Little is known, from a clinical perspective, about the use of wrist motion during daily living activities. This work aimed to identify an informative list of physical tasks that could be measured practically in a clinical setting. <br /> Measurement methods including data gloves were investigated, but these were not used for reasons of practicality and accuracy. A commercial electrogoniometer system was chosen and used to measure wrist motion in flexion/extension and radial/ulnar deviation planes while eighteen right-handed, healthy, volunteer subjects (twelve male and six female, aged 23 to 56 years, mean 29.9 years) carried out mock-ups of the twelve everyday tasks listed in the Michigan Hand Questionnaire. <br /> The 2-plane data from each task-measurement test were displayed on an angle-angle scatter plot, overlaid with an elliptical, estimated maximum-motion envelope. <br /> The mean ranges of motion, averaged over all eighteen subjects, varied widely between tasks: 1.3° of flexion/extension (S.D. 1.49°) and 1.4° of radial/ulnar deviation (S.D. 2.10°) were seen while holding a glass of water, and corresponding values of 61.4° (S.D. 12.1°) and 24.3° (S.D. 7.79°) while buttoning a shirt. Frequency plots were also generated to show which wrist positions were most commonly used during the tasks. <br /> Qualitative and quantitative methods were used to reduce the original task list to just four tasks which represented a wide range of aspects of wrist motion, including large mean ranges of motion and mean locations that were displaced away from the neutral wrist position. <br /> These four short-listed tasks (holding a frying pan, turning a key in a lock, holding a glass of water and buttoning a shirt) could all be carried out whilst seated, with little reliance on other physiological joints and with low-cost props. <br /> The overall approach described in this thesis could be refined into a useful clinical tool, either for identifying motion impairments tracking individual patients’ progress. In particular, the use of the elliptical estimated motion envelopes gave immediate and useful context to the task data.

The purpose of this study was to characterize glenohumeral joint laxity and stiffness using instrumented arthrometry. To evaluate the validity of an instrumented measurement system we compared cutaneous and bone-pinned measures of laxity and stiffness that replicate previously reported in vivo methodology. Characterization of capsular laxity was achieved through determination of the sagittal plane translational area at increasing levels of quantified force. Finally, a method for increasing the objectivity of the standard manual laxity examination was developed for the orthopaedic clinician to quantify humeral head translation and capsular volume in vivo. We hypothesized that: 1) cutaneous measures could accurately predict bone-pinned measures, 2) capsular laxity would increase with increasing levels of applied force, and 3) manual cutaneous, manual bone-pinned, and force-displacement bone-pinned measures of translation would be equal. Thirty fresh frozen cadaveric shoulder specimens (mean age=70��14 years) were tested. The shoulders were thawed and mounted to a custom-made shoulder-testing apparatus. Displacement was measured using an electromagnetic tracking system. Sensors were secured cutaneously and with bone-pins to the scapula and humerus. Force-displacement testing was performed using a load applicator and manual displacement testing utilized the anterior/posterior drawer and inferior sulcus tests. A comparison of cutaneous and bone-pinned measures of laxity and stiffness revealed good to excellent criterion validity (r=0.68 to 0.79). Examination of displacement measures at increasing levels of force revealed increasing capsular laxity with symmetric directional compliance. No significant difference was observed between anterior and posterior translation (0.4 mm, p=.55), with significant differences between inferior and anterior (4.6 mm, p<.0001) and between inferior and posterior (5.1 mm, p<.0001). A comparison of manual cutaneous to bone-pinned manual and kinetic measures of translation revealed a significant difference between methods (p=.0024) and between directions (p<.0001) with no significant interaction (p=.0948). Estimations of the force required to achieve clinical end-point suggest that greater force is required in the anterior (173 N) direction compared to posterior (123 N) and inferior (121 N). We have developed two new methods to measure glenohumeral joint kinematics and reported new information regarding normal kinematics of the glenohumeral joint. / Graduation date: 2001

Thesis (Ph.D)--Electrical and Computer Engineering, Georgia Institute of Technology, 2008. / Committee Chair: Anderson, David; Committee Member: Gray, Alexander; Committee Member: Ma, Xiaoli; Committee Member: Mersereau , Russell; Committee Member: Wills, Donald.

Function of the shoulder complex is highly dependent on the relationship between the scapula and the humerus. Etiologies for the disruption of the glenohumeral relationship include impaired or abnormal scapular function, motion, or position. The lateral scapular slide test (LSST) has been developed as a clinical tool to assess this phenomenon, also known as scapular dyskinesis. The primary purpose of this study was to determine the validity of the LSST by comparing the clinical measurements on the skin surface to the actual anatomical distance between the scapula and the spine as seen on radiographic images. The secondary purpose of this study was to determine the intra-rater and inter-rater reliability of the LSST. Nine subjects (18 shoulders) were assessed with the clinical LSST and radiographic images in three test positions (0��, 45��, and 90�� of glenohumeral abduction). Comparison of the clinical LSST measurements with the radiographs revealed the LSST to be valid (>0.80) in only the 0�� and 45�� test positions with respective Pearson correlation values of 0.91 and 0.98. Excellent (>0.75) intra-rater ICC (2,1) reliability (0.91-0.97) was found for all three test positions. Inter-rater ICC (2,1) reliability values were excellent for the 0�� (0.87) and 45�� (0.83) test positions, and fair to good for the 90�� position (0.71). This study demonstrated that the LSST is an accurate and consistent measure of scapular movement and position for the 0�� and 45�� test positions. Clinicians should exercise caution when interpreting measurements obtained at the 90�� test position because the validity and reliability values did not reach established standards. / Graduation date: 2002

This paper presents some mathematical results concerning the measurement of motion of contours. A fundamental problem of motion measurement in general is that the velocity field is not determined uniquely from the changing intensity patterns. Recently Hildreth & Ullman have studied a solution to this problem based on an Extremum Principle [Hildreth (1983), Ullman & Hildreth (1983)]. That is, they formulate the measurement of motion as the computation of the smoothest velocity field consistent with the changing contour. We analyse this Extremum principle and prove that it is closely related to a matching scheme for motion measurement which matches points on the moving contour that have similar tangent vectors. We then derive necessary and sufficient conditions for the principle to yield the correct velocity field. These results have possible implications for the design of computer vision systems, and for the study of human vision.

No description available.

A laser-based automated mechanical mobility measurement system has been developed that can obtain a very high spatial resolution of frequency response functions (FRFs) for experimental modal analysis where one-dimensional structural motion predominates. With this system FRFs are measured and recorded in a format that is readily imported into a popular modal analysis software. A scanning laser Doppler velocimeter is coupled to a multi-channel FFf analyzer system for efficient data collection and management of spatially distributed FRFs. The objectives in designing this measurement system is to take advantage of the laser's non-contacting nature, its high spatial resolution, and its fast point-to-point movement. By using the scanning capabilities of the laser, experimental mobility FRF data can be collected in those structures that have dominant response in one direction at up to 16,000,000 positions. Moreover, the laser does not mass load the structure thus making the structure time invariant unlike "roving" accelerometers. The design and implementation of this automated mechanical mobility measurement system is presented. Instrumentation interfacing and control issues as well as software development issues are addressed in this thesis. Procedures required to implement the laser-based measurement system are presented. The performance of the laser-based system is presented along with an illustrative example of its use on a free-free rectangular plate where the vibration response is primarily in one direction. / Master of Science

[Truncated abstract] Measuring the kinematics of joints and implants following orthopaedic surgery is important since joint motion directly influences the functional outcome of the patient and the longevity of the implant. Radiostereometric Analysis (RSA) has been used to assess the motion over time of various joints and implant designs following corrective orthopaedic and joint replacement surgery for more than 20 years in more than 10,000 patients around the world. While the use of RSA reduces the risk of implanting potentially inferior prostheses on a large scale, conventional methodological procedures are based on the acquisition of static, stereographic x-ray images that are not suitable for measuring skeletal kinematics in a dynamic manner. The purpose of this thesis was to design, validate and test a novel technique for dynamically assessing the skeletal motion of human subjects using RSA and single-plane digital x-ray video fluoroscopy. The validation procedure utilised two in-vitro phantom models of human joints capable of simulating normal kinematic motion. These phantom models were supplied with realistic spatial displacement protocols derived from cadaveric specimens. The spatial positions of a series of tantalum markers that were implanted in each skeletal segment were measured using RSA. Skeletal motion was determined in x-ray fluoroscopy images by minimising the difference between the markers measured and projected in the single image plane. Accuracy was determined in terms of bias and precision by analysing the deviation between the applied displacement protocol and measured pose estimates. ... The RSA and low dose single-plane fluoroscopy technique developed, validated and tested in this thesis is capable of dynamically measuring the kinematics of any joint in the human body, following the implantation of small metallic markers in the surrounding bone during corrective orthopaedic surgery. The kinematics of joints with replacement prostheses, such as the total knee replacement (TKR), can be analysed in addition to the kinematics of joints without replacement prostheses, such as the sacroiliac joint. The technique may be used in the future on groups of human subjects enrolled in controlled trials that are designed to analyse the kinematics of the shoulder, spine, hip, knee, patella or ankle joints for the purposes of quantitatively comparing the kinematics of different prosthesis designs and various corrective orthopaedic procedures.

Thesis (MScEng)--Stellenbosch University, 2011. / ENGLISH ABSTRACT: Nystagmus is an eye movement pattern that consists of a drifting gaze component, known as the slow phase, followed by a corrective quick phase component. The presence of nystagmus or the lack thereof under certain conditions can be used for various diagnostic purposes including the diagnosis of physiological, pathological and neurological conditions. The angular velocity of the quick phase can make the detection of nystagmus a challenging task for the untrained eye, since the quick phases are usually comparable with saccadic eye motions. The goal is thus to develop a fully automated diagnostic tool that can identify the presents of nystagmus in a patient’s eye motions. In this thesis, an appropriate eye tracking method was selected from a number of eye tracking methods that are commonly implemented in the literature. A video-oculography goggle concept was chosen based on criteria such as invasiveness, sampling rate, accuracy and telemedicine capability, amongst other nystagmus related necessities. A binocular video-oculography concept was chosen that satisfied the technical requirements and provided a cost-effective design. An automated analysis algorithm was developed for automatic nystagmus identification from eye motion data. The algorithm was validated by testing the performance of the algorithm on an optokinetic nystagmus signal. It proved to provide a reliable automatic identification of nystagmus beats, even in signals that contained nystagmus as well as random motion components. A statistical analysis showed that the algorithm provided a sensitivity of 91.8% and a specificity of 96.5% for pure nystagmus signals, and a sensitivity and specificity of 87.8% and 91.1% respectively for mixed signals. / AFRIKAANSE OPSOMMING: Nystagmus is ’n oogbewegingspatroon wat bestaan uit ’n dwalende tuurkomponent, wat die stadige fase genoem word, gevolg deur ’n vinnige korrigereringsbeweging wat bekend staan as die vinnige fase. Die teenwoordigheid van nystagmus, of afwesigheid daarvan in sekere gevalle, kan gebruik word in ’n verskeidenheid diagnostiese toepassings, onder andere die diagnose van fisiologiese-, patalogiese- en neurologiese kwale. Die hoeksnelheid van die vinnige fase lei daartoe dat nystagmus dikwels moeilik is om te bespeur vir ongeöefende oë, aangesien dit vergelykbaar is met saccade bewegings. Die doel van hierdie navorsing is dus die ontwikkeling van ’n stelsel wat ’n volledige automatiese identifisering van nystagmus kan behartig. ’n Gepaste oogvolgtegniek was gekies vanuit ’n aantal verskillende oogvolgmetodes wat dikwels in die praktyk gebruik word. Die finale keuse was ’n skermbril, video-oogvolgmetode wat gekies was op grond van kriteria soos onder andere, invallendheid, meetfrekwensie, akkuraatheid en geskiktheid vir telemedisyne toepassings. Die ontwikkelde brilkonsep bied ’n koste-effektiewe oplossing, met die moontlikheid om albei oë te volg en bevredig al die bogenoemde tegniese spesifikasies. ’n Geoutomatiseerde nystagmus identifiseringsalgoritme is ontwikkel. Die algoritme se effektiwiteit is getoets op optokinetiese nystagmusseine. Betroubare resultate is vekry vanaf die algoritme, selfs in die geval van gemengde seine wat bestaan uit arbritrêre- en nystagmus komponente. Statistiese analiese het gewys dat die algoritme ’n sensitiwiteit van 91.8% en ’n spesifisiteit van 96.5% kon behaal vir seine met slegs nystagmus inhoud. Vir gemengde inhoud seine het die algoritme ’n sensitiwiteit van 87.8% en spesifisiteit van 91.1% behaal.

Thesis (MSc)--Stellenbosch University, 2015. / ENGLISH ABSTRACT: There are several ports around the world currently experiencing problems with moored vessel motions. Extreme vessel motions are mainly caused by long waves, which can become trapped inside a harbour basin. The extreme motions can cause downtime in port operations and in some instances cause mooring lines to break. Methods and procedures currently available to measure motions of moored vessels require vessel specific information as input. The implementation of these methods is seen as impractical to implement on every vessel visiting the port and require the physical measurement of some points on the vessel and/or the placement of some kind of measurement device on the vessel. A new Six Degree of Freedom (6DOF) motion measurement system for a moored vessel is presented in this document. The system analyses a video image sequence from one camera. The method estimates the 3D rigid motion for an object of known size by using a Pose from Orthography and Scaling with ITerations (POSIT) algorithm. The object for which the motion is estimated is located on the deck of the vessel and within the camera field of view. Geometric rigid body calculations allow for the calculation of camera perspective rotations and translation of an object on the vessel. Further geometric calculations allow for converting camera perspective motions to the 6DOF object motions. The primary objective of this study was to validate and verify the motions obtained from two proof-of-concept tracking systems. For evaluation purposes, the validation was done by using a small scale physical model set-up in a hydraulics laboratory and using a known method as reference. The Keoship system from the Council for Scientific and Industrial Research (CSIR) is currently one of the most accurate small scale vessel motion measurement systems and was used as reference. The first method tested was the tracking of a 2D LED rectangle mounted on the vessel. This method tracked a 2D object and was primarily used as a stepping stone to measure movement of a 3D object. The second method tracked a 3D object on the vessel. Each tracking method was tested for four different wave conditions with each condition additionally repeated twice as repeatability tests, resulting in a total of 12 tests for each tracking method. When comparing the 2D LED tracking and 3D Object tracking data to data measured with the Keoship system, results show that in general, the 3D Object tracking data compared better to the Keoship data. Tests under controlled conditions enabled a direct estimation of the absolute accuracy of the two developed methods. The verification and accuracy test results, indicated that the 2D LED tracking system should not be pursued further. The results also indicated that for prototype motions exceeding 0.6 m (i.e. storm events) the 3D Object tracking system would have an accuracy close to the maximum allowable accuracy criterion of 0.1 m. This makes the system viable at its current proof-of-concept stage for further development which would enable rapid deployment during a storm event in a prototype situation. / AFRIKAANSE OPSOMMING: Daar is verskeie hawens regoor die wêreld wat tans bewegings probleme op gemeerde skepe ervaar. Hierdie buitensporige bewegings word veroorsaak deur lang periode golwe wat binne die hawe bekkens vasgekeer word. Dit kan daartoe lei dat hawe bedrywighede tot stilstand kom en in ernstige gevalle ook veroorsaak dat meringslyne breek. Huidige metodes vir die meet van skeepsbewegings op vasgemeerde skepe, vereis skeep spesifieke inligting as inset. Die toepassing van hierdie metodes op elke skip wat die hawe besoek, word as onprakties beskou, aangesien dit die fisiese meting van sekere punte op die skip behels. In sekere gevalle is dit selfs nodig om meet toestelle op die skip te plaas. In hierdie dokument word ‘n nuwe metode aangebied om die ses grade van vryheid bewegings vir ‘n vasgemeerde skip te meet. Hierdie stelsel analiseer ‘n video beeld reeks van een kamera. Die metode bereken die 3D rigiede beweging van ‘n voorwerp, waarvan die grootte bekend is. ’n ‘Pose from Orthography and scaling with Iterations’ (POSIT) algoritme word hiervoor gebruik. Die voorwerp waarvoor beweging gemeet word is op die dek van die skip en in kamera sig. Rigiede geometriese voorwerp berekeninge word gebruik om die rotasie en translasie vanuit ‘n kamera perspektief te bereken. Verdere geometriese berekeninge maak dit moontlik om die bewegings vanuit die kamera perspektief te omskep in die ses grade van vryheid bewegings van die voorwerp. Die hoof doelwit van hierdie ondersoek was om die gemete bewegings van twee beweging stelsels te valideer en te verifieer. Die validasie en verifiëring was in ‘n hidrolise laboratorium met ‘n klein skaal model opstelling getoets. ‘n Meet metode van skeepsbeweging op klein skaal wat reeds bekend is, is gebruik as ‘n verwysingsraamwerk waarteen die metings vergelyk kan word. Die Keoship stelsel van die Wetenskaplike Nywerheids Navorsings Raad (WNNR) is tans een van die mees akkurate klein skaal skeepsbeweging meet stelsels, en was as verwysing gebruik. Die eerste bewegings metode is getoets op ‘n 2D reghoek vervaaridig uit ligstralede diodes. Hierdie metode het die 2D voorwerp gevolg en is hoofsaaklik gebruik as ‘n boublok om die beweging van ‘n 3D voorwerp te volg. Die tweede metode het die beweging van ‘n 3D voorwerp op ‘n skip gevolg. Vir elke meet metode was daar vier verskillende golf toestande. Elke golf toestand was ook ‘n verdere twee keer herhaal vir herhaalbaarheids doeleindes. Saam met die herhaalbaarheids toetse was daar in totaal, 12 toetse vir elkeen van die twee metodes gedoen. Met die Keoship metode as verwysing, bewys hierdie toetse dat die 3D metode beter resultate lewer as die 2D metode. Toetse onder beheerde toestande, het dit moontlik gemaak om die absolute akkuraatheid van albei sisteme wat ontwikkel was, te evalueer. Verifikasie en akuraatheids toetse het aangedui dat verdere ontwikkeling van die 2D metode gestuit moet word. Die resultate het ook aangedui dat die 3D metode ‘n akuraatheid baie na aan die maatstaf van 0.1 m sal hê wanneer prototipe bewegings 0.6 m oorskrei (b.v. gedurende ‘n storm). Dit sal die oplossing lewensvatbaar maak by die huidige bewys van konsep fase vir die verdere ontwikkeling wat vinnige ontplooiing gedurende ‘n storm sal moontlik maak.