Dr Charith Abhayaratne
PhD
School of Electrical and Electronic Engineering
Senior Lecturer
EEE Foundation year tutor
EEE accreditation team lead
Communications Research Group
+44 114 222 5893
Full contact details
School of Electrical and Electronic Engineering
Sir Frederick Mappin Building
Mappin Street
Sheffield
S1 3JD
- Profile
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I received the B.E. degree in electrical and electronic engineering from The University of Adelaide, Australia, in 1998, and the PhD. degree in electronic and electrical engineering from the University of Bath, U.K., in 2002. I am a recipient of the Alain Bensoussan Fellowship awarded by the European Research Consortium for Informatics and Mathematics (ERCIM) to carry out postdoctoral research at the Centre of Mathematics and Computer Science (CWI), The Netherlands (2002), and the National Research Institute for Computer Science and Control (INRIA), Sophia Antipolis, France (2003). During the fellowship, my research was on adaptive wavelet transforms for image and video coding and analysis. After the fellowship, I was a postdoctoral research associate at Queen Mary, University of London, where I worked on wavelet based scalable video coding research. In 2005, I joined the University of Sheffield as a lecturer.
My research is focused on signal processing and machine learning for multimedia security, automated understanding of visual content (computer vision) and video coding. I lead a group of researchers working on these topics. In terms of multimedia security, I am working on methodologies for robust and imperceptible data hiding and exploring block-chain technology for multimedia content tracking and protection. In terms of visual content understanding, my current work is on understanding and modelling of visual salience in the context of robotic and UAV applications, automated recognition of human activities of daily living in the context of assisted living and modelling of complex 2D and 3D shapes leading to real time number and object recognition. In terms of video coding, current research includes coding of high dynamic range (HDR) video, ultra high definition (UHD) video and 360 degrees video. Current and recently concluded research has been funded by Innovate UK, EPSRC and Industry sponsors.
Currently, I serve as an associate editor for IEEE Transactions in Image Processing, IEEE Access and Elsevier Journal of Information Security and Applications (JISA) and I have served as a guest editor for Signal Processing: Image Communication (in 2009). At present, I am serving as a member of the EPSRC peer review college, a committee member of the British Standards Institution (BSI) group IST/037 coding of picture, audio, multimedia and hypermedia information and a member of Multimedia Security and Forensics Technical Committee of Asia-Pacific Signal and Information Processing Association (APSIPA). I have served as the UK Liaison for the European Association for Signal Processing (EURASIP) and a member of the IEEE Multimedia Communications technical committee from 2010-2019. In 2004-2006, I have contributed to the development of the scalable video standardisation and wavelet video exploration activities within the ISO/IEC Moving Picture Expert Group (MPEG).
- Qualifications
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- PhD (Electronic and Electrical Engineering), The University of Bath, UK 2002
- BE Class 1 Hons. (Electrical and Electronic Engineering), The University of Adelaide, Australia, 1998
- PGCertHE, The University of Sheffield, UK, 2008
- FHEA, MIET, MIEEE
- Research interests
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- AI and machine learning for computer vision.
- AI and machine learning for multimedia security and forensics.
- Multi-modal sensing, data analysis and machine learning.
- Signal, image, video and graph processing and analysis.
- Video and image coding, streaming and visual quality metrics.
- Applications in robotics, creative industries, security and surveillance, assisted living, healthcare, remote sensing, sports visual analysis, computational imaging, digital manufacturing and international standards (JPEG and MPEG).
- Publications
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Journal articles
- Region-of-interest aware 3D ResNet for classification of COVID-19 chest computerised tomography scans. IEEE Access, 11, 28856-28872.
- GHOSM : Graph-based Hybrid Outline and Skeleton Modelling for shape recognition. ACM Transactions on Multimedia Computing, Communications, and Applications, 19(2s), 1-23.
- Handcrafted localized phase features for human action recognition. Image and Vision Computing, 123.
- Making sense of neuromorphic event data for human action recognition. IEEE Access, 9, 82686-82700.
- Modeling temporal visual salience for human action recognition enabled visual anonymity preservation. IEEE Access, 8, 213806-213824. View this article in WRRO
- AGSF: Adaptive graph formulation and hand-crafted graph spectral features for shape representation. IEEE Access, 8, 182260-182272. View this article in WRRO
- Embedding distortion analysis in wavelet-domain watermarking. ACM Transactions on Multimedia Computing, Communications, and Applications, 15(4). View this article in WRRO
- Graph spectral domain feature learning with application to in-air hand-drawn number and shape recognition. IEEE Access, 7, 159661-159673. View this article in WRRO
- Referenced compressed sensing for accurate and fast spatio-temporal signal reconstruction. Journal of Electronic Imaging, 28(4). View this article in WRRO
- Global motion compensated visual attention-based video watermarking. Journal of Electronic Imaging, 25(6). View this article in WRRO
- Visual Attention-Based Image Watermarking. IEEE Access, 4, 8002-8018. View this article in WRRO
- Quality Scalability Aware Watermarking for Visual Content. IEEE Transactions on Image Processing, 25(11), 5158-5172. View this article in WRRO
- Automated background subtraction technique for electron energy‐loss spectroscopy and application to semiconductor heterostructures. Journal of Microscopy, 262(2), 157-166. View this article in WRRO
- On robustness against JPEG2000: a performance evaluation of wavelet-based watermarking techniques. Multimedia Systems, 1-14.
- Redundancy controllable scalable unbalanced multiple description bitstream generation for peer-to-peer video streaming. Signal Processing: Image Communication.
- 2D+t wavelet domain video watermarking. Advances in Multimedia, 2012. View this article in WRRO
- Reversible wavelet filter banks with side informationless spatially adaptive low-pass filters. J ELECTRON IMAGING, 20(3).
- Scalable watermark extraction for real-time authentication of JPEG 2000 images. Journal of Real-Time Image Processing, 1-19.
- Video based technology for ambient assisted living: A review of the literature. J AMB INTEL SMART EN, 3(3), 253-269. View this article in WRRO
- Special issue on scalable coded media beyond compression. SIGNAL PROCESS-IMAGE, 24(6), 415-416.
- A Generalised Model for Distortion Performance Analysis of Wavelet Based Watermarking. DIGITAL WATERMARKING, 5450, 363-378.
- Robust Visual Content Representation Using Compression Modes Driven Low-level Visual Descriptors. ADVANCES IN MULTIMEDIA MODELING, PROCEEDINGS, 5371, 322-332.
- Reversible integer-to-integer mapping of N-point orthonormal block transforms. Signal Processing, 87(5), 950-969.
- Scalable near-lossless image coding. Journal of Electronic Imaging, 15(4).
Chapters
- Automated EELS Core-Loss Edge Detection for Quantification of the Chemical Composition of Nano-Structured Semiconductors, Encyclopedia of Materials: Electronics (pp. V3-605-V3-618).
- High Efficiency Video Coding (HEVC) for Next Generation Video Applications, Academic Press Library in signal Processing - Image and Video Compression and Multimedia (pp. 93-117). Elsevier
- Automated EELS core-loss edge detection for quantification of the chemical composition of nano-structured semiconductors In NN (Ed.), Elsevier Encyclopedia of Materials Section 2: Nanoscale Materials for Electronics Elsevier
Conference proceedings papers
- WCBnet: Weighted Convolutional Block Modelling of Signed-Value Error Levels for Image-Wise Copy-Move and Splicing Detection. 2023 IEEE 25th International Workshop on Multimedia Signal Processing (MMSP), Vol. 00 (pp 1-6), 27 September 2023 - 27 September 2023.
- SSDB-Net: A Single-Step Dual Branch Network for Weakly Supervised Semantic Segmentation of Food Images. 2023 IEEE 25th International Workshop on Multimedia Signal Processing (MMSP), Vol. 00 (pp 1-6), 27 September 2023 - 27 September 2023.
- TRAIT: A Trusted Media Distribution Framework. 2023 24th International Conference on Digital Signal Processing (DSP), 11 June 2023 - 11 June 2023.
- Exploration of verbal descriptions and dynamic indoors environments for people with sight loss. Extended Abstracts of the 2023 CHI Conference on Human Factors in Computing Systems
- Graph neural network based child activity recognition. 2022 IEEE International Conference on Industrial Technology (ICIT) (pp 1-8). Shanghai, China, 22 August 2022 - 25 August 2022.
- 2D Pose Estimation based Child Action Recognition. TENCON 2022 - 2022 IEEE Region 10 Conference (TENCON), 1 November 2022 - 4 November 2022.
- Covid-19 diagnostic using 3D deep transfer learning for classification of volumetric computerised tomography chest scans. ICASSP 2021 - 2021 IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP) (pp 8573-8577). Toronto, Ontario, Canada, 6 June 2021 - 11 June 2021.
- Video watermarking for persistent and robust tracking of entertainment content (PARTEC). Computational Intelligence and Machine Learning : Proceedings of the 7th International Conference on Advanced Computing, Networking, and Informatics (ICACNI 2019) (pp 185-198). West Bengal, India, 20 December 2019 - 21 December 2019.
- Graph spectral domain features for static hand gesture recognition. 2019 27th European Signal Processing Conference (EUSIPCO). A Coruna, Spain, 2 September 2019 - 6 September 2019. View this article in WRRO
- Adaptive Graph Formulation for 3D Shape Representation. ICASSP 2019 - 2019 IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP) (pp 1947-1951), 12 May 2019 - 17 May 2019. View this article in WRRO
- Temporal salience based human action recognition. 2019 IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP) (pp 2017-2021). Brighton, United Kingdom, 12 May 2019 - 17 May 2019. View this article in WRRO
- Graph Spectral Domain Blind Watermarking. ICASSP 2019 - 2019 IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP) (pp 2492-2496), 12 May 2019 - 17 May 2019. View this article in WRRO
- Privacy Protected Recognition of Activities of Daily Living in Video. 3rd IET International Conference on Technologies for Active and Assisted Living (TechAAL 2019) View this article in WRRO
- Graph Spectral Domain Shape Representation. 2018 26th European Signal Processing Conference (EUSIPCO) (pp 598-602), 3 September 2018 - 7 September 2018. View this article in WRRO
- Visual Saliency Guided High Dynamic Range Image Compression. 2018 26th European Signal Processing Conference (EUSIPCO) (pp 166-170), 3 September 2018 - 7 September 2018. View this article in WRRO
- The JPEG-blockchain framework for GLAM services. 2018 IEEE International Conference on Multimedia & Expo Workshops (ICMEW) (pp 1-6), 23 July 2018 - 27 July 2018. View this article in WRRO
- Graph spectral domain watermarking for unstructured data from sensor networks. 2017 22nd International Conference on Digital Signal Processing (DSP), 23 August 2017 - 25 August 2017. View this article in WRRO
- Towards baseline-independent analysis of compressive sensed functional magnetic resonance image data. 2017 22nd International Conference on Digital Signal Processing (DSP), 23 August 2017 - 25 August 2017. View this article in WRRO
- Graph spectral domain feature representation for in-air drawn number recognition. 2017 25th European Signal Processing Conference (EUSIPCO), 28 August 2017 - 2 September 2017. View this article in WRRO
- Phase Feature-based Activity Level Estimation for Assisted Living. 2nd IET International Conference on Technologies for Active and Assisted Living (TechAAL 2016)
- Real-time recognition of activity levels for ambient assisted living. 2015 IEEE 5th International Conference on Consumer Electronics - Berlin (ICCE-Berlin), 6 September 2015 - 9 September 2015.
- Mapping-free high dynamic range image compression. 2015 IEEE 5th International Conference on Consumer Electronics - Berlin (ICCE-Berlin), 6 September 2015 - 9 September 2015.
- Development of automated background subtraction technique for electron energy-loss spectroscopy. http://www.mmc2015.org.uk/ (pp P.4027-P.4027). Manchester, 29 June 2015 - 2 July 2015.
- An optimal learning parameter for running Gaussian-based referenced compressive. 2nd IET International Conference on Intelligent Signal Processing 2015 (ISP)
- Video-based activity level recognition for assisted living using motion features. Proceedings of the 9th International Conference on Distributed Smart Camera - ICDSC '15, 8 September 2015 - 11 September 2015.
- Colour space transforms for improved video compression. International Conference on Systems, Signals, and Image Processing (pp 219-222)
- Multi-scale dithering for contouring artefacts removal in compressed UHD video sequences. 2014 IEEE Global Conference on Signal and Information Processing (GlobalSIP), 3 December 2014 - 5 December 2014.
- Running Gaussian reference-based reconstruction for video compressed sensing. 2014 IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP), 4 May 2014 - 9 May 2014.
- A new saliency model using intra coded High Efficiency Video Coding (HEVC) frames. Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics), Vol. 8325 LNCS(PART 1) (pp 580-592)
- Fast compressed sensing reconstruction using the least squares and signal correlation. IET Conference Publications, Vol. 2013(619 CP)
- Classification of remotely compressively sensed data. IET Conference Publications, Vol. 2013(619 CP)
- Kinect depth stream pre-processing for hand gesture recognition. 2013 IEEE International Conference on Image Processing, ICIP 2013 - Proceedings (pp 3735-3739)
- Distortion constrained robustness scalable watermarking. IET Conference Publications, Vol. 2012(600 CP)
- Robust watermarking for scalable image coding-based content adaptation. IET Conference Publications, Vol. 2012(600 CP)
- Inter-description motion vector redundancy control for scalable multiple description video coding. IET Conference Publications, Vol. 2012(600 CP)
- Visual saliency estimation for video. International Workshop on Image Analysis for Multimedia Interactive Services
- Visual attention-based watermarking. Proceedings - IEEE International Symposium on Circuits and Systems (pp 2653-2656)
- Robustness analysis of blindwatermarking for quality scalable image compression. European Signal Processing Conference (pp 810-814)
- Scalable multiple description video coding using successive refinement of side quantizers. 28th Picture Coding Symposium, PCS 2010 (pp 602-605)
- Successive refinement of overlapped cell side quantizers for scalable multiple description coding. 28th Picture Coding Symposium, PCS 2010 (pp 286-289)
- Video watermarking using motion compensated 2D+t+2D filtering. MM and Sec'10 - Proceedings of the 2010 ACM SIGMM Multimedia and Security Workshop (pp 127-136)
- Multiple description scalar quantization with successive refinement. European Signal Processing Conference (pp 2268-2272)
- A framework for evaluating wavelet based watermarking for scalable coded digital item adaptation attacks. Proceedings of SPIE - The International Society for Optical Engineering, Vol. 7248
- Multiple description image coding using several multiple description scalar quantizers. Proceedings of SPIE - The International Society for Optical Engineering, Vol. 7257
- Embedding distortion modeling for non-orthonormal wavelet based watermarking schemes. Proceedings of SPIE - The International Society for Optical Engineering, Vol. 7248
- Fully Scalable Multiple Description Image Coding. 2009 IEEE INTERNATIONAL WORKSHOP ON MULTIMEDIA SIGNAL PROCESSING (MMSP 2009) (pp 99-104)
- Distributed Multiple Description Image Coding. 2009 IEEE INTERNATIONAL WORKSHOP ON MULTIMEDIA SIGNAL PROCESSING (MMSP 2009) (pp 245-249)
- THE EFFECT OF QUALITY SCALABLE IMAGE COMPRESSION ON ROBUST WATERMARKING. 2009 16TH INTERNATIONAL CONFERENCE ON DIGITAL SIGNAL PROCESSING, VOLS 1 AND 2 (pp 409-416)
- Evaluation of watermark robustness to JPEG2000 based content adaptation attacks. IET Conference Publications(543 CP) (pp 789-794)
- Content adaptation resilient low-level visual features for content based image retrieval. IET Conference Publications(543 CP) (pp 164-169)
- View this article in WRRO Morphological wavelet domain watermarking. European Signal Processing Conference (pp 2539-2543)
- Scalable coded domain low-level visual feature extraction. IET Conference Publications(534 CP)
- A watermark evaluation bench for content adaptation modes. IET Conference Publications(534 CP)
- Reducing aliasing in wavelets based downsampling for improved resolution scalability. 2005 INTERNATIONAL CONFERENCE ON IMAGE PROCESSING (ICIP), VOLS 1-5 (pp 2281-2284)
- Texture-adaptive mother wavelet selection for texture analysis. 2005 International Conference on Image Processing (ICIP), Vols 1-5 (pp 2061-2064)
- Texture-adaptive mother wavelet selection for texture analysis. Proceedings - International Conference on Image Processing, ICIP, Vol. 2 (pp 1290-1293)
- Reducing aliasing in wavelets based downsampling for improved resolution scalability. Proceedings - International Conference on Image Processing, ICIP, Vol. 2 (pp 898-901)
- On the influence of motion vector precision limiting in scalable video coding. International Conference on Signal Processing Proceedings, ICSP, Vol. 2 (pp 1143-1146)
- Wavelet filter banks with a 2D spatially adaptive low pass filter for scalable image coding. Picture Coding Symposium 2004 (pp 565-570)
- Scalable generation and coding of motion vectors for highly scalable video coding. Picture Coding Symposium 2004 (pp 571-576)
- Texture analysis using adaptive biorthogonal wavelet packets. Proceedings - International Conference on Image Processing, ICIP, Vol. 5 (pp 1197-1200)
- 2D wavelet transforms with a spatially adaptive 2D low pass filter. Report - Helsinki University of Technology, Signal Processing Laboratory, Vol. 46 (pp 93-96)
- On the influence of motion vector precision limiting in scalable video coding. 2004 7th International Conference on Signal Processing Proceedings, ICSP (pp 1145-1148)
- Spatially adaptive integer lifting with no side information for lossless video coding. Picture Coding Symposium (pp 495-499)
- Orthonormal integer block transforms for lossless coding : Design and performance analysis. VISUAL COMMUNICATIONS AND IMAGE PROCESSING 2003, PTS 1-3, Vol. 5150 (pp 1719-1729)
- N-point discrete cosine transforms that map integers to integers for lossless image/video coding. Picture Coding Symposium (pp 417-421)
- Discrete wavelet transforms that have an adaptive low pass filter. SEVENTH INTERNATIONAL SYMPOSIUM ON SIGNAL PROCESSING AND ITS APPLICATIONS, VOL 2, PROCEEDINGS (pp 487-490)
- Modifying integer wavelet transforms for scalable near-lossless image coding. VISUAL COMMUNICATIONS AND IMAGE PROCESSING 2003, PTS 1-3, Vol. 5150 (pp 1697-1708)
- A novel morphological subband decomposition scheme for 2D+t wavelet video coding. ISPA 2003: PROCEEDINGS OF THE 3RD INTERNATIONAL SYMPOSIUM ON IMAGE AND SIGNAL PROCESSING AND ANALYSIS, PTS 1 AND 2 (pp 239-244)
- Adaptive integer to integer wavelet transforms using update lifting. Proceedings of SPIE - The International Society for Optical Engineering, Vol. 5207(2) (pp 813-824)
- Quantization of adaptive 2D wavelet decompositions. IEEE International Conference on Image Processing, Vol. 3 (pp 209-212)
- Embedded to lossless coding of motion compensated prediction residuals in lossless video coding. Proceedings of SPIE - The International Society for Optical Engineering, Vol. 4310 (pp 175-185)
- On the influence of motion vector precision limiting in scalable video coding. Proceedings 7th International Conference on Signal Processing, 2004. Proceedings. ICSP '04. 2004.
Datasets
- Research students
Student Degree Status Primary /Secondary Alwaely B PhD Graduated Primary Pal S PhD Graduated Primary
Bhowmik D PhD Graduated Primary Feng T PhD Graduated Primary Hotrakool W PhD Graduated Primary
Majid M PhD Graduated Primary
Oakes M PhD Graduated Primary Wang Y PhD Graduated Primary Dai X MPhil Graduated Primary
Yu Z MPhil Graduated Primary
Angadi V PhD Graduated Secondary