Improved movement and fingerprint analysis using statistical shape analysis in computer vision
Submitting Institution
University of NottinghamUnit of Assessment
Mathematical SciencesSummary Impact Type
TechnologicalResearch Subject Area(s)
Mathematical Sciences: Statistics
Information and Computing Sciences: Artificial Intelligence and Image Processing
Summary of the impact
Methodologies for shape analysis developed by the Shape and Object Data
Analysis group at The
University of Nottingham (UoN) have underpinned important applications
resulting in a range of
benefits for companies and organisations, including in human movement
capture and fingerprint
modelling.
Firstly, the economic benefits of the methodologies developed at
Nottingham to capture human
movement data without a calibration trial have been used by a commercial
software company,
Charnwood Dynamics Ltd, and have saved time for its users and increased
portability. Secondly,
by incorporating research methods into practice, practitioners have
improved standard processes,
which have resulted in efficiency savings. Organisations which have
benefitted from the research
methods include the German Federal Police, where the methodology has been
used in modelling
growth in adolescent fingerprints, resulting in lower error rates and a
reduction in false matches.
Underpinning research
Computer Vision has become a key enabling technology across a range of
industrial and medical
applications, including forensics, manufacturing, transport and disease
diagnosis. A recent Frost &
Sullivan analysis reports the global market for Machine Vision (the
automated application of
Computer Vision techniques) as $4.5 billion in 2012, projected to reach
$6.75 billion by 2016 -
tinyurl.com/o9f4jm7. A core
requirement in many of these applications is the ability to recognise
shapes; statistical shape analysis provides an important tool for
achieving accurate shape
recognition for difficult problems and under demanding operating
conditions.
Pioneering research undertaken at UoN by Dr Huiling Le (UoN, 1991 to
date, Associate Professor
and Reader in Probability, School of Mathematical Sciences) provided the
first detailed structure of
Euclidean shape spaces [A1-A3]. Expanding on earlier work on the
differential geometric structure
of the shape and size-and-shape spaces [Le & Kendall, Annals of
Statistics, 1993], Le produced
detailed methodology for mean shape and mean size-and-shape estimation
[A2] in 1995 and
derivation of uniqueness conditions for the Fréchet mean [A2, A3] between
1995 and 2001. This
research is part of a large body of work in shape theory and shape
analysis conducted over the
past 20 years by Le with Professor Ian Dryden, Professor Andrew Wood and
colleagues (UoN,
Dryden 2000-2010 and 2012 to date, Wood 1999 to date, both Professors of
Statistics, School of
Mathematical Sciences), that extends to the analysis of more general
manifold valued data, e.g.
[A4] and recent support from [A7, A8]. Practical results from these
insights have been codified into
an open source statistical package [A5] by Dryden, allowing researchers
and practitioners access
to these and other shape analysis methods in applications that require,
and hence benefit from,
accurate shape analysis. The software package, `shapes', was first made
publicly available in 2003
as part of an EPSRC-funded grant [A6]. This has since been regularly
updated by Dryden.
A specific example of a key research insight developed at Nottingham is
the work on mean size-
and-shapes by Le. Size-and-shape analysis is carried out where objects are
compared with
rotation and translation invariance, but not scale invariance. In 1995, Le
[A2] gave definitive details
of estimation of the mean size-and-shape and outlined various important
properties including
uniqueness of the mean. A fundamental question of practical interest is
whether the population and
sample mean size-and-shapes are unique; Le [A2] gave conditions for
uniqueness which can be
readily checked, and for shape and size-and-shape estimation this requires
knowledge of the
sectional curvature of the size-and-shape space, which was originally
derived by Le & Kendall in
1993. A practical implementation of the sample mean size-and-shape
estimate is available in
Dryden's `shapes' package [A5], which is substantially based upon the
research undertaken by the
Nottingham group, as well as exploiting early theory developed elsewhere.
References to the research
The three publications that best indicate the quality of the research are
indicated *
[A1]* Kendall, D. G., Barden, D., Carne, T. K. and Le, H. (1999).
Shape and Shape Theory. Wiley,
Chichester. DOI: 10.1002/9780470317006.fmatter (available on request)
[A2]* Le, H. (1995). Mean size-and-shapes and mean shapes: a
geometric point of view.
Advances in Applied Probability, 27, 44-55. http://www.jstor.org/stable/1428094
(also available on
request)
[A3]* Le, H. (2001). Locating Fréchet means with application to
shape spaces. Advances in
Applied Probability, 33, 324-338. DOI:10.1239/aap/999188316
[A4] Dryden, I.L., Koloydenko, A. and Zhou, D. (2009).
Non-Euclidean statistics for covariance
matrices, with applications to diffusion tensor imaging. Annals of Applied
Statistics, 3, 1102-1123.
DOI:10.1214/09-AOAS249
Grants:
[A6] EPSRC grant GR/R55757/0 `Identifying structure from shape and
image data' PI: Dryden. Co-
Is: Le and Wood. £157,196, 2001-2004.
[A7] EPSRC grant EP/K022547/1 `Statistical Analysis of
Manifold-Valued Data' PI: Wood. Co-Is:
Le, Dryden and Preston. £611,045, 2013-2016.
[A8] Royal Society Wolfson Research Merit Award `Object data
analysis, with applications to
medical images and molecular shapes' PI: Dryden. £60,000, 2012-2017.
Details of the impact
The impacts from the research developments at Nottingham in shape
analysis have been made
possible via a number of routes, including making the `shapes' software
[A5] freely available and
the description of the work in textbooks, such as Dryden and Mardia's book
on Statistical Shape
Analysis (1998, Wiley) and Kendall et al. [A1] in 1999, which have sold
approximately 1800 and
760 copies respectively (as of 14/08/2013). These have helped to create
links with users in
industry and the police, who having become aware of the research and
software via these links
have subsequently made contact with Nottingham directly or via other
academic collaborators.
The `shapes' package [A5] in particular has been one of the more popular
downloaded packages
on the CRAN (Comprehensive R Archive Network) website. Data from the
University of California
Los Angeles mirror on 30/09/2010 (http://neolab.stat.ucla.edu/cranstats/),
one of the few from the
92 mirror sites in 43 countries/regions (http://cran.r-project.org/mirmon_report.html)
that provides
download data, reported that out of 2531 contributed packages the `shapes'
package was the
112th most downloaded (520 downloads) from the 116th most separate IP
addresses (379 IPs),
i.e. in the top 5% of downloaded contributed R packages at that time (the
most downloaded
package from the mirror had 935 downloads, less than twice that of the
`shapes' package). Sites at
which the `shapes' package was publicised throughout the period 2003-2013
include locally at
www.maths.nottingham.ac.uk/~ild/shapes
and the SUNY Stony Brook Morphometrics website
http://life.bio.sunysb.edu/morph/.
Commercial software
One specific illustration of the impact of the research on size-and-shape
analysis [A2] is through
the work of Dr Joel Mitchelson who works for Charnwood Dynamics Ltd and
the start-up company
Ogglebox Sensory Computing Ltd. Charnwood Dynamics has an established 3D
movement
analysis brand, Codamotion (www.codamotion.com),
which is used in many settings, including
clinical analysis, mobile gait labs, biomechanics, sports, orthotics and
prosthetics, ergonomics,
virtual reality and visualisation (tinyurl.com/kr64xfw,
page 12). The company has an average
annual turnover of £713k (2006-12) and is one of 8 main global players in
the market for marker-based
3D movement analysis for life sciences (clinical and research use).
Mitchelson first confirms in his letter [B1] that: "The published
results on shape spaces from
University of Nottingham were instrumental in proving the convergence of
an algorithm for
measurement of the mean size-and-shape of a moving cluster of 3D
markers. The algorithm and
proof have now been accepted for publication in the Journal of
Biomechanics, and are
implemented in the open source library, Open3DMotion [tinyurl.com/ldyhkkc]."
The publication mentioned here is [B2], which makes clear its reliance on
Le's work. Mitchelson's
work arose after he contacted Le for a copy of [A3]. This led to
independent work by Mitchelson
and his team which, in particular, uses the sectional curvature
calculations for size-and-shape
space from Le & Kendall 1993 in the condition for uniqueness of the
mean [A2, Condition C] to
develop further results for occluded data. Mitchelson states by way of
clarification that:
"This library forms the basis of the calculation engine within
Codamotion's commercial ODIN
software (http://www.codamotion.com/the-odin-software-suite.html)
[Introduced in October 2011]."
He adds: "The benefit to Codamotion customers is that the method
allows rigid motions of clusters
of markers on a human body to be tracked without a calibration trial,
which can save them time. It
also allows small portable 3D movement analysis systems to be moved
around to measure very
large volumes, using reference markers used to transform measurements
from a moving system to
a static reference frame. This opens up new market opportunities for the
company, particularly for
analysis of sports movements in the field, and ergonomics in industrial
environments. The
published shape space results from University of Nottingham are
important for giving confidence in
the results obtained from these new products."
That impact from this has already been realised is made explicit by
Mitchelson in an email dated
23 July 2013 (copy on file): "A beta version of the algorithm has been
in the software for some
months. We're already able to engage with customers and potential
customers about this due to
the solid mathematical foundation, which is a result of the
size-and-shape spaces work."
Fingerprinting
A further illustration is through the work of Dr Thomas Hotz (Ilmenau
University of Technology) with
the Bundeskriminalamt (Federal Criminal Police Office of Germany), where
Nottingham research
has led to efficiency savings after the methods were introduced into
standard operating procedure
within the Force. Hotz describes the profound impact of Nottingham
research in [B3]:
"The aim of the study was to understand and predict the impact growth
has on fingerprints of
adolescents [B4, B5]. The difficulty automated fingerprint
identification systems face when
confronted with fingerprints of adolescents was that the points of
interest used in matching
algorithms move during growth, so that either tolerances in matching
have to be increased,
resulting in a worsened overall performance, or the fingerprint can no
longer reliably be found in
records after some years of growth. Understanding growth firstly is a
matter of understanding
whether it occurs isotropically, i.e. uniformly in all directions. If
that were the case the shapes would
not change during growth. We thus used the software package "shapes"
developed by that
[Nottingham] group [A5] as well as the methods described by the book
co-authored by Ian Dryden
in order to measure the anisotropy of growth. We found it to occur
essentially isotropically,
reducing the task of predicting its effects to the prediction of a
single number, the growth factor,
which simplified matters dramatically."
In specific experiments, [B4], error rates on a test set of 462
fingerprints were halved by scaling;
this result was confirmed on the Bundeskriminalamt's database of 3.25
million right index
fingerprints, where nine failures to retrieve a juvenile fingerprint out
of 48 such identification
attempts could be avoided by rescaling. Hotz notes the rescaling "...effect
had not been
understood, the European Union asked for a study to be conducted in this
direction [Official J
European Union, L131, 52, Regulation 390/2009, Annex 2, Article 2], and
decided against the use
of fingerprints of children under the age of 12 in visa applications [in
May 2009]." This clearly
demonstrates the importance of this problem and moreover the importance of
the `shapes'
package in this context. Further, Hotz notes: "It is worth mentioning
that, roughly at the same time,
the U.S. Department of Justice also had a study on the topic conducted
which however appears to
have failed to determine the effect of growth on fingerprints, and to
produce a useful means for
predicting it. This study did not use any shape analysis to look at
anisotropy first, as they probably
did not know of these techniques."
Overall, Hotz summarises by saying: "... I believe that without the
Nottingham Group's research,
making it available through software and textbooks, spreading their
knowledge through further
publications and conferences, this study could not have been conducted."
Thus Hotz's acquaintance with shape analysis, heavily influenced by
personal contact with and
publications of the members of the Nottingham group, has been key in
solving the problem at
hand. As Hotz notes in his letter, the results of his study were
disseminated in 2011 at conferences
involving persons from academia, industry and public office, e.g. from the
biometrics industry such
as Morpho (www.morpho.com),
representatives of security forces such as the Metropolitan Police
Service, and from the European Commission Joint Research Centre.
Other impacts of the work
There are other beneficiaries of the `shapes' package and, more broadly,
of the underlying
research undertaken at Nottingham. These include an impact as a teaching
aid by introducing
geometric morphometrics to biologists via an on-line workbook [B6], a
face-shape study in patients
with epilepsy [B7], use in radar signal processing, and applications in
car headlight shape design
[B8]. It is thus likely that the strong interest from the groups mentioned
here and others will ensure
impact from the Nottingham research will grow in reach and significance
yet further.
Sources to corroborate the impact
[B1] Letter from Ogglebox Sensory Computing, Charnwood Dynamics
Ltd, Leicester detailing work
on human movement modelling software (copy on file).
[B2] Mitchelson, J.R. (2013). MOSHFIT: Algorithms for
occlusion-tolerant mean shape and rigid
motion from 3D movement data. Journal of Biomechanics, 46 (13), 2326-2329.
http://www.jbiomech.com/article/S0021-9290(13)00262-5/abstract
(copy also on file)
[B3] Letter from Ilmenau University of Technology detailing work
on fingerprint modelling of
adolescents with the German Federal Police (copy on file).
[B4] Gottschlich, C. et al. (2011). Modeling the growth of
fingerprints improves matching for
adolescents. IEEE Transactions on Information Forensics and Security, 6
(3), 1165-1169. (copy on
file or through DOI:
10.1109/TIFS.2011.2143406).
[B5] Hotz, T. et al. (2011). Statistical Analyses of Fingerprint
Growth. BIOSIG 2011 - Proceedings,
Lecture Notes in Informatics, P-191, 11-20. (copy on file or through
http://subs.emis.de/LNI/Proceedings/Proceedings191/11.pdf).
[B6] Zelditch, M.L., Swiderski, D.L. and Sheets, D.H. (2012).
Geometric Morphometrics for
Biologists, Second Edition. On-line companion materials. ISBN:
9780123869036
http://booksite.elsevier.com/9780123869036/
(includes full pdf of workbook)
[B7] Chinthapalli, K. et al. (2012). Atypical face-shape and
genomic structural variants in epilepsy.
Brain: A Journal of Neurology, 135(10), 3101-3114. DOI:
10.1093/brain/aws232. (copy also on file)
[B8] Ishihara, S. and Ishihara, K., Morphometrics and Kansei
Engineering, in Proceedings of 10th
QMOD Conference. Quality Management and Organizational Development. Our
Dreams of
Excellence (Editors: Dahlgaard-Park, S. and Dahlgaard, J.), 18-20 June,
2007 in Helsingborg,
Sweden, Issue 026, No 142. www.ep.liu.se/ecp/026/142/ecp0726142.pdf
(copy also on file)