Adaptive bilateral extensor for image interpolation

The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file.Title from title screen of research.pdf file viewed on (February 23, 2007)Includes bibliographical references.Thesis (M.S.) University of Missouri-Columbia 2006.Dissertations, Academic -- University of Missouri--Columbia -- Computer science.A novel algorithm for image interpolation, referred to as adaptive bilateral extensor interpolation, is proposed in this thesis. It combines useful features of an extensor based algorithm, utilizing a non-linear mapping between Euclidean distances and pixel intensities for interpolation. An adaptive robust structure tensor is employed to obtain the existence and orientation of edge boundaries. In addition, an edge-preserving bilateral filter consisting of spatial and intensity components is used to preventing interpolation across edge boundaries. Results show the adaptive bilateral extensor to be qualitatively and quantitatively superior to current state-of-the-art interpolation algorithms. The adaptive bilateral extensor is particularly advantageous since it is able to super sample an image without producing aliasing or artifacts in the interpolated result. The proposed algorithm is also applied to pan-sharpen remote sensing images

A multimedia package for patient understanding and rehabilitation of non-contact anterior cruciate ligament injuries

Non-contact anterior cruciate ligament (ACL) injury is one of the most common ligament injuries in the body. Many patients’ receive graft surgery to repair the damage, but have to undertake an extensive period of rehabilitation. However, non-compliance and lack of understanding of the injury, healing process and rehabilitation means patient’s return to activities before effective structural integrity of the graft has been reached. When clinicians educate the patient, to encourage compliance with treatment and rehabilitation, the only tools that are currently widely in use are static plastic models, line diagrams and pamphlets. As modern technology grows in use in anatomical education, we have developed a unique educational and training package for patient’s to use in gaining a better understanding of their injury and treatment plan. We have combined cadaveric dissections of the knee (and captured with high resolution digital images) with reconstructed 3D modules from the Visible Human dataset, computer generated animations, and images to produce a multimedia package, which can be used to educate the patient in their knee anatomy, the injury, the healing process and their rehabilitation, and how this links into key stages of improving graft integrity. It is hoped that this will improve patient compliance with their rehabilitation programme, and better long-term prognosis in returning to normal or near-normal activities. Feedback from healthcare professionals about this package has been positive and encouraging for its long-term use

MECHANICAL METRICS OF THE PROXIMAL FEMUR ARE PRECISE AND ASSOCIATED WITH HIP MUSCLE PROPERTIES: A MAGNETIC RESONANCE BASED FINITE ELEMENT STUDY

Proximal femoral (hip) fractures are a life-threatening injury which affects 30,000 Canadians annually. Improved muscle and bone strength assessment methods may reduce fracture occurrence rates in the future. Magnetic resonance (MR) imaging has potential to assess proximal femoral bone strength in vivo through usage of finite element (FE) modeling. Though, to precisely assess bone strength, knowledge of a technique’s measurement error is needed. Hip muscle properties (e.g., lean muscle and fat area) are intrinsically linked to proximal femoral bone strength; however, it is unclear which muscles and properties are most closely associated with bone strength. This thesis is focused on MR-based FE modeling (MR-FE) of the proximal femur and surrounding muscle properties (e.g., hip abductor fat area, hip extensor muscle area). The specific objectives of this research were 1) to characterize the short-term in vivo measurement precision of MR-FE outcomes (e.g., failure load) of the proximal femur for configurations simulating fall and stance loading, and 2) explore associations between upper thigh muscle and fat properties (e.g., hip abductor fat area, knee extensor muscle area) with MR-FE failure loads of the proximal femur. In vivo precision errors (assessed via root mean square coefficient of variation, CV%RMS from repeated measures) of MR-FE outcomes ranged from 3.3-11.8% for stress and strain outcomes, and 6.0-9.5% for failure loads. Hip adductor muscle area and total muscle area correlated with failure load of the fracture-prone neck and intertrochanteric region under both fall and stance loading (correlation coefficients ranged from 0.416-0.671). This is the first study to report the in vivo short-term precision errors of MR-FE outcomes at the proximal femur. Also, this is the first study to relate upper-thigh muscle and fat properties with MR-FE derived failure loads. Results indicate that MR-FE outcomes have comparable precision to computed tomography (CT) based FE outcomes and are related to hip muscle area

Building a Bird: Musculoskeletal Modeling and Simulation of Wing-Assisted Incline Running during Avian Ontogeny

Flapping flight is the most power-demanding mode of locomotion, associated with a suite of anatomical specializations in extant adult birds. In contrast, many developing birds use their forelimbs to negotiate environments long before acquiring “flight adaptations,” recruiting their developing wings to continuously enhance leg performance and, in some cases, fly. How does anatomical development influence these locomotor behaviors? Isolating morphological contributions to wing performance is extremely challenging using purely empirical approaches. However, musculoskeletal modeling and simulation techniques can incorporate empirical data to explicitly examine the functional consequences of changing morphology by manipulating anatomical parameters individually and estimating their effects on locomotion. To assess how ontogenetic changes in anatomy affect locomotor capacity, we combined existing empirical data on muscle morphology, skeletal kinematics, and aerodynamic force production with advanced biomechanical modeling and simulation techniques to analyze the ontogeny of pectoral limb function in a precocial ground bird (Alectoris chukar). Simulations of wing-assisted incline running (WAIR) using these newly developed musculoskeletal models collectively suggest that immature birds have excess muscle capacity and are limited more by feather morphology, possibly because feathers grow more quickly and have a different style of growth than bones and muscles. These results provide critical information about the ontogeny and evolution of avian locomotion by (i) establishing how muscular and aerodynamic forces interface with the skeletal system to generate movement in morphing juvenile birds, and (ii) providing a benchmark to inform biomechanical modeling and simulation of other locomotor behaviors, both across extant species and among extinct theropod dinosaurs

Oxygen cost of dynamic or isometric exercise relative to recruited muscle mass

BACKGROUND: Oxygen cost of different muscle actions may be influenced by different recruitment and rate coding strategies. The purpose of this study was to account for these strategies by comparing the oxygen cost of dynamic and isometric muscle actions relative to the muscle mass recruited via surface electrical stimulation of the knee extensors. METHODS: Comparisons of whole body pulmonary Δ [Formula: see text] O(2 )were made in seven young healthy adults (1 female) during 3 minutes of dynamic or isometric knee extensions, both induced by surface electrical stimulation. Recruited mass was quantified in T(2 )weighted spin echo magnetic resonance images. RESULTS: The Δ [Formula: see text] O(2 )for dynamic muscle actions, 242 ± 128 ml • min(-1 )(mean ± SD) was greater (p = 0.003) than that for isometric actions, 143 ± 99 ml • min(-1). Recruited muscle mass was also greater (p = 0.004) for dynamic exercise, 0.716 ± 282 versus 0.483 ± 0.139 kg. The rate of oxygen consumption per unit of recruited muscle ([Formula: see text]) was similar in dynamic and isometric exercise (346 ± 162 versus 307 ± 198 ml • kg(-1 )• min(-1); p = 0.352), but the [Formula: see text] calculated relative to initial knee extensor torque was significantly greater during dynamic exercise 5.1 ± 1.5 versus 3.6 ± 1.6 ml • kg(-1 )• Nm(-1 )• min(-1 )(p = 0.019). CONCLUSION: These results are consistent with the view that oxygen cost of dynamic and isometric actions is determined by different circumstances of mechanical interaction between actin and myosin in the sarcomere, and that muscle recruitment has only a minor role

Muscle damage indicated by maximal voluntary contraction strength changes from immediately to 1 day after eccentric exercise of the knee extensors

The present study examined if the magnitude of changes in indirect muscle damage markers could be predicted by maximal voluntary isometric contraction (MVIC) torque changes from immediately to 1 day after eccentric exercise. Twenty-eight young men performed 100 maximal isokinetic (60°/s) eccentric contractions of the knee extensors. MVIC torque, potentiated doublet torque, voluntary activation (VA) during MVIC, shear modulus of rectus femoris (RF), vastus medialis and lateralis, and muscle soreness of these muscles were measured before, immediately after, and 1–3 days post-exercise. Based on the recovery rate of the MVIC torque from immediately to 1-day post-exercise, the participants were placed to a recovery group that showed an increase in the MVIC torque (11.3–79.9%, n = 15) or a no-recovery group that showed no recovery (−71.9 to 0%, n = 13). No significant difference in MVIC torque decrease immediately post-exercise was found between the recovery (−33 ± 12%) and no-recovery (−32 ± 9%) groups. At 1–3 days, changes in MVIC torque (−40 to −26% vs. −22 to −12%), potentiated doublet torque (−37 to −22% vs. −20 to −9%), and proximal RF shear modulus (29–34% vs. 8–15%) were greater (p \u3c 0.05) for the no-recovery than recovery group. No significant group differences were found for muscle soreness. The recovery rate of MVIC torque was correlated (p \u3c 0.05) with the change in MVIC torque from baseline to 2 (r = 0.624) or 3 days post-exercise (r = 0.526), or peak change in potentiated doublet torque at 1–3 days post-exercise from baseline (r = 0.691), but not correlated with the changes in other dependent variables. These results suggest that the recovery rate of MVIC torque predicts changes in neuromuscular function but not muscle soreness and stiffness following eccentric exercise of the knee extensors