2,057 research outputs found
Optimal Radiometric Calibration for Camera-Display Communication
We present a novel method for communicating between a camera and display by
embedding and recovering hidden and dynamic information within a displayed
image. A handheld camera pointed at the display can receive not only the
display image, but also the underlying message. These active scenes are
fundamentally different from traditional passive scenes like QR codes because
image formation is based on display emittance, not surface reflectance.
Detecting and decoding the message requires careful photometric modeling for
computational message recovery. Unlike standard watermarking and steganography
methods that lie outside the domain of computer vision, our message recovery
algorithm uses illumination to optically communicate hidden messages in real
world scenes. The key innovation of our approach is an algorithm that performs
simultaneous radiometric calibration and message recovery in one convex
optimization problem. By modeling the photometry of the system using a
camera-display transfer function (CDTF), we derive a physics-based kernel
function for support vector machine classification. We demonstrate that our
method of optimal online radiometric calibration (OORC) leads to an efficient
and robust algorithm for computational messaging between nine commercial
cameras and displays.Comment: 10 pages, Submitted to CVPR 201
EtÀisyyden huomioiva kaksiulotteinen viivakoodi mobiilikÀyttötapauksiin
Global internet use is becoming increasingly mobile, and mobile data usage is growing exponentially. This puts increasing stress on the radio frequency spectrum that cellular and Wi-Fi networks use. As a consequence, research has also been conducted to develop wireless technologies for other parts of the electromagnetic spectrum â namely, visible light.
One approach of using the visible light channel for wireless communication leverages barcodes. In this thesis, we propose a 2D barcode that can display different information based on the distance between the barcode and the scanner. Earlier research on distance-sensitive barcodes has focused on providing a closer viewer more information as a closer viewer can see more detail. In contrast, we target use cases where a clear physical separation between users of different roles can be made, such as presentation systems.
We evaluate two methods of achieving distance-awareness: color-shifting of individual colors, where a color changes tone at longer distances, and color blending, where two colors blend into a third color at longer viewing distances. Our results show that a modern smartphone is capable of leveraging color-shifting in ideal conditions, but external changes such as ambient lighting render color-shifting unusable in practical scenarios. On the other hand, color blending is robust in varying indoor conditions and can be used to construct a reliable distance-aware barcode.
Accordingly, we employ color blending to design a distance-aware barcode. We implement our solution in an off-the-shelf Android smartphone. Experimental results show that our scheme achieves a clear separation between close and far viewers. As a representative use case, we also implement a presentation system where a single barcode provides the presenter access to presentation tools and the audience access to auxiliary presentation material.Maailmanlaajuinen internetin kĂ€yttö muuttuu yhĂ€ liikkuvammaksi, ja mobiilidatan kĂ€yttö kasvaa eksponentiaalisesti. TĂ€mĂ€ kohdistaa yhĂ€ suurempia vaatimuksia radiotaajuusspektriin, jota mobiili- ja Wi-Fi-verkot kĂ€yttĂ€vĂ€t. NĂ€in ollen tutkijat ovat kehittĂ€neet langattomia teknologioita hyödyntĂ€en myös muita sĂ€hkömagneettisen spektrin osia â erityisesti nĂ€kyvÀÀ valoa.
Yksi nÀkyvÀn valon sovellus langattomassa viestinnÀssÀ ovat viivakoodit. TÀssÀ työssÀ kehitÀmme kaksiulotteisen viivakoodin, joka pystyy vÀlittÀmÀÀn eri tietoa katselijoille eri etÀisyyksillÀ. Aiempi etÀisyyden huomioivien viivakoodien tutkimus on keskittynyt tarjoamaan lÀhellÀ olevalle katselijalle enemmÀn tietoa, koska lÀheinen katselija nÀkee viivakoodin tarkemmin. SitÀ vastoin me keskitymme kÀyttötapauksiin, joissa eri kÀyttÀjÀroolien vÀlillÀ on selkeÀ etÀisyydellinen ero, kuten esimerkiksi esitelmissÀ puhujan ja yleisön vÀlillÀ.
Tarkastelemme kahta menetelmÀÀ: yksittÀisten vÀrien muutoksia etÀisyyden muuttuessa ja kahden vÀrin sekoittumista etÀisyyden kasvaessa. Tulostemme perusteella nykyaikainen Àlypuhelin pystyy hyödyntÀmÀÀn yksittÀisten vÀrien muutoksia ihanteellisissa olosuhteissa, mutta ulkoiset tekijÀt, kuten ympÀristön valaistus, aiheuttavat liian suuria vÀrimuutoksia kÀytÀnnön kÀyttötapauksissa. Toisaalta vÀrien sekoittuminen on johdonmukaista muuttuvassa sisÀympÀristössÀ ja sitÀ voidaan kÀyttÀÀ luotettavan viivakoodin luomisessa.
NÀin ollen me suunnittelemme etÀisyyden huomioivan viivakoodin hyödyntÀen vÀrien sekoittumista. Toteutamme ratkaisumme yleisesti saatavilla olevalle Android-Àlypuhelimelle. Kokeellisten tulostemme perusteella menetelmÀmme saavuttaa selkeÀn erottelun lÀheisten ja kaukaisten katselijoiden vÀlillÀ. EsimerkkikÀyttötapauksena toteutamme myös esitelmÀjÀrjestelmÀn, jossa sama viivakoodi antaa lÀhellÀ olevalle puhujalle nopean pÀÀsyn esitystyökaluihin ja kauempana olevalle yleisölle pÀÀsyn esityksen apumateriaaliin
Survey and Systematization of Secure Device Pairing
Secure Device Pairing (SDP) schemes have been developed to facilitate secure
communications among smart devices, both personal mobile devices and Internet
of Things (IoT) devices. Comparison and assessment of SDP schemes is
troublesome, because each scheme makes different assumptions about out-of-band
channels and adversary models, and are driven by their particular use-cases. A
conceptual model that facilitates meaningful comparison among SDP schemes is
missing. We provide such a model. In this article, we survey and analyze a wide
range of SDP schemes that are described in the literature, including a number
that have been adopted as standards. A system model and consistent terminology
for SDP schemes are built on the foundation of this survey, which are then used
to classify existing SDP schemes into a taxonomy that, for the first time,
enables their meaningful comparison and analysis.The existing SDP schemes are
analyzed using this model, revealing common systemic security weaknesses among
the surveyed SDP schemes that should become priority areas for future SDP
research, such as improving the integration of privacy requirements into the
design of SDP schemes. Our results allow SDP scheme designers to create schemes
that are more easily comparable with one another, and to assist the prevention
of persisting the weaknesses common to the current generation of SDP schemes.Comment: 34 pages, 5 figures, 3 tables, accepted at IEEE Communications
Surveys & Tutorials 2017 (Volume: PP, Issue: 99
Recommended from our members
Multimedia delivery in the future internet
The term âNetworked Mediaâ implies that all kinds of media including text, image, 3D graphics, audio
and video are produced, distributed, shared, managed and consumed on-line through various networks,
like the Internet, Fiber, WiFi, WiMAX, GPRS, 3G and so on, in a convergent manner [1]. This white
paper is the contribution of the Media Delivery Platform (MDP) cluster and aims to cover the Networked
challenges of the Networked Media in the transition to the Future of the Internet.
Internet has evolved and changed the way we work and live. End users of the Internet have been confronted
with a bewildering range of media, services and applications and of technological innovations concerning
media formats, wireless networks, terminal types and capabilities. And there is little evidence that the pace
of this innovation is slowing. Today, over one billion of users access the Internet on regular basis, more
than 100 million users have downloaded at least one (multi)media file and over 47 millions of them do so
regularly, searching in more than 160 Exabytes1 of content. In the near future these numbers are expected
to exponentially rise. It is expected that the Internet content will be increased by at least a factor of 6, rising
to more than 990 Exabytes before 2012, fuelled mainly by the users themselves. Moreover, it is envisaged
that in a near- to mid-term future, the Internet will provide the means to share and distribute (new)
multimedia content and services with superior quality and striking flexibility, in a trusted and personalized
way, improving citizensâ quality of life, working conditions, edutainment and safety.
In this evolving environment, new transport protocols, new multimedia encoding schemes, cross-layer inthe
network adaptation, machine-to-machine communication (including RFIDs), rich 3D content as well as
community networks and the use of peer-to-peer (P2P) overlays are expected to generate new models of
interaction and cooperation, and be able to support enhanced perceived quality-of-experience (PQoE) and
innovative applications âon the moveâ, like virtual collaboration environments, personalised services/
media, virtual sport groups, on-line gaming, edutainment. In this context, the interaction with content
combined with interactive/multimedia search capabilities across distributed repositories, opportunistic P2P
networks and the dynamic adaptation to the characteristics of diverse mobile terminals are expected to
contribute towards such a vision.
Based on work that has taken place in a number of EC co-funded projects, in Framework Program 6 (FP6)
and Framework Program 7 (FP7), a group of experts and technology visionaries have voluntarily
contributed in this white paper aiming to describe the status, the state-of-the art, the challenges and the way
ahead in the area of Content Aware media delivery platforms
Visual wireless communications with smartphones
The advent of smartphones has certainly brought many advantages for communications among people. Due to their diverse features, smartphones allow to exchange information in different ways. The most widespread communication technologies for mobile devices - such as WiFi, Bluetooth and Long Term Evolution - exploit wireless transmissions based on electromagnetic radio signals. However, the use of these technologies present some issues with respect to security, coverage and interference.
Recent studies have revealed new approaches for data exchange, such as visible light communication. Using an optical channel for data transmission provides interesting advantages over current technologies: the use of unlicensed spectrum, no interference with radio signal, secure communication and no need for a special infrastructure.
In this thesis, we implemented an application that transfers data between smartphones through visible light communications. To this purpose, the application employs QR codes shown on the display to encode transmitted data and the front-facing camera for receiving the data. We also designed a supporting communication protocol for ensuring a successful transmission between two smartphones. Finally, we evaluated our solution in terms of power consumption and communication performance. The results showed that our solution is suitable for exchanging files of small size
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ReSCon '11, Research Student Conference: Book of Abstracts
The fourth SED Research Student Conference (ReSCon2011) was hosted over three days, 20-22 June 2011, in the Hamilton Centre at Brunel University. The conference consisted of technical presentations, a poster session and social events. which focused on current research being conducted within the School of Engineering and Design by postgraduate research students from the School. The conference is held annually, and ReSCon plays a key role in contributing to research and innovations within the School
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