|dc.description.abstract||Biometric authentication through face recognition has been an active area of
research for the last few decades, motivated by its application-driven demand. The popularity
of face recognition, compared to other biometric methods, is largely due to its
minimum requirement of subject co-operation, relative ease of data capture and similarity
to the natural way humans distinguish each other.
3D face recognition has recently received particular interest since three-dimensional
face scans eliminate or reduce important limitations of 2D face images, such as illumination
changes and pose variations. In fact, three-dimensional face scans are usually captured
by scanners through the use of a constant structured-light source, making them invariant
to environmental changes in illumination. Moreover, a single 3D scan also captures the
entire face structure and allows for accurate pose normalisation.
However, one of the biggest challenges that still remain in three-dimensional face
scans is the sensitivity to large local deformations due to, for example, facial expressions.
Due to the nature of the data, deformations bring about large changes in the 3D geometry
of the scan. In addition to this, 3D scans are also characterised by noise and artefacts such
as spikes and holes, which are uncommon with 2D images and requires a pre-processing
stage that is speci c to the scanner used to capture the data.
The aim of this thesis is to devise a face signature that is compact in size and
overcomes the above mentioned limitations. We investigate the use of facial regions and
landmarks towards a robust and compact face signature, and we study, implement and
validate a region-based and a landmark-based face signature. Combinations of regions and
landmarks are evaluated for their robustness to pose and expressions, while the matching
scheme is evaluated for its robustness to noise and data artefacts.||en_US