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IEEE International Conference on Multimedia and Expo (ICME)

作者： Ketan Tang Oscar C. Au Lu Fang Jiahao Pang Yuanfang Guo Jiali Li The Hong Kong University of Science and Technology CAS Key Laboratory of Technology in Geo-spatial Information Processingand Application System University of Science and Technology of China

Subpixel-based downsampling has shown its advantages over pixel-based downsampling in terms of preserving more spatial details along edges and generating sharper images, at the cost of certain amount of color-fringing artifacts in the downsampled image. To balance the sharpness and color-fringing artifacts, some algorithms are proposed to design optimal anti-aliasing (AA) filters, which are either image independent, or computationally too expensive. And all of the existing AA filters are designed for fixed downsampling factor, which makes them impractical for real applications. In this paper we propose two fast algorithms to design AA filter for arbitrary factor subpixel downsampling based on frequency analysis of the input image. The proposed algorithms generate image dependent AA filter which is as good as the state-of-the-art algorithm, but much faster.

关键词： Algorithm design and analysis Cutoff frequency Shape Frequency-domain analysis Interpolation Signal processing algorithms Time measurement

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A Comparative Study of Single-polarized and Polarimetric SAR Images Applied on Unsupervised Classification

A Comparative Study of Single-polarized and Polarimetric SAR...

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IEEE International Conference on Radar

作者： Junrong Qu Xiaolan Qiu Key Laboratory of Technology in Geo-spatial Information and Application System Aerospace Information Research Institute Chinese Academy of Sciences School of Electronic Electrical and Communication Engineering University of Chinese Academy of Sciences Beijing China Key Laboratory of Technology in Geo-spatial Information and Application System Aerospace Information Research Institute Chinese Academy of Sciences Beijing China

ISBN: (纸本)9781665468893

SAR image understanding is a significant but also challenging issue in practice. In order to detect the difference between single-polarized and polarimetric SAR (PolSAR) data and explore more information from the pre one, we use GF3 data for experiments and adopt the Deep Clustering with Convolutional Autoencoders (DCEC) algorithm for single-polarized SAR image unsupervised classification. Using both the Kappa coefficient and mutual information derived from the confusion matrix, the results of single-polarized SAR data and PolSAR data are compared. It shows that the classification results of single-polarized SAR data match with the polarimetric ones to some extent, and their results are comparable in some specific applications. This paper presents the potential of information mining from single-polarized SAR images, as well as gives some references for the selection and trade-off between single- and full-polarized SAR data.

关键词： Image resolution Correlation Clustering algorithms Scattering Radar imaging Radar polarimetry Classification algorithms

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Ocean Oil Spill Classification with Polarimetric SAR Based on VGG16 Multi-Feature Extraction

Ocean Oil Spill Classification with Polarimetric SAR Based o...

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2021 SAR in Big Data Era, BIGSARDATA 2021

作者： Ren, Huimin Li, Fangfang Han, Bing Hong, Wen Dong, Yingbo Wu, Bitong QiLu Research Institute Aerospace Information Research Institute Chinese Academy of Sciences Jinan China Aerospace Information Research Institute Chinese Academy of Sciences Key Laboratory of Technology in Geospatial Information Processing and Application System Beijing China

ISBN: (纸本)9781665401234

Fully polarimetric synthetic aperture radar (PolSAR) technology performs well in oil spill detection because of its rich target scattering information. Aiming at the problem that oil spill detection scheme based on polarization feature and deep learning has large sample requirements and high information redundancy, we propose a classification scheme combining with RBFSVM classifier and VGG16 based on transfer network. The ability of our method to distinguish different oil films is analyzed through a radarsat-2 POLSAR image of the North Sea oil spill experiment. © 2021 IEEE.

关键词： Oil spills

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Statistical analysis of typical target regions of multi-Aspect SAR based on parametric model 14

Statistical analysis of typical target regions of multi-Aspe...

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14th European Conference on Synthetic Aperture Radar, EUSAR 2022

作者： Yue, Xiaoyang Teng, Fei Zhang, Zhiguo Lin, Yun Hong, Wen Key Laboratory of Spatial Information Processing and Application System Technology Chinese Academy of Sciences Beijing China Aerospace Information Research Institute Chinese Academy of Sciences Beijing China School of Electronic Electrical and Communication Engineering University of Chinese Academy of Sciences Beijing China School of Electronic Information Engineering North China University of Technology Beijing China

ISBN: (纸本)9783800758234

Multi-Aspect SAR can obtain rich backscatter information about the illuminated scene. For different kinds of targets in the scene, scattering information related to the geometric characteristics of the target is shown in the imaging scene at the same angle. For a certain reference target in the scene, it exhibits azimuth-based backscatter characteristics in the imaging scene under observation from different angles. In our article, a parametric statistical model is used to express characteristics of typical targets at different angles and characteristic differences between different targets. Two parameters-And-Are used to represent characteristic difference of typical targets. © 2022 Institute of Electrical and Electronics Engineers Inc.. All rights reserved.

关键词： Synthetic aperture radar

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Radar image simulation of complex targets

Radar image simulation of complex targets

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6th International Conference on Radar, RADAR 2011

作者： Tang, Kan Zhang, Yueting Chen, Hongzhen Xiong, Wenchang Wang, Hongqi Key Laboratory of Spatial Information Processing and Application System Technology Chinese Academy of Sciences NO. 9 Beiyitiao Zhongguancun Beijing 100190 China National Key Laboratory of Microwave Imaging Technology NO. 19 Beisihuan Xilu Beijing 100190 China Institute of Electronics Chinese Academy of Sciences NO. 19 Beisihuan Xilu Beijing 100190 China

ISBN: (纸本)9781424484416

In this paper, we propose a novel radar imaging simulator with precise simulation of geometry and relative simulation of radiometry, to assist target recognition. The simulator is based on an new visualization procedure and a Lambertian-specular mixture model. Simulated results are compared with MiniSAR image of airplane C-130 evaluating the efficiency. © 2011 IEEE.

关键词： Radar imaging

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Radar imaging simulation for typical urban structures based on analytical models

Radar imaging simulation for typical urban structures based ...

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6th International Conference on Radar, RADAR 2011

作者： Chen, Hongzhen Zhang, Yueting Tang, Kan Xiong, Wenchang Ding, Chibiao Key Laboratory of Spatial Information Processing and Application System Technology Chinese Academy of Sciences NO. 9 Beiyitiao Zhongguancun Beijing 100190 China National Key Laboratory of Microwave Imaging Technology NO.19 Beisihuan Xilu Beijing 100190 China Institute of Electronics Chinese Academy of Sciences NO.19 Beisihuan Xilu Beijing 100190 China

ISBN: (纸本)9781424484416

This paper proposes a novel radar imaging simulator based on analytical electromagnetic and geometric models for a common typical kind of urban structure. The analytical models are presented not only for improving the efficiency of the simulation but also for direct and further understanding the features in the SAR image. © 2011 IEEE.

关键词： Radar imaging

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Copyright protection in named data networking

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International Conference on Wireless Communications and Signal processing (WCSP)

作者： Xiaobin Tan Zifei Zhou Cliff Zou Yukun Niu Xin Chen CAS Key Laboratory of Technology in Geo-spatial Information Processing and Application System University of Science and Technology of China China Department of Electrical Engineering and Computer Science University of Central Florida USA

As a new Internet architecture, Named Data Networking (NDN) decouples location from the data itself to achieve security, scalability, and mobility. Although router-side data caching used in NDN reduces data acquisition delay, it introduces a new copyright protection challenge: how to prevent unauthorized users to retrieve data cached in routers that are out of the control of its publisher? Current approaches that rely on a common encryption key among authorized users cannot protect copyright well since if one authorized user secretly leaks the key, we cannot tell who has leaked the key out. In this paper, we present a split-based scheme to solve this copyright protection problem for large-sized data. The data is split into a large part that could be cached in routers for all users to retrieve, and a small part that is unique for each authorized user. This scheme exploits the fact that in the bit-wise OR operation, both bit 0 and bit 1 can OR with 1 to generate the same result of bit 1. The analysis of our scheme shows that it has a good performance in terms of copyright protection, data retrieval efficiency, and overhead.

关键词： Copyright protection Encryption Watermarking Internet Computer architecture Receivers

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An adaptive Enhanced Imaging Method for Multi-aspect SAR

An adaptive Enhanced Imaging Method for Multi-aspect SAR

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2021 CIE International Conference on Radar, Radar 2021

作者： Teng, Fei Lin, Yun Yue, Xiaoyang Feng, Shanshan Hong, Wen Aerospace Information Research Institute Chinese Academy of Sciences Beijing China Key Laboratory of Technology in Geospatial Information Processing and Application System Chinese Academy of Sciences Beijing China School of Electronic Information Engineering North China University of Technology Beijing China

ISBN: (纸本)9781665498142

Compared with traditional SAR working modes, multi-aspect SAR can provide images with higher resolution and signal-to-noise ratio (SNR) due to its larger synthetic aperture. However, the SNR does not increase with the increase of the aperture length. This is because the scattering is no longer isotropic as traditional SAR when the viewing angle is large. In this paper, an adaptive enhanced imaging method for multi-aspect SAR is proposed. The resolution and the SNR are maximized by scattering analysis performed simultaneously with imaging. In the process of image generation, the scattering characteristic is analyzed and all targets are divided into two categories: isotropic and anisotropic. Then different image formation strategies are used for isotropic and anisotropic target. A C-band circular SAR data is used to validate our method. © 2021 IEEE.

关键词： adaptive anisotropic scattering imaging Multi-aspect SAR

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Efficient background picture coding for videos obtained from static cameras

Efficient background picture coding for videos obtained from...

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IEEE Visual Communications and Image processing (VCIP)

作者： Fangdong Chen Li Li Dong Liu Houqiang Li Zhuoyi Lv Haitao Yang CAS Key Laboratory of Technology in Geo-spatial Information Processing and Application System University of Science and Technology of China Hefei China Huawei Technologies Co. Ltd. Shenzhen China

With the exponential growth of surveillance videos, conference videos and sports videos, videos with static cameras present an unprecedented challenge for high-efficiency video coding technology. The existing schemes developed for these videos mostly encode the background as the long-term reference (LTR) to further improve the coding efficiency. However, since the bit allocation of the long-term background reference is not intensively studied, the coding efficiency is still unsatisfactory. Based on the stability analysis of the video content, an efficient background picture coding algorithm for videos obtained from static cameras, which is embedded with the basic unit level bit allocation, is proposed in this paper. Experimental results reveal that on top of the default mode in HEVC, our method offers the performance with 10.8% BD-rate reduction on average. Compared with the state-of-the-art algorithm, it still outperforms for kinds of test sequences with negligible increases of computational complexity in both encoder and decoder.

关键词： Encoding Videos Cameras Distortion Stability analysis Video coding Delays

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Improving resistance to adversarial deformations by regularizing gradients

arXiv

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arXiv 2020年

作者： Xia, Pengfei Li, Bin CAS Key Laboratory of Technology in Geo-spatial Information Processing and Application Systems Department of Electronic Engineering and Information Science University of Science of Technology of China Hefei China

Improving the resistance of deep neural networks against adversarial attacks is important for deploying models to realistic applications. Currently, most defense methods are designed to defend against additive noise attacks, their performance cannot be guaranteed when against non-additive noise attacks. In this paper, we focus on adversarial deformations, a typical class of non-additive noise attacks, and propose a flow gradient regularization with random start to improve the resistance of models. Theoretically, we prove that, compared with input gradient regularization, regularizing flow gradients is able to get a tighter bound. Across multiple datasets, architectures, and adversarial deformations, our experimental results consistently indicate that models trained with flow gradient regularization can acquire a better resistance than trained with input gradient regularization with a large margin. Moreover, compared with adversarial training, our method can achieve better results in optimization-based and gradient-free attacks, and combining these two methods can improve the resistance against deformation attacks further. Finally, we give a unified form of gradient regularization, which can be used to derive the corresponding form when facing other types of attack. Copyright © 2020, The Authors. All rights reserved.

关键词： Deformation

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