The Design of a Low-Cost Traffic Calming Radar - Development of a radar solution intended to demonstrate proof of concept

This study aimed to develop a radar solution that would aid the traffic calming efforts of the CSIR business campus. The Institute of Transportation Engineers defined traffic calming as "The combination of mainly physical measures that reduce the negative effects of motor vehicle use." Radar-based solutions have been proven to help reduce the speeds of motorists in areas with speed restrictions. Unfortunately, these solutions are expensive and difficult to import. Thus, this dissertation's main focus is to produce a detailed blueprint of a radar-based solution, with technical specifications that are similar to those of commercial and experimental systems at relatively low-cost. With the above mindset, the project was initiated with the user requirements being stated. Then a detailed study of current experimental and commercial radar-based traffic calming systems followed. Thereafter, the technical and non-technical requirements were derived from user requirements, and the technical specifications obtained from the literature study. A review of fundamental radar and signal processing principles was initiated to give background knowledge for the design and simulation process. Consequently, a detailed design of the system's functional components was conceptualized, which included the hardware, software, and electrical aspects of the system as well as the enclosure design. With the detailed design in mind, a data-collection system was built. The data-collection system was built to verify whether the technical specifications, which relate to the detection performance and the velocity accuracy of the proposed radar design, were met. This was done to save on buying all the components of the proposed system while proving the design's technical feasibility. The data-collection system consisted of a radar sensor, an Analogue to Digital Converter (ADC), and a laptop computer. The radar sensor was a k-band, Continuous Wave (CW) transceiver, which provided I/Q demodulated data with beat frequencies ranging from DC to 50 kHz. The ADC is an 8-bit Picoscope 2206B portable oscilloscope, capable of sampling frequencies of up to 50 MHz. The target detection and the velocity estimation algorithms were executed on a Samsung Series 7 Chronos laptop. Preliminary experiments enabled the approximation of the noise intensity of the scene in which the radar would be placed. These noise intensity values enabled the relationship between the Signal to Noise Ratio (SNR) and the velocity error to be modelled at specific ranges from the radar, which led to a series of experiments that verified the prototypes' ability to accurately detect and estimate the vehicle speed at distances of up to 40 meters from the radar. The cell-averaging constant false alarm rate (CA-CFAR) detector was chosen as an optimum detector for this application, and parameters that produced the best results were found to be 50 reference cells and 12 guard cells. The detection rate was found to be 100% for all coherent processing intervals (CPIs) tested. The prototype was able to detect vehicle speeds that ranged from 2 km/h up to 60 km/h with an uncertainty of ±0.415 km/h, ±0.276 km/h, and ±0.156 km/h using a CPI of 0.0128 s, 0.256 s, and 0.0512 s respectively. The optimal CPI was found to be 0.0512 s, as it had the lowest mean velocity uncertainty, and it produced the largest first detection SNR of the CPIs tested. These findings were crucial for the feasibility of manufacturing a low-cost traffic calming solution for the South African market

AI for time-resolved imaging: from fluorescence lifetime to single-pixel time of flight

Time-resolved imaging is a field of optics which measures the arrival time of light on the camera. This thesis looks at two time-resolved imaging modalities: fluorescence lifetime imaging and time-of-flight measurement for depth imaging and ranging. Both of these applications require temporal accuracy on the order of pico- or nanosecond (10−12 − 10−9s) scales. This demands special camera technology and optics that can sample light-intensity extremely quickly, much faster than an ordinary video camera. However, such detectors can be very expensive compared to regular cameras while offering lower image quality. Further, information of interest is often hidden (encoded) in the raw temporal data. Therefore, computational imaging algorithms are used to enhance, analyse and extract information from time-resolved images. "A picture is worth a thousand words". This describes a fundamental blessing and curse of image analysis: images contain extreme amounts of data. Consequently, it is very difficult to design algorithms that encompass all the possible pixel permutations and combinations that can encode this information. Fortunately, the rise of AI and machine learning (ML) allow us to instead create algorithms in a data-driven way. This thesis demonstrates the application of ML to time-resolved imaging tasks, ranging from parameter estimation in noisy data and decoding of overlapping information, through super-resolution, to inferring 3D information from 1D (temporal) data

Advances in Sonar Technology

The demand to explore the largest and also one of the richest parts of our planet, the advances in signal processing promoted by an exponential growth in computation power and a thorough study of sound propagation in the underwater realm, have lead to remarkable advances in sonar technology in the last years.The work on hand is a sum of knowledge of several authors who contributed in various aspects of sonar technology. This book intends to give a broad overview of the advances in sonar technology of the last years that resulted from the research effort of the authors in both sonar systems and their applications. It is intended for scientist and engineers from a variety of backgrounds and even those that never had contact with sonar technology before will find an easy introduction with the topics and principles exposed here

Anomaly detection & object classification using multi-spectral LiDAR and sonar

In this thesis, we present the theory of high-dimensional signal approximation of multifrequency signals. We also present both linear and non-linear compressive sensing (CS) algorithms that generate encoded representations of time-correlated single photon counting (TCSPC) light detection and ranging (LiDAR) data, side-scan sonar (SSS) and synthetic aperture sonar (SAS). The main contributions of this thesis are summarised as follows: 1. Research is carried out studying full-waveform (FW) LiDARs, in particular, the TCSPC data, capture, storage and processing. 2. FW-LiDARs are capable of capturing large quantities of photon-counting data in real-time. However, the real-time processing of the raw LiDAR waveforms hasn’t been widely exploited. This thesis answers some of the fundamental questions: • can semantic information be extracted and encoded from raw multi-spectral FW-LiDAR signals? • can these encoded representations then be used for object segmentation and classification? 3. Research is carried out into signal approximation and compressive sensing techniques, its limitations and the application domains. 4. Research is also carried out in 3D point cloud processing, combining geometric features with material spectra (spectral-depth representation), for object segmentation and classification. 5. Extensive experiments have been carried out with publicly available datasets, e.g. the Washington RGB Image and Depth (RGB-D) dataset [108], YaleB face dataset1 [110], real-world multi-frequency aerial laser scans (ALS)2 and an underwater multifrequency (16 wavelengths) TCSPC dataset collected using custom-build targets especially for this thesis. 6. The multi-spectral measurements were made underwater on targets with different shapes and materials. A novel spectral-depth representation is presented with strong discrimination characteristics on target signatures. Several custom-made and realistically scaled exemplars with known and unknown targets have been investigated using a multi-spectral single photon counting LiDAR system. 7. In this work, we also present a new approach to peak modelling and classification for waveform enabled LiDAR systems. Not all existing approaches perform peak modelling and classification simultaneously in real-time. This was tested on both simulated waveform enabled LiDAR data and real ALS data2 . This PhD also led to an industrial secondment at Carbomap, Edinburgh, where some of the waveform modelling algorithms were implemented in C++ and CUDA for Nvidia TX1 boards for real-time performance. 1http://vision.ucsd.edu/~leekc/ExtYaleDatabase/ 2This dataset was captured in collaboration with Carbomap Ltd. Edinburgh, UK. The data was collected during one of the trials in Austria using commercial-off-the-shelf (COTS) sensors

Radar Imaging in Challenging Scenarios from Smart and Flexible Platforms

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Radar Technology

In this book “Radar Technology”, the chapters are divided into four main topic areas: Topic area 1: “Radar Systems” consists of chapters which treat whole radar systems, environment and target functional chain. Topic area 2: “Radar Applications” shows various applications of radar systems, including meteorological radars, ground penetrating radars and glaciology. Topic area 3: “Radar Functional Chain and Signal Processing” describes several aspects of the radar signal processing. From parameter extraction, target detection over tracking and classification technologies. Topic area 4: “Radar Subsystems and Components” consists of design technology of radar subsystem components like antenna design or waveform design

Fourierdomänen modengekoppelte Laser: Aufklärung der Funktionsweise und Erschließung neuer Anwendungsbereiche

Mit der Fourierdomänen Modenkopplung (FDML) wurde vor kurzem ein neuer Operationsmodus für sehr schnell in der Wellenlänge abstimmbare Laser entdeckt, bei dem ein schmalbandiger Spektralfilter resonant zur Lichtumlaufzeit im Resonator abgestimmt wird. Diese FDML-Laser, deren genaue Funktionsweise noch unverstanden ist, gehören zu den schnellsten weit abstimmbaren Lichtquellen und eignen sich besonders für die optische Kohärenztomografie (OCT), die ein junges dreidimensionales Bildgebungsverfahren darstellt. In dieser Arbeit wurden zwei Ziele parallel verfolgt. Zum einen sollten durch Optimierungen und Erweiterungen des Lasers neue Anwendungsmöglichkeiten insbesondere in der OCT ermöglicht, gleichzeitig aber auch neue Erkenntnisse über die genaue Funktionsweise der Fourierdomänen Modenkopplung auf physikalischer Ebene gewonnen werden. In dem eher anwendungsorientierten Teil dieser Arbeit wurde zunächst eine neue Methode entwickelt, mit der es in der OCT mit schnell abstimmbaren Lasern möglich ist, zweidimensionale Schnitte bei einer bestimmten Tiefe, sogenannte en face Schnitte, ohne aufwändige Computerberechnung zu erhalten. Während diese Schnitte bisher nur sehr rechenintensiv durch Nachbearbeitung und Extraktion aus einem vollständig aufgenommenen dreidimensionalen Datensatz gewonnen werden konnten, lassen diese sich nun um ein Vielfaches schneller aufnehmen und darstellen. Weiterhin wurde durch den Eigenbau eines auf Abstimmgeschwindigkeit optimierten Spektralfilters die Aufnahmegeschwindigkeit eines mit einem FDML-Laser betriebenen OCT-Systems um über eine Größenordnung erhöht, so dass dieses nun mit Abstand zu den schnellsten Systemen gehört. Obwohl bei diesen hohen Geschwindigkeiten das Signal-Rausch-Verhältnis durch Schrotrauschen bereits limitiert wird, konnten Aufnahmen sehr hoher Qualität erzeugt werden, was a priori nicht selbstverständlich war. Im Grundlagenteil dieser Arbeit wurde das Verständnis der Operationsweise der Fourierdomänen Modenkopplung erweitert. Da FDML-Laser vollständig aus Glasfaserkomponenten aufgebaut sind und Längen von mehreren Kilometern aufweisen, wurde der Einfluss der Faserdispersion auf sowohl Linienbreite und Rauschverhalten untersucht. Mit einer speziellen dispersionskompensierten Resonatorgeometrie konnte dabei ein einfaches Modell des Einflusses der Dispersion auf die Kohärenzlänge validiert und eine deutliche Erhöhung dieser erreicht werden. Ein umfassenderes Modell der Operationsweise von FDML-Lasern ist wünschenswert, um experimentell schwer zugängliche Fragestellungen beantworten zu können. Auf dem Weg dahin müssen zunächst alle physikalischen Effekte im Resonator, welche zur Lasertätigkeit beitragen, aufgeklärt werden. Hierzu wurde die zeitabhängige Leistung eines FDML-Lasers durch verschiedene Terme in der nichtlinearen Schrödingergleichung modelliert, numerisch ausgewertet und mit experimentellen Daten verglichen. Dadurch konnten wichtige an der Laseroperation beteiligte Prozesse aufgeklärt und eine Basis für weitergehende Simulationen geschaffen werden

Avalanche studies and model validation in Europe, SATSIE. 1st annual report

During the first year ofthe SATSIE project, emphasis was on preparatory activities, i.e., development of sensors and data analysis methods, installation of new equipment in the experimental facilities, exploration of different options for developing new models, and establishing a web-site for communication within the project and to the interested public. Two measurement campaigns could be conducted at the full-scale site Ryggform (Norway), albeit with limited instrumentation only, as had been anticipated. At all the chutes, however, intensive experimentation has begun and has already produced intriguing preliminary results that will be tested and extended in the second project year. In view of the planned model development, candidate rheological approaches and entrainment mechanisms have been investigated for their relevance and applicability. In the following, we summarise the main activities and results in the six work packages ofthe project and the expenditures of each partner during the reporting period. In six separate chapters, a more detailed account of the activities and results of all the work packages is given. The Appendix collects several scientific papers and reports written in the first year of SATSIE are collected for referenceEuropean Commissio

An investigation of real time ultrasound Doppler techniques for tissue motion and deformation analysis

Cardiovascular disease accounts for more than 50% of all deaths in the Western world. Atherosclerosis is responsible for the vast majority of these diseases. There are a range of risk factors for atherosclerosis that affect the endothelial lining vessel wall cells to cause endothelial dysfunction, which then predisposes to a localized build-up of 'plaque' tissue that narrows the lumen of the arteries. Plaque rupture promotes localized vasospasm, thrombosis and embolism causing downstream tissue death, resulting in severe disability or death from, for instance, heart attack (in the coronary circulation) or stroke (in the cerebral circulation). Narrowing of the lumen and plaque rupture are associated with high tissue stresses and tissue under perfusion, which will alter local arterial and myocardial wall dynamics and elastic properties. Hence visualization of tissue dynamic and deformation property changes is crucial to detect atherosclerosis in the earliest stages to prevent acute events.The objective of this dissertation research is to develop new techniques based on Doppler ultrasound to investigate and visualize changes in tissue dynamic and deformation properties due to atherosclerosis in cardiac and vascular applications. A new technique, to correct for the Doppler angle dependence for tissue motion analysis has been developed. It is based on multiple ultrasound beams, and has been validated in vitro to study tissue dynamic properties. It can measure tissue velocity magnitude with low bias (5%) and standard deviation (10%), and tissue velocity orientation with a bias less than 5 degrees and a standard deviation below 5 degrees. A new Doppler based method, called strain rate, has also been developed and validated in vitro for the quantification of regional vessel or myocardial wall deformation. Strain rate is derived from the velocity information and can assess tissue deformation with an accuracy of 5% and a standard deviation less than 10%. Some examples of cardiac strain rate imaging have been gathered and are described in this thesis. Strain rate, as all Doppler based techniques, suffers from angle dependence limitation. A method to estimate one-component strain rate in any direction in the two-dimensional image not necessarily along the ultrasound beam has been developed. The method allows correcting for the strain rate bias along any user-defined direction. It is also shown that the full strain rate tensor can theoretically be extracted from the velocity vector field acquired by multiple beam tissue vector velocity technique. In vitro experiments have shown that qualitative two-component strain rate tensor can be derived. Two-component vector velocity from the moving tissue was acquired and two two-component strain rate images were derived. The images showed agreement with the expected deformation pattern