Unsynchronized 4D Barcodes

We present a novel technique for optical data transfer between public displays and mobile devices based on unsynchronized 4D barcodes. We assume that no direct (electromagnetic or other) connection between the devices can exist. Time-multiplexed, 2D color barcodes are displayed on screens and recorded with camera equipped mobile phones. This allows to transmit information optically between both devices. Our approach maximizes the data throughput and the robustness of the barcode recognition, while no immediate synchronization exists. Although the transfer rate is much smaller than it can be achieved with electromagnetic techniques (e.g., Bluetooth or WiFi), we envision to apply such a technique wherever no direct connection is available. 4D barcodes can, for instance, be integrated into public web-pages, movie sequences or advertisement presentations, and they encode and transmit more information than possible with single 2D or 3D barcodes

Improving mobile color 2D-barcode JPEG image readability using DCT coefficient distributions

Two dimensional (2D) barcodes are becoming a pervasive interface for mobile devices, such as camera smartphones. Often, only monochrome 2D-barcodes are used due to their robustness in an uncontrolled operating environment of smartphones. Nonetheless, we are seeing an emerging use of color 2D-barcodes for camera smartphones. Most smartphones 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 captured 2D-barcode images. In this paper, we analyzed the Discrete Cosine Transform (DCT) coefficient distributions of generalized 2D-barcodes using colored data cells, each comprising of 4, 8 and 10 colors. Using these DCT distributions, we improved the JPEG compression of such mobile barcode images. By altering the JPEG compression parameters based on the DCT coefficient distribution of the barcode images, our 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 10 colors 2D-barcode system; and analyzed its performance in comparison to the default and alternative JPEG schemes. We have found that our improved scheme does provide a marked improvement for the successful decoding of the 10 colors 2D-barcode system

Distance transform and template matching based methods for localization of barcodes and QR codes

Visual codes play an important role in automatic identification, which became an inseparable part of industrial processes. Thanks to the revolution of smartphones and telecommunication, it also becomes more and more popular in everyday life, containing embedded web addresses or other small informative texts. While barcode reading is straightforward in images having optimal parameters (fo cus, illumination, code orientation, and position), localization of code regions is still challenging in many scenarios. Every setup has its own characteristics, there fore many approaches are justifiable. Industrial applications are likely to have more fixed parameters like illumination, camera type and code size, and processing speed and accuracy are the most important requirements. In everyday use, like with smart phone cameras, a wide variety of code types, sizes, noise levels and blurring can be observed, but the processing speed is often not crucial, and the image acquisition process can be repeated in order for successful detection. In this paper, we address this problem with two novel methods for localization of 1D barcodes based on template matching and distance transformation, and a third method for QR codes. Our proposed approaches can simultaneously localize sev eral different types of codes. We compare the effectiveness of the proposed methods with several approaches from the literature using public databases and a large set of synthetic images as a benchmark. The evaluation shows that the proposed methods are efficient, having 84.3% Jaccard accuracy, superior to other approaches. One of the presented approaches is an improvement on our previous work. Our template matching based method is computationally more complex, however, it can be adapted to specific code types producing high accuracy. The other method uses distance transformation, which is fast and gives rough regions of interests that can contain valid visual code candidates

Functional inks and indicators for Smart Tag based intelligent packaging applications

Smart Tags are functional, information transmitting elements that combine 2D barcodes and environmental sensing into a cost effective tag that can be attached to e.g. product packages, where additional elements should not increase the product costs significantly. Important feature of these Smart Tags is that they can be attached to products in very high-speed production lines, which makes them suitable to fast moving consumer goods. Because the Smart Tags are sensitive to environmental conditions, they are dynamic, but they also enable context aware services as each of them can be unique. The enabling technologies behind these Smart Tags are i) 2D barcodes and ii) functional inks, such as thermochromic and photochromic inks, and iii) printed visual indicators. In this paper, different ink and indicator technologies are used to build Smart Tags. Both commercial inks and developmental grades are in focus. Furthermore, it is evaluated if these tags can be detected by mobile phone reader

SBVLC:Secure Barcode-based Visible Light Communication for Smartphones

2D barcodes have enjoyed a significant penetration rate in mobile applications. This is largely due to the extremely low barrier to adoption – almost every camera-enabled smartphone can scan 2D barcodes. As an alternative to NFC technology, 2D barcodes have been increasingly used for security-sensitive mobile applications including mobile payments and personal identification. However, the security of barcode-based communication in mobile applications has not been systematically studied. Due to the visual nature, 2D barcodes are subject to eavesdropping when they are displayed on the smartphone screens. On the other hand, the fundamental design principles of 2D barcodes make it difficult to add security features. In this paper, we propose SBVLC - a secure system for barcode-based visible light communication (VLC) between smartphones. We formally analyze the security of SBVLC based on geometric models and propose physical security enhancement mechanisms for barcode communication by manipulating screen view angles and leveraging user-induced motions. We then develop three secure data exchange schemes that encode information in barcode streams. These schemes are useful in many security-sensitive mobile applications including private information sharing, secure device pairing, and contactless payment. SBVLC is evaluated through extensive experiments on both Android and iOS smartphones

2D Color Code Interference Cancellation by Super Imposing Methodology

Abstract-Today the 2-D barcodes have become more popular for information embedding. To encode information with high spatial density while ensuring robust reading by an optical system is the main goal of a barcode system. To enhance the density of information, different ink colors could be used. A High Capacity Color Barcode framework is proposed by exploiting the spectral diversity afforded by the Cyan, Magenta, Yellow print colorant channels and the complimentary Red, Green and Blue channels, respectively, used for capturing color images. Here a three-fold increase in the data rate is achieved by encoding independent data in the C, M, and Y print colorant channels and decoding the data from the complimentary R, G, and B channels captured via a mobile phone camera. This paper presents a framework of color barcode for mobile phone applications by exploiting the spectral diversity afforded by the cyan (C), magenta (M), and yellow (Y) print colorant channels which is more commonly used for color printing and the complementary in order to red (R), green (G), and blue (B) channels, respectively, used for capturing color images. In this paper the system exploit this spectral diversity to understand three-fold increase in the data rate by encoding independent data in the C, M, and Y print colorant channels and decoding the data from the complementary R, G, and B channels captured via a mobile phone camera. To mitigate the effect of cross-channel interference among the print colorant and capture color channels, the system develops an algorithm for interference cancellation which is based on a physically-motivated mathematical model for the print and capture processes. To collect the model parameters which are necessary for cross-channel interference cancellation, this scheme proposes a super imposing methodology. Experimental result clears that the scheme framework successfully overcomes the impact of the color interference, providing a low bit error rate and a high decoding rate for each of the colorant channels when used with a corresponding error correction scheme

Using RGB colour combination in coloured quick response (QR) code algorithm to enhance QR code capacity

A Quick Response (QR) Code is a two-dimensional barcode that stores characters and can be read by any smartphone camera. The QR code has the capability to encode various data formats and languages; nevertheless, existing black and white QR code offers limited data storage. Even though there exist research on coloured QR Code to increase the storage capacity, requirement for larger data capacity by end user keep increasing. Hence, this thesis proposes a coloured QR Code algorithm which utilizes RGB colour combination to allow a larger data storage. The proposed algorithm integrates the use of compression, multiplexing, and multilayer techniques in encoding and decoding the QR code. Furthermore, it also introduces a partial encoding/decoding algorithm that allows the stored data to be manipulated. The algorithm that includes encoding and decoding processes is based on the red, green, and blue (RGB) colour techniques, which are used to create high capacity coloured QR code. This is realised in the experiments that store American Standard Code for Information Interchange (ASCII) characters. The ASCII text characters are used as an input and performance is measured by the number of characters that can be stored in a single black and white QR code version 40 (i.e. the benchmark) and also the coloured QR code. Other experiment metrics include percentage of missing characters, number of produced QR code, and elapsed time to create the QR code. Simulation results indicate that the proposed algorithm stores 29 times more characters than the black and white QR code and 9 times more than other coloured QR code. Hence, this shows that the coloured QR Code has the potential of becoming a useful mini-data storage as it does not rely on internet connection