Les méthodes de recalage d’images, qui ont pour but l’alignement de deux ou plusieurs images dans un même système de coordonnées, sont parmi les algorithmes les plus anciens et les plus utilisés en vision par ordinateur. Les méthodes de recalage servent à établir des correspondances entre des images (prises à des moments différents, par différents senseurs ou avec différentes perspectives), lesquelles ne sont pas évidentes pour l’œil humain. Un type particulier d’algorithme de recalage, connu comme « les méthodes de recalage déformables à l’aide de modèles graphiques » est devenu de plus en plus populaire ces dernières années, grâce à sa robustesse, sa scalabilité, son efficacité et sa simplicité théorique. La gamme des problèmes auxquels ce type d’algorithme peut être adapté est particulièrement vaste. Dans ce travail de thèse, nous proposons plusieurs extensions à la théorie de recalage déformable à l’aide de modèles graphiques, en explorant de nouvelles applications et en développant des contributions méthodologiques originales.Notre première contribution est une extension du cadre du recalage à l’aide de graphes, en abordant le problème très complexe du recalage d’une tranche avec un volume. Le recalage d’une tranche avec un volume est le recalage 2D dans un volume 3D, comme par exemple le mapping d’une tranche tomographique dans un système de coordonnées 3D d’un volume en particulier. Nos avons proposé une formulation scalable, modulaire et flexible pour accommoder des termes d'ordre élevé et de rang bas, qui peut sélectionner le plan et estimer la déformation dans le plan de manière simultanée par une seule approche d'optimisation. Le cadre proposé est instancié en différentes variantes, basés sur différentes topologies du graph, définitions de l'espace des étiquettes et constructions de l'énergie. Le potentiel de notre méthode a été démontré sur des données réelles ainsi que des données simulées dans le cadre d’une résonance magnétique d’ultrason (où le cadre d’installation et les stratégies d’optimisation ont été considérés).Les deux autres contributions inclues dans ce travail de thèse, sont liées au problème de l’intégration de l’information sémantique dans la procédure de recalage (indépendamment de la dimensionnalité des images). Actuellement, la plupart des méthodes comprennent une seule fonction métrique pour expliquer la similarité entre l’image source et l’image cible. Nous soutenons que l'intégration des informations sémantiques pour guider la procédure de recalage pourra encore améliorer la précision des résultats, en particulier en présence d'étiquettes sémantiques faisant du recalage un problème spécifique adapté à chaque domaine.Nous considérons un premier scénario en proposant un classificateur pour inférer des cartes de probabilité pour les différentes structures anatomiques dans les images d'entrée. Notre méthode vise à recaler et segmenter un ensemble d'images d'entrée simultanément, en intégrant cette information dans la formulation de l'énergie. L'idée principale est d'utiliser ces cartes estimées des étiquettes sémantiques (fournie par un classificateur arbitraire) comme un substitut pour les données non-étiquettées, et les combiner avec le recalage déformable pour améliorer l'alignement ainsi que la segmentation.Notre dernière contribution vise également à intégrer l'information sémantique pour la procédure de recalage, mais dans un scénario différent. Dans ce cas, au lieu de supposer que nous avons des classificateurs arbitraires pré-entraînés à notre disposition, nous considérons un ensemble d’annotations précis (vérité terrain) pour une variété de structures anatomiques. Nous présentons une contribution méthodologique qui vise à l'apprentissage des critères correspondants au contexte spécifique comme une agrégation des mesures de similarité standard à partir des données annotées, en utilisant une adaptation de l’algorithme « Latent Structured Support Vector Machine ». / Image registration methods, which aim at aligning two or more images into one coordinate system, are among the oldest and most widely used algorithms in computer vision. Registration methods serve to establish correspondence relationships among images (captured at different times, from different sensors or from different viewpoints) which are not obvious for the human eye. A particular type of registration algorithm, known as graph-based deformable registration methods, has become popular during the last decade given its robustness, scalability, efficiency and theoretical simplicity. The range of problems to which it can be adapted is particularly broad. In this thesis, we propose several extensions to the graph-based deformable registration theory, by exploring new application scenarios and developing novel methodological contributions.Our first contribution is an extension of the graph-based deformable registration framework, dealing with the challenging slice-to-volume registration problem. Slice-to-volume registration aims at registering a 2D image within a 3D volume, i.e. we seek a mapping function which optimally maps a tomographic slice to the 3D coordinate space of a given volume. We introduce a scalable, modular and flexible formulation accommodating low-rank and high order terms, which simultaneously selects the plane and estimates the in-plane deformation through a single shot optimization approach. The proposed framework is instantiated into different variants based on different graph topology, label space definition and energy construction. Simulated and real-data in the context of ultrasound and magnetic resonance registration (where both framework instantiations as well as different optimization strategies are considered) demonstrate the potentials of our method.The other two contributions included in this thesis are related to how semantic information can be encompassed within the registration process (independently of the dimensionality of the images). Currently, most of the methods rely on a single metric function explaining the similarity between the source and target images. We argue that incorporating semantic information to guide the registration process will further improve the accuracy of the results, particularly in the presence of semantic labels making the registration a domain specific problem.We consider a first scenario where we are given a classifier inferring probability maps for different anatomical structures in the input images. Our method seeks to simultaneously register and segment a set of input images, incorporating this information within the energy formulation. The main idea is to use these estimated maps of semantic labels (provided by an arbitrary classifier) as a surrogate for unlabeled data, and combine them with population deformable registration to improve both alignment and segmentation.Our last contribution also aims at incorporating semantic information to the registration process, but in a different scenario. In this case, instead of supposing that we have pre-trained arbitrary classifiers at our disposal, we are given a set of accurate ground truth annotations for a variety of anatomical structures. We present a methodological contribution that aims at learning context specific matching criteria as an aggregation of standard similarity measures from the aforementioned annotated data, using an adapted version of the latent structured support vector machine (LSSVM) framework.

No description available.

Point cloud registration is an extensively studied field in computer vision, featuring a variety of existing methods, all aimed at achieving the common objective of determining a transformation that aligns two point clouds. Methods like the Iterative Closet Point (ICP) and Fast Global Registration (FGR) have shown to work well for many years, but recent work has explored different learning-based approaches, showing promising results. This work compares the performance of two learning-based methods GeoTransformer and RegFormer against three baseline methods ICP point-to-point, ICP point-to-plane, and FGR. The comparison was conducted on data provided by the Swedish Defence Research Agency (FOI), where the data was captured with a photon-counting LiDAR sensor. Findings suggest that while ICP point-to-point and ICP point-to-plane exhibit solid performance, the GeoTransformer demonstrates the potential for superior outcomes. Additionally, the RegFormer and FGR perform worse than the ICP variants and the GeoTransformer.

Value-added tax (VAT) was introduced in South Africa in 1991 by the Value-Added Tax Act (89 of 1991) (the VAT Act). The South African VAT system is a destination-based, consumption-type VAT and is levied on goods or services consumed in South Africa. The definition of enterprise is an important definition in the VAT Act and it sets out the persons, activities and supplies that are to be included in the VAT base. It is compulsory for a person that conducts an enterprise in South Africa to register for VAT if the threshold set for taxable supplies is exceeded. There are interpretational problems and uncertainties in respect of the definition of “enterprise” and when an enterprise is conducted in South Africa or partly in South Africa. The purpose of this research study was to interpret the term enterprise for South African VAT purposes, to identify interpretational challenges and uncertainties and to suggest what must be addressed through guidance and interpretation by the South African Revenue Service (SARS) to provide more clarity. The research methodology followed to achieve the set objectives was normative research which is a form of legal research, specifically doctrinal. The requirements in terms of the VAT Act for levying of VAT, registration for VAT and the conducting of an enterprise in South Africa were explored and interpretational challenges and uncertainties were identified. The requirements for levying of and registration for VAT/ GST, in New Zealand, in terms of information supplied by the EU and guidance supplied in respect thereof by the OECD were analysed and discussed. The information obtained was used to establish how the interpretational problems and uncertainties that were identified are dealt with in New Zealand and in terms of the information and guidance from the EU and the OECD. The interpretational challenges and uncertainties identified include the reference in the definition of enterprise in Section 1(1) of the VAT Act to activities that must be conducted continuously or regularly in South Africa or partly in South Africa. Uncertainty as to the interpretation of the term “utilised or consumed in the Republic” also exists. Guidance in respect of these interpretational problems and uncertainties is necessary to enable suppliers and consumers to determine with certainty if a person is obliged to register for and levy VAT on supplies made in South Africa. / MCom (South African and International Tax) ,North-West University, Potchefstroom Campus, 2015

Value-added tax (VAT) was introduced in South Africa in 1991 by the Value-Added Tax Act (89 of 1991) (the VAT Act). The South African VAT system is a destination-based, consumption-type VAT and is levied on goods or services consumed in South Africa. The definition of enterprise is an important definition in the VAT Act and it sets out the persons, activities and supplies that are to be included in the VAT base. It is compulsory for a person that conducts an enterprise in South Africa to register for VAT if the threshold set for taxable supplies is exceeded. There are interpretational problems and uncertainties in respect of the definition of “enterprise” and when an enterprise is conducted in South Africa or partly in South Africa. The purpose of this research study was to interpret the term enterprise for South African VAT purposes, to identify interpretational challenges and uncertainties and to suggest what must be addressed through guidance and interpretation by the South African Revenue Service (SARS) to provide more clarity. The research methodology followed to achieve the set objectives was normative research which is a form of legal research, specifically doctrinal. The requirements in terms of the VAT Act for levying of VAT, registration for VAT and the conducting of an enterprise in South Africa were explored and interpretational challenges and uncertainties were identified. The requirements for levying of and registration for VAT/ GST, in New Zealand, in terms of information supplied by the EU and guidance supplied in respect thereof by the OECD were analysed and discussed. The information obtained was used to establish how the interpretational problems and uncertainties that were identified are dealt with in New Zealand and in terms of the information and guidance from the EU and the OECD. The interpretational challenges and uncertainties identified include the reference in the definition of enterprise in Section 1(1) of the VAT Act to activities that must be conducted continuously or regularly in South Africa or partly in South Africa. Uncertainty as to the interpretation of the term “utilised or consumed in the Republic” also exists. Guidance in respect of these interpretational problems and uncertainties is necessary to enable suppliers and consumers to determine with certainty if a person is obliged to register for and levy VAT on supplies made in South Africa. / MCom (South African and International Tax) ,North-West University, Potchefstroom Campus, 2015

Lung cancer is a disease affecting millions of people every year and poses a serious threat to global public health. Accurate lung cancer staging is crucial to choose an appropriate treatment protocol and to determine prognosis, this requires the acquisition of contrast-enhanced diagnostic CT (d-CT) that is usually followed by a PET/CT scan. Information from both d-CT and PET scan is used by the clinician in the staging process; however, these images are not intrinsically aligned because they are acquired on different days and on different scanners. Establishing anatomical correspondence, i.e., aligning the d-CT and the PET images is an inherently difficult task due to the absence of a direct relationship between the intensities of the images. The CT acquired during the PET/CT scan is used for attenuation correction (AC-CT) and is implicitly aligned with the PET image as they are acquired at the same time using a hybrid scanner. Patients are required to maintain shallow breathing for both scans. In contrast to that, the d-CT image is acquired after the injection of a contrast agent, and patients are required to maximally inhale, for better view of the lungs. Differences in the AC-CT and d-CT image volumes are thus due to differences in breathhold positions and image contrast. Nonetheless, both images are from the same modality. In this thesis, we present a new approach that aligns the d-CT with the PET image through an indirect registration process that uses the AC-CT. The deformation field obtained after the registration of the AC-CT to d-CT is used to align the PET image to the d-CT. Conventional image registration techniques deform the entire image using homogeneous regularization without taking into consideration the physical properties of the various anatomical structures. This homogeneous regularization may lead to physiologically and physically implausible deformations. To register the d-CT and AC-CT images, we developed a 3D registration framework based on a fluid transformation model including three physically motivated properties: (i) sliding motion of the lungs against the pleura; (ii) preservation of rigid structures; and (iii) preservation of topology. The sliding motion is modeled using a direction dependent regularization that decouples the tangential and the normal components of the external force term. The rigid shape of the bones is preserved using a spatially varying filter for the deformations. Finally, the topology is maintained using the concept of log-unbiased deformations. To solve the multi-modal registration problem due to the contrast injected for the d-CT, but lack thereof in the AC-CT, we use local cross correlation (LCC) as the similarity measure. To illustrate and validate the proposed registration framework, different intra-patient CT datasets are used, including the NCAT phantom, EMPIRE10 and POPI datasets. Results show that our proposed registration framework provides improved alignment and physically motivated deformations when compared to the classic elastic and fluid registration techniques. The final goal of our work was to demonstrate the clinical utility of our new approach that aligns d-CT and PET/AC-CT images for fusion. We apply our method to ten real patients. Our results show that the PET images have much improved alignment with the d-CT images using our proposed registration technique. Our method was successful in providing a good overlap of the lungs, improved alignment of the tumours and a lower target registration error for landmarks in comparison to the classic fluid registration. The main contribution of this thesis is the development of a comprehensive registration framework that integrates important physical properties into a state-of-the-art transformation model with application to lung imaging in cancer.

The advancement in ICT in recent decades has transformed every aspect of life, including medical care. The most sophisticated example of this is electronic health (e-health), which in developed counties has been a major contributor to enhancing the overall quality of healthcare services. However, e-health remains primitive in developing countries, whether they are relatively poor like Jordan or wealthy like Qatar. Barriers to successful e-health adoption in developing countries are attributable either to superimposing the technology itself while ignoring staff preparedness to integrated e-health or financial inhibitions to making such fundamental changes to healthcare delivery. Staff preparedness is related to educating or training healthcare staff, particularly nurses, who have fewer opportunities to attend training, or are sometimes ignored. Hence, the focus of this research is to evaluate the preparedness of nursing community for e-health adaption in the developing countries, taking Qatar and Jordan as case studies, in order to identify existing challenges and the key requirements to establish an educational framework that can be integrated in nursing curricula or professional development to promote e-health adaptation by nurses. This research critically reviews previous literature related to the research project, identifying the challenges to e-health preparedness, and analyses nursing and midwifery curricula from different countries with regard to e-health and ICT. The findings show that e-health modules are not generally included in any higher education nursing programme, with only a few transcripts showing basic computing or ICT modules. E-health national strategies for both Jordan and Qatar were analysed to identify whether the inclusion of professional training on e-health has been considered as part of e-heath strategy. In addition, analysis of e-health national strategies for other leading countries in the field of e-heath was conducted, finding that there is a decided gap between developed and developing countries with regard to e-health. The level of readiness in nursing was investigated and to identify the main barriers for using e-health/e-nursing in Jordan and Qatar. The results showed the top challenges facing e-health are educational-related aspects, hence a plan for promoting and providing education on the benefits and use of ehealth processes and applications is advised, with prerequisite ICT training, as the results showed that nurses lack sufficient knowledge about e-health processes and applications. The findings from earlier tasks were used to identify the requirements and then propose the framework to achieve main goal of this research in providing a roadmap. The framework was constructed in accordance to with the Technology Acceptance Model (TAM), followed by evaluation by different expert groups. All the groups voted for the suggested structure of the framework to be taken to the next phase of deployment. The final task was to evaluate the attitude of the nursing community working towards the possibility of implementing an e-learning system, which has been presented as the main platform in the proposed framework. The findings have demonstrated a very positive attitude from the nursing staff towards the idea of using e-learning. There also does not appear to be any apparent obstacles to deploying the concept of e-health as the audience in question have the necessary computer skills. In summary, this research project has contributed in presenting framework and some useful findings related to e-health in general and in Qatar and Jordan in particular. The proposed framework can be as a roadmap for future e-heath/e-nursing projects, in addition, it can be utilised with some modifications to foster similar electronic applications.

A new method of registering multiple range datasets collected in a GPS-denied, tunnel-like environment is presented. The method is designed to function with minimal user inputs and be effective over a wide range of changes in observation angle. The method is initially developed to operate on data in a general 2.5D coordinate system. Then, the general registration method is specifically tailored to a 2.5D spherical coordinate system. To apply the method, the range data is first filtered with a series of discrete Gaussian-based filters to construct a second-order Taylor series approximation to the surface about each sampled point. Finally, principal curvatures are calculated and compared across neighboring datasets to determine homologies and the best fit transfer matrix. The new method relaxes the minimum change in perspective requirement between neighboring datasets typical of other algorithms. Results from the application of the method on both synthetic and real-world data are shown. The real-world data comes from a series of high explosive tests performed in a tunnel environment. The tunnels were oriented horizontally in rock and constructed with boring equipment. The tunnel surfaces were surveyed with a Faro Focus3D terrestrial panorama scanning light detection and ranging (lidar) system both before and after a high explosive device was detonated inside the tunnel with the intent of documenting damage to the tunnel surface.

Thesis (MCur (Interdisciplinary Health Sciences. Nursing Science))--University of Stellenbosch, 2010. / ENGLISH ABSTRACT: A nurse has to develop certain concepts, attitudes, knowledge and skills in nursing. For the purpose of this study the researcher explored a private nursing school in the Southern Cape with the focus on their personal-professional developmental (PPD) programme. The researcher explored the feasibility of this programme by describing the pre-registration nurses’ perceptions on the value and contribution of the programme to their personal and professional development. In particular, the exploration addressed the nurses from a multicultural setting who found it difficult to adapt to the nursing norms, values or working culture. This was done in order to make a difference in the nature of the above-mentioned programme so that it would suit the nurses from different cultures and also set up a programme which will ensure quality nursepatient care through enhanced communication skills, empathy and critical thinking abilities. The objectives set for this study were to explore the perceptions of pre-registration nurses from a multicultural setting who were involved in this programme in order to determine whether the PPD programme contributed to their life enrichment and level of knowledge and to explore the perceptions of the professional nurses supervising the pre-registration nurses with regard to additional knowledge, skills and attitudes gained after the completion of the PPD programme. A quantitative research approach with a smaller qualitative component and a descriptive design was selected. The population for this study comprised all the pre-registration nurses of the abovementioned school (N=120) and all the professional nurses who worked closely with the preregistration nurses (N=27). A structured questionnaire and semi-structured interviews were used to collect the data. The sample of pre-registration nurses who took part included the entire population (n=120). The non-probability purposive sampling of the professional nurses who took part in this study comprised 14 participants. Reliability and validity were assured by means of a pre-test of the questionnaire and the use of experts in nursing education, research methodology and statistics. Data were collected personally by the researcher. Ethical approval was obtained from Stellenbosch University and the head of the particular private hospital. Informed written consent was obtained from the participants. It seemed that the multicultural pre-registration nurses felt the PPD programme was effective and contributed to the skills they needed to be passionate and knowledgeable nurses. On completion of the study key recommendations were made regarding the improvement of communication between pre-registration nurses and management at ward level, the implementation of a structured programme with measurable, accessible outcomes, and the provision of classes in computer literacy as well as basic research skills. / AFRIKAANSE OPSOMMING: ʼn Verpleegster moet sekere konsepte, houdings, kennis en vaardighede in die verpleegkultuur ontwikkel. Vir die doel van die studie het die navorser ’n privaat verpleegskool in die Suid-Kaap ondersoek wat hul toespits op ’n unieke persoonlike professionele ontwikkelingsprogram (PPO). Die lewensvatbaarheid van hierdie program, asook die vlak van kennis wat die voorgraadse verpleegsters bereik het en ná voltooiing van die program op pasiënte toepas, is deur die navorser ondersoek. Hierdie program het ten doel om voorgraadse verpleegsters bevoeg te verklaar t.o.v. lewensverryking betreffende kommunikasievaardighede, empatie en kritiese denke. Die doel van die studie was om die persepsies van multikulturele voorgraadse verpleegsters ten opsigte van die genoemde program vas te stel ten einde te bepaal of hierdie program wel bygedra het tot hul lewensverryking en vlak van kennis. Persepsies van professionele verpleegkundiges onder wie se toesig hierdie genoemde verpleegsters werksaam was, is ondersoek om vas te stel of voorgraadse verpleegsters addisionele kennis, vaardighede, empatie en kritiese denke met behulp van die program bekom het. ’n Kwantitatiewe studie met ʼn kleiner kwalitatiewe komponent en ʼn beskrywende ontwerp is gekies. Die populasie het bestaan uit al die voorgraadse verpleegsters van die genoemde skool (N=120) en al die professionele verpleegkundiges wat betrokke is by bogenoemde verpleegsters (N=27). ’n Gestruktureerde vraelys en semi-gestruktureerde onderhoude is gebruik om data in te samel. Die totale populasie verpleegsters is ingesluit in die studie (n=120). ’n Nie-waarskynlikheids- doelgerigte steekproef van professionele verpleegkundiges wat deelgeneem het was 14. Geldigheid en betroubaarheid is verseker deur die uitvoer van ʼn vooraf toetsing van die vraelys, asook deur kenners in verpleegonderrig, navorsingsmetodologie en statistiek te konsulteer. Data is persoonlik deur die navorser ingesamel. Etiese goedkeuring is van die Universiteit Stellenbosch en die hoof van die spesifieke privaat hospitaal verkry. Geskrewe ingeligte toestemming is van al die deelnemers verkry. Dit wil voorkom asof die voorgraadse verpleegsters in die multikulturele werksomgewing van mening was dat die PPO-program effektief bygedra het tot hul passie vir verpleging en hulle verryk het met kennis. Ná afloop van die studie is die hoof-aanbevelings gedoen ten opsigte van verbeterde kommunikasievaardighede tussen voorgraadse verpleegsters en bestuur op grondvlak, die instelling van ’n gestruktureerde program met meetbare, bereikbare uitkomste, asook die aanbieding van rekenaarklasse en basiese navorsingsklasse.

Modèle 3D d'objet, séquences vidéos monoscopiques, estimation de la pose 3D, recalage 3D/2D, texture, flot optique, translation et rotation de grande amplitude, occultation, appariement par bloc, interpolation temporelle, modélisation ondulatoire, critère de visibilité, analyse de déformations faciales, description MPEG-4 du visage, prototype déformable, bouche, yeux, B-splines, classification floue non supervisée, méthode du simplexe, synthèse de déformations faciales..