27 research outputs found
Robust image steganography method suited for prining = Robustna steganografska metoda prilagođena procesu tiska
U ovoj doktorskoj dizertaciji prezentirana je robustna steganografska metoda razvijena i
prilagođena za tisak. Osnovni cilj metode je pružanje zaštite od krivotvorenja ambalaže.
Zaštita ambalaže postiže se umetanjem više bitova informacije u sliku pri enkoderu, a potom
maskiranjem informacije kako bi ona bila nevidljiva ljudskom oku. Informacija se pri
dekoderu detektira pomoću infracrvene kamere. Preliminarna istraživanja pokazala su da u
relevantnoj literaturi nedostaje metoda razvijenih za domenu tiska. Razlog za takav
nedostatak jest činjenica da razvijanje steganografskih metoda za tisak zahtjeva veću količinu
resursa i materijala, u odnosu na razvijanje sličnih domena za digitalnu domenu. Također,
metode za tisak često zahtijevaju višu razinu kompleksnosti, budući da se tijekom
reprodukcije pojavljuju razni oblici procesiranja koji mogu kompromitirati informaciju u slici
[1]. Da bi se sačuvala skrivena informacija, metoda mora biti otporna na procesiranje koje se
događa tijekom reprodukcije.
Kako bi se postigla visoka razina otpornosti, informacija se može umetnuti unutar
frekvencijske domene slike [2], [3]. Frekvencijskoj domeni slike možemo pristupiti pomoću
matematičkih transformacija. Najčešće se koriste diskretna kosinusna transformacija (DCT),
diskretna wavelet transformacija (DWT) i diskretna Fourierova transformacija (DFT) [2], [4].
Korištenje svake od navedenih transformacija ima određene prednosti i nedostatke, ovisno o
kontekstu razvijanja metode [5]. Za metode prilagođene procesu tiska, diskretna Fourierova
transformacija je optimalan odabir, budući da metode bazirane na DFT-u pružaju otpornost
na geometrijske transformacije koje se događaju tijekom reprodukcije [5], [6].
U ovom istraživanju korištene su slike u cmyk prostoru boja. Svaka slika najprije je
podijeljena u blokove, a umetanje informacije vrši se za svaki blok pojedinačno. Pomoću
DFT-a, ???? kanal slikovnog bloka se transformira u frekvencijsku domenu, gdje se vrši
umetanje informacije. Akromatska zamjena koristi se za maskiranje vidljivih artefakata
nastalih prilikom umetanja informacije. Primjeri uspješnog korištenja akromatske zamjene za
maskiranje artefakata mogu se pronaći u [7] i [8]. Nakon umetanja informacije u svaki
slikovni blok, blokovi se ponovno spajaju u jednu, jedinstvenu sliku. Akromatska zamjena
tada mijenja vrijednosti c, m i y kanala slike, dok kanal k, u kojemu se nalazi umetnuta
informacija, ostaje nepromijenjen. Time nakon maskiranja akromatskom zamjenom označena
slika posjeduje ista vizualna svojstva kao i slika prije označavanja. U eksperimentalnom dijelu rada koristi se 1000 slika u cmyk prostoru boja. U digitalnom
okruženju provedeno je istraživanje otpornosti metode na slikovne napade specifične za
reprodukcijski proces - skaliranje, blur, šum, rotaciju i kompresiju. Također, provedeno je
istraživanje otpornosti metode na reprodukcijski proces, koristeći tiskane uzorke. Objektivna
metrika bit error rate (BER) korištena je za evaluaciju. Mogućnost optimizacije metode
testirala se procesiranjem slike (unsharp filter) i korištenjem error correction kodova (ECC).
Provedeno je istraživanje kvalitete slike nakon umetanja informacije. Za evaluaciju su
korištene objektivne metrike peak signal to noise ratio (PSNR) i structural similarity index
measure (SSIM). PSNR i SSIM su tzv. full-reference metrike. Drugim riječima, potrebne su i
neoznačena i označena slika istovremeno, kako bi se mogla utvrditi razina sličnosti između
slika [9], [10]. Subjektivna analiza provedena je na 36 ispitanika, koristeći ukupno 144
uzorka slika. Ispitanici su ocijenjivali vidljivost artefakata na skali od nula (nevidljivo) do tri
(vrlo vidljivo).
Rezultati pokazuju da metoda posjeduje visoku razinu otpornosti na reprodukcijski proces.
Također, metoda se uistinu optimizirala korištenjem unsharp filtera i ECC-a. Kvaliteta slike
ostaje visoka bez obzira na umetanje informacije, što su potvrdili rezultati eksperimenata s
objektivnim metrikama i subjektivna analiza
Recommended from our members
Harnessing Simulated Data with Graphs
Physically accurate simulations allow for unlimited exploration of arbitrarily crafted environments. From a scientific perspective, digital representations of the real world are useful because they make it easy validate ideas. Virtual sandboxes allow observations to be collected at-will, without intricate setting up for measurements or needing to wait on the manufacturing, shipping, and assembly of physical resources. Simulation techniques can also be utilized over and over again to test the problem without expending costly materials or producing any waste.
Remarkably, this freedom to both experiment and generate data becomes even more powerful when considering the rising adoption of data-driven techniques across engineering disciplines. These are systems that aggregate over available samples to model behavior, and thus are better informed when exposed to more data. Naturally, the ability to synthesize limitless data promises to make approaches that benefit from datasets all the more robust and desirable.
However, the ability to readily and endlessly produce synthetic examples also introduces several new challenges. Data must be collected in an adaptive format that can capture the complete diversity of states achievable in arbitrary simulated configurations while too remaining amenable to downstream applications. The quantity and zoology of observations must also straddle a range which prevents overfitting but is descriptive enough to produce a robust approach. Pipelines that naively measure virtual scenarios can easily be overwhelmed by trying to sample an infinite set of available configurations. Variations observed across multiple dimensions can quickly lead to a daunting expansion of states, all of which must be processed and solved. These and several other concerns must first be addressed in order to safely leverage the potential of boundless simulated data.
In response to these challenges, this thesis proposes to wield graphs in order to instill structure over digitally captured data, and curb the growth of variables. The paradigm of pairing data with graphs introduced in this dissertation serves to enforce consistency, localize operators, and crucially factor out any combinatorial explosion of states. Results demonstrate the effectiveness of this methodology in three distinct areas, each individually offering unique challenges and practical constraints, and together showcasing the generality of the approach. Namely, studies observing state-of-the-art contributions in design for additive manufacturing, side-channel security threats, and large-scale physics based contact simulations are collectively achieved by harnessing simulated datasets with graph algorithms
Recommended from our members
Bridging the Gap Between People, Mobile Devices, and the Physical World
Human-computer interaction (HCI) is being revolutionized by computational design and artificial intelligence. As the diversity of user interfaces shifts from personal desktops to mobile and wearable devices, yesterday’s tools and interfaces are insufficient to meet the demands of tomorrow’s devices. This dissertation describes my research on leveraging different physical channels (e.g., vibration, light, capacitance) to enable novel interaction opportunities. We first introduce FontCode, an information embedding technique for text documents. Given a text document with specific fonts, our method can embed user-specified information (e.g., URLs, meta data, etc) in the text by perturbing the glyphs of text characters while preserving the text content. The embedded information can later be retrieved using a smartphone in real time. Then, we present Vidgets, a family of mechanical widgets, specifically push buttons and rotary knobs that augment mobile devices with tangible user interfaces. When these widgets are attached to a mobile device and a user interacts with them, the nonlinear mechanical response of the widgets shifts the device slightly and quickly. Subsequently, this subtle motion can be detected by the Inertial Measurement Units (IMUs), which is commonly installed on mobile devices.
Next, we propose BackTrack, a trackpad placed on the back of a smartphone to track finegrained finger motions. Our system has a small form factor, with all the circuits encapsulated in a thin layer attached to a phone case. It can be used with any off-the-shelf smartphone, requiring no power supply or modification of the operating systems. BackTrack simply extends the finger tracking area of the front screen, without interrupting the use of the front screen.
Lastly, we demonstrate MoiréBoard, a new camera tracking method that leverages a seemingly irrelevant visual phenomenon, the moiré effect. Based on a systematic analysis of the moiré effect under camera projection, MoiréBoard requires no power nor camera calibration. It can easily be made at a low cost (e.g., through 3D printing) and ready to use with any stock mobile device with a camera. Its tracking algorithm is computationally efficient and can run at a high frame rate. It is not only simple to implement, but also tracks devices at a high accuracy, comparable to the state-of-the-art commercial VR tracking systems
Entropy in Image Analysis II
Image analysis is a fundamental task for any application where extracting information from images is required. The analysis requires highly sophisticated numerical and analytical methods, particularly for those applications in medicine, security, and other fields where the results of the processing consist of data of vital importance. This fact is evident from all the articles composing the Special Issue "Entropy in Image Analysis II", in which the authors used widely tested methods to verify their results. In the process of reading the present volume, the reader will appreciate the richness of their methods and applications, in particular for medical imaging and image security, and a remarkable cross-fertilization among the proposed research areas
Information embedding and retrieval in 3D printed objects
Deep learning and convolutional neural networks have become the main tools of computer vision. These techniques are good at using supervised learning to learn complex representations from data. In particular, under limited settings, the image recognition model now performs better than the human baseline. However, computer vision science aims to build machines that can see. It requires the model to be able to extract more valuable information from images and videos than recognition. Generally, it is much more challenging to apply these deep learning models from recognition to other problems in computer vision.
This thesis presents end-to-end deep learning architectures for a new computer vision field: watermark retrieval from 3D printed objects. As it is a new area, there is no state-of-the-art on many challenging benchmarks. Hence, we first define the problems and introduce the traditional approach, Local Binary Pattern method, to set our baseline for further study. Our neural networks seem useful but straightfor- ward, which outperform traditional approaches. What is more, these networks have good generalization. However, because our research field is new, the problems we face are not only various unpredictable parameters but also limited and low-quality training data.
To address this, we make two observations: (i) we do not need to learn everything from scratch, we know a lot about the image segmentation area, and (ii) we cannot know everything from data, our models should be aware what key features they
should learn. This thesis explores these ideas and even explore more. We show how to use end-to-end deep learning models to learn to retrieve watermark bumps and tackle covariates from a few training images data. Secondly, we introduce ideas from synthetic image data and domain randomization to augment training data and understand various covariates that may affect retrieve real-world 3D watermark bumps. We also show how the illumination in synthetic images data to effect and even improve retrieval accuracy for real-world recognization applications
Shortest Route at Dynamic Location with Node Combination-Dijkstra Algorithm
Abstract— Online transportation has become a basic
requirement of the general public in support of all activities to go
to work, school or vacation to the sights. Public transportation
services compete to provide the best service so that consumers
feel comfortable using the services offered, so that all activities
are noticed, one of them is the search for the shortest route in
picking the buyer or delivering to the destination. Node
Combination method can minimize memory usage and this
methode is more optimal when compared to A* and Ant Colony
in the shortest route search like Dijkstra algorithm, but can’t
store the history node that has been passed. Therefore, using
node combination algorithm is very good in searching the
shortest distance is not the shortest route. This paper is
structured to modify the node combination algorithm to solve the
problem of finding the shortest route at the dynamic location
obtained from the transport fleet by displaying the nodes that
have the shortest distance and will be implemented in the
geographic information system in the form of map to facilitate
the use of the system.
Keywords— Shortest Path, Algorithm Dijkstra, Node
Combination, Dynamic Location (key words
Recommended from our members
Impact of access control and copyright in e-learning from user’s perspective in the United Kingdom
This thesis was submitted for the award of Doctor of Philosophy and was awarded by Brunel University LondonThe widespread adoption of E-Learning has largely been driven by the recommendations of educational technologists seeking to convey the benefits of E-Learning as a valuable accessory to teaching and possible solution for distance-based education. Research in the E-Learning domain has mainly focused on providing and delivering content andinfrastructure. Security issues are usually not taken as central concern in most implementations either because systems are usually deployed in controlled environments, or because they take the one-to-one tutoring approach, not requiring strict security measures. The scope of this research work is to investigate the impact of Access Control and Copyright in E-Learning system. An extensive literature review, theories from the field of information systems, psychology and cognitive sciences, distance and online learning, as well as existing E-Learning models show that research in E-learning is still hardly concerned with the issues of security. It is obvious that E-learning receives a new meaning as technology advances and business strategies change. The trends of learning methods have also led to the adjustment of National Curriculum and standards. However, research has also shown that any strategy or development supported by the Internet requires security and is therefore faced with challenges. This thesis is divided into six Chapters. Chapter 1 sets the scene for the research rationale and hypotheses, and identifies the aims and objectives. Chapter 2 presents the theoretical background and literature review. Chapter 3 is an in-depth review of the methods and methodology with clear justification of their adaptation and explains the underlying principles. Chapter 4 is based on the results and limitations obtained from the six case studies observations supported with literature review and ten existing models, while Chapter 5 is focused on the questionnaire survey. Chapter 6 describes the proposed Dynamic E-Learning Access Control and Copyright Framework (DEACCF) and the mapping of the threats from the Central Computing and Telecommunications Agency (CCTA) Risk Analysis and Management Method (CRAMM) to Annualised Loss Expectancy (ALE). Chapter 7 presents the conclusions and recommendations, and the contribution to knowledge with further development plans for future work
CURATION AND MANAGEMENT OF CULTURAL HERITAGE THROUGH LIBRARIES
Libraries, museums and archives hold valuable collections in a variety of media, presenting a vast
body of knowledge rooted in the history of human civilisation. These form the repository of the
wisdom of great works by thinkers of past and the present. The holdings of these institutions are
priceless heritage of the mankind as they preserve documents, ideas, and the oral and written
records. To value the cultural heritage and to care for it as a treasure bequeathed to us by our
ancestors is the major responsibility of libraries. The past records constitute a natural resource
and are indispensable to the present generation as well as to the generations to come. Libraries
preserve the documentary heritage resources for which they are primarily responsible. Any loss of
such materials is simply irreplaceable. Therefore, preserving this intellectual, cultural heritage
becomes not only the academic commitment but also the moral responsibility of the
librarians/information scientists, who are in charge of these repositories.
The high quality of the papers and the discussion represent the thinking and experience of experts
in their particular fields. The contributed papers also relate to the methodology used in libraries
in Asia to provide access to manuscripts and cultural heritage. The volume discusses best practices
in Knowledge preservation and how to collaborate and preserve the culture. The book also deals with
manuscript and archives issues in the digital era.
The approach of this book is concise, comprehensively, covering all major aspects of preservation
and conservation through libraries. The readership of the book is not just limited to library and
information science professionals, but also for those involved in conservation, preservation,
restoration or other related disciplines. The book will be useful for librarians, archivists and
conservators.
We thank the Sunan Kalijaga University, Special Libraries Association- Asian Chapter for their
trust and their constant support, all the contributors for their submissions, the members of the Local
and International Committee for their reviewing effort for making this publication possible
Uber-in-light: Unobtrusive visible light communication leveraging complementary color channel
Abstract:
Recently, Visible Light Communication (VLC) over a screen-camera channel has drawn considerable attention to unobtrusive design. It overcomes the distractive nature of traditional coded image approaches (e.g., barcodes). Previous unobtrusive methods fall into two categories: (1) utilizing alpha channel, a well known concept in computer graphics, to encode bits into the pixel translucency change with off-the-shelf smart devices; and (2) leveraging the spatial-temporal flicker-fusion property of human vision system with the fast frame rate of modern displays. However, these approaches heavily rely on high-end devices to achieve both unobtrusive and high accuracy screen-camera-based data communication without affecting video-viewing experience. Unlike previous approaches, we propose Uber-in-light, a novel unobtrusive and accurate VLC system, that enables real-time screen-camera communication, applicable to any screen and camera. The proposed system encodes the data as complementary intensity changes over Red, Green, and Blue (RGB) color channels that could be successfully decoded by camera while leaving the human visual perception unaffected. We design a MFSK modulation scheme with dedicated frame synchronization signal embedded in an orthogonal color channel to achieve high throughput. Furthermore, together with the complementary color intensity, an enhanced MUSIC-based demodulation scheme is developed to ensure highly accurate data transmission. Our user experience experiments confirmed the effectiveness of delivering unobtrusive data across different types of video content and resolutions. Extensive real-time performance evaluations are conducted using our prototype implementation to demonstrate the efficiency and reliability of the proposed system under diverse wireless environments
Secure Transmission in Wireless Sensor Networks Data Using Linear Kolmogorov Watermarking Technique
In Wireless sensor networks (WSNs), All communications between different
nodes are sent out in a broadcast fashion. These networks are used in a variety
of applications including military, environmental, and smart spaces. Sensors
are susceptible to various types of attack, such as data modification, data
insertion and deletion, or even physical capture and sensor replacement. Hence
security becomes important issue in WSNs. However given the fact that sensors
are resources constrained, hence the traditional intensive security algorithms
are not well suited for WSNs. This makes traditional security techniques, based
on data encryption, not very suitable for WSNs. This paper proposes Linear
Kolmogorov watermarking technique for secure data communication in WSNs. We
provide a security analysis to show the robustness of the proposed techniques
against various types of attacks. This technique is robust against data
deletion, packet replication and Sybil attack