Coexisting Parallelogram Method to Handle Jump Point on Hough Transform-based Clock Skew Measurement

In this paper, we improve the robustness of the Hough transform-based clock skew measurement on the occurrence of a jump point. The current Hough transform-based skew method uses angle (θ), thickness (ω), and region (β), to create a parallelogram that covers the densest part of an offset-set. However, the assumption that all offsets are considered to line up roughly in only one direction restricts the ability of the current method when handling an offset-set in which its densest part is located separately, the jump point condition. By acquiring the parallelogram from coexisting angle-region tuples at the beginning and the ending parts of the offset-set, we completed the ability of the Hough transform-based method to handle the jump point. When handling the jump point problem, the proposed coexisting parallelogram method could reach 0.35 ppm accuracy compared with tens ppm by the current methods

Autonomous, Collaborative, Unmanned Aerial Vehicles for Search and Rescue

Search and Rescue is a vitally important subject, and one which can be improved through the use of modern technology. This work presents a number of advances aimed towards the creation of a swarm of autonomous, collaborative, unmanned aerial vehicles for land-based search and rescue. The main advances are the development of a diffusion based search strategy for route planning, research into GPS (including the Durham Tracker Project and statistical research into altitude errors), and the creation of a relative positioning system (including discussion of the errors caused by fast-moving units). Overviews are also given of the current state of research into both UAVs and Search and Rescue

Teat detection for an automated milking system

Application time when placing all four cups to the udder of a cow is the primary time constraint in high capacity group milking. A human labourer can manually apply four cups per animal as it passes on a rotary carousel in less than ten seconds. Existing automated milking machines typically have an average attachment time in excess of one minute. These systems apply the cups to each udder quadrant individually. To speed up the process it is proposed to attach all four cups simultaneously. To achieve this, the 3D position and orientation of each teat must be known in approximate real time. This thesis documents the analysis of a stereo-vision system for teat location and presents further developments of the system for detection of teat orientation. Test results demonstrate the suitability of stereovision for teat location but indicate that further refinement of the system is required to produce increased accuracy and precision. The additional functionality developed for the system to determine teat orientation has also been tested. Results show that while accurate determination of teat orientation is possible issues still exist with reliability and robustness

NOVEL METHODS OF MERIDIONAL AND CIRCUMFERENTIAL ANTERIOR CHAMBER ANGLE IMAGING

Ph.DDOCTOR OF PHILOSOPH

Belle II Technical Design Report

The Belle detector at the KEKB electron-positron collider has collected almost 1 billion Y(4S) events in its decade of operation. Super-KEKB, an upgrade of KEKB is under construction, to increase the luminosity by two orders of magnitude during a three-year shutdown, with an ultimate goal of 8E35 /cm^2 /s luminosity. To exploit the increased luminosity, an upgrade of the Belle detector has been proposed. A new international collaboration Belle-II, is being formed. The Technical Design Report presents physics motivation, basic methods of the accelerator upgrade, as well as key improvements of the detector.Comment: Edited by: Z. Dole\v{z}al and S. Un

Catalytic steam reformer tubes non-destructive inspection technology investigation and advancement : a dissertation presented in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Engineering at Massey University, Manawatu Campus, New Zealand

Catalytic Steam reforming is a chemical synthesis process used in the production of hydrogen by mixing hydrocarbon with steam in the presence of a metal-based catalyst. This is achieved in a steam reformer plant where the mixture of gases is elevated to high pressure and temperature through a continuous process for efficient mass production of syngas to meet the global hydrogen demand. One of the challenges in operating a steam reformer plant is monitoring and maintaining the tubular reactors (Reformer tube). Under the severe service conditions the tubes a subjected to various degradation mechanism which ultimately determine the service life. With the tubes accounting to over 20% of the capital cost of a reformer plant, it is of great significance to maximise the service life of each tubes, which has been the motivation to the advancement in metallurgy and NDT technology around reformer tubes from the introduction of Catalytic Steam reforming in the early 20th century. Under the influence of long-term exposure of mechanical stressing and elevated temperature, reformer tube is subjected to a material degrading phenomenon call creep deformation. In 1952, F.R. Larson and J. Miller devised the Larson-Miller Parameter which predicts the lifetime of a material based on service temperature and stress-rupture time and for decades this method was used design and managed reformer tubes on a time-based strategy of 10,000 service hour. However, case studies have time and time shown premature rupture of reformer tube causing unexpected downtime resulting in significant loss in production and asset. Hence engineers and researchers have worked on a more direct method of assessing the remaining service life of reformer tubes. Inline pipe inspection is a hot area of research in robotics and automation. Eddy current, laser profilometry, ultrasonic and infrared thermography is the four technology that is currently dominating the Reformer industry, of which laser profilometry assessment being the only method capable of early stage creep detection. While other fields of pipe inspection have advanced and industrially applied over past decades, it is the author's opinion that NDT technology for reformer tube is outdated with areas of innovation. The aim of this research is to investigate an alternative solution to overcome the challenges and limited faced in modern systems and contribute to the advancement of NDT of Catalytic Steam reformer tubes. Presented in this dissertation is a new framework for an autonomous Reformer Tube inspection system, which incorporates a number of innovative elements for improved creep damage assessment. The program for this work is comprised of three studies. In the first study, the challenges around process profilometry dataset is demonstrated, the limitation in the available methods is discussed, and the impacts in regards to detection creep deformation is identified. Based on the finding, a three-stage creep detection algorithm (CDA) is derived, offering a dynamic solution to distinguish two modes of isotropic and anisotropic creep deformation. The system is experimentally assessed using a set of profilometry measurements collected from retire reformer tube. In the second study, a novel method for tracking a motion of an object moving inside a reformer tube is devised. Literature study showed that conventional profilometry system suffers from measurement uncertainty cause from an uncontrolled rotation of measurement instruction during an inspection. Because location information gives valuable insight as to the performance of the plant, the long-range optic solution is conceptualised, based on polarising filters and Malus Law, to overcome these limitations. In this research, a proof of concept experiment is conducted to evaluate and justify the conceptual method through the development of a working prototype. This novel technique is named Optical Position Tracking (OPT) system. Presented in the final study is an autonomous reformer tube inspection system developed on the basis of the results and finding in the first portion of the research. The contribution of this research is demonstrated with a working prototype justifying the practicality of CDA and the OPT system. The design incorporates wireless communication, modular design, and modern semiconductor sensing technology. In conclusion, this research met the first milestone for an ongoing research to progress the NTD industry

Map-Based Localization for Unmanned Aerial Vehicle Navigation

Unmanned Aerial Vehicles (UAVs) require precise pose estimation when navigating in indoor and GNSS-denied / GNSS-degraded outdoor environments. The possibility of crashing in these environments is high, as spaces are confined, with many moving obstacles. There are many solutions for localization in GNSS-denied environments, and many different technologies are used. Common solutions involve setting up or using existing infrastructure, such as beacons, Wi-Fi, or surveyed targets. These solutions were avoided because the cost should be proportional to the number of users, not the coverage area. Heavy and expensive sensors, for example a high-end IMU, were also avoided. Given these requirements, a camera-based localization solution was selected for the sensor pose estimation. Several camera-based localization approaches were investigated. Map-based localization methods were shown to be the most efficient because they close loops using a pre-existing map, thus the amount of data and the amount of time spent collecting data are reduced as there is no need to re-observe the same areas multiple times. This dissertation proposes a solution to address the task of fully localizing a monocular camera onboard a UAV with respect to a known environment (i.e., it is assumed that a 3D model of the environment is available) for the purpose of navigation for UAVs in structured environments. Incremental map-based localization involves tracking a map through an image sequence. When the map is a 3D model, this task is referred to as model-based tracking. A by-product of the tracker is the relative 3D pose (position and orientation) between the camera and the object being tracked. State-of-the-art solutions advocate that tracking geometry is more robust than tracking image texture because edges are more invariant to changes in object appearance and lighting. However, model-based trackers have been limited to tracking small simple objects in small environments. An assessment was performed in tracking larger, more complex building models, in larger environments. A state-of-the art model-based tracker called ViSP (Visual Servoing Platform) was applied in tracking outdoor and indoor buildings using a UAVs low-cost camera. The assessment revealed weaknesses at large scales. Specifically, ViSP failed when tracking was lost, and needed to be manually re-initialized. Failure occurred when there was a lack of model features in the cameras field of view, and because of rapid camera motion. Experiments revealed that ViSP achieved positional accuracies similar to single point positioning solutions obtained from single-frequency (L1) GPS observations standard deviations around 10 metres. These errors were considered to be large, considering the geometric accuracy of the 3D model used in the experiments was 10 to 40 cm. The first contribution of this dissertation proposes to increase the performance of the localization system by combining ViSP with map-building incremental localization, also referred to as simultaneous localization and mapping (SLAM). Experimental results in both indoor and outdoor environments show sub-metre positional accuracies were achieved, while reducing the number of tracking losses throughout the image sequence. It is shown that by integrating model-based tracking with SLAM, not only does SLAM improve model tracking performance, but the model-based tracker alleviates the computational expense of SLAMs loop closing procedure to improve runtime performance. Experiments also revealed that ViSP was unable to handle occlusions when a complete 3D building model was used, resulting in large errors in its pose estimates. The second contribution of this dissertation is a novel map-based incremental localization algorithm that improves tracking performance, and increases pose estimation accuracies from ViSP. The novelty of this algorithm is the implementation of an efficient matching process that identifies corresponding linear features from the UAVs RGB image data and a large, complex, and untextured 3D model. The proposed model-based tracker improved positional accuracies from 10 m (obtained with ViSP) to 46 cm in outdoor environments, and improved from an unattainable result using VISP to 2 cm positional accuracies in large indoor environments. The main disadvantage of any incremental algorithm is that it requires the camera pose of the first frame. Initialization is often a manual process. The third contribution of this dissertation is a map-based absolute localization algorithm that automatically estimates the camera pose when no prior pose information is available. The method benefits from vertical line matching to accomplish a registration procedure of the reference model views with a set of initial input images via geometric hashing. Results demonstrate that sub-metre positional accuracies were achieved and a proposed enhancement of conventional geometric hashing produced more correct matches - 75% of the correct matches were identified, compared to 11%. Further the number of incorrect matches was reduced by 80%

Data Acquisition Applications

Data acquisition systems have numerous applications. This book has a total of 13 chapters and is divided into three sections: Industrial applications, Medical applications and Scientific experiments. The chapters are written by experts from around the world, while the targeted audience for this book includes professionals who are designers or researchers in the field of data acquisition systems. Faculty members and graduate students could also benefit from the book

A scalable packetised radio astronomy imager

Includes bibliographical referencesModern radio astronomy telescopes the world over require digital back-ends. The complexity of these systems depends on many site-specific factors, including the number of antennas, beams and frequency channels and the bandwidth to be processed. With the increasing popularity for ever larger interferometric arrays, the processing requirements for these back-ends have increased significantly. While the techniques for building these back-ends are well understood, every installation typically still takes many years to develop as the instruments use highly specialised, custom hardware in order to cope with the demanding engineering requirements. Modern technology has enabled reprogrammable FPGA-based processing boards, together with packet-based switching techniques, to perform all the digital signal processing requirements of a modern radio telescope array. The various instruments used by radio telescopes are functionally very different, but the component operations remain remarkably similar and many share core functionalities. Generic processing platforms are thus able to share signal processing libraries and can acquire different personalities to perform different functions simply by reprogramming them and rerouting the data appropriately. Furthermore, Ethernet-based packet-switched networks are highly flexible and scalable, enabling the same instrument design to be scaled to larger installations simply by adding additional processing nodes and larger network switches. The ability of a packetised network to transfer data to arbitrary processing nodes, along with these nodes' reconfigurability, allows for unrestrained partitioning of designs and resource allocation. This thesis describes the design and construction of the first working radio astronomy imaging instrument hosted on Ethernet-interconnected re- programmable FPGA hardware. I attempt to establish an optimal packetised architecture for the most popular instruments with particular attention to the core array functions of correlation and beamforming. Emphasis is placed on requirements for South Africa's MeerKAT array. A demonstration system is constructed and deployed on the KAT-7 array, MeerKAT's prototype. This research promises reduced instrument development time, lower costs, improved reliability and closer collaboration between telescope design teams