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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

Construction of a Motion Capture System

Lindequist, Jonas, Lönnblom, Daniel January 2004 (has links)
<p>Motion capture is the process of capturing movements from real life into a computer. Existing motion capture systems are often very expensive and require advanced hardware that makes the process complex. This thesis will answer the following question: is it possible to create an optical motion capture system using only a single low cost Dvcamera (Digital Video Camera), that still will produce accurate motion capture data? To answer this question and construct our motion capture system we need to complete these following steps:</p><p>• Create a usable film sequence.</p><p>• Analyze the sequence.</p><p>• Create motion capture data.</p><p>• Apply the motion capture data for 3D character and analyze the outcome.</p><p>The method chosen for this thesis is constructive research. In short terms it is the study of whether we can or cannot build a new artifact. The following theoretic tools were used in the process of creating a motion capture system: Color theory, RGB, Connected component labeling, Skeletons in 3D animation, Calculating angels using trigonometry, .x files and Quaternions. We have found that an optical motion capture system is very complex and it is hard to produce as a low budget system. Our attempt did not live up to our expectations. The idea with using only one DV camera was to simplify the system since it would require no calibration or syncronisation. It would also make the system cost efficient and more available to the general public. The single camera solution unfortunatly created a number of problems in our system. Our system does however work with less complex movements. It can produce motion capture data that is accurate enough to be used in low budget games. It is also cost effective compared to other systems on the market. The system has a very easy setup and does not need any calibration in addition to the init position.</p>
2

3d Marker Tracking For Human Gait Analysis

Kucuk, Can 01 December 2005 (has links) (PDF)
This thesis focuses on 3D marker tracking for human gait analysis. In KISS Gait Analysis System at METU, a subject&#039 / s gait is recorded with 6 cameras while 13 reflective markers are attached at appropriate locations on his/her legs and feet. These images are processed to extract 2 dimensional (2D) coordinates of the markers in each camera. The 3 dimensional (3D) coordinates of the markers are obtained by processing the 2D coordinates of the markers with linearization and calibration algorithms. Then 3D trajectories of the markers are formed using the 3D coordinates of the markers. In this study, software which takes the 2D coordinates of markers in each camera and processes them to form the 3D trajectories of the markers is developed. Kalman Filter is used in formation of 3D trajectories. The results are found to be satisfactory.
3

Head Rotation Detection in Marmoset Monkeys

January 2014 (has links)
abstract: Head movement is known to have the benefit of improving the accuracy of sound localization for humans and animals. Marmoset is a small bodied New World monkey species and it has become an emerging model for studying the auditory functions. This thesis aims to detect the horizontal and vertical rotation of head movement in marmoset monkeys. Experiments were conducted in a sound-attenuated acoustic chamber. Head movement of marmoset monkey was studied under various auditory and visual stimulation conditions. With increasing complexity, these conditions are (1) idle, (2) sound-alone, (3) sound and visual signals, and (4) alert signal by opening and closing of the chamber door. All of these conditions were tested with either house light on or off. Infra-red camera with a frame rate of 90 Hz was used to capture of the head movement of monkeys. To assist the signal detection, two circular markers were attached to the top of monkey head. The data analysis used an image-based marker detection scheme. Images were processed using the Computation Vision Toolbox in Matlab. The markers and their positions were detected using blob detection techniques. Based on the frame-by-frame information of marker positions, the angular position, velocity and acceleration were extracted in horizontal and vertical planes. Adaptive Otsu Thresholding, Kalman filtering and bound setting for marker properties were used to overcome a number of challenges encountered during this analysis, such as finding image segmentation threshold, continuously tracking markers during large head movement, and false alarm detection. The results show that the blob detection method together with Kalman filtering yielded better performances than other image based techniques like optical flow and SURF features .The median of the maximal head turn in the horizontal plane was in the range of 20 to 70 degrees and the median of the maximal velocity in horizontal plane was in the range of a few hundreds of degrees per second. In comparison, the natural alert signal - door opening and closing - evoked the faster head turns than other stimulus conditions. These results suggest that behaviorally relevant stimulus such as alert signals evoke faster head-turn responses in marmoset monkeys. / Dissertation/Thesis / Masters Thesis Electrical Engineering 2014
4

Construction of a Motion Capture System

Lindequist, Jonas, Lönnblom, Daniel January 2004 (has links)
Motion capture is the process of capturing movements from real life into a computer. Existing motion capture systems are often very expensive and require advanced hardware that makes the process complex. This thesis will answer the following question: is it possible to create an optical motion capture system using only a single low cost Dvcamera (Digital Video Camera), that still will produce accurate motion capture data? To answer this question and construct our motion capture system we need to complete these following steps: • Create a usable film sequence. • Analyze the sequence. • Create motion capture data. • Apply the motion capture data for 3D character and analyze the outcome. The method chosen for this thesis is constructive research. In short terms it is the study of whether we can or cannot build a new artifact. The following theoretic tools were used in the process of creating a motion capture system: Color theory, RGB, Connected component labeling, Skeletons in 3D animation, Calculating angels using trigonometry, .x files and Quaternions. We have found that an optical motion capture system is very complex and it is hard to produce as a low budget system. Our attempt did not live up to our expectations. The idea with using only one DV camera was to simplify the system since it would require no calibration or syncronisation. It would also make the system cost efficient and more available to the general public. The single camera solution unfortunatly created a number of problems in our system. Our system does however work with less complex movements. It can produce motion capture data that is accurate enough to be used in low budget games. It is also cost effective compared to other systems on the market. The system has a very easy setup and does not need any calibration in addition to the init position.
5

An Explorative Study of Interaction with Tracked Objects in a Virtual Reality Game

Golan, Jonathan January 2019 (has links)
In recent years, Internet enabled objects (Internet of Things) and their augmentation through virtual reality has become both technically possible and increasingly advanced. This paper explores how interaction between physical IoTs and their virtual and digital twins can be advanced. Three virtual reality games focusing on three different interactions were created. One game focused on rotating, another on pushing and pulling, and a third on lifting and dropping. All games revolved around the use of real tracked cardboard boxes which were represented in the games by a virtual box in the same relative position and rotation to the player, allowing participants to manipulate the virtual boxes by manipulating the physical boxes. 14 participants were asked to play the games and were afterwards interviewed in regards to the games, their interactions with them, their enjoyability and their thoughts regarding them and the concept in general. The results were acquired from game performance, the reflections of the participants, and the subsequent analysis of recorded audio and video. The study presents the difficulties, challenges and opportunities of such a system, while also providing insight into lessons learned from the creation of the system and the games. The main contributions of the paper are the lessons learned in creating the games and experiences in addition to a few specific areas of interest for future research on the area, namely the importance of ergonomic consideration and affordance evaluation. / De senaste åren har föremål kopplade till Internet (Internet of Things eller Sakernas Internet) och deras augmentering genom virtuell verklighet både blivit möjligt och mer tekniskt avancerat. Denna rapport utforskar hur interaktioner mellan fysiska IoT föremål och deras virtuella och digitala tvillingar kan förbättras. Tre VR-spel med fokus på tre olika interaktioner utvecklades. Ett av spelen fokuserade på rotation, ett annat på rörelsen fram och tillbaka, och det tredje på rörelsen upp och ner. Alla spel involverade användandet av riktiga kartonglådor som representerades i spelet av en virtuell låda i samma position och rotation i relation till spelaren, vilket lät spelaren manipulera de virtuella lådorna genom att manipulera de fysiska lådorna. 14 deltagare ombads spela spelen och intervjuades i efterhand angående spelen, interaktionerna, underhållningsvärdet och deras tankar kring konceptet. Resultaten kom från deltagarnas prestationer i spelen, deras reflektioner och efterföljande analys av inspelad audio och video. Studien presenterar svårigheter, utmaningar och möjligheter hos det beskrivna systemet och delar med sig av insikter från skapandeprocessen av systemet och spelen. Studiens huvudsakliga bidrag är de nämnda insikterna från skapandeprocessen samt ett par specifika intresseområden för framtida forskning: vikten av hänsyn till ergonomi och utvärdering av affordans.
6

Piezoresistive Nano-Composites: Characterization and Applications

Hyatt, Thomas B. 25 June 2010 (has links) (PDF)
Innovative multifunctional materials are essential to many new sensor applications. Piezoresistive nano-composites make up a promising class of such materials that have the potential to provide a measurable response to strain over a much wider range than typical strain gages. Commercial strain gages are currently dominated by metallic sensors with a useable range of a few percent strain at most. There are, however, many applications that would benefit from a reliable wide-range sensor. These might include the study of explosive behavior, instrumentation of flexible components, motion detection for compliant mechanisms and hinges, human-technology interfaces, and a wide variety of bio-mechanical applications where structural materials may often be approximated as elastomeric. In order to quantify large strains, researchers often use optical methods which are tedious and difficult. This thesis proposes a new material and technique for quantifying large strain (up to 40%) by use of piezoresistive nano-composite strain gages. The nano-composite strain gage material is manufactured by suspending nickel nano-strands within a biocompatible silicone matrix. Study and design iteration on the strain gage material requires an improved understanding of the electrical behavior and conduction path within the material when strained. A percolation model has been suggested for numerical approximations, but has only provided marginal results for lack of data. Critical missing information in the percolation model is the nano-strand cluster size, and how that size changes in response to strain. These data are gathered using a dynamic technique in the scanning electron microscope called voltage contrast. Cluster sizes were found to vary in size by approximately 6% upon being strained to 10%. A feasibility study is also conducted on the nano-composite to show its usability as a strain gage. High Displacement Strain Gages (HDSGs) were manufactured from the nano-composite. HDSGs measured the strain of bovine ligament under prescribed loading conditions. Results demonstrate that HDSGs are an accurate means for measuring ligament strains across a broad spectrum of applied deformations.

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