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dc.contributor.advisorFisher, Robert B.
dc.contributor.authorLukins, Timothy Campbell
dc.date.accessioned2009-06-24T11:28:29Z
dc.date.available2009-06-24T11:28:29Z
dc.date.issued2009-06-30
dc.identifier.urihttp://hdl.handle.net/1842/2830
dc.descriptionInstitute of Perception, Action and Behaviour
dc.description.abstractRecent advances in 4D data acquisition systems in the field of Computer Vision have opened up many exciting new possibilities for the interpretation of complex moving surfaces. However, a fundamental problem is that this has also led to a huge increase in the volume of data to be handled. Attempting to make sense of this wealth of information is then a core issue to be addressed if such data can be applied to more complex tasks. Similar problems have been historically encountered in the analysis of 3D static surfaces, leading to the extraction of higher-level features based on analysis of the differential geometry.en
dc.description.abstractOur central hypothesis is that there exists a compact set of similarly useful descriptors for the analysis of dynamic 4D surfaces. The primary advantages in considering localised changes are that they provide a naturally useful set of invariant characteristics. We seek a constrained set of terms - a vocabulary - for describing all types of deformation. By using this, we show how to describe what the surface is doing more effectively; and thereby enable better characterisation, and consequently more effective visualisation and comparison.en
dc.description.abstractThis thesis investigates this claim. We adopt a bottom-up approach of the problem, in which we acquire raw data from a newly constructed commercial 4D data capture system developed by our industrial partners. A crucial first step resolves the temporal non-linear registration between instances of the captured surface. We employ a combined optical/range flow to guide a conformation over a sequence. By extending the use of aligned colour information alongside the depth data we improve this estimation in the case of local surface motion ambiguities. By employing a KLT/thin-plate-spline method we also seek to preserve global deformation for regions with no estimate.en
dc.description.abstractWe then extend aspects of differential geometry theory for existing static surface analysis to the temporal domain. Our initial formulation considers the possible intrinsic transitions from the set of shapes defined by the variations in the magnitudes of the principal curvatures. This gives rise to a total of 15 basic types of deformation. The change in the combined magnitudes also gives an indication of the extent of change. We then extend this to surface characteristics associated with expanding, rotating and shearing; to derive a full set of differential features.en
dc.description.abstractOur experimental results include qualitative assessment of deformations for short episodic registered sequences of both synthetic and real data. The higher-level distinctions extracted are furthermore a useful first step for parsimonious feature extraction, which we then proceed to demonstrate can be used as a basis for further analysis. We ultimately evaluate this approach by considering shape transition features occurring within the human face, and the applicability for identification and expression analysis tasks.en
dc.contributor.sponsorEngineering and Physical Sciences Research Council (EPSRC)en
dc.format.extent31184049 bytes
dc.format.mimetypeapplication/pdf
dc.language.isoenen
dc.relation.hasversion"Colour Constrained 4D Flow”, British Machine Vision Conference (BMVC), Oxford, UK, 2005en
dc.relation.hasversion"Qualitative Characterisation of Deforming Surfaces", 3D Presentation, Visualisation and Transmission (3DPVT) conference, Chapel Hill, USA, 2006en
dc.relation.hasversion"A Mark-up Language for Describing Dynamic Surfaces”, British Machine Vision Association Symposium on 3D Video: Analysis, Display and Applications, London, UK, 2008en
dc.subjectcomputer visionen
dc.subjectsurface geometryen
dc.subjectdeformationen
dc.subjectregistrationen
dc.subjectface analysisen
dc.titleQualifying 4D Deforming Surfaces by Registered Differential Featuresen
dc.typeThesis or Dissertationen
dc.type.qualificationlevelDoctoralen
dc.type.qualificationnamePhD Doctor of Philosophyen


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