An Optical Design Configuration for Wireless Data Transmission

The concept of 2D barcodes is of great relevance for use in wireless data transmission between handheld electronic devices. In a typical setup, any file on a cell phone for example can be transferred to a second cell phone through a series of images on the LCD which are then captured and decoded through the camera of the second cell phone. In this research, a new approach for data modulation in 2D barcodes is introduced, and its performance is evaluated in comparison to other standard methods of barcode modulation. In the proposed method, Orthogonal Frequency Division Multiplexing (OFDM) modulation is used together with Differential Phase Shift Keying (DPSK) over adjacent frequency domain elements to modulate intensity of individual pixels. It is shown that the bit error rate performance of the proposed system is superior to the current state of the art in various scenarios. A specific aim of this study is to establish a system that is proven tolerant to camera motion, picture blur and light leakage within neighboring pixels of an LCD. Furthermore, intensity modulation requires the input signal used to modulate a light source to be positive, which requires the addition of a dc bias. In the meantime, the high crest factor of OFDM requires a lower modulation index to limit clipping distortion. These two factors result in poor power efficiency in radio over fiber applications in which signal bandwidth is generally much less than the carrier frequency. In this study, it is shown that clipping a bipolar radio frequency signal at zero level, when it has a carrier frequency sufficiently higher than its bandwidth, results in negligible distortion in the pass band and most of the distortion power is concentrated in the baseband. Consequently, with less power provided to the optical carrier, higher power efficiencies and better receiver sensitivity will result. Finally, a more efficient optical integrated system is introduced to implement the proposed intensity modulation method which is optimized for radio over fiber applications

Computer Vision and Image Processing Techniques for Mobile Applications

Camera phones have penetrated every corner of society and have become a focal point for communications. In our research we extend the traditional use of such devices to help bridge the gap between physical and digital worlds. Their combined image acquisition, processing, storage, and communication capabilities in a compact, portable device make them an ideal platform for embedding computer vision and image processing capabilities in the pursuit of new mobile applications. This dissertation is presented as a series of computer vision and image processing techniques together with their applications on the mobile device. We have developed a set of techniques for ego-motion estimation, enhancement, feature extraction, perspective correction, object detection, and document retrieval that serve as a basis for such applications. Our applications include a dynamic video barcode that can transfer significant amounts of information visually, a document retrieval system that can retrieve documents from low resolution snapshots, and a series of applications for the users with visual disabilities such as a currency reader. Solutions for mobile devices require a fundamentally different approach than traditional vision techniques that run on traditional computers, so we consider user-device interaction and the fact that these algorithms must execute in a resource constrained environment. For each problem we perform both theoretical and empirical analysis in an attempt to optimize performance and usability. The thesis makes contributions related to efficient implementation of image processing and computer vision techniques, analysis of information theory, feature extraction and analysis of low quality images, and device usability

Resource saving Approach of visual tracking fiducial marker recognition for unmanned aerial vehicle

Unmanned aerial vehicle (UAV) tracking fiducial marker is a challenging problem, because of camera system vibration, which causes visible frame-to-frame jitter in the airborne videos and unclear marker vision. Multirotors have very limited weight carrying, controller, and battery power resources. While obtaining and processing motion blurred images, which have no useful information, requires much more image processing subsystem resources. The paper presents blurry image frame elimination based approach of UAV resource saving fiducial marker visual tracking. The proposed approach integrates accelerometer and visual data processing algorithms to predict image blur and skip blurred frames. Experiments have been performed to verify the validity of the proposed approach

A review of the current trends and future directions of camera barcode reading

Modern mobile phones or smartphones have become a pervasive and affordable device for users at different levels of age around the world. Smartphones equipped with many useful sensors, including camera, barometer, accelerometer, and digital compass. The sensors on smartphones attracted researchers and developers to develop mobile applications (apps) and study the potential use of the sensors to support daily life activities. Unlike other types of sensor, the smartphone camera has been underutilized. Analysis of the literature suggested that smartphone camera mainly serves for personal and social photography. Practically, a smartphone camera can be used as an imaging device for reading a barcode. Although barcode has been used for identifying products and items, the use of a smartphone camera as a reading device has not been explored thoroughly. Further, scholarly resources describing the fundamental knowledge of smartphone camera barcode reading is not available in the literature which could be the reason contributed to slow research progress of the domain. Therefore, this study aims to review the current trends and future directions of smartphone camera for barcode reading. Specifically, the study reviews the literature on the types of applications that are currently available and run on the standard mobile platform for reading a barcode. It also analyzes the necessary components that made up barcode reading apps. Further, the review identifies technical and non-technical issues that are critical for the development of the apps. The contributions of this work are twofold, first, it provides the fundamental knowledge on the building blocks of camera barcode reading apps, and second, it explores the issues in the current camera barcode reading apps that could encourage exploration towards addressing the issues. Practically, the findings could spark new research ideas to address the current issues related to the use of smartphone camera for barcode reading in the near future

Recognition of QR codes on cylindrical surface based on 3D perspective transformation

传统的Qr码识别算法只适用于打印在平面上的条码,提出了一种有效识别打印在饮料瓶等圆柱面上的Qr码。通过对图像轮廓进行角点检测确定回字定位图形,在此基础上筛选条码关键轮廓并对其进行霍夫变换提取圆柱面上的透视椭圆信息,同时结合透视椭圆的参数和三维透视变换,有效构建了圆柱面条码像素从二维图像平面直接映射到三维图像空间的变换矩阵,重构打印在平面或圆柱面上的Qr码目标。实验结果表明,该算法对平面或圆柱面Qr条码的识别有较高的准确率。Traditional QR code recognition algorithm is usually applied to the barcode printed on flat surface only.A lowcost approach to recognize the curved QR codes printed on bottles or cans is proposed in this paper.The width proportion and corners of image contours are extracted to confirm the positioning patterns and an efficient Hough transformation ellipse fitting method is employed to extract the elliptic information.In combination with the parameters of perspective ellipse and 3D perspective transformation,the transformation matrix of barcode pixels on a cylindrical surface is constructed by direct mapping from the 2D image plane to 3D image space.The experiment result proves the algorithm has the high-accuracy recognition ability of barcodes no matter on the flat or the cylindrical surface.福建省自然科学基金资助项目(2010H6026

Automatikus azonosítás és hitelesítés vizuális kódokkal

Az automatikus azonosítás egyik legfontosabb és széles körben alkalmazott eleme a vizuális kódokkal történő azonosítás. A különbözô szimbólumokkal és mintákkal megjelenített azonosítók teszik lehetôvé a gépek számára az elektronikus leolvasást, ami nagyban segíti és gyorsítja a feldolgozást pl. a bolti pénztáraknál, raktári átvételnél, nagy sebességű feldolgozási helyeken, gyártósorokon. A szokásosan használt, geometriai minták szerint tervezett kódok általában típusokat vagy egyedeket azonosítanak. Elôállíthatók azonban olyan mintázatok, melyek természetüknél fogva egyediek és így eredetiség vagy hitelesség ellenôrzésére is alkalmazhatók. Jelen írásunkban bemutatunk egy módszert QR kódok gyors és pontos detektálására mobil készülékkel készített fényképeken, valamint egy természetes mintázat felismerésére kidolgozott eljárásunkat. Alkalmazási területként bemutatunk egy olyan lehetséges hibrid vizuális kód konstrukciót, melyben mesterséges és természetes mintázatok együttes alkalmazásával elérhetô az azonosítás és a hitelesítés is

Reflective-Physically Unclonable Function based System for Anti-Counterfeiting

Physically unclonable functions (PUF) are physical security mechanisms, which utilize inherent randomness in processes used to instantiate physical objects. In this dissertation, an extensive overview of the state of the art in implementations, accompanying definitions and their analysis is provided. The concept of the reflective-PUF is presented as a product security solution. The viability of the concept, its evaluation and the requirements of such a system is explored