JPEG compression of monochrome 2D-barcode images using DCT coefficient distributions

Two dimensional (2D) barcodes are becoming a pervasive interface for mobile devices, such as camera phones. Often, only monochrome 2D-barcodes are used due to their robustness in an uncontrolled operating environment of camera phones. Most camera phones capture and store such 2D-barcode images in the baseline JPEG format. As a lossy compression technique, JPEG does introduce a fair amount of error in the decoding of captured 2D-barcode images. In this paper, we introduce an improved JPEG compression scheme for such barcode images. By altering the JPEG compression parameters based on the DCT coefficient distribution of such barcode images, the improved compression scheme produces JPEG images with higher PSNR value as compared to the baseline implementation. We have also applied our improved scheme to a real 2D-barcode system - the QR Code and analyzed its performance against the baseline JPEG scheme

Development Of A Novel Finder Pattern For Effective Color 2D-Barcode Detection

With a camera mobile phone, which has become a must-have device, 2D-barcode works as an interface to bridge the physical and digital world. As the notion of ubiquitous computing has permeated, developing a new 2D-barcode and its applications has been a growing trend worldwide. A 2D-barcode symbol consists of two broad areas: data area and guide area. The components of the latter is collectively called finder pattern and used in locating the 2D-barcode symbol. The failure of finding the target symbol prevents a barcode reader from successfully decoding the barcode. Hence, designing a functional finder pattern is one of the key for improving the robustness of barcode reading, and thus, the entire 2D-barcode system. We have designed a novel finder pattern integrated with a color 2D-barcode for camera mobile phone applications. Through the development and evaluation of the finder pattern for effective color 2D-barcode detection, this paper discusses keys to improve the functionality and reliability of finder patterns, which should be kept in mind when designing a finder pattern for any 2D-barcode symbol

Design of data validation solutions using high density 2D colored codes and a (2,2) xor-based color interference visual cryptography scheme

Tese (doutorado)—Universidade de Brasília, Faculdade de Tecnologia, Departamento de Engenharia Elétrica, 2018.A validação de dados nos sistemas de informação utiliza majoritariamente algoritmos criptográficos em sistemas que, geralmente, não utilizam materiais não eletrônicos como parte da infraestrutura do criptossistema. Nesse trabalho, foram desenvolvidos dois sistemas de armazenamento e recuperação de dados através da proposta de uma nova tecnologia de códigos de barra colorido bidimensional e de um novo esquema de criptografia visual. Os códigos de barras bidimensionais têm sido amplamente estudados, mas ainda continuam sem contar com um padrão que consiga transmitir alta quantidade de informação em pequenos espaços impressos. As aplicações desse modelo de transmissão tem como motivação a necessidade de armazenar (e recuperar) uma alta quantidade de informação em pequenas áreas impressas, como por exemplo, para utilização de dados criptográficos que sejam processados sem conexão e armazenados em pequenos espaços impressos, como os de caixas de remédios ou caixas de cigarros. O código de barras colorido 2D proposto nesse trabalho é chamado de High Density 2 Dimensional Code (HD2DC) e possui 8 diferentes tamanhos. O HD2DC permite a utilização de 5 ou 8 cores em cada tamanho e conta com o algoritmo de correção de erro Reed-Solomon com 3 diferentes níveis (10%, 20% e 30%). O HD2DC foi desenvolvido com o objetivo de ser um padrão de código de barras colorido 2D para operações de transmissão de grande quantidade de informações em pequenas ou médias áreas de impressão. Criptografia visual é uma técnica que cifra uma imagem secreta em duas ou mais imagens chave. A decodificação de qualquer esquema de criptografia visual depende do sistema visual humano e a maioria das propostas existentes consideram para a decodificação a utilização da sobreposição de duas ou mais lâminas físicas com n x n (n ≥ 2) pixels expandidos. O esquema de criptografia visual proposto nesse trabalho considera a utilização de duas imagens. A primeira é uma lâmina física feita por uma impressão colorida em Policloreto de Polivinila (PVC) transparente de 3 milímetros, enquanto que a segunda é uma imagem colorida apresentada na tela do visor de um smartphone. Ambas as imagens não geram expansão de pixels. A obtenção das melhores cores utilizadas nesse criptossistema foi realizada através de estudos físicos do comportamento da interferência de cor entre a tela do smartphone e a cor utilizada na impressão do PVC transparente. Essa nova proposta possui um alto nível de usabilidade para validação de dados em transações eletrônicas e conta com um custo muito baixo de implementação. Um sistema robusto de validação de dados é criado quando é combinada a criptografia visual proposta com o HD2DC. O HD2DC tem a capacidade de armazenar uma das imagens chave, no caso a que deve ser mostrada no visor do celular, essa arquitetura de codificação aumenta a percepção de segurança e explora a usabilidade do celular por meio da utilização da câmera e da tela como ferramentas para mostrar a imagem cifrada da criptografia visual.Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Digital data validation generally requires that algorithms are ran into on cryptographic systems that, usually, do not use non-electronic devices as part of their information security infrastructure. This work presents two information storage and retrieval systems: a new colored two-dimensional barcode technology and a novel visual cryptography scheme. Two-dimensional barcodes have been a topic of research for several decades, but there is still no standard that stores and retrieves high amounts of data. Recently, new requirements have been imposed on applications that use 2D barcodes as a communication channel, such as the capability of storing information into a small printed area. This particular requirement is specially important for 2D barcodes that store cryptographic primitives to be processed off-line. This is the case of barcodes in products like cigarettes and medicines, which are used for data validation and product verification. The proposed 2D colored barcode is called High Density Two-Dimensional Code (HD2DC) and is currently one of the 2D barcodes with the highest data density. HD2DC can be generated in 8 different sizes, with 5 or 8 colors. To increase robustness, the system uses a Reed-Solomon error correction algorithm with 3 different levels: Low, Medium and High, which provide approximately 10%, 20% and 30% error correction, respectively. Visual cryptography (VC) is a technique that encodes the content of a secret image into two or more images, which are called shares. These shares are printed on transparencies and superimposed (requiring a good alignment) to reveal (visually) the original secret image, i.e. without requiring any computation. Current visual cryptography schemes use at least 2 shares (transparencies) as keys. With respect to the secret image size, most of these schemes produce a n x n (n ≥ 2) size expansion of the shares and the decoded image. The proposed Visual Cryptography scheme, on the other hand, uses two shares and does not require a size expansion. The first share is a colored film printed on a Polyvinyl Chloride (PVC) surface of 3 millimeters, while the second share is a colored image displayed on a smartphone or tablet. In this work, we performed a physical evaluation of the color interference properties of these two shares (the printed PVC transparency and the image displayed on the mobile device) to find the most adequate color space to be used in the proposed cryptosystem. We also propose a strong validation system combining our Xor-Based Visual Cryptography scheme with HD2DC. HD2DC has the capability of storing the share that is shown on the mobile device display. This encoding architecture enhances security perception and explores the mobile device usability, using its screen to display a Visual Cryptography share

Design of nameplates editor

Diplomová práce se zabývá problematikou typových štítků, používaných pro značení výrobků v sériové výrobě. V rešeršní části práce je uvedena problematika používaných médií typových štítků a jejich tisku. Je analyzována problematika obsahu a návrhu štítků. Výsledkem práce je grafický editor pro návrh štítků a jejich převod do jazyku ZPL II. Tento jazyk používají zejména tiskárny firmy Zebra Technologies, které jsou velmi rozšířené.The diploma thesis deals with the problematics of type labels, used for marking of products in series production. The research part of the thesis deals with the issues of the used label media and label printing. The issue of content and design of labels is analyzed. The result of thesis is a graphic editor for designing labels and their translation into ZPL II. This language is mainly used by Zebra Technologies printers, which are very common used in industry.

VRCodes : embedding unobtrusive data for new devices in visible light

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2012.Cataloged from PDF version of thesis.Includes bibliographical references (p. 97-101).This thesis envisions a public space populated with active visible surfaces which appear different to a camera than to the human eye. Thus, they can act as general digital interfaces that transmit machine-compatible data as well as provide relative orientation without being obtrusive. We introduce a personal transceiver peripheral, and demonstrate this visual environment enables human participants to hear sound only from the location they are looking in, authenticate with proximal surfaces, and gather otherwise imperceptible data from an object in sight. We present a design methodology that assumes the availability of many independent and controllable light transmitters where each individual transmitter produces light at different color wavelengths. Today, controllable light transmitters take the form of digital billboards, signage and overhead lighting built for human use; light-capturing receivers take the form of mobile cameras and personal video camcorders. Following the software-defined approach, we leverage screens and cameras as parameterized hardware peripherals thus allowing flexibility and development of the proposed framework on general-purpose computers in a manner that is unobtrusive to humans. We develop VRCodes which display spatio-temporally modulated metamers on active screens thus conveying digital and positional information to a rolling-shutter camera; and physically-modified optical setups which encode data in a point-spread function thus exploiting the camera's wide-aperture. These techniques exploit how the camera sees something different from the human. We quantify the full potential of the system by characterizing basic bounds of a parameterized transceiver hardware along with the medium in which it operates. Evaluating performance highlights the underutilized temporal, spatial and frequency dimensions available to the interaction designer concerned with human perception. Results suggest that the one-way point-to-point transmission is good enough for extending the techniques toward a two-way bidrectional model with realizable hardware devices. The new visual environment contains a second data layer for machines that is synthetic and quantifiable; human interactions serve as the context.by Grace Woo.Ph.D

Usage of two-dimensional barcodes for camera position estimation in AR applications

Tato práce se zabývá tvorbou algoritmu pro odhad polohy kamery využitím QR kódů v aplikacích rozšířené reality. Ten musí zvládnout pracovat i s více kódy v obraze. K tomu je využito knihovny počítačového vidění OpenCV a programovacího jazyka Python. Algoritmus je poté zahrnut do jednoduše použitelné knihovny. Vytvořené řešení je porovnáváno vůči ArUco referenčním značkám. Nakonec je vytvořena ukázková aplikace.This thesis deals with the creation of algorithm for camera pose estimation using QR codes in augmented reality applications. It must be able to work with multiple codes in the image. The OpenCV computer vision library and the Python programming language are used for this. The algorithm is then included in an easy-to-use library. The created solution is compared against ArUco markers. Finally, a sample application is created.

Dual-layered and wavelength-multiplexed optical barcode for high data storage

A novel barcode system design to achieve high data storage using more than one layer is introduced theoretically and tested partially in the laboratory. Compared to other existing barcode systems, diffraction gratings are used as core elements in the barcode symbol. As any other barcode system, the novel model requires a source of light, the barcode symbol and photodiode detectors. Theoretical background from optics has been used to design the entire system along with all the positioning of its components. After part-testing the design in laboratory, the barcode system design has been changed to achieve better results. Experiments have showed that the initial proposed Light Emitting Diode (LED) source light cannot deliver 5mm spot light over a range of 50cm and therefore, white Light Amplification by Stimulated Emission of Radiation (LASER) light has been adopted as replacement. The diffractions from the barcode symbol are captured by detectors built with SI photo diodes, which are designed to detect this range of wavelengths. The barcode symbol is composed of small 5mm by 5mm grating modules and the largest possible symbol size defined is 80 modules (5cmx5cm). Experimental works have proved that intensity of the light can be used to uniquely identify each grating rather than the entire spectrum diffracted. A better design is proposed where the detectors are positioned under the barcode symbol and capture the light intensity of the first diffracted order. Theoretical investigations state that diffraction gratings with different lines per mm diffract different sets of wavelengths spectrum. This characteristic allows a set of unique gratings to be used in the barcode symbol which hence allow data to be represented or stored. Character (Char) sets are defined to help encode and decode data in the barcode symbol. High data storage has been achieved through the use of two layers. Multiple layers offer the possibility to increase the number of unique sets of gratings which in turn increase the data representation capacity. Using two layers with 16 unique sets of gratings has proved to be able to store around 100 bytes of data. The system has the potential to use more than two layers and using 4 layers with 16 unique gratings per layer will achieve 200 bytes. The thesis has proved through theoretical and experimental work that diffraction gratings can be used in barcode system to represent data and multiple layers adds the benefit of increasing data storage. Further work is also suggested

Konzeption und Umsetzung einer mobilen Applikation zur Validierung von f\"alschungssicheren Produktlabeln

Due to increasing numbers of product piracy worldwide, a cost-effective method for verifying the origin of a product is to be developed. For this purpose, a certificate of authenticity can be created using precisely measurable, unique properties of special physical objects that are difficult to reconstruct. In the context of the present work, this is a counterfeit-proof label composed of randomly distributed gold nanospheres or rods in a semi-transparent material. The characteristic positioning of the label's elements can be precisely measured using a smartphone's camera and additional technologies. This can create an offline usable verification method for the general public without the need for an existing network connection. The present work provides a first part of the proof of concept that such a system and especially the associated algorithmic computation method can be implemented and efficiently used in a mobile application. In addition, a method suitable in practice for transmitting and securing the required information is determined in each case. Furthermore, the results of the validation of counterfeit-proof product labels are analyzed in detail and existing weaknesses are pointed out. -- Auf Grund weltweit steigender Zahlen der Produktpiraterie soll ein kosteng\"unstiges Verfahren zur Verifizierung der Herkunft eines Produktes entwickelt werden. Daf\"ur l\"asst sich durch exakt messbare, einzigartige, jedoch schwer rekonstruierbare Eigenschaften spezieller physischer Objekte ein Echtheitszertifikat kreieren. Dieses ist im Kontext der vorliegenden Arbeit ein f\"alschungssicheres Label, das sich in einem semi-transparenten Material aus zuf\"allig verteilten Goldnanok\"ugelchen oder -st\"abchen zusammensetzt. Die charakteristischen Positionierungen der Elemente des Labels lassen sich mit der Kamera eines Smartphones und zus\"atzlichen Technologien pr\"azise messen. Dadurch kann f\"ur die breite Bev\"olkerung ohne die Notwendigkeit einer bestehenden Netzwerkverbindung ein offline verwendbares Verifikationsverfahren erschaffen werden. Die vorliegende Arbeit liefert einen ersten Teil des Machbarkeitsnachweises, dass ein derartiges System und insbesondere das damit einhergehende algorithmische Berechnungsverfahren in einer mobilen Applikation implementier -- und effizient einsetzbar ist. Zudem wird je eine in der Praxis geeignete Methode zur \"Ubermittlung und Sicherung der ben\"otigten Informationen eruiert. Des Weiteren werden die Resultate der Validierung von f\"alschungssicheren Produktlabeln ausf\"uhrlich analysiert und vorhandene Schw\"achen aufgezeigt.Comment: Thesis for: Informatik Bachelor; Advisor: Dr. Markus Friedrich, Dr. Sebastian Feld, Prof. Dr. Dr. Ulrich R\"uhrmair; in Germa

Produção de filmes indicadores contendo antocianinas da casca da batata-doce (Ipomoea batatas L.)

TCC (graduação) - Universidade Federal de Santa Catarina. Centro Tecnológico. Engenharia de Alimentos.As embalagens são grandes aliadas da segurança de alimentos devido à proteção que proporcionam contra agentes externos. Porém, as embalagens comuns e mais utilizadas no mercado precisam da inovação para atender consumidores cada vez mais exigentes, serem sustentáveis e sobretudo para assegurar a qualidade do alimento. No entanto, apesar de a grande maioria ser reciclável, elas são consideradas grandes vilãs do meio ambiente por causa de seus materiais que não se degradam facilmente. Como alternativa, estuda-se o uso de materiais biodegradáveis como a quitosana e o polivinil álcool para a produção de embalagens biodegradáveis. Além disso, existem embalagens inteligentes que, além de proteção, têm a função de informar o consumidor sobre os aspectos e o estado de conservação dos alimentos, podendo também serem biodegradáveis. A indústria de alimentos gera toneladas de resíduos anualmente, sendo que estes poderiam ser utilizados para outros fins. As cascas da batata-doce Ipomoeas Batatas L. são um exemplo disto, pois são ricas em antocianinas, as quais alteram a cor de acordo com o pH em que estão inseridas. Assim, o objetivo deste estudo foi desenvolver e caracterizar filmes indicadores à base de polímeros biodegradáveis - quitosana e polivinil álcool - e das antocianinas provenientes da casca da batata-doce, a qual provém de um resíduo da indústria alimentícia. A extração das antocianinas foi realizada com água acidificada como solvente na proporção água/ácido clorídrico, 100/1 %v/v a 35 ℃ e 100 rpm, sendo o tempo de extração mais eficiente em 60 minutos. Os filmes formados por quitosana, polivinil álcool e antocianinas foram produzidos pela técnica de casting, analisados e aplicados em carne bovina por meio de testes colorimétricos com o objetivo de avaliar a possibilidade de utilização dos filmes em alimentos. Logo, os resultados obtidos mostraram que os filmes incorporados com antocianinas não tiveram higroscopicidade alterada, contudo a espessura e a solubilidade aumentaram. O filme mostrou-se opaco suficiente para proteger os alimentos e as ligações químicas entre as antocianinas e o filme polimérico interagem através de ligações de hidrogênio. A análise colorimétrica, assim como o teste de aplicação, mostraram que os filmes alteram a cor de maneira perceptível de acordo com a mudança do pH, fazendo com que seja possível a aplicação dos filmes em alimentos como embalagens inteligentes.Packaging is a great ally of food safety due to the protection it provides against external agents. But, common and most used packaging in the market needs innovation to meet increasingly demanding consumers, be sustainable and above all to ensure food quality. However, while the vast majority are recyclable, they are considered big environmental villains because of their materials that do not easily degrade. Alternatively, the use of biodegradable materials such as chitosan and polyvinyl alcohol to produce biodegradable packaging is studied. In addition, there are smart packaging that, in addition to protection, have the function of informing the consumer about the aspects and the state of conservation of food, and may also be biodegradable. The food industry generates tons of waste annually, which could be used for other purposes. Ipomoeas Batatas L. sweet potato peels are an example of this, they are rich in anthocyanins, which change the color according to the pH in which they are inserted. Thus, the objective of this study was to develop and characterize indicator films based on biodegradable polymers - chitosan and polyvinyl alcohol - and anthocyanins from sweet potato peel, which comes from a food industry residue. The anthocyanins were extracted with acidified water as a solvent in the water/hydrochloric acid ratio, 100/1% v/v at 35 ℃ and 100 rpm, being the most efficient extraction time in 60 minutes. The films formed by chitosan, polyvinyl alcohol and anthocyanins were produced by casting method, analyzed and applied in beef through colorimetric tests in order to evaluate the possibility of using the films in food. Therefore, the results showed that the films incorporated with anthocyanins did not have changed hygroscopicity, however the thickness and solubility increased. The film was opaque enough to protect food and the chemical bonds between anthocyanins and the polymeric film interact through hydrogen bonds. The colorimetric analysis as well as the application test showed that the films change the color noticeably according to the pH change, making possible to apply the films in food as intelligent packaging