图像视频中ENF信号的分析及应用综述

doi:10.3969/j.issn.0255-8297.2019.05.001

摘要/Abstract

摘要： 多媒体录制设备在交流电场或交流电器设备环境中录制视频、图像或音频时，会同时记录电网频率的波动.电网频率（electric network frequency，ENF）具有实时性、连续性以及同电网一致性等特点.因此从这些录制的多媒体文件中估计出的ENF信号是一种很好的时间戳，可用于信息源检测、操作取证及媒体同步等任务.尽管音频、图像和视频中ENF信号存在的形式截然不同，但检测和估计的思路是一致的，部分处理手段是通用的.目前，ENF信号在音频这一载体的研究中已经积累了一些成果，而在图像视频分析中的研究还处于起步阶段.为了更全面地了解图像和视频中ENF信号的特点、估计方法及在信息取证等方面的应用，对相关研究成果进行了梳理总结.首先通过分析图像视频捕获过程来探究ENF信号的形成机理与特点，然后对ENF信号检测和估计中存在的问题及相关方法进行了总结分析，最后介绍了图像视频ENF信号在信息取证方面的应用并指出未来可能的研究方向.

关键词: 电网频率信号, 视频, 信号估计, 信息源检测, 操作取证, 媒体同步, 时间戳

Abstract: Under the circumstance of alternate current (AC) electric field or around AC electrical equipment, multimedia recording equipment can capture the frequency fluctuation of electric networks simultaneously as it records video, image or audio programs. Electric network frequency (ENF) has the characteristics of real-time, continuity and consistency with surrounding electric networks, thus, the ENF information estimated from these multimedia files can be used for time stamping, information source detection, operation forensics, and media synchronization. In spite of different signal formats of ENF in audio, image and video programs, the detection and estimation methods of ENF are similar, and some processing methods are universal. Up to now, plenty of research works have been done on ENF in audio, but the works on ENF in image and video are far more behind. This paper presents a comprehensive review on the relevant researches, including characteristics, estimation and applications of ENF in images and videos. Firstly, the characteristics of ENF signal are explored by analyzing the processes of capturing images and videos. Then, the problems existing in the detection and estimation of ENF signal and corresponding solving approaches are summarized and analyzed. Finally, the applications of ENF in information forensics and the possible research directions in the future are discussed.

Key words: electric network frequency signal, video, signal estimation, information source detection, operation forensics, media synchronization, time stamp

中图分类号:

TP391.4

崔三帅, 毛毛雨, 林晓丹, 康显桂. 图像视频中ENF信号的分析及应用综述[J]. 应用科学学报, 2019, 37(5): 573-589.

CUI Sanshuai, MAO Maoyu, LIN Xiaodan, KANG Xiangui. Survey on Analysis and Applications of Electric Network Frequency (ENF) Signals in Image and Video[J]. Journal of Applied Sciences, 2019, 37(5): 573-589.

参考文献

[1] Koenig B E. Authentication of forensic audio recordings[J]. Journal of the Audio Engineering Society, 1990, 38(1/2):3-33.
[2] Grigoras C. Forensic analysis of the digital audio recordings-the electric network frequency criterion[J]. Forensic Science International, 2003, 136:368-369.
[3] Grigoras C. Digital audio recording analysis:the electric network frequency (ENF) criterion[J]. International Journal of Speech Language and the Law, 2005, 12(1):63-76.
[4] Grigoras C. Applications of ENF criterion in forensic audio, video, computer and telecommunication analysis[J]. Forensic Science International, 2007, 167(2/3):136-145.
[5] 曾春艳,王志锋,王静,等. 数字音频篡改被动检测研究综述[J]. 计算机工程与应用,2019, 55(2):1-11. Zeng C Y, Wang Z F, Wang J, et al. Survey of passive detection of digital audio tampering[J]. Computer Engineering and Applications, 2019, 55(2):1-11. (in Chinese).
[6] Hua G, Bi G, Thing V L L. On Practical issues of electric network frequency based audio forensics[J]. IEEE Access, 2017, 5:20640-20651.
[7] Garg R, Varna A L, Wu M. "Seeing" ENF:natural time stamp for digital video via optical sensing and signal processing[C]//Proceedings of the 19th ACM International Conference on Multimedia, 2011:23-32.
[8] Sigrist L, Egido I, Miguelez E L, et al. Sizing and controller setting of ultracapacitors for frequency stability enhancement of small isolated power systems[J]. IEEE Transactions on Power Systems, 2015, 30(4):2130-2138.
[9] 汤涌. 电力系统安全稳定综合防御体系框架[J]. 电网技术,2012, 36(8):1-5. Tang Y. Framework of comprehensive defense architecture for power system security and stability[J]. Power System Technology, 2012, 36(8):1-5. (in Chinese)
[10] 常烨骙,李卫东,巴宇,等. 基于运行安全的频率控制性能评价新方法[J]. 电工技术学报,2019, 34(6):1218-1229.Chang Y K, Li W D, Ba Y, et al. A new method for frequency control performance assessment on operation security[J]. Transactions of China Electrotechnical Society, 2019, 34(6):1218-1229. (in Chinese)
[11] 中华人民共和国国家质量监督检验检疫总局, 中国国家标准化管理委员会. GB/T 15945-2008:电能质量-电力系统频率偏差[S]. 北京:中国标准出版社.
[12] Viswanathan S, Li Y, Tan R. Natural time stamping using electrical power grid[C]//IEEE International Conference on Information Processing in Sensor Networks, 2017:269-270.
[13] Li Y, Tan R, Yau D K Y. Natural time stamping using power line electromagnetic radiation[C]//IEEE International Conference on Information Processing in Sensor Networks, 2017:55-66.
[14] Toadere F. Process simulation in digital camera system[J]. Proceedings of SPIE-The International Society for Optical Engineering, 2012, 8436:1-8.
[15] Chen J Q, Venkataraman K, Bakin D, et al. Digital camera imaging system simulation[J]. IEEE Transactions on Electron Devices, 2009, 56(11):2496-2505.
[16] 王世和,陈远金,刘彬. CCD与CMOS国内外技术发展综述[J]. 内燃机与配件, 2017(13):112-114. Wang S H, Chen Y J, Liu B. Summary of the development of CCD and CMOS technology at home and abroad[J]. Internal Combustion Engine & Parts, 2017(13):112-114. (in Chinese)
[17] 雷蕾,李红涛. 基于CCD与CMOS图像传感新技术的研究[J]. 科技创新导报,2010(14):4-5. Lei L, Li H T. Research on new technology of image sensing based on CCD and CMOS[J]. Science and Technology Innovation Herald, 2010(14):4-5. (in Chinese)
[18] Gu J, Hitomi Y, Mitsunaga T, et al. Coded rolling shutter photography:flexible space-time sampling[C]//Proceedings of IEEE International Conference on Computational Photography (ICCP), 2010:1-8.
[19] Hui S, Hajj-Ahmad A, Garg R, et al. Exploiting rolling shutter for ENF signal extraction from video[C]//Proceedings of IEEE International Conference on Image Processing (ICIP), 2014:5367-5371.
[20] Hui S, Hajj-Ahmad A, Wong C W, et al. ENF signal induced by power grid:a new modality for video synchronization[C]//Proceedings of the 2nd ACM International Workshop on Immersive Media Experiences, 2014:13-18.
[21] Garg R, Varna A L, Hajj-Ahmad A, et al. "Seeing" ENF:power-signature-based timestamp for digital multimedia via optical sensing and signal processing[J]. IEEE Transactions on Information Forensics and Security, 2013, 8(9):1417-1432.
[22] Schmidt R O. Multiple emitter location and signal parameter estimation[J]. IEEE Transactions on Antennas & Propagation, 1986, 34(3):276-280.
[23] Kailath T, Paulraj A, Roy R. ESPRIT-estimation of signal parameters via rotational invariance techniques[J]. IEEE Transactions on Acoustics Speech and Signal Processing, 1989, 37(7):984-995.
[24] Hajj-Ahmad A, Garg R, Wu M. Spectrum combining for ENF signal estimation[J]. IEEE Signal Processing Letters, 2013, 20(9):883-886.
[25] Su H, Hajj-Ahmad A, Wu M, et al. Exploring the use of ENF for multimedia synchronization[C]//Proceedings of IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP), 2014:4613-4617.
[26] Hajj-Ahmad A, Berkovich A, Wu M. Exploiting power signatures for camera forensics[J]. IEEE Signal Processing Letters, 2016, 23(5):713-717.
[27] Vidyamol K, George E, Jo J P. Exploring electric network frequency for joint audio-visual synchronization and multimedia authentication[C]//Proceedings of International Conference on Intelligent Computing, Instrumentation and Control Technologies (ICICICT), 2017:240-246.
[28] Vatansever S, Dirik A E, Memon N. Detecting the presence of ENF signal in digital videos:a superpixel-based approach[J]. IEEE Signal Processing Letters, 2017, 24(10):1463-1467.
[29] Vatansever S, Dirik A E. The effect of light source on ENF based video forensics[J]. Journal of the University of Uluda, School of Engineeing, 2017, 22(1):53-64.
[30] Wong C W, Hajj-Ahmad A, Wu M. Invisible geo-location signature in a single image[C]//Proceedings of IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP), 2018:1987-1991.
[31] Vatansever S, Dirik A E, Memon N. Analysis of rolling shutter effect on ENF-based video forensics[J]. IEEE Transactions on Information Forensics and Security, 2019, 14(9):2262-2275.
[32] Vatansever S, Dirik A E, Memon N. Factors affecting ENF based time-of-recording estimation for video[C]//Proceedings of IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP), 2019:2497-2501.
[33] Choi J, Wong C. ENF signal extraction for rolling-shutter videos using periodic zero-padding[C]//IEEE International Conference on Acoustics, Speech and Signal Processing, 2019:2667-2671.
[34] Yao W, Zhao J, Till M J, et al. Source location identification of distribution-level electric network frequency signals at multiple geographic scales[J]. IEEE Access, 2017, 5:11166-11175.
[35] Hua G, Zhang Y, Goh J, Thing V L L. Audio authentication by exploring the absoluteerror-map of ENF signals[J]. IEEE Transactions on Information Forensics and Security, 2016, 11(5):1003-1016.