Dr Steve Sangwine

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Brief biography

Picture of Steve I am a retired former Senior Lecturer at the University of Essex, UK. I worked in the School of Computer Science and Electronic Engineering, from 2001 to 2021, full-time until October 2016, and then 50% part-time, retiring at the end of March 2021. I'm still doing research at my own pace, with collaborators overseas.

At the time the School was created, I served as one of three Deputy Heads, firstly for Development in academic year 2007-8, including curriculum development and recruitment, and then Teaching in part of academic year 2008-9. I was on Research Leave in academic year 2009-10. From 2010 to 2012 and again in 2015-16 I was Director of Undergraduate Studies. In 2012-13, 2013-14 and 2015-16 I was on Research Leave in the Spring Term (January-April 2013, 2014 and 2016). My research interests are in the theory and practice of signal and image processing with vector samples - typically colour images and 3-dimensional signal samples. This is achieved by working in hypercomplex algebras, mainly the quaternions and biquaternions. Since 2010 I've also been interested in the wider field of Clifford algebras, of which the quaternions are special a case. The story of how I ended up working in this field is recounted below.

I was born in London in 1956 and have never lived more than about 100km away. Since my late school years I have been interested in electronics and I have spent my whole career working in electronics in one way or another, although my technical interests now are somewhat removed from circuits and electronic design, and in recent years I've become more oriented towards mathematics, publishing some papers in mathematical rather than engineering journals.

I studied Electronic Engineering at the University of Southampton graduating with a BSc in 1979. For the next five years I worked at the former Harwell Laboratory of the UKAEA which, at the time, was a much larger organization than it is now. After a short period working in commercial industry I joined the University of Reading in January 1985 as a Lecturer in the Department of Engineering. During my first six years at Reading I worked on my PhD in digital circuit test (fault diagnosis), graduating in 1991. I also wrote the first edition of Electronic Components and Technology, which has since been through two further editions, in 1994 and in 2007 (see cover picture and full details on this page).

In 1992 I started working on colour image processing, supervising my first research student, Dr Alan Pritchard, with Robin Horne as co-supervisor. I next supervised Dr Amy Thornton, then Dr Will Berriss and Dr Anthony Bardos. During this time I edited (with Robin Horne) The Colour Image Processing Handbook (see details below), which was published in 1998. About this time, I first got interested in hypercomplex numbers and made contact with Dr Todd Ell in Minnesota, with whom I have worked since 1998. We've published quite a few papers together and advanced the theory and practice of colour image processing using hypercomplex filters and transforms.

I left the University of Reading at the end of 2000, and joined the University of Essex working in the Department of Electronic Systems Engineering, one of the two departments that merged in 2007 to create the school I worked in until 2021.

Before leaving Reading, I obtained my first major research grant from the Engineering and Physical Sciences Research Council (EPSRC). Three researchers worked on this grant (Dr Carolyn Evans at Reading, and Dr Eddie Moxey and Dr Barnabas Gatsheni at Essex). You can see the papers we published in my publication list on this page. The idea of the work was to discover new colour image filters based on hypercomplex (quaternion) coefficients. This work has since been supported by two more grants from EPSRC, both to support the collaboration I have with Todd Ell.

In 2001, shortly after arriving at Essex, Dr Nicolas Le Bihan came to see me and told me about his work on signal processing using quaternion linear algebra. Nicolas and I have worked together since, and the collaboration was supported by a small grant from EPSRC. In 2005, with financial support from the <PDF icon> Royal Academy of Engineering, and CNRS in France I was able to spend 7 months working as a Visiting Researcher (Chercheur Invité in French) at the Laboratoire des Images et des Signaux (now part of a larger lab called GIPSA), in Grenoble, working with Nicolas. We have published some papers together, and also developed a quaternion toolbox for Matlab (see below) which I now use also for the work with Todd Ell. Many of our algorithms and results are implemented in this toolbox, so anybody can try out the methods (well, not quite anybody, you have to know quite a bit about signal and image processing and mathematics). During my time in Grenoble, I worked also with Salem Said, a research student in the lab, supervised by Nicolas, and the three of us developed a complexified quaternion version of the quaternion transform earlier developed by Todd Ell and myself. We (Todd, myself, Nicolas, Salem) are still working on understanding the complexified quaternions - they are a form of geometric algebra, which suggests to us many possibilities in signal and image processing. From 2008 I also worked with Daniel Alfsmann at the Ruhr-Universität Bochum in Germany on aspects of hypercomplex algebras with application to signal processing, and we have published a paper setting out the details of biquaternion divisors of zero.

For the last decade I have worked with Dr Eckhard Hitzer, and visited Japan in the spring of 2015 for two weeks to work on Clifford algebras with him (see below for the software that resulted from this collaboration). We've also published papers on our Clifford Algebra toolbox, and novel algorithms that are implemented in (and were developed using) the toolbox.

During all this time, I taught among other things, digital system design using VHDL, and I supervised a couple of MSc projects and a PhD project in the area of network-on-chip, and two PhDs in hypercomplex image processing. You can see what else I taught in the listing below.

Publications

Book cover picture Book cover picture Book cover picture Book cover picture Book cover picture Book cover picture

Teaching

I have taught a variety of material, including Digital Signal Processing, Digital System Design, Algorithms and Data Structures, Computer Systems, Circuit Theory, Microprocessor Architectures, Digital IC Design, Internet Computing, and Mathematics for Computing.

My teaching duties for 2020-21 were:

I won't be teaching from here on, as I am retired.

Resources

This section contains links to some offshoots of my work that are freely available. I support the open source software movement, and several of the items below are licensed under the GNU General Public Licence.

Professional activities

Trustee, University and College Union (UCU), 2024-2029.
Honorary Treasurer, University and College Union (UCU), 2017-2023.
President (2008-2010 and 2014-15) and Vice-President (2005-2008) Essex Local Association of the UCU (formerly AUT).
Member UCU National Executive Committee 2010-2016, serving on Education Committee (2010-2013 and 2014-2016), Legal Support Review Panel (2010-2013) and the National Council of the Teacher Support Network/Recourse (now known as Education Support Partnership) (2011-2016).

Formerly Honorary Secretary (1995-97) and President (1997-99), Reading Local Association AUT.

President (2007-2009), Treasurer (2016-2021) Staff Common Room Association, University of Essex.

Technical Interests

I'm an enthusiast for Ada, and used it for research from 1986 until about 2006. I'm also an enthusiast for LaTeX which I have used on both Windows, Mac OS X, and Linux platforms. I've typeset many journal and conference papers and several books, including authoring LaTeX style files. Since 2005 I have also been a keen user of Matlab (see above). Since retirement I've learned Ruby and used it on Ubuntu running on a Raspberry Pi 4 for remote monitoring of my boat.

Leisure interests

I have been interested in railways since the age of 11. In November 1994 I travelled on the Eurostar service between London and Paris through the Channel Tunnel very soon after it opened, and an account is available (now 30 years old).

I am also interested in genealogy (with an unusual name like mine that is not surprising perhaps). For a bit more information, see here.

I've been a vegetarian for a long time, and a vegan since 2000.

Contact details

Email:     Use my first and last names as they appear at the top of
           this page without a space followed by at gmail dotcom;
           or through my Sourceforge account (username=sangwine)

Google: sz2xU7wAAAAJ
ORCID : 0000-0002-4569-5630
SCOPUS: 7003346836

PGP:    Public Key Fingerprint: E15C 974C 09CE E5AD 8E44  6A40 4186 115F 56B1 90ED

Social media: I don't!
Created: 24 January 2001
Updated: 2 October 2024