Imetrum - allowing convenient cost-effective high precision measurements using video-based metrology (for redaction)
Submitting InstitutionUniversity of Bristol
Unit of AssessmentGeneral Engineering
Summary Impact TypeTechnological
Research Subject Area(s)
Information and Computing Sciences: Artificial Intelligence and Image Processing, Computer Software, Information Systems
Summary of the impact
From strains within a single carbon fibre to deflections in a bridge, dam
or railway line, accurate measurement is vital to industry and public
infrastructure. In many engineering contexts, traditional approaches to
measurement are inadequate or involve unacceptable costs and delays. These
shortcomings have been addressed by the University of Bristol's research
into high-precision, video-based metrology and its application through
Imetrum, a spin-out company. Imetrum was founded in 2003 and launched its
first product - the Video Gauge - in 2007. In the area of mechanical
testing, the company has brought the first video-based extensometry system
that can be supplied calibrated to international standards to market. For
structural monitoring and safety inspections, deformation measurements are
usually required. The Imetrum system is being used to precisely measure
such deformations in rail bridges and other vital parts of the
infrastructure without costly and inconvenient interruptions to their
operation. Imetrum has approximately doubled its turnover each year since
2007. [text removed for publication].
Metrology underpins much of engineering, and improvements in metrology
can have significant and wide-ranging benefits. The initial work at the
University of Bristol to secure such improvements was carried out as part
of the EPSRC-funded `Innovative Approaches to Composite Structures' (IACS)
programme. IACS involved investigating novel design and manufacture
approaches that required access to mechanical test data that were not
available through conventional technology. Specifically, small strains
needed to be measured in small and delicate samples , which required
the use of non-contact methods.
Previous work in Bristol's Faculty of Engineering had demonstrated that
sub-pixel resolution could be obtained in tracking target areas within
video streams and that the movements of those targets could be used to
measure structural displacements in flexible, large-span road bridges .
This work needed significant development in several areas to generate a
workable, laboratory-based tool for strain measurement in mechanical
testing within the IACS project. These areas included improved tracking
algorithms, better understanding of the factors controlling accuracy,
resolution, errors and reliability, and issues around system integration
to develop a potentially marketable product, and were addressed by
Setchell (UoB 1997-2012 and now Technical Director of Imetrum), Towse (UoB
PhD student 1995-2000), Potter (UoB since 1995 and a Director of Imetrum
since 2003) and Wisnom (UoB since 1987) . After further development of
the technique, it was patented for the monitoring of aircraft structures
by the University in 2003 .
Additional development in all of these areas has taken place within the
University spin-out company Imetrum Limited. This has driven an order of
magnitude improvement in resolution over the system used in the original
work and has led to an extensometry system that can be supplied with a
calibration certificate traceable to international standards as required
by the industrial customer base - a world first. Close liaison has been
maintained between the University and Imetrum to develop the systems for
applications in materials testing.
The IACS programme ran from 1995 to 1998. The recognition that current
strain-measurement approaches were inadequate was deduced in 1997. A
specific programme to link the video analysis capabilities and the
materials and testing expertise across the Faculty of Engineering
commenced that year. The development of the Imetrum video metrology
systems for structural monitoring and other applications, see for example
, has relied on an ongoing relationship between Imetrum and the Faculty
of Engineering through EngD projects within the Faculty's Systems Centre.
References to the research
 *A. Towse, K.D. Potter, M.R. Wisnom and R.D. Adams, 1998. Specimen
size effects in the tensile failure strain of an epoxy adhesive.
Journal of Materials Science, 33, 4307-4314,
 J.H.G. Macdonald, C.A. Taylor, B.T. Thomas and E.L. Dagless, 1998. Real
time remote monitoring of dynamic displacements by computer vision.
Proceedings of the Sixth Society for Earthquake and Civil Engineering
Dynamics Conference, Oxford, 389-396 (can be supplied upon request).
 *A. Towse, C.J. Setchell, K.D. Potter, A.B. Clarke, J.H.G. Macdonald,
M.R. Wisnom and R.D. Adams, 2001. Use experience with a developmental
general purpose non-contacting extensometer with high resolution.
Nontraditional methods of sensing stress, strain and damage in materials
and structures, West Conshohocken, Pa, USA, 1999, ASTM Special
Technical Publication 1323, 2, 36-51 (can be supplied upon request).
 *K.D. Potter and C. Setchell. 2003. Positional measurement of a
feature within an image and monitoring an aircraft structure,
US2006115133 and EP1563252 Patents.
 J. Martin, J.-J.Heyder-Bruckner, C.D.L. Remillat, F.L. Scarpa, K.D.
Potter and M. Ruzzene, 2008. The hexachiral prismatic wingbox concept.
Physica Status Solidi, B: Basic Research, 245(3), 570-577,
* References that best indicate the quality of the underpinning research.
Details of the impact
The broad area of research into non-contact metrology has expanded
greatly in recent years with several techniques competing in the
marketplace. Many of these techniques are only applicable within specific
scale ranges, require specific preparation of the surfaces to be examined
or need highly trained staff to make use of very complex measurement
approaches that are sensitive to operator error. By contrast, the
video-based technology, originally developed at the University of Bristol
and commercialised through Imetrum, overcomes most of these limitations.
The current Imetrum products are directly derived from the research
carried out at, and are protected by a patent assigned to, the University
. These products would not exist without the Bristol research - this
research provides the fundamental understanding, the technology and the
market knowledge on which Imetrum was based.
Despite launching its first product during a recession, in 2007, Imetrum
has almost doubled its turnover in each year of operation, [text
removed for publication] and currently sells its materials-testing
products internationally. [text removed for publication]. Most
sales are now exports, including to China, the USA, France, Germany,
Scandinavia, the Czech Republic, Brazil and Korea.
Current Imetrum customers include major engineering companies such as
Airbus, Rolls-Royce, BAE Systems, Amey and Network Rail as well as
specialist companies such as the Red Bull and McLaren F1 teams [a], which
are using the system for both materials characterisation and measuring
deflections in structural testing. To further expand application areas,
ongoing TSB-funded research is being undertaken by Imetrum in areas such
as the monitoring of nuclear power systems.
The current state-of-the-art technique, based on the Bristol research and
Imetrum developments, is embedded in systems for the real-time or
post-processed measurement of displacements, strains, rotations and other
deformations across a wide range of industrial applications. It has, for
example, enabled the detailed measurement of strains in single,
5µm-diameter carbon fibres or even at the nanometre scale range within
electron microscope images, through to deflections in bridges and dams.
Imetrum has realised significant impact across a range of sectors
including railways and Formula 1.
Composites: Within the mechanical test area, the Imetrum
technology is now widely used in research and development, including at
the National Composites Centre, to understand the details of failure
processes in ideal and defective materials. This is a very important
current topic of research in composite materials in support of increasing
industrial applications of these materials. It is also routinely used to
acquire hard-to-measure data in support of virtual engineering simulations
for such topics as dimensional fidelity in large moulded parts. Many of
the measurement applications for which Imetrum's Video Gauge is routinely
used in the academic environment would either not be achievable by any
other approach or could only be achieved at much greater cost.
Railway Infrastructure: The resolution of the system developed for
structural monitoring is sufficiently fine to enable it to measure the
displacement of rail lines due to individual wheels passing along the
rail. This permits the direct measurement of track deflections and is
currently being used to identify whether the track responds safely to the
passage of a train. Traditional measurements only measure the maximum
deflection and fail to capture all the deformation. The Imetrum system
overcomes this problem entirely [b]. In another example, bridges on the
Paddington to Penzance main line were monitored for deflection to check
their safety. Deflections of less than 1mm were detected with good
fidelity, with deflections associated with individual engines and
carriages being clearly and separately resolved [c].
In terms of the monitoring tasks undertaken, the Imetrum solution usually
means that there is no need to access a structure directly. This offers
benefits in terms of timescales, safety and cost to asset owners and the
public at large. For example, for rail-track measurements, as there is no
need to access a railway directly, there is no need to obtain a possession
order to allow access, which will typically remove around a six week
delay. In addition, the work itself can be carried out by just one or two
individuals rather than the five or six typically required (e.g. to act as
lookouts). Additionally, workers are not put at risk, either from live
traffic loads or working at height, and delays are not caused to the
infrastructure users. When the system is used to monitor bridges, road
closures are not required during its installation avoiding costs in the
range of £10,000s - £100,000s. Imetrum generally provides these
measurements as a service to its clients. This element of the Imetrum
business is now growing rapidly [text removed for publication].
[text removed for publication]:The impact of the technology to
date has also been important in terms of improved understanding of
materials and structural responses and reduction of the costs to industry
and academia in generating such understandings. For example, the
development by Imetrum of systems capable of calibration to international
standards has eliminated a major limitation on the take-up of such
non-contact strain measurement technology in the materials test area. Such
technology underpins much advanced engineering, significantly reducing the
costs of acquiring data and allowing previously difficult-to-gather data
to be routinely collected, such as data from high temperature tests (up to
1,000oC). This is being used in the rapid characterisation of
novel composite material solutions for use in hot structures in racing
Imetrum has just launched a new product allowing direct strain mapping of
test samples whilst retaining the very high fidelity strain measurement
that is the hallmark of Imetrum products. This new product should enable
an acceleration of sales into the materials-testing market.
Sources to corroborate the impact
The impact can be corroborated by:
- Technical Director, Imetrum.
The specific documents referred to are:
[a] Imetrum website news article - Imetrum Continues to Expand,
[b] Imetrum website case study - Measuring Voids.
[c] Imetrum website case study - Rail Bridges.