and effectiveness of our system. In particular, with the real data, when compared with the results of a single stereo pair, the fused reconstruction results of the multiple stereo pairs obtained 30% and 15% improvement corresponding to the planarity and angle error respectively. © 2019 IOP Publishing Ltd.

关键词： Virtual reality

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Human Head Pose Estimation through Temporal Enhanced and Accurate Self-Supervised Depth Prediction

SSRN

引用

SSRN 2021年

作者： Liu, Baiyi Yu, Huimin Liu, Biyang Long, Yangqi College of Information Science and Electronic Engineering Zhejiang University China ZJU League Research & Development Center State Key Lab of CAD&CG Zhejiang University China Zhejiang Province Key Laboratory of Information Processing Communication and Networking China

Integrating depth information is beneficial for human head pose estimation. However, in current methods, the depth is acquired by hardware devices, which is cumbersome for daily-life applications. In this paper, we propose to leverage the depth from a depth prediction network to estimate the head pose. Benefit from the projection loss, only RGB videos are necessary to train the network. Furthermore, considering the temporal information is ignored in current depth prediction models, we design a Double Temporal Correlation Network (DTCNet), where the features of adjacent frames are fused to boost current feature. After obtaining the depth, head point clouds can be constructed. Finally, an improved ICP algorithm is proposed to register the point clouds of two views and realize pose estimation. In the experiments, the effectiveness of DTCNet is demonstrated on the KITTI dataset and that of our head pose estimation framework is demonstrated on the Biwi and 300W-LP datasets. © 2021, The Authors. All rights reserved.

关键词： Forecasting

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Deep Learning-Based Channel Estimation for Double-RIS Aided Massive MIMO System

arXiv

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arXiv 2022年

作者： Liu, Mengbing Li, Xin Ning, Boyu Huang, Chongwen Sun, Sumei Yuen, Chau Singapore University of Technology and Design Singapore487372 Singapore The National Key Laboratory of Science and Technology on Communications University of Electronic Science and Technology of China Chengdu611731 China The College of Information Science and Electronic Engineering The Zhejiang Provincial Key Laboratory of Information Processing Communication and Networking Zhejiang University Hangzhou310027 China The International Joint Innovation Center Zhejiang University Haining314400 China The Institute for Infocomm Research Agency for Science Technology and Research 138632 Singapore

Reconfigurable Intelligent Surface (RIS) is considered as an energy-efficient solution for future wireless communication networks due to its fast and low-cost configuration. In this letter, we consider the estimation of cascaded channels in a double-RIS aided massive multiple-input multiple-output system, which is a critical challenge due to the large number of antennas equipped at the base station and passive RIS elements. To tackle this challenge, we propose a skip-connection attention (SC-attention) network that utilizes self-attention layers and skip-connection structure to improve the channel estimation performance from the noisy pilot-based observations. Simulation results compare the proposed SC-attention network with other benchmark methods and show that SC-attention network can effectively improve the accuracy performance on normalized mean square error (NMSE) for cascaded links in a double-RIS aided system. © 2022, CC BY.

关键词： Channel estimation

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