• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 64
  • 10
  • 7
  • 7
  • 3
  • 3
  • 2
  • 2
  • 2
  • 1
  • 1
  • 1
  • Tagged with
  • 141
  • 141
  • 28
  • 26
  • 23
  • 23
  • 18
  • 17
  • 16
  • 15
  • 14
  • 14
  • 12
  • 12
  • 12
  • 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.
41

Estimation of translational motion by simplified planar compound-like eye schemes

Lin, Gwo-Long 14 December 2007 (has links)
This dissertation presents a technique for recovering translational motion parameters using two simplified planar compound-like eye schemes, namely a parallel trinocular system and a single-row Superposition-type Planar Compound-like Eye (SPCE). In the parallel trinocular scheme, a least squares estimation algorithm is developed for recovering the translational motion parameters. The proposed approach resolves the matrix singularity problem encountered when attempting to recover motion parameters using a conventional binocular scheme. To further reduce the computational complexity of the motion estimation process, a compact closed-form scheme is also proposed to estimate the translational motion parameters. The closed-form algorithm not only resolves the matrix singularity problem, but also avoids the requirement for matrix manipulation. As a result, it has a low computational complexity and is therefore an ideal solution for performing motion estimation in complex, real-world visual imaging applications following an initial image filtering process. The performance of the closed-form algorithm is evaluated by performing a series of numerical simulations in which translational displacements of various magnitudes in three-dimensional space are recovered in both noise-free and perturbed environments. In general, the results demonstrate that the translational motion parameters can be reconstructed with a high degree of accuracy provided that the motion in the depth direction is limited to small displacements only. Having developed a motion estimation scheme for a parallel trinocular system, additional charge coupled device (CCD) cameras are added in the horizontal direction to create a single-row SPCE. Translational motion models for the SPCE are then constructed by stacking the optical flow equations in the horizontal direction. The ego-translational parameters are then extracted using a simple least squares estimation algorithm. The simulation results reveal that the introduction of additional cameras to the machine vision system ensures an excellent motion estimation performance without the need for filters of any kind even when the viewing field is characterized by significant noise or the CCD deployment within the SPCE configuration has a non-uniform distribution. Overall, the parallel binocular scheme and single-row SPCE configuration presented in this dissertation demonstrate a high degree of robustness toward noise and enable the motion estimation process to be performed in a rapid and computationally efficient manner using a simple least squares approximation approach. Whilst science can not realistically hope to improve upon the visioning capabilities found in the insect world, the techniques presented in this dissertation nonetheless provide a sound foundation for the development of artificial planar-array compound-like eyes which mimic the mechanisms at work in biological compound eyes and attain an enhanced visioning performance as a result.
42

Silhouette based gait recognition [electronic resource] : research resource and limits / by Laura Helena Malavé.

Malavé, Laura Helena. January 2003 (has links)
Title from PDF of title page. / Document formatted into pages; contains 115 pages. / Thesis (M.S.C.S.)--University of South Florida, 2003. / Includes bibliographical references. / Text (Electronic thesis) in PDF format. / ABSTRACT: As is seen from the work on gait recognition, there is a de-facto consensus about the silhouette of a person being the low-level representation of choice. It has been hypothesized that the performance degradation that is observed when one compares sequences taken on different surfaces, hence against different backgrounds, or when one considers outdoor sequences is due to the low silhouette quality and its variation. If only one can get better silhouettes the perfomance of gait recognition would be high. This thesis challenges that hypothesis. In the context of the HumanID Gait Challenge problem, we constructed a set of ground truth silhouttes over one gait cycles for 71 subjects, to test recognition across two conditions, shoe and surface. Using these, we show that the performance with ground truth silhouette is as good as that obtained by those obtained by a basic background subtraction algorithm. / ABSTRACT: Therefore further research into ways to enhance silhouette extraction does not appear to be the most productive way to advance gait recognition. We also show, using the manually specified part level silhouettes, that most of the gait recognition power lies in the legs and the arms. The recognition power in various static gait recognition factors as extracted from a single view image, such as gait period, cadence, body size, height, leg size, and torso length, does not seem to be adequate. Using cummulative silhouette error images, we also suggest that gait actually changes when one changes walking surface; in particular the swing phase of the gait gets effected the most. / System requirements: World Wide Web browser and PDF reader. / Mode of access: World Wide Web.
43

Identifizierung leistungsrelevanter Parameter für die biomechanische Leistungsdiagnostik am Beispiel des Angriffsschlages im Volleyball

Kuhlmann, Claas 19 November 2010 (has links) (PDF)
Die vorliegende Arbeit beschäftigt sich mit der Analyse des Volleyballangriffsschlages von der Position vier unter Wettkampfbedingungen. Der Angriffsschlag von dieser Position ist oft die spielentscheidende Einflußgröße, da die meisten Punkte von dieser Position aus erzielt werden. Es handelt sich um einen komplexen Bewegungsablauf und es gibt eine Vielzahl an Untersuchungen, die sich mit der bewegungsanalytischen Untersuchung des Angriffsschlages befassen. Eine Herausforderung der generellen Problemstellung liegt darin, den Bewegungsablauf adäquat zu parametrisieren. Verschiedene Studien beschäftigten sich beispielsweise ausschließllich mit der Armbewegung während der Schlagphase oder mit der Beinbewegung während der Absprungphase. Die Dissertation ist darauf ausgerichtet eine breite Datenbasis für die Analyse von Volleyballangriffsschlägen zu schaffen. Der innovative Charakter der Arbeit liegt dabei in drei wesentlichen Punkten: - Definition leistungsrelevanter Parameter - Analyse von Angriffsschlägen unter Wettkampfbedingungen . große Stichprobe Insbesondere die Analyse von Angriffsschlägen während internationaler Wettkämpfe stellt dabei eine Herausforderung dar und hebt diese Arbeit von anderen Studien in der Literatur ab. Einerseits bietet dieser Ansatz die Möglichkeit "reale" Bewegungsabläufe im Spiel zu betrachten, andererseits verringert sich dadurch die Standardisierbarkeit der Umgebungsbedingungen. Die methodische Innovation liegt darin, zu untersuchen, welche Bewegungsabläufe unter echten Wettkampfbedingungen ausgeführt werden. Die wissenschaftliche Innovation liegt in der Identifikation und Definition leistungsrelevanter Parameter, die den Bewegungsablauf quantifizieren können. Damit kann ein Einblick gewonnen werden, was unter Spielbedingungen einen erfolgreichen Angriffsschlag ausmacht.
44

FPCA Based Human-like Trajectory Generating

Dai, Wei 01 January 2013 (has links)
This thesis presents a new human-like upper limb and hand motion generating method. The work is based on Functional Principal Component Analysis and Quadratic Programming. The human-like motion generating problem is formulated in a framework of minimizing the difference of the dynamic profile of the optimal trajectory and the known types of trajectory. Statistical analysis is applied to the pre-captured human motion records to work in a low dimensional space. A novel PCA FPCA hybrid motion recognition method is proposed. This method is implemented on human grasping data to demonstrate its advantage in human motion recognition. One human grasping hierarchy is also proposed during the study. The proposed method of generating human-like upper limb and hand motion explores the ability to learn the motion kernels from human demonstration. Issues in acquiring motion kernels are also discussed. The trajectory planning method applies different weight on the extracted motion kernels to approximate the kinematic constraints of the task. Multiple means of evaluation are implemented to illustrate the quality of the generated optimal human-like trajectory compared to the real human motion records.
45

Biomechanical evaluation of independent transfers and pressure relief tasks in persons with SCI: Pilot study

Cresta, Tony J 01 June 2006 (has links)
Persons with paraplegia who use a manual wheelchair for mobility are at high risk for overuse injuries in the upper extremities. Years of shoulder overuse performing transfers, wheelchair propulsion, dressing, bathing, and household chores, (activities of daily living or ADL) leads to an increased incidence of cumulative trauma to the shoulders. Few studies have addressed the stressful task of wheelchair transfers among SCI individuals. The goal of this pilot study is to develop valid and reliable measurement technologies to quantify shoulder musculoskeletal stressors during wheelchair transfers and pressure relief tasks among individuals with SCI. Using a standard wheelchair, 10 participants were asked to perform 3 typical pairs of independent transfer tasks: wheelchair to/from bed, wheelchair to/from commode, and wheelchair to/from vehicle. Also, two pressure relief tasks (P/R) were performed sitting in a wheelchair, one using the armrest and one using the wheels. By observation, the transfers in descending order from the most demanding to the least demanding were as follows: vehicle, commode, and bed. During a P/R using the wheels there is a 40% greater max shoulder force and a 47% greater mean shoulder force than when using the armrest. The max shoulder force of over 1000 N is generated at the initial push off, during a P/R using the wheels, then the force drops 45% to an average of 558 N. The max shoulder force of 722 N at the initial push off, during a P/R using the Armrest, drops 48% and then averages 378 N. During a P/R using the wheels there is a 104% greater max shoulder torque and a 17% greater mean shoulder torque than when using the armrest. As in the initial large amount of shoulder force there is also a large amount of shoulder torque that drops 77% during a P/R using the wheels. The shoulder torque decreases 62% during a P/R using the armrest. Because of the greater distance the body's Center of Mass (COM) travels during the P/R using the armrest, 24% more work is done.
46

Enhanced video coding based on video analysis and metadata information

Jeon, Hyun-Ho 20 August 2007 (has links)
Achieving high compression ratio without significant loss of quality is the main goal of the most standard video coding systems. Since consecutive frames of a general video sequence have high correlations, the temporal redundancy between frames is removed by using motion estimation and motion compensation techniques. In this thesis, we investigate the use of video content information within the video coding system and propose a new video coding approach that can save significant bit-rates of the compressed video. Main units of the proposed coding scheme include the scene analyzer and image interpolator. The scene analyzer at the encoder extracts scene-modeling parameters from input sequences. The image interpolator at the decoder reconstructs the video frames by using the transmitted modeling parameters. The scene analyzer consists of the camera motion detector and image-matching module. We propose a new camera motion detection method that directly analyzes the 2-D distribution of inter-frame motion fields. Experimental results show that the proposed method provides higher detection accuracy and faster computation time than the 1-D angle histogram-based method. A robust image-matching method that is invariant to scale changes, rotations, and illumination changes has been presented. Invariance to these changes is achieved by adopting mutual information as a measure of similarity and adaptively changing the size and orientation of the local matching windows. To reduce ambiguities of the local matching, a global matching technique has been combined with the local matching. To evaluate the performance of the proposed coding scheme, we have integrated the camera motion detector, the image-matching module, and the image interpolator with the standard MPEG-4 video codec. We compare our method with the standard MPEG-4 codec in terms of bit rates, computation time, and subjective and objective qualities.
47

Intuitive Generation of Realistic Motions for Articulated Human Characters

Min, Jianyuan 02 October 2013 (has links)
A long-standing goal in computer graphics is to create and control realistic motion for virtual human characters. Despite the progress made over the last decade, it remains challenging to design a system that allows a random user to intuitively create and control life-like human motions. This dissertation focuses on exploring theory, algorithms and applications that enable novice users to quickly and easily create and control natural-looking motions, including both full-body movement and hand articulations, for human characters. More specifically, the goals of this research are: (1) to investigate generative statistical models and physics-based dynamic models to precisely predict how humans move and (2) to demonstrate the utility of our motion models in a wide range of applications including motion analysis, synthesis, editing and acquisition. We have developed two novel generative statistical models from prerecorded motion data and show their promising applications in real time motion editing, online motion control, offline animation design, and motion data processing. In addition, we have explored how to model subtle contact phenomena for dexterous hand grasping and manipulation using physics-based dynamic models. We show for the first time how to capture physically realistic hand manipulation data from ambiguous image data obtained by video cameras.
48

Efficacy of a Multifaceted Gait Analysis Approach: Applications to Function following Limb Salvage Surgery for Bone Sarcoma

Christopher Carty Unknown Date (has links)
The purpose of this investigation was to assess the efficacy of a multifaceted gait analysis approach using a group of twenty osteosarcoma patients who underwent limb salvage surgery. Mean age at time of surgery was 16.1 years (range: 7-29), mean age at time of evaluation was 23.55 years (range: 11-43). Nine patients were treated with a Stryker Howmedica Modular Resection System (Stryker Kalamazoo, USA) and eleven patients were treated with a Stanmore custom made prosthesis (Stanmore implants worldwide Ltd, Stanmore, UK). Ten control participants with a mean age of 24.9 (range: 14-36) were recruited for the study. Ethical approval was gained through The University of Queensland Ethics Committee and The Royal Children’s Hospital and Health Service district Ethics Committee. Investigations included subjective, kinematic, kinetic, electromyographic and bioenergetic assessments. The subjective assessment incorporated results from the Musculoskeletal Tumour Society Rating Scale (MSTS) and the Toronto Extremity Salvage Score (TESS). Overall impairment was found to be 83.33% according to results of the MSTS and overall disability was found to be 86.00% according to results of the TESS. Kinematic findings showed that limb salvage participants walked with reduced velocity (p < 0.01) and increased step asymmetry (p < 0.01). Patients exhibited an increase in plantarflexion during the loading response (p < 0.001) and during terminal stance (p < 0.05), and an increase in dorsiflexion during mid-stance (p < 0.001). Knee kinematics revealed reduced extension during the loading response (p < 0.001) and increased frontal plane excursion throughout the gait cycle (p < 0.01). Patients exhibited increased lateral lean during loading response at the trunk (p < 0.05). Kinetic findings revealed a reduction in the magnitude of vertical ground reaction force during the loading response (p < 0.001) and a reduction in the magnitude of the anterior/posterior ground reaction shear force during terminal stance (p = 0.01). Furthermore, the internal ankle plantarflexor moment in terminal stance was reduced (p < 0.001), all sagittal plane knee moments were reduced (p < 0.05) and the internal hip adductor moment in terminal stance was reduced (p < 0.01). Electromyographic findings found that the limb salvage participants activated their rectus femoris for a significantly prolonged period (p < 0.5) and exhibited increased bilateral co-contraction of their rectus femoris and medial hamstring muscles (p < 0.05) compared with control participants. Bioenergetic findings revealed that the limb salvage participants exhibited an increased energetic cost (p < 0.01) and consumption rate (p < 0.01). Moderate correlations were observed between electromyographic and bioenergetic findings. Multivariate methods suggested that muscle removal, knee extension strength and knee flexion range of motion were all significant predictors of locomotor function. Length of bone resection and time from surgery were not predictive of post-operative function. The findings supported the efficacy of a multifaceted gait analysis approach for the assessment of pathological function under research conditions. The combined approach, using multiple measurements, allowed determination of functional status following musculoskeletal alteration. This enabled identification of primary and secondary compensations and allowed recommendations for improved treatment and rehabilitation.
49

Studies of hip impingement diagnosis

Yazdi Far, Mahshid January 2014 (has links)
Hip impingement is a hip associated abnormality which develops among young and middle-aged individuals. It reduces the activity of those affected and if it is not detected at early stage, it can result in osteoarthritis. In this thesis a reliable framework for studying impingement detection is developed. Current clinical methods in detecting hip impingement involve measuring three angles, first the patient’s leg being flexed until maximum angle, second patient’s leg being flexed until 90° then adducted until maximum angle, and third patient’s leg being flexed until 90° afterwards internally rotated until the maximum angle also known as FADIR (Flexion, adduction in 90° flexion and internal rotation in 90° flexion) test. This is a manual method and relies heavily on surgeons experience and even pain tolerance of the patient and the method is prone to error. The use of computational programmes are known to be more accurate and reliable as the kinematic of contact can easily be studied using the digitised bones of the hip joint assuming that the impingement is determined by bone to bone contact kinematics. Current impingement studies assume that the kinematics of hip joint can be studied by assuming the centre of rotation is fixed for hip joint. For highly conforming joints this assumption is acceptable but for cases where conformity is poor the presence of soft tissue and soft tissue loading becomes very important. The important need in orthopaedics field is to develop a model without too much simplification. In this thesis for the first time the complete computational model of hip with soft tissue has been used to detect the impingement in a specific patient. The effect of centre of rotation and soft tissue are considered on impingement detection. In this study the femur, acetabulum, cartilage and ligaments of specific patients were modelled in MIMICs (Materialise' Interactive Medical Image Control System) using both MRI and CT scan. 3D hip models with and without soft tissues of normal hip, hip with impingement and hip with impingement after reshaping were modelled. The hip models were meshed in 3-Matic. The hip models were imported to Abaqus and boundary conditions were applied. Impingement zone and impingement angle was detected in Abaqus. Different centre of rotation was applied to consider the effect of centre of rotation to detect impingement. Experimental studies were set up to validate the hip models. Mocap, Wiimote, MotionNode and goniometer were used together at the same time to measure the flexion, adduction and internal rotation in 90⁰ of flexion in twenty two healthy volunteers. Validity and reliability of all of the methods were calculated. It is the first time that reliability and validity of Wiimote and MotionNode are considered to be used in medical application. Our results show that the model with soft tissue is closer to the experimental results. It shows that the soft tissue in hip model affects hip impingement angle and hip biomechanics. This finding also shows that, if the boundary condition is closer to the real hip, then the results of computer-aided program will be more reliable.
50

Corporeidade, educação infantil e formação docente

Montano, Vera Regina Rozendo January 2007 (has links)
142f. / Submitted by Suelen Reis (suziy.ellen@gmail.com) on 2013-05-07T18:27:22Z No. of bitstreams: 1 Dissertacao_Vera Montano.pdf: 625465 bytes, checksum: 61bd8e82a27a35f7944d2e5d658cdc15 (MD5) / Approved for entry into archive by Rodrigo Meirelles(rodrigomei@ufba.br) on 2013-05-08T12:16:31Z (GMT) No. of bitstreams: 1 Dissertacao_Vera Montano.pdf: 625465 bytes, checksum: 61bd8e82a27a35f7944d2e5d658cdc15 (MD5) / Made available in DSpace on 2013-05-08T12:16:31Z (GMT). No. of bitstreams: 1 Dissertacao_Vera Montano.pdf: 625465 bytes, checksum: 61bd8e82a27a35f7944d2e5d658cdc15 (MD5) Previous issue date: 2007 / Esta Dissertação de mestrado se propõe a contribuir para a elucidação de como a qualidade da prática docente na Educação Infantil está na dependência do domínio das experiências psicocorporais por parte do educador, uma vez que é da sua responsabilidade a organização do meio pedagógico propício à aprendizagem e ao desenvolvimento da criança. Compreender, vivenciar e dominar sua corporeidade, por parte do educador contribui para a organização das estruturas psicocorporais em desenvolvimento na criança. Re-significar a vivência corporal, por parte do educador infantil, o capacita para uma prática estruturante de si mesmo e , conseqüentemente, da criança no que se refere ao desenvolvimento de suas estruturas psicocorporais. As teorias sobre a corporeidade e o psiquismo, que embasam este estudo, provêm da Psicossomática, da Psicomotricidade, da Psicomotricidade Relacional, da Bioenergética, da Ludicidade, aplicadas à Educação Infantil. Esta Dissertação propõe que na formação do educador, principalmente do educador infantil, sejam incluídas vivências que o capacitem a melhor conhecer sua corporeidade e a disponibilizá-la na relação pedagógica com as crianças, seus educandos. / Salvador

Page generated in 0.0736 seconds