Dr Charith Abhayaratne

PhD

School of Electrical and Electronic Engineering

Senior Lecturer

Headshot of Charith Abhayaratne
Profile picture of Headshot of Charith Abhayaratne
c.abhayaratne@sheffield.ac.uk
+44 114 222 5893
Sir Frederick Mappin Building

Full contact details

Dr Charith Abhayaratne
School of Electrical and Electronic Engineering
Sir Frederick Mappin Building
Mappin Street
Sheffield
S1 3JD
Profile

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
  • 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
  • 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

Journal articles

  • Mohottala S, Gawesha A, Kasthurirathna D, Samarasinghe P & Abhayaratne C (2025) . Computer Vision and Image Understanding, 259.
  • Xue S, Wu L & Abhayaratne C (2025) . IEEE Access, 1-1.
  • Xue S & Abhayaratne C (2023) . IEEE Access, 11, 28856-28872.
  • Alwaely B & Abhayaratne C (2023) . ACM Transactions on Multimedia Computing, Communications, and Applications, 19(2s), 1-23.
  • Hejazi SM & Abhayaratne C (2022) . Image and Vision Computing, 123.
  • Al-Obaidi S, Al-Khafaji H & Abhayaratne C (2021) . IEEE Access, 9, 82686-82700.
  • Al-Obaidi S, AL-Khafaji H & Abhayaratne C (2020) . IEEE Access, 8, 213806-213824.
  • Alwaely B & Abhayaratne C (2020) . IEEE Access, 8, 182260-182272.
  • Bhowmik D & Abhayaratne C (2019) . ACM Transactions on Multimedia Computing, Communications, and Applications, 15(4).
  • Alwaely B & Abhayaratne C (2019) . IEEE Access, 7, 159661-159673.
  • Hotrakool W & Abhayaratne C (2019) . Journal of Electronic Imaging, 28(4).
  • Oakes M, Bhowmik D & Abhayaratne C (2016) . Journal of Electronic Imaging, 25(6).
  • Bhowmik D, Oakes M & Abhayaratne C (2016) . IEEE Access, 1-1.
  • Bhowmik D & Abhayaratne C (2016) . IEEE Transactions on Image Processing, 25(11), 5158-5172.
  • Angadi V, Abhayaratne C & Walther T (2016) . Journal of Microscopy, 262(2), 157-166.
  • Bhowmik D & Abhayaratne C (2013) . Multimedia Systems, 1-14.
  • Majid M & Abhayaratne C (2012) Redundancy controllable scalable unbalanced multiple description bitstream generation for peer-to-peer video streaming. Signal Processing: Image Communication.
  • Bhowmik D & Abhayaratne C (2012) . Advances in Multimedia, 2012.
  • Abhayaratne C (2011) . J ELECTRON IMAGING, 20(3).
  • Abhayaratne C & Bhowmik D (2011) . Journal of Real-Time Image Processing, 1-19.
  • Cardinaux F, Bhowmik D, Abhayaratne C & Hawley MS (2011) . J AMB INTEL SMART EN, 3(3), 253-269.
  • Abhayaratne C, Izquierdo E, Mrak M & Tubaro S (2009) . SIGNAL PROCESS-IMAGE, 24(6), 415-416.
  • Abhayaratne GCK (2007) . Signal Processing, 87(5), 950-969.
  • Abhayaratne GCK (2006) . Journal of Electronic Imaging, 15(4).

Book chapters

  • Angadi VC, Abhayaratne C & Walther T (2023) , Encyclopedia of Materials Electronics (pp. V3-V3-618).
  • Angadi VC, Abhayaratne C & Walther T (2023) , Encyclopedia of Materials: Electronics (pp. 605-618). Elsevier
  • Bhowmik D, Abhayaratne C & Green S (2020) (pp. 185-198). Springer Singapore
  • Wang Y, Abhayaratne C & Mrak M (2014) , Academic Press Library in Signal Processing (pp. 93-117). Elsevier
  • Oakes M & Abhayaratne C (2014) (pp. 580-592).
  • Bhowmik D & Abhayaratne C (2009) A Generalised Model for Distortion Performance Analysis of Wavelet Based Watermarking In Kim HJ, Katzenbeisser S & Ho ATS (Ed.) (pp. 363-378).
  • Abhayaratne C & Muzammil F (2009) Robust Visual Content Representation Using Compression Modes Driven Low-level Visual Descriptors In Huet B, Smeaton A, MayerPatel K & Avirthis Y (Ed.) (pp. 322-332).

Conference proceedings

  • Wang Z & Abhayaratne C (2024) Weakly-supervised localization of manipulated image regions using multi-resolution learned features.. BMVC Workshop proceedings. Glasgow, UK, 25 November 2024 - 25 November 2024.
  • Wang Z & Abhayaratne C (2023) . 2023 IEEE 25th International Workshop on Multimedia Signal Processing (MMSP) Proceedings. Poitiers, France, 27 September 2023 - 27 September 2023.
  • Cai Q & Abhayaratne C (2023) . 2023 IEEE 25th International Workshop on Multimedia Signal Processing (MMSP) Proceedings. Poitiers, France, 27 September 2023 - 27 September 2023.
  • Rainey J, Elawady M, Abhayartne C & Bhowmik D (2023) . 2023 24th International Conference on Digital Signal Processing (DSP). Island of Rhodes, Greece, 11 June 2023 - 11 June 2023.
  • Alrashidi A, Cudd P, Abhayaratne C & Gotoh Y (2023) . CHI '23: Proceedings of the 2023 CHI Conference on Human Factors in Computing Systems (pp 110). Hamburg, Germany, 23 April 2023 - 23 April 2023.
  • Mohottala S, Samarasinghe P, Kasthurirathna D & Abhayaratne C (2023) . 2022 IEEE International Conference on Industrial Technology (ICIT) (pp 1-8). Shanghai, China, 22 August 2022 - 25 August 2022.
  • Mohottala S, Abeygunawardana S, Samarasinghe P, Kasthurirathna D & Abhayaratne C (2022) . TENCON 2022 - 2022 IEEE Region 10 Conference (TENCON) (pp 1-7). Hong Kong, Hong Kong, 1 November 2022 - 1 November 2022.
  • Xue S & Abhayaratne C (2021) . 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.
  • Alwaely B & Abhayaratne C (2019) . 2019 27th European Signal Processing Conference (EUSIPCO). A Coruna, Spain, 2 September 2019 - 6 September 2019.
  • Al-Obaidi S & Abhayaratne C (2019) . 3rd IET International Conference on Technologies for Active and Assisted Living (TechAAL 2019). London, UK, 25 March 2019 - 25 March 2019.
  • Alwaely B & Abhayaratne C (2019) . ICASSP 2019 - 2019 IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP) (pp 1947-1951). Brighton, United Kingdom, 12 May 2019 - 12 May 2019.
  • Al-Obaidi S & Abhayaratne C (2019) . 2019 IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP) (pp 2017-2021). Brighton, United Kingdom, 12 May 2019 - 17 May 2019.
  • Al-Khafaji H & Abhayaratne C (2019) . ICASSP 2019 - 2019 IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP) (pp 2492-2496). Brighton, United Kingdom, 12 May 2019 - 12 May 2019.
  • Alwaely B & Abhayaratne C (2018) . 2018 26th European Signal Processing Conference (EUSIPCO) (pp 598-602). Rome, Italy, 3 September 2018 - 3 September 2018.
  • Feng T & Abhayaratne C (2018) . 2018 26th European Signal Processing Conference (EUSIPCO) (pp 166-170). Rome, Italy, 3 September 2018 - 3 September 2018.
  • Bhowmik D, Natu A, Ishikawa T, Feng T & Abhayaratne C (2018) . 2018 IEEE International Conference on Multimedia & Expo Workshops (ICMEW). San Diego, CA, USA, 23 July 2018 - 23 July 2018.
  • Al-Khafaji H & Abhayaratne C (2017) . Digital Signal Processing (DSP), 2017 22nd International Conference on. London, UK, 23 August 2017 - 23 August 2017.
  • Hotrakool W & Abhayaratne C (2017) . Digital Signal Processing (DSP), 2017 22nd International Conference on. London, United Kingdom, 23 August 2017 - 23 August 2017.
  • Alwaely B & Abhayaratne C (2017) . 2017 25th European Signal Processing Conference (EUSIPCO) (pp 370-374). Kos, Greece, 28 August 2017 - 28 August 2017.
  • Pal S & Abhayaratne C (2016) . 2nd IET International Conference on Technologies for Active and Assisted Living (TechAAL 2016) (pp 10 (6 .)-10 (6 .))
  • Pal S, Feng T & Abhayaratne C (2015) . 2015 IEEE 5th International Conference on Consumer Electronics - Berlin (ICCE-Berlin) (pp 485-488), 6 September 2015 - 9 September 2015.
  • Feng T, Pal S & Abhayaratne C (2015) . 2015 IEEE 5th International Conference on Consumer Electronics - Berlin (ICCE-Berlin) (pp 172-175), 6 September 2015 - 9 September 2015.
  • Hotrakool W & Abhayaratne C (2015) . 2nd Proceedings of IET International Conference on Intelligent Signal Processing 2015 (ISP), Vol. 2015(CP670). London, UK, 1 December 2015 - 1 December 2015.
  • Pal S & Abhayaratne C (2015) . Proceedings of the 9th International Conference on Distributed Smart Cameras (pp 62-67)
  • Angadi VC, Abhayaratne & Walther T (2015) . http://www.mmc2015.org.uk/ (pp P.4027-P.4027). Manchester, 29 June 2015 - 2 July 2015.
  • Hotrakool W & Abhayaratne C (2014) . 2014 IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP) (pp 2001-2005). Florence, Italy, 4 May 2014 - 4 May 2014.
  • Wang Y, Abhayaratne C, Weerakkody R & Mrak M (2014) . 2014 IEEE Global Conference on Signal and Information Processing (GlobalSIP) (pp 1014-1018), 3 December 2014 - 5 December 2014.
  • Wang Y, Abhayaratne C, Weerakkody R & Mrak M (2014) Colour space transforms for improved video compression. International Conference on Systems Signals and Image Processing (pp 219-222)
  • Hotrakool W & Abhayaratne C (2013) . Iet Conference Publications, Vol. 2013(619 CP)
  • Alharbiy AA & Abhayaratne C (2013) . Iet Conference Publications, Vol. 2013(619 CP)
  • Asad M & Abhayaratne C (2013) . 2013 IEEE International Conference on Image Processing Icip 2013 Proceedings (pp 3735-3739)
  • Bhowmik D & Abhayaratne C (2012) . Iet Conference Publications, Vol. 2012(600 CP)
  • Bhowmik D & Abhayaratne C (2012) . Iet Conference Publications, Vol. 2012(600 CP)
  • Majid M & Abhayaratne C (2012) . Iet Conference Publications, Vol. 2012(600 CP)
  • Oakes M & Abhayaratne C (2012) . International Workshop on Image Analysis for Multimedia Interactive Services
  • Oakes M, Bhowmik D & Abhayaratne C (2011) . Proceedings IEEE International Symposium on Circuits and Systems (pp 2653-2656)
  • Majid M & Abhayaratne C (2010) . 28th Picture Coding Symposium Pcs 2010 (pp 286-289)
  • Bhowmik D & Abhayaratne C (2010) . Mm and Sec 10 Proceedings of the 2010 ACM Sigmm Multimedia and Security Workshop (pp 127-136)
  • Bhowmik D, Abhayaratne C & Oakes M (2010) Robustness analysis of blindwatermarking for quality scalable image compression. European Signal Processing Conference (pp 810-814)
  • Majid M & Abhayaratne C (2010) . 28th Picture Coding Symposium Pcs 2010 (pp 602-605)
  • Majid M & Abhayaratne C (2009) Multiple description scalar quantization with successive refinement. European Signal Processing Conference (pp 2268-2272)
  • Majid M & Abhayaratne C (2009) Fully Scalable Multiple Description Image Coding. 2009 IEEE INTERNATIONAL WORKSHOP ON MULTIMEDIA SIGNAL PROCESSING (MMSP 2009) (pp 99-104)
  • Majid M & Abhayaratne C (2009) Distributed Multiple Description Image Coding. 2009 IEEE INTERNATIONAL WORKSHOP ON MULTIMEDIA SIGNAL PROCESSING (MMSP 2009) (pp 245-249)
  • Bhowmik D & Abhayaratne C (2009) 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)
  • Bhowmik D & Abhayaratne C (2009) . Proceedings of SPIE the International Society for Optical Engineering, Vol. 7248
  • Bhowmik D & Abhayaratne C (2009) . Proceedings of SPIE the International Society for Optical Engineering, Vol. 7248
  • Majid M & Abhayaratne C (2009) . Proceedings of SPIE the International Society for Optical Engineering, Vol. 7257
  • Bhowmik D & Abhayaratne C (2008) . Iet Conference Publications(543 CP) (pp 789-794)
  • Abhayaratne C (2008) . Iet Conference Publications(543 CP) (pp 164-169)
  • Bhowmik D & Abhayaratne GCK (2007) Morphological wavelet domain watermarking. European Signal Processing Conference (pp 2539-2543)
  • Muzammil F & Abhayaratne C (2007) . Iet Conference Publications(534 CP)
  • Bhowmik D & Abhayaratne C (2007) . Iet Conference Publications(534 CP)
  • Abhayaratne GCK (2005) . Proceedings International Conference on Image Processing Icip, Vol. 2 (pp 898-901)
  • Abhayaratne GCK (2005) Reducing aliasing in wavelets based downsampling for improved resolution scalability. 2005 INTERNATIONAL CONFERENCE ON IMAGE PROCESSING (ICIP), VOLS 1-5 (pp 2281-2284)
  • Abhayaratne GCK, Jermyn IH & Zerubia J (2005) Texture-adaptive mother wavelet selection for texture analysis. 2005 International Conference on Image Processing (ICIP), Vols 1-5 (pp 2061-2064)
  • Abhayaratne GCK, Jermyn IH & Zerubia J (2005) . Proceedings International Conference on Image Processing Icip, Vol. 2 (pp 1287-1290)
  • Mrak M, Abhayaratne GCK & Izquierdo E (2004) On the influence of motion vector precision limiting in scalable video coding. 2004 7th International Conference on Signal Processing Proceedings ICSP (pp 1145-1148)
  • Abhayaratne GCK (2004) Wavelet filter banks with a 2D spatially adaptive low pass filter for scalable image coding. Picture Coding Symposium 2004 (pp 565-570)
  • Mrak M, Å prljan N, Abhayaratne GCK & Izquierdo E (2004) Scalable generation and coding of motion vectors for highly scalable video coding. Picture Coding Symposium 2004 (pp 571-576)
  • Abhayaratne GCK, Jermyn IH & Zerubia J (2004) Texture analysis using adaptive biorthogonal wavelet packets. Proceedings International Conference on Image Processing Icip, Vol. 5 (pp 1197-1200)
  • Abhayaratne GCK (2004) 2D wavelet transforms with a spatially adaptive 2D low pass filter. Report Helsinki University of Technology Signal Processing Laboratory, Vol. 46 (pp 93-96)
  • Mrak M, Abhayaratne GCK & Izquierdo E (2004) On the influence of motion vector precision limiting in scalable video coding. International Conference on Signal Processing Proceedings ICSP, Vol. 2 (pp 1143-1146)
  • Pesquet-Popescu B, Heijmans H, Abhayaratne GCK & Piella G (2003) Quantization of adaptive 2D wavelet decompositions. IEEE International Conference on Image Processing, Vol. 3 (pp 209-212)
  • Charith G & Abhayaratne K (2003) Spatially adaptive integer lifting with no side information for lossless video coding. Picture Coding Symposium (pp 495-499)
  • Charith G & Abhayaratne K (2003) N-point discrete cosine transforms that map integers to integers for lossless image/video coding. Picture Coding Symposium (pp 417-421)
  • Abhayaratne GCK, Piella G, Pesquet-Popescu B & Heijmans H (2003) Adaptive integer to integer wavelet transforms using update lifting. Proceedings of SPIE the International Society for Optical Engineering, Vol. 5207(2) (pp 813-824)
  • Charith G & Abhayaratne K (2003) 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)
  • Charith G & Abhayaratne K (2003) Modifying integer wavelet transforms for scalable near-lossless image coding. VISUAL COMMUNICATIONS AND IMAGE PROCESSING 2003, PTS 1-3, Vol. 5150 (pp 1697-1708)
  • Charith G & Abhayaratne K (2003) 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)
  • Charith G, Abhayaratne K & Heijmans HJAM (2003) 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)
  • Abhayaratne GCK & Monro DM (2001) . Proceedings of SPIE the International Society for Optical Engineering, Vol. 4310 (pp 175-185)
  • Mrak M, Abhayaratne GCK & Izquierdo E () . Proceedings 7th International Conference on Signal Processing, 2004. Proceedings. ICSP '04. 2004., Vol. 2 (pp 1143-1146)

Datasets

  • Al-khafaji H & Abhayaratne C .

Preprints

  • Wang Z & Abhayaratne C (2025) , arXiv.
  • Li H & Abhayaratne C (2025) , arXiv.
  • Yang K, Ouyang H, Wang X, Lu B, Wang Y, Abhayaratne C, Li S, Jin L & Deng T (2025) NLS: Natural-Level Synthesis for Hardware Implementation Through GenAI..
  • Yang K, Ouyang H, Wang X, Lu B, Wang Y, Abhayaratne C, Li S, Jin L & Deng T (2025) , arXiv.
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

Links

Information and Communications Engineering