Thesis (MSc)--University of Stellenbosch, 2005. / ENGLISH ABSTRACT: Sign Language is a fully-fledged natural language possessing its own syntax and grammar; a fact which implies that the problem of machine translation from a spoken source language to Sign Language is at least as difficult as machine translation between two spoken languages. Sign Language, however, is communicated in a modality fundamentally different from all spoken languages. Machine translation to Sign Language is therefore burdened not only by a mapping from one syntax and grammar to another, but also, by a non-trivial transformation from one communicational modality to another. With regards to the computer visualization of Sign Language; what is required is a three dimensional, temporally accurate, visualization of signs including both the manual and nonmanual components which can be viewed from arbitrary perspectives making accurate understanding and imitation more feasible. Moreover, given that facial expressions and movements represent a fundamental basis for the majority of non-manual signs, any system concerned with the accurate visualization of Sign Language must rely heavily on a facial animation component capable of representing a well-defined set of emotional expressions as well as a set of arbitrary facial movements. This thesis investigates the development of such a computer facial animation system. We address the problem of delivering coordinated, temporally constrained, facial animation sequences in an online environment using VRML. Furthermore, we investigate the animation, using a muscle model process, of arbitrary three-dimensional facial models consisting of multiple aligned NURBS surfaces of varying refinement. Our results showed that this approach is capable of representing and manipulating high fidelity three-dimensional facial models in such a manner that localized distortions of the models result in the recognizable and realistic display of human facial expressions and that these facial expressions can be displayed in a coordinated, synchronous manner. / AFRIKAANSE OPSOMMING: Gebaretaal is 'n volwaardige natuurlike taal wat oor sy eie sintaks en grammatika beskik. Hierdie feit impliseer dat die probleem rakende masjienvertaling vanuit 'n gesproke taal na Gebaretaal net so moeilik is as masjienvertaling tussen twee gesproke tale. Gebaretaal word egter in 'n modaliteit gekommunikeer wat in wese van alle gesproke tale verskil. Masjienvertaling in Gebaretaal word daarom nie net belas deur 'n afbeelding van een sintaks en grammatika op 'n ander nie, maar ook deur beduidende omvorming van een kommunikasiemodaliteit na 'n ander. Wat die gerekenariseerde visualisering van Gebaretaal betref, vereis dit 'n driedimensionele, tyds-akkurate visualisering van gebare, insluitend komponente wat met en sonder die gebruik van die hande uitgevoer word, en wat vanuit arbitrêre perspektiewe beskou kan word ten einde die uitvoerbaarheid van akkurate begrip en nabootsing te verhoog. Aangesien gesigsuitdrukkings en -bewegings die fundamentele grondslag van die meeste gebare wat nie met die hand gemaak word nie, verteenwoordig, moet enige stelsel wat te make het met die akkurate visualisering van Gebaretaal boonop sterk steun op 'n gesigsanimasiekomponent wat daartoe in staat is om 'n goed gedefinieerde stel emosionele uitdrukkings sowel as 'n stel arbitrre gesigbewegings voor te stel. Hierdie tesis ondersoek die ontwikkeling van so 'n gerekenariseerde gesigsanimasiestelsel. Die probleem rakende die lewering van gekordineerde, tydsbegrensde gesigsanimasiesekwensies in 'n intydse omgewing, wat gebruik maak van VRML, word aangeroer. Voorts word ondersoek ingestel na die animasie (hier word van 'n spiermodelproses gebruik gemaak) van arbitrre driedimensionele gesigsmodelle bestaande uit veelvoudige, opgestelde NURBS-oppervlakke waarvan die verfyning wissel. Die resultate toon dat hierdie benadering daartoe in staat is om hoë kwaliteit driedimensionele gesigsmodelle só voor te stel en te manipuleer dat gelokaliseerde vervormings van die modelle die herkenbare en realistiese tentoonstelling van menslike gesigsuitdrukkings tot gevolg het en dat hierdie gesigsuitdrukkings op 'n gekordineerde, sinchroniese wyse uitgebeeld kan word.

Thesis (MSc (Computer Science))--University of Stellenbosch, 2005. / Sign Languages such as South African Sign Language, are proper natural languages; they have their own vocabularies, and they make use of their own grammar rules. However, machine translation from a spoken to a signed language creates interesting challenges. These problems are caused as a result of the differences in character between spoken and signed languages. Sign Languages are classified as visual-spatial languages: a signer makes use of the space around him, and gives visual clues from body language, facial expressions and sign movements to help him communicate. It is the absence of these elements in the written form of a spoken language that causes the contextual ambiguities during machine translation. The work described in this thesis is aimed at resolving the ambiguities caused by a translation from written English to South African Sign Language. We designed and implemented a preprocessor that uses areas of linguistics such as anaphora resolution and a data structure called a scene graph to help with the spatial aspect of the translation. The preprocessor also makes use of semantic and syntactic analysis, together with the help of a semantic relational database, to find emotional context from text. This analysis is then used to suggest body language, facial expressions and sign movement attributes, helping us to address the visual aspect of the translation. The results show that the system is flexible enough to be used with different types of text, and will overall improve the quality of a machine translation from English into a Sign Language.

Thesis (MScIng)--University of Stellenbosch, 2006. / ENGLISH ABSTRACT: We designed a generic avatar animator for use in sign language related projects. The animator is capable of animating any given avatar that is compliant with the H-Anim standard for humanoid animation. The system was designed with the South African Sign Language Machine Translation (SASL-MT) project in mind, but can easily be adapted to other sign language projects due to its generic design. An avatar that is capable of accurately performing sign language gestures is a special kind of avatar and is referred to as a signing avatar. In this thesis we investigate the special characteristics of signing avatars and address the issue of finding a generic design for the animation of such an avatar. / AFRIKAANSE OPSOMMING: Ons het ’n generiese karakteranimasiestelsel ontwikkel vir gebruik in gebaretaal verwante projekte. Die animasiestelsel het die vermo¨e om enige karaktermodel wat met die H-Anim standaard versoenbaar is, te animeer. Die animasiestelsel is ontwerp met die oog op gebruik in die South African Sign Language Machine Translation (SASL-MT) projek, maar kan maklik aangepas word vir ander gebaretaalprojekte te danke aan die generiese ontwerp. ’n Karaktermodel wat in staat is om gebare akkuraat te maak is ’n spesiale tipe karaktermodel wat bekend staan as ’n gebaretaal avatar (Engels : signing avatar). In hierdie tesis ondersoek ons die spesiale eienskappe van ’n gebaretaal avatar en beskou die soektog na ’n generiese ontwerp vir die animering van so ’n karaktermodel.