323 research outputs found

    Digital Image Processing

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    This book presents several recent advances that are related or fall under the umbrella of 'digital image processing', with the purpose of providing an insight into the possibilities offered by digital image processing algorithms in various fields. The presented mathematical algorithms are accompanied by graphical representations and illustrative examples for an enhanced readability. The chapters are written in a manner that allows even a reader with basic experience and knowledge in the digital image processing field to properly understand the presented algorithms. Concurrently, the structure of the information in this book is such that fellow scientists will be able to use it to push the development of the presented subjects even further

    Advances in Stereo Vision

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    Stereopsis is a vision process whose geometrical foundation has been known for a long time, ever since the experiments by Wheatstone, in the 19th century. Nevertheless, its inner workings in biological organisms, as well as its emulation by computer systems, have proven elusive, and stereo vision remains a very active and challenging area of research nowadays. In this volume we have attempted to present a limited but relevant sample of the work being carried out in stereo vision, covering significant aspects both from the applied and from the theoretical standpoints

    Depth Recovery with Rectification using Single-Lens Prism based Stereovision System

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    Ph.DDOCTOR OF PHILOSOPH

    A Systematic Literature Survey of Unmanned Aerial Vehicle Based Structural Health Monitoring

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    Unmanned Aerial Vehicles (UAVs) are being employed in a multitude of civil applications owing to their ease of use, low maintenance, affordability, high-mobility, and ability to hover. UAVs are being utilized for real-time monitoring of road traffic, providing wireless coverage, remote sensing, search and rescue operations, delivery of goods, security and surveillance, precision agriculture, and civil infrastructure inspection. They are the next big revolution in technology and civil infrastructure, and it is expected to dominate more than $45 billion market value. The thesis surveys the UAV assisted Structural Health Monitoring or SHM literature over the last decade and categorize UAVs based on their aerodynamics, payload, design of build, and its applications. Further, the thesis presents the payload product line to facilitate the SHM tasks, details the different applications of UAVs exploited in the last decade to support civil structures, and discusses the critical challenges faced in UASHM applications across various domains. Finally, the thesis presents two artificial neural network-based structural damage detection models and conducts a detailed performance evaluation on multiple platforms like edge computing and cloud computing

    Applications of Advanced Imaging Methods: Macro-Scale Studies of Woven Composites and Micro-Scale Measurements on Heated IC Packages

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    As a representative advanced imaging technique, the digital image correlation (DIC) method has been well established and widely used for deformation measurements in experimental mechanics. This methodology, both 2D and 3D, provides qualitative and quantitative information regarding the specimen’s non-uniform deformation response. Its full-field capabilities and non-contacting approach are especially advantageous when applied to heterogeneous material systems such as fiber-reinforced composites and integrated chip (IC) packages. To increase understanding of damage evolution in advanced composite material systems, a series of large deflection bending-compression experiments and model predictions have been performed for a woven glass-epoxy composite material system. Stereo digital image correlation has been integrated with a compression-bending mechanical loading system to simultaneously quantify full-field deformations along the length of the specimen. Specifically, the integrated system is employed to experimentally study the highly non-uniform full-field strain fields on both compression and tension surfaces of the heterogeneous specimen undergoing compression-bending loading. Theoretical developments employing both small and large deformation models are performed. Results show (a) that the Euler–Bernoulli beam theory for small deformations is adequate to describe the shape and deformations when the axial and transverse displacement are quite small, (b) that a modified Drucker’s equation effectively extends the theoretical predictions to the large deformation region, providing an accurate estimate for the buckling load, the post-buckling axial load-axial displacement response of the specimen and the axial strain along the beam centerline, even in the presence of observed anticlastic (double) specimen curvature near mid-length for all fiber angles (that is not modeled), (c) for the first time show that the quantities σeff - εeff are linearly related on both the compression and tension surfaces of a beam-compression specimen in the range 0 ≤ εeff \u3c 0.005 as the specimen undergoes combined bending-compression loading. In addition, computational studies also show the consistency with the experimental σeff - εeff results on both surfaces. In a separate set of studies, SEM-based imaging at high magnification is used with 2D-DIC to measure thermal deformations at the nano-scale on cross-sections of IC package to improve understanding of the highly heterogeneous nature of the deformations in IC chips. Full-field thermal deformation experiments on different materials within an IC chip cross-section have been successfully obtained for areas from 50x50 μm2 to 10x10 μm2 and at temperatures from RT to ≈ 200oC using images obtained with a Zeiss Ultraplus Thermal Field Emission SEM. Initially, polishing methods for heterogeneous electronic packages containing silicon, Cu bump, WPR layer, substrate and FLI (First level interconnect) were evaluated with the goal of achieving sub-micron surface flatness. Studies have shown that surface flatness of 700nm is achievable, though this level is unacceptable when using e-beam photolithography for nanoscale patterning. Fortunately, a novel self-assembly technique was identified and used to obtain a dense, randomly isotropic, high contrast pattern over the surface of the entire heterogeneous region on an IC package for SEM imaging and DIC. Experiments performed on baseline materials for temperatures in the range 25°C to 200°C demonstrates that the complete process is effective for quantifying the thermal coefficient of expansion for nickel, aluminum and brass. The experiments on IC cross-sections were performed when viewing 25μm x 25μm areas and correcting image distortions using software developed at USC. The results clearly show the heterogeneous nature of the specimen surface and non-uniform strain field across the complex material constituents for temperatures ranging from RT to 200°C. Experimental results confirm that the method is capable of measuring local thermal expansion in selected regions, improving our understanding of these heterogeneous material systems under controlled thermal-environmental conditions

    A Simplified Phase Display System for 3D Surface Measurement and Abnormal Surface Pattern Detection

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    Today’s engineering products demand increasingly strict tolerances. The shape of a machined surface plays a critical role to the desired functionality of a product. Even a small error can be the difference between a successful product launch and a major delay. It is important to develop tools that confirm the quality and accuracy of manufactured products. The key to assessing the quality is robust measurement and inspection tools combined with advanced analysis. This research is motivated by the goals of 1) developing an advanced optical metrology system that provides accurate 3D profiles of target objects with curvature and irregular texture and 2) developing algorithms that can recognize and extract meaningful surface features with the consideration of machining process information. A new low cost measurement system with a simple coherent interferometric fringe projection system is developed. Comparing with existing optical measurement systems, the developed system generates fringe patterns on object surface through a pair of fiber optics that have a relatively simple and flexible configuration. Three-dimensional measurements of a variety of surfaces with curvatures demonstrate the applicability and flexibility of the developed system. An improved phase unwrapping algorithm based on a flood fill method is developed to enhance the performance of image processing. The developed algorithm performs phase unwrapping under the guidance of a hybrid quality map that is generated by considering the quality of both acquired original intensity images and the calculated wrapped phase map. Advances in metrology systems enable engineers to obtain a large amount of surface information. A systematic framework for surface shape characterization and abnormal pattern detection is proposed to take the advantage of the availability of high definition surface measurements through advanced metrology systems. The proposed framework evaluates a measured surface in two stages. The first step focuses on the extraction of general shape (e.g., surface form) from measurement for surface functionality evaluation and process monitoring. The second step focuses on the extraction of application specific surface details with the consideration of process information (e.g., surface waviness). Applications of automatic abnormal surface pattern detection have been demonstrated. In summary, this research focuses on two core areas: 1) developing metrology system that is capable of measuring engineered surfaces accurately; 2) proposing a methodology that can extract meaningful information from high definition measurements with consideration of process information and product functionality.PHDMechanical EngineeringUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttps://deepblue.lib.umich.edu/bitstream/2027.42/136999/1/xinweng_1.pd

    Depth Super-Resolution with Hybrid Camera System

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    An important field of research in computer vision is the 3D analysis and reconstruction of objects and scenes. Currently, among all the the techniques for 3D acquisition, stereo vision systems are the most common. More recently, Time-of-Flight (ToF) range cameras have been introduced. The focus of this thesis is to combine the information from the ToF with one or two standard cameras, in order to obtain a high- resolution depth imageopenEmbargo per motivi di segretezza e/o di proprietà dei risultati e informazioni di enti esterni o aziende private che hanno partecipato alla realizzazione del lavoro di ricerca relativo alla tes

    Система оцінки глибини зображення за потоковим відео

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    Робота публікується згідно наказу ректора від 27.05.2021 р. №311/од "Про розміщення кваліфікаційних робіт вищої освіти в репозиторії університету". Керівник дипломної роботи: к.т.н., старший викладач кафедри авіаційних комп’ютерно-інтегрованих комплексів, Василенко Микола ПавловичToday, the tasks of computer vision are becoming very relevant, more and more people are automating work in production due to some kind of software processes and machine devices, which can make job easier or more accurate. Based on this, it was decided to consider in detail the problem of stereo vision without using neural networks, or other more complex methods, since their use required costly methods of training, setting and controlling parameters. The main task was to create a mechanism taking into account the price and quality, due to the fact that there is no cheap analogue on the internet market, which was suitable for the task of simple recognition of 3D scenes and made it possible to analyze the environment in which it is located, namely, to find out at what distance objects are located, what is their size, and so on. In the course of the work, the method of using two web cameras was chosen, which were configured and calibrated for the task of stereo vision. The conditions of projective geometry and the relationship between the two cameras are also considered, since without this, the operation of the main algorithm of the work could not be successful at all. An algorithm and program have been created for the device to operate in streaming mode, which allows directly know the exact characteristics in LIVE video mode.Сьогодні завдання комп’ютерного зору стають дуже актуальними, все більше людей автоматизують роботу на виробництві завдяки якимсь програмним процесам та машинним пристроям, які можуть полегшити роботу або зробити її більш точною. З цього приводу було вирішено детально розглянути проблему стереозору без використання нейронних мереж або інших більш складних методів, оскільки їх використання вимагало дорогих методів навчання, встановлення та контролю параметрів. Основним завданням було створити механізм з урахуванням ціни та якості, завдяки тому, що на Інтернет-ринку немає дешевого аналога, який був би придатним для завдання простого розпізнавання тривимірних сцен і дав можливість аналізувати середовище, в якому він знаходиться, а саме з’ясувати, на якій відстані знаходяться об’єкти, який їх розмір тощо. В ході роботи було обрано метод використання двох веб-камер, які були налаштовані та відкалібровані для завдання стерео зору. Також розглядаються умови проективної геометрії та взаємозв'язок між двома камерами, оскільки без цього робота основного алгоритму роботи взагалі не могла б бути успішною. Створено алгоритм та програму для роботи пристрою в потоковому режимі, що дозволяє безпосередньо знати точні характеристики в режимі LIVE video
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