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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Real Time Human Tracking in Unconstrained Environments

Gao, Hongzhi January 2011 (has links)
The tabu search particle filter is proposed in this research based on the integration of the modified tabu search metaheuristic optimization and the genetic particle filter. Experiments with this algorithm in real time human tracking applications in unconstrained environments show that it is more robust, accurate and faster than a number of other existing metaheuristic filters, including the evolution particle filter, particle swarm filter, simulated annealing filter, path relink filter and scatter search filter. Quantitative evaluation illustrates that even with only ten particles in the system, the proposed tabu search particle filter has a success rate of 93.85% whereas the success rate of other metaheuristic filters ranged from 68.46% to 17.69% under the same conditions. The accuracy of the proposed algorithm (with ten particles in the tracking system) is 2.69 pixels on average, which is over 3.85 times better than the second best metaheuristic filters in accuracy and 18.13 times better than the average accuracy of all other filters. The proposed algorithm is also the fastest among all metaheuristic filters that have been tested. It achieves approximately 50 frames per second, which is 1.5 times faster than the second fastest algorithm and nineteen times faster than the average speed of all other metaheuristic filters. Furthermore, a unique colour sequence model is developed in this research based on a degenerated form of the hidden Markov model. Quantitative evaluations based on rigid object matching experiments illustrate that the successful matching rate is 5.73 times better than the widely used colour histogram. In terms of speed, the proposed algorithm achieves twice the successful matching rate in about three quarters of the processing time consumed by the colour histogram model. Overall, these results suggest that the two proposed algorithms would be useful in many applications due to their efficiently, accuracy and ability to robustly track people and coloured objects.
2

Closed-Loop Tracking System Provides Reference for Data Collection Exercises

Wallace, Keith, Weinberg, Patrick 10 1900 (has links)
International Telemetering Conference Proceedings / October 26-29, 1992 / Town and Country Hotel and Convention Center, San Diego, California / A computational system was developed to support data collection for advanced airborne technology research. Basic research is conducted using a variety of sensing devices for collection of flight characteristics data from aircraft. To maximize control over as many variables as possible during research activities, a controlled aircraft tracking environment is needed to provide reference data for real-time operation and post-mission analysis. The solution to this requirement is realized with the ACMI Interface System (ACINTS). The ACINTS extracts real-time tracking data from a closed-loop telemetered tracking array, reprocesses needed parameters, provides reference data (positioning and control commands) to the sensor device, and records aircraft kinematics for later correlation with other collected data.
3

Tracking a tennis ball using image processing techniques

Mao, Jinzi 30 August 2006
In this thesis we explore several algorithms for automatic real-time tracking of a tennis ball. We first investigate the use of background subtraction with color/shape recognition for fast tracking of the tennis ball. We then compare our solution with a cascade of boosted Haar classifiers [68] in a simulated environment to estimate the accuracy and ideal processing speeds. The results show that background subtraction techniques were not only faster but also more accurate than Haar classifiers. Following these promising results, we extend the background subtraction and develop other three improved techniques. These techniques use more accurate background models, more reliable and stringent criteria. They allow us to track the tennis ball in a real tennis environment with cameras having higher resolutions and frame rates. <p>We tested our techniques with a large number of real tennis videos. In the indoors environment, We achieved a true positive rate of about 90%, a false alarm rate of less than 2%, and a tracking speed of about 20 fps. For the outdoors environment, the performance of our techniques is not as good as the indoors cases due to the complexity and instability of the outdoors environment. The problem can be solved by resetting our system such that the camera focuses mainly on the tennis ball. Therefore, the influence of the external factors is minimized.<p>Despite the existing limitations, our techniques are able to track a tennis ball with very high accuracy and fast speed which can not be achieved by most tracking techniques currently available. We are confident that the motion information generated from our techniques is reliable and accurate. Giving this promising result, we believe some real-world applications can be constructed.
4

Tracking a tennis ball using image processing techniques

Mao, Jinzi 30 August 2006 (has links)
In this thesis we explore several algorithms for automatic real-time tracking of a tennis ball. We first investigate the use of background subtraction with color/shape recognition for fast tracking of the tennis ball. We then compare our solution with a cascade of boosted Haar classifiers [68] in a simulated environment to estimate the accuracy and ideal processing speeds. The results show that background subtraction techniques were not only faster but also more accurate than Haar classifiers. Following these promising results, we extend the background subtraction and develop other three improved techniques. These techniques use more accurate background models, more reliable and stringent criteria. They allow us to track the tennis ball in a real tennis environment with cameras having higher resolutions and frame rates. <p>We tested our techniques with a large number of real tennis videos. In the indoors environment, We achieved a true positive rate of about 90%, a false alarm rate of less than 2%, and a tracking speed of about 20 fps. For the outdoors environment, the performance of our techniques is not as good as the indoors cases due to the complexity and instability of the outdoors environment. The problem can be solved by resetting our system such that the camera focuses mainly on the tennis ball. Therefore, the influence of the external factors is minimized.<p>Despite the existing limitations, our techniques are able to track a tennis ball with very high accuracy and fast speed which can not be achieved by most tracking techniques currently available. We are confident that the motion information generated from our techniques is reliable and accurate. Giving this promising result, we believe some real-world applications can be constructed.
5

Assembly Guidance in Augmented Reality Environments Using a Virtual Interactive Tool

Yuan, M. L., Ong, S. K., Nee, Andrew Y. C. 01 1900 (has links)
The application of augmented reality (AR) technology for assembly guidance is a novel approach in the traditional manufacturing domain. In this paper, we propose an AR approach for assembly guidance using a virtual interactive tool that is intuitive and easy to use. The virtual interactive tool, termed the Virtual Interaction Panel (VirIP), involves two tasks: the design of the VirIPs and the real-time tracking of an interaction pen using a Restricted Coulomb Energy (RCE) neural network. The VirIP includes virtual buttons, which have meaningful assembly information that can be activated by an interaction pen during the assembly process. A visual assembly tree structure (VATS) is used for information management and assembly instructions retrieval in this AR environment. VATS is a hierarchical tree structure that can be easily maintained via a visual interface. This paper describes a typical scenario for assembly guidance using VirIP and VATS. The main characteristic of the proposed AR system is the intuitive way in which an assembly operator can easily step through a pre-defined assembly plan/sequence without the need of any sensor schemes or markers attached on the assembly components. / Singapore-MIT Alliance (SMA)
6

Real-time tracking of instruments : Visualizing endoscope position on placental vasculature image / Realtidsspårning av instrument : Visualisering av endoskops position på bild av placentas vaskulärsystem

Huusmann, Johan January 2017 (has links)
Twin-to-twin transfusion syndrome (TTTS) is a complication of blood flow among fetuses sharing a single placenta. TTTS is associated with high mortality rates; however there is treatment available which significantly increases the rate of survival. The treatment procedure is although far from perfect. Limited by a narrow field of view, it is a challenging task for the surgeon to mentally visualize the vascular structures of the placenta while trying to navigate across the areas of interest. Previous research within both medical imaging and tracking technologies has been conducted but there is no perfect solution on how to solve these issues. This paper is part of a two-part project attempting to provide an application which can make the surgical procedure easier. The two parts are image stitching and real-time tracking, this paper focusing on the latter. This is done by choosing an appropriate tracking method which can provide location and orientation of a small sensor. The 3D data gathered from the sensor is processed by various transformations so that the bounding box of the camera movement can be mapped directly onto the image generated by the stitching process. The same transformations are applied to data collected from the sensor at a rate of 60 Hz, resulting in a responsive system. By comparing the x-value and y-value of a calculated point to the bounding box, this point can be converted to its corresponding pixel in the image. The system is responsive and by visually comparing the digital position in the image to its corresponding real world position it seems accurate enough, even though a few pixels misalignment will occur. / Tvillingstransfusionssyndrom (TTTS) är en komplikation av blodflöde som kan uppstå hos foster som delar placenta. TTTS associeras medhöga dödstal, emellertid finns det behandlingar som signifikant ökar chanserna för fostrens överlevnad. Behandlingsprocessen är docklångt ifrån perfekt. Begränsad av ett smalt synfält är det en utmanande uppgift för kirurgen att mentalt föreställa sig placentansvaskulärsystem samtidigt som denne försöker att navigera mellan alla intresseområden. Forskning inom både bildbehandling ochspårningsteknologier är inget främmande men det finns ännu ingen självklar lösning på dessa problem. Den här rapporten är en del av etttvåstegsprojekt vars mål är att framställa en applikation som kan underlätta behandlingen. De två delarna är image stitching ochrealtidsspårning, där den här rapporten fokuserar på det sistnämnda. Detta görs genom att välja en lämplig spårningsmetod som kan mätabåde position samt orientering av en sensor. 3D-datan från sensorn behandlas av olika matematiska transformationer så att denomskrivande rektangeln av kamerans rörelser kan placeras på bilden erhållen från stitchingprocessen. På samma sätt behandlas deninformation som hämtas från sensorn i realtid med en frekvens på 60 Hz, vilket resulterar i ett snabbreagerande system. Genom att jämförax-värde och y-värde från en beräknad punkt med den omskrivande rektangeln, kan den här punkten översättas till sin motsvarande pixel ibilden. Systemet reagerar snabbt på indata och genom att visuellt jämföra den digitala positionen i bilden mot den motsvarande positionen iden riktiga världen ger systemet ett tillfredställande resultat, även om punkten kommer att ha ett par pixlars felmarginal.
7

Implementation of IIOT technology in welding robots for improving connectivity and enhancing productivity

Ravichandran, Divya, Thirunavukkarasu, Maneesh Srinivas January 2023 (has links)
In the prevailing industrial revolution, most industries are on the path towards the digitalization journey. To incorporate several digital technologies in the organization data reliability and accuracy act as key enablers. To achieve the set goals, the connectivity of the machines is considered a prominent endeavour. Such connectivity can be achieved by implementing IIOT technology, the connected IIOT architecture enables interoperability, where the computerized machine can seamlessly communicate and transfer information among them. The purpose of this study was to examine the potential impacts of integrating IIOT into the organizational framework and further explore the advantages gained in terms of productivity and maintenance. This intended study concentrated on the welding department in VCE and prioritized specific robots for the research. In addition, to improve the connectivity and visualize the data a customizable dashboard was created to facilitate real-time tracking of the robots and an alert system was developed to notify the problems in real-time. To carry out the study this research was intended to use a particular IIOT software Thingworx from the PTC community. The research was carried out with extensive interviews and personal observation on the shop floor following a qualitative analysis methodology. Through the interviews, the prioritized entities were focused and based on the end user’s requirement the selected data tags were visualized. Furthermore, the findings from the research were analyzed and discussed on how IIOT technology could potentially benefit an organization is presented. / I den rådande industriella revolutionen är de flesta industrier på väg mot digitaliseringsresan. Att införliva flera digitala teknologier i organisationen fungerar datatillförlitlighet och noggrannhet som viktiga möjliggörare. För att uppnå de uppsatta målen anses maskinernas anslutningsmöjligheter vara en framträdande strävan. Sådan anslutning kan uppnås genom att implementera IIOT-teknik, vilket möjliggör interoperabilitet, där den datoriserade maskinen sömlöst kan kommunicera och överföra information mellan dem. Syftet med denna studie var att undersöka de potentiella effekterna av att integrera IIOT i det organisatoriska ramverket och ytterligare utforska fördelarna som uppnåddes i termer av produktivitet och underhåll. Denna tilltänkta studie koncentrerade sig på svetsavdelningen i VCE och prioriterade specifika robotar för forskningen. För att förbättra anslutningen och visualisera data skapades dessutom en anpassningsbar instrumentpanel för att underlätta realtidsspårning av robotarna och ett varningssystem utvecklades för att meddela problemen i realtid. För att genomföra studien var denna forskning avsedd att använda en speciell IIOT-programvara Thingworx från PTC-gemenskapen. Forskningen genomfördes med omfattande intervjuer och observation på verkstadsgolvet enligt en kvalitativ analysmetodik. Genom intervjuerna fokuserades de prioriterade enheterna och baserat på slutanvändarens krav visualiserades de valda datataggarna. Vidare har resultaten från forskningen analyserats och diskuterats om hur IIOT-teknik potentiellt skulle kunna gynna en organisation.
8

ROBOTIC-ASSISTED BEATING HEART SURGERY

Bebek, Ozkan 25 January 2008 (has links)
No description available.
9

Medical Imaging of Magnetic Micromotors Through Scattering Tissues

Aziz, Azaam 17 March 2021 (has links)
Micro- and nanorobots (MNRs) are small autonomous devices capable of performing complex tasks and have been demonstrated for a variety of non-invasive biomedical applications, such as tissue engineering, drug delivery or assisted fertilization. However, translating such approaches to an in vivo environment is critical. Current imaging techniques do not allow localization and tracking of single or few micromotors at high spatiotemporal resolution in deep tissue. This thesis addresses some of these limitations, by exploring the use of two optical-based techniques (IR and photoacoustic imaging (PAI)) and a combination of both US and PAI. First, we employ an IR imaging setup to visualize mobile reflective micromotors under scattering phantoms and ex vivo mouse skull tissues, without using any labels. The reflective micromotor reflects more than tenfold the light intensity of a simple particle. However, the achieved penetration depth was ca. 100 μm (when using ex vivo tissues), limiting this technique to superficial biomedical applications. In this regard, PAI plays a role that combines the advantages of US such as penetration depth and real-time imaging with the molecular specificity of optics. For the first time, in this thesis, this method is evaluated for dynamic process monitoring, in particular for tracking single micromotor in real-time below ~1 cm deep phantom and ex vivo tissue. However, the precise function control of MNRs in living organisms, demand the combination of both anatomical and functional imaging methods. Therefore, in the end, we report the use of a hybrid US and PA system for the real-time tracking of magnetically driven micromotors (single and swarms) in phantoms, ex vivo, and in vivo (in mice bladder and uterus), envisioning their application for targeted drug-delivery. This achievement is of great importance and opens the possibilities to employ medical micromotors in a living organism and perform a medical task while being externally controlled and monitored.:ABSTRACT 1 1 INTRODUCTION 5 1.1 Motivation 5 1.2 Background 7 1.2.1 Microrobotics 7 1.2.2 Medical Imaging 9 1.3 Objectives and Structure of Thesis 12 2 FUNDAMENTALS 15 2.1 Optical Imaging 15 2.1.1. Reflection-based Imaging 17 2.1.2. Fluorescence-based Imaging 18 2.1.1 Light-Tissue Interaction 20 2.2 Photoacoustic Imaging 23 2.2.1 Theory 23 2.2.2 Implementation 25 2.3 Ultrasound Imaging 26 2.3.1 Theory 26 2.3.2 Implementation 28 3 MATERIALS AND METHODS 30 3.1 Fabrication of Magnetic Micropropellers 30 3.1.1 3D Laser Lithography of Polymeric Resin 30 3.1.2 Self-assembly of SiO2 Particles 31 3.1.3 Electron Beam Evaporation 32 3.1.4 Surface Functionalization 33 3.2 Fabrication of Phantom Tissue and Microfluidic Channels 34 3.2.1 Fabrication of PDMS-Glycerol Phantom 34 3.2.2 Fabrication of Agarose Phantom 35 3.2.3 Phantom based on Ex vivo Tissues (Chicken Breast and Mice Skull) 36 3.2.4 Microfluidic Channel Platform 37 3.3 Sample Characterization 38 3.3.1 Optical Microscopy 38 3.3.2 Scanning Electron Microscopy 38 3.4 Magnetic Actuation 39 3.4.1 Magnetic Force 39 3.4.2 Magnetic Torque 39 3.5 Ethic Statement for Mice Experiments 41 4 OPTICAL IMAGING OF MICROROBOTS 42 4.1 Concept of Reflective Micromotors 42 4.2 Fabrication of Reflective Micromotors 44 4.3 IR Imaging Actuation Setup 45 4.4 Actuation and Propulsion Performance below Phantom 47 4.5 Actuation and Propulsion Performance below Ex Vivo Skull Tissue 50 4.6 Actuation and Propulsion Performance in Blood 51 5 PHOTOACOUSTIC IMAGING OF MICROROBOTS 55 5.1 Absorbers for Deep Tissue Imaging 55 5.2 Absorber Micromotor Design and Fabrication 56 5.3 Photoacoustic Imaging Setup 58 5.4 Actuation Performance below Phantom Tissue 60 5.5 Actuation Performance below Ex Vivo Tissue 65 6 HYBRID ULTRASOUND AND PHOTOACOUSTIC IMAGING 67 6.1 Hybrid Ultrasound/Photoacoustic System 68 6.2 Fabrication and Characterization of Micromotors 69 6.3 Actuation and Propulsion Performance below Phantom 69 6.4 Actuation and Propulsion Performance below Ex Vivo Tissues 71 6.5 Actuation and Propulsion Performance in Mice 72 6.5.1 Swimming of Micromotors in Bladder 72 6.5.2 Actuation of Micromotors in Uterus 74 6.5.3 3D Multispectral Imaging 76 6.5.4 Towards Targeted Drug Delivery 77 7 SUMMARY AND PERSPECTIVES 80 7.1 Summary 80 7.2 Future Perspectives 83 7.2.1 Contrats Enhancing Labels 84 7.2.2 Novel Imaging Concepts 85 8 REFERENCES 88 9 APPENDIX 105 List of Figures 105 List of Tables 107 Abbreviations 108 List of Publications 109 Acknowledgements 110 Selbstständigkeitserklärung 111 Curriculum Vitae 112
10

Real-Time IR Tracking of Single Reflective Micromotors through Scattering Tissues

Aziz, Azaam, Medina-Sánchez, Mariana, Koukourakis, Nektarios, Wang, Jiawei, Kuschmierz, Robert, Radner, Hannes, Czarske, Jürgen W., Schmidt, Oliver G. 13 July 2021 (has links)
Medical micromotors have the potential to lead to a paradigm shift in future biomedicine, as they may perform active drug delivery, microsurgery, tissue engineering, or assisted fertilization in a minimally invasive manner. However, the translation to clinical treatment is challenging, as many applications of single or few micromotors require real-time tracking and control at high spatiotemporal resolution in deep tissue. Although optical techniques are a popular choice for this task, absorption and strong light scattering lead to a pronounced decrease of the signal-to-noise ratio with increasing penetration depth. Here, a highly reflective micromotor is introduced which reflects more than tenfold the light intensity of simple gold particles and can be precisely navigated by external magnetic fields. A customized optical IR imaging setup and an image correlation technique are implemented to track single micromotors in real-time and label-free underneath phantom and ex vivo mouse skull tissues. As a potential application, the micromotors speed is recorded when moving through different viscous fluids to determine the viscosity of diverse physiological fluids toward remote cardiovascular disease diagnosis. Moreover, the micromotors are loaded with a model drug to demonstrate their cargotransport capability. The proposed reflective micromotor is suitable as theranostic tool for sub-skin or organ-on-a-chip applications.

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