Towards parameter-less 3D mesh segmentation

This thesis focuses on the 3D mesh segmentation process. The research demonstrated how the process can be done in a parameterless approach which allows full automation with accurate results. Applications of this research include, but not limited to, 3D search engines, 3D character animation, robotics environment recognition, and augmented reality

An ontogenetic and comparative analysis of the bony semicircular canal form.

The semicircular canals – part of the vestibular system – are housed inside the petrous temporal bone. They detect angular acceleration of the head and are vital for gaze stabilisation and locomotion. The morphology of the semicircular canals is imperative for its function, given that alterations in variables such as length, circularity, position within the head or cross-section area can alter the sensitivity and the frequencies at which they can detect these accelerations. Given this tight association between form and function, the semicircular canal form must be highly regulated, as variation may give rise to functionally deleterious geometries. The unique morphology of a species’ canals has been used extensively to infer function, particularly where agility and locomotion is concerned. This work first investigates the semicircular canal form in humans to assess whether bone-remodelling dysregulation can lead to increased variation in form. Second, the ontogeny of the semicircular canal is evaluated to assess whether ossification is the limiting factor for canal form development. Lastly, the morphology of the canals across a set of mammalian species was evaluated to assess its relationship to the size of the perilymphatic space. A dataset of CT and microCT images that includes perinatal and adult humans, mice at several developmental stages, and a wider adult mammalian group was analysed using traditional morphometrics, geometric morphometrics and cross-section shape metrics. In summary, this study shows that the overall shape and size of the human semicircular canals are established in utero and remain stable thereafter, although minute changes around the perimeter of the canals were observed, suggesting that regulation of the canal form continues until late adulthood regardless of any potential bone-remodelling dysregulation. In mice, canal form continued to develop postnatally until the point of ossification, after which the results are similar to those of the human. This suggests that ossification may be the limiting factor for mammalian canal development. Lastly, the cross-section shape of the bony canals seems to vary with the size of the perilymphatic space, and it appears that it is possible to infer the size of the perilymphatic space using the cross-section aspect ratio