7,908 research outputs found
Deep Perceptual Mapping for Thermal to Visible Face Recognition
Cross modal face matching between the thermal and visible spectrum is a much
de- sired capability for night-time surveillance and security applications. Due
to a very large modality gap, thermal-to-visible face recognition is one of the
most challenging face matching problem. In this paper, we present an approach
to bridge this modality gap by a significant margin. Our approach captures the
highly non-linear relationship be- tween the two modalities by using a deep
neural network. Our model attempts to learn a non-linear mapping from visible
to thermal spectrum while preserving the identity in- formation. We show
substantive performance improvement on a difficult thermal-visible face
dataset. The presented approach improves the state-of-the-art by more than 10%
in terms of Rank-1 identification and bridge the drop in performance due to the
modality gap by more than 40%.Comment: BMVC 2015 (oral
Infrared face recognition: a comprehensive review of methodologies and databases
Automatic face recognition is an area with immense practical potential which
includes a wide range of commercial and law enforcement applications. Hence it
is unsurprising that it continues to be one of the most active research areas
of computer vision. Even after over three decades of intense research, the
state-of-the-art in face recognition continues to improve, benefitting from
advances in a range of different research fields such as image processing,
pattern recognition, computer graphics, and physiology. Systems based on
visible spectrum images, the most researched face recognition modality, have
reached a significant level of maturity with some practical success. However,
they continue to face challenges in the presence of illumination, pose and
expression changes, as well as facial disguises, all of which can significantly
decrease recognition accuracy. Amongst various approaches which have been
proposed in an attempt to overcome these limitations, the use of infrared (IR)
imaging has emerged as a particularly promising research direction. This paper
presents a comprehensive and timely review of the literature on this subject.
Our key contributions are: (i) a summary of the inherent properties of infrared
imaging which makes this modality promising in the context of face recognition,
(ii) a systematic review of the most influential approaches, with a focus on
emerging common trends as well as key differences between alternative
methodologies, (iii) a description of the main databases of infrared facial
images available to the researcher, and lastly (iv) a discussion of the most
promising avenues for future research.Comment: Pattern Recognition, 2014. arXiv admin note: substantial text overlap
with arXiv:1306.160
Design and commission of an experimental test rig to apply a full-scale pressure load on composite sandwich panels representative of aircraft secondary structure
This paper describes the design of a test rig, which is used to apply a representative pressure load to a full-scale composite sandwich secondary aircraft structure. A generic panel was designed with features to represent those in the composite sandwich secondary aircraft structure. To provide full-field strain data from the panels, the test rig was designed for use with optical measurement techniques such as thermoelastic stress analysis (TSA) and digital image correlation (DIC). TSA requires a cyclic load to be applied to a structure for the measurement of the strain state; therefore, the test rig has been designed to be mounted on a standard servo-hydraulic test machine. As both TSA and DIC require an uninterrupted view of the surface of the test panel, an important consideration in the design is facilitating the optical access for the two techniques. To aid the test rig design a finite element (FE) model was produced. The model provides information on the deflections that must be accommodated by the test rig, and ensures that the stress and strain levels developed in the panel when loaded in the test rig would be sufficient for measurement using TSA and DIC. Finally, initial tests using the test rig have shown it to be capable of achieving the required pressure and maintaining a cyclic load. It was also demonstrated that both TSA and DIC data can be collected from the panels under load, which are used to validate the stress and deflection derived from the FE model
Hyperspectral imaging for the remote sensing of blood oxygenation and emotions
This PhD project is a basic research and it concerns with how human’s
physiological features, such as tissue oxygen saturation (StO2), can be
captured from a stand-off distance and then to understand how this remotely
acquired physiological feature can be deployed for biomedical and other
applications.
This work utilises Hyperspectral Imaging (HSI) within the diffuse optical
scattering framework, to assess the StO2 in a contactless remote sensing
manner. The assessment involves a detailed investigation about the wavelength
dependence of diffuse optical scattering from the skin as well as body tissues,
under various forms of optical absorption models. It is concluded that the threechromophore
extended Beer Lambert Law model is better suited for assessing
the palm and facial tissue oxygenations, especially when spectral data in the
wavelengths region of [516-580]nm is used for the analysis.
A first attempt of using the facial StO2 to detect and to classify people’s
emotional state is initiated in this project. The objective of this work is to
understand how strong emotions, such as distress that caused by mental or
physical stimulations, can be detected using physiological feature such as
StO2. Based on data collected from ~20 participants, it is found that the
forehead StO2 is elevated upon the onset of strong emotions that triggered by
mental stimulation. The StO2 pattern in the facial region upon strong emotions
that are initiated by physical stimulations is quite complicated, and further work
is needed for a better understanding of the interplays between bodily physique,
individual’s health condition and blood transfusion control mechanism. Most of
this work has already been published and future research to follow up when the
author returns back to China is highlighted
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