The own-group bias in face recognition (OGB) is the greater facility to distinguish and recognize people from one's own group at the expense of people from other-groups. The OGB has been studied for many years, however, very little research focuses on finding a way to decrease or eliminate it, through training. Reporting five studies involving memory or matching tasks, the aim of the present thesis was to develop and to explore to what extent training can decrease or remove the OGB. French White participants, and South African White, Black and Coloured participants took part in different studies, using Black and White faces as stimuli. In each study, White participants from both countries presented the expected OGB prior to any intervention. However, the presence of the OGB in South African Black participants was detected only in one (matching task) study, instead recording a higher discrimination performance by Black participants for White faces in the other studies. As expected, South African Coloured participants did not display increased discrimination performance for any of the other stimuli groups, both being out-group stimuli. Results from the training studies revealed either (a) no effect of a distributed training in feature focus over 5 weeks; (b) an increase of the OGB after a focus on critical facial features; (c) a decrease of the OGB in a task-specific training using pictures whose quality had been manipulated, and; (d) an important implication of the presence/absence of the target in a field detection study. With some promising results, the present work contributes to our understanding of how training could be used to improve face-recognition, and especially other-group face recognition.

A configuração e o formato das estruturas craniofaciais, a oclusão dentária, a musculatura orofacial bem como a harmonia facial são determinantes para as características próprias da face humana. Instrumentos manuais como paquímetro e fitas métricas têm sido tradicionalmente utilizados para realizar as medidas antropométricas, diretamente de um sujeito em ambiente clínico. O avanço tecnológico possibilitou transformar a aquisição destas medidas analógicas em medições digitais, tornando possível aquisições rápidas, precisas e sem radiação. Tais informações podem, ainda, ser arquivadas para futuras análises e compartilhamento de informações com colegas e pacientes. A estereofotogrametria tem se destacado dentre as novas técnicas de captação de imagens tridimensionais, onde um grupo de câmeras de rápida captura fotografam a imagem do indivíduo a partir de variadas angulações. Atualmente, sistemas portáteis de estereofotogrametria vêm sendo propostos no mercado por apresentarem maior praticidade e simplicidade no manuseio. A proposta do presente estudo foi avaliar a precisão e a reprodutibilidade de um sistema de estereofotogrametria 3D portátil (Vectra H1, Canfield Scientific, Fairfield, NJ, EUA) em medições dos tecidos moles faciais de 30 participantes e de um cubo de medidas definidas, comparando tais medidas com as obtidas por um sistema de estereofotogrametria 3D fixo (Vectra M3, Canfield Scientific, Fairfield, NJ, EUA), de precisão e reprodutibilidade estabelecidas e validadas, através de análise quantitativa dos possíveis erros. Foram realizadas marcações craniométricas transitórias em tecido mole da face nos 30 participantes do estudo (n=30), sendo estes submetidos à aquisição de imagens pela técnica da estereofotogrametria, tanto pelo sistema fixo Vectra M3, quanto pelo sistema portátil Vectra H1. Trinta pontos de referência (landmarks) foram utilizados para realizar as medidas (em mm) de 34 distâncias. Quanto ao cubo, foram avaliados, no total, 20 ângulos, 20 áreas e 9 distâncias lineares. Os resultados obtidos pela metodologia estabelecida, juntamente com a correlação aos achados da literatura, permitiram concluir que o sistema portátil Vectra H1 apresentou precisão e repetibilidade comparáveis com o sistema fixo Vectra M3, evidenciando sua capacidade de capturar imagens tridimensionais de modo eficaz, o que torna viável seu uso nas mais diversas aplicações clínicas / The human face presents characteristics according to dental occlusion, facial harmony, orofacial musculature, besides the format and configuration of craniofacial structures. Traditionally, anthropometric measurements have been acquired through direct measurements of a subject inside clinical environment, using calipers and metric tapes to measure distance between arches and landmarks. Along with scientific breakthrough, the data, used to be analogic, became digital. It opened the possibility of quick, precise and radiation-free acquisitions, with its details being simultaneously archived for future analysis and being able to be easily shared with patients and colleagues. Among new facial analysis methods the stereophotogrammetry technique has emerged, where a group of cameras with fast acquisition take photographs of the subject from multiple angles. Nowadays, portable stereophotogrammetric are being proposed, as they are more practical and easy to use. The aim of this work was analyze the accuracy and reproducibility of a portable 3D stereophotogrammetric system (Vectra H1, Candield, Fairfeld, NJ, USA) in measurements of facial soft tissue of 30 participants and defined measures of a cube, comparing these measurements with those obtained by a set 3D stereophotogrammetric system (Vectra M3, Candield, Fairfeld, NJ, USA), which has it\'s accuracy and reproducibility previously validated, through quantitative analysis of possible errors. Thirty temporary landmarks were used to make the measurements (in mm) of 34 distances in 30 participants (n=30). Regarding the cube, 20 angles, 20 areas and 9 linear distances were evaluated. The obtained results by the established methodology, along with the correlation to literature findings, allowed us to conclude that the Vectra H1 portable system has shown accuracy and reproducibility as good as the Vectra M3 set system, evidencing it\'s capability to reliably capture tridimensional images, what makes practicable it\'s use in the most diverse clinical applications

A face humana apresenta características próprias de acordo com a oclusão dentária, harmonia facial, musculatura orofacial, além do formato e configuração das estruturas craniofaciais. Tradicionalmente, medidas antropométricas têm sido adquiridas através de medições diretas de um sujeito em ambiente clínico, utilizando-se de compassos e fita métrica para medir distâncias ou arcos entre pontos de referência. Com o avanço científico e tecnológico, os dados anteriormente analógicos passaram então a ser digitais. Isto abriu a possibilidade de aquisição rápida, precisa e sem radiação, com suas informações sendo simultaneamente arquivadas para análises futuras e podendo ser compartilhadas facilmente com pacientes e colegas. Dentre as novas modalidades de análise facial a técnica da estereofotogrametria tem se destacado, onde um grupo de câmeras de captura rápida fotografam o sujeito a partir de múltiplos ângulos. O objetivo desse trabalho foi analisar o perfil facial de um grupo de jovens adultos brasileiros assintomáticos para Disfunções Temporomandibulares (DTMs), com idade entre 18 e 30 anos através da técnica da estereofotogrametria, definindo características faciais comuns a este grupo, criar um banco de dados de mensurações faciais de uma parcela da população brasileira adulta jovem saudável para uso em futuros estudos complementares e testar a precisão e repetibilidade do aparelho Vectra M3®. Participaram do estudo 60 brasileiros adultos jovens sem DTM, sendo 30 homens (GH) e 30 mulheres (GM). O diagnóstico da DTM foi realizado com o Research Diagnostic Criteria For Temporomandibular Disorders (RDC/TMD). Após avaliação Odontológica inicial, foram realizadas marcações craniométricas transitórias em tecido mole e estes sujeitos foram submetidos à aquisição de imagens pela técnica da estereofotogrametria. Trinta e um pontos de referência (landmarks) foram utilizadas para realizar as medidas (em mm) de 42 distâncias. A repetibilidade do aparelho foi testada em 20% da amostra (12 sujeitos), não havendo diferença estatisticamente significante (p>0,05) em nenhuma das 42 distâncias entre a primeira e a segunda aquisição. Os resultados obtidos possibilitaram a criação de um banco de dados de mensurações faciais de uma parcela população brasileira jovem saudável. As distâncias Tr-N, N-Sn, Tr-G, Ls-Sto, Sto-Li, En[r]-En[l] e Prn-Sn não mostraram-se estatisticamente diferentes entre os grupos GH e GM, sendo que as outras 35 medidas apresentaram-se significantemente maiores no grupo GH. O aparelho de estereofotogrametria Vectra M3® mostrou alto grau de precisão e repetibilidade. / The human face presents characteristics according to dental occlusion, facial harmony, orofacial musculature, besides the format and configuration of craniofacial structures. Traditionally, anthropometric measurements have been acquired through direct measurements of a subject inside clinical environment, using calipers and metric tapes to measure distance between arches and landmarks. Along with scientific breakthrough, the data, used to be analogic, became digital. It opened the possibility of quick, precise and radiation-free acquisitions, with its details being simultaneously archived for future analysis and being able to be easily shared with patients and colleagues. Among new facial analysis methods the stereophotogrammetry technique has emerged, where a group of cameras with fast acquisition take photographs of the subject from multiple angles. The aim of this work was analyze the anthropometric profile of a group consisted of young Brazilian adults without symptoms of Temporomandibular Disorders (TMDs), aged between 18 and 30 years old, defining facial characteristics that are common to them, create a database of facial measurements for a portion of a young healthy Brazilian population to be used in future works and test the precision and repeatability of the Vectra M3® equipment. 60 young adult Brazilians without TMD participated in this study, 30 males and 30 females. The TMD diagnose was accomplished with the Research Diagnostic Criteria For Temporomandibular Disorders (RDC/TMD). After early Odontological exam, temporary craniometrical landmarks were performed in soft tissue and those subjects underwent to imaging acquisition by the stereophotogrammetry technique. 31 landmarks were used to make the measurements (in mm) of 42 distances. The equipment repeatability was tested in 20% of the sample (12 subjects), not having statistically significant difference (p>0.05) in none of the 42 distances between first and second acquisitions. The obtained results allowed the creation of a database containing facial distances of a portion of a young healthy Brazilian population. The distances Tr-N, N-Sn, Tr-G, Ls-Sto, Sto-Li, En[r]-En[l] e Prn-Sn didn\'t show statistical difference between the group GH and GM, while the other 35 distances were significantly greater in GH. The equipment Vectra M3® showed a high level of precision and repeatability.

Os sistemas de estereofotogrametria digital representam um método não radioativo, seguro, preciso e objetivo para quantificar as dimensões dos tecidos moles faciais. Novos equipamentos têm despontado como alternativa viável nas especialidades que tratam do complexo craniofacial. A estereofotogrametria se destaca pela completa ausência de radiação ionizante, alta velocidade de aquisição, grandes ângulos de visualização, navegação virtual da imagem e possibilidade de integração com outros sistemas de imagens. Quando um novo método é proposto, torna-se necessário avaliar a sua confiabilidade na obtenção de resultados. O objetivo deste estudo foi analisar a repetibilidade intraexaminador em medidas faciais lineares e angulares, em um sistema de estereofotogrametria digital utilizado para avaliação da morfologia facial. A amostra final consistiu em 30 indivíduos adultos brasileiros com idade entre 18 e 45 anos, média de 26,71± 6,53 anos. Vinte e cinco mulheres e cinco homens, saudáveis, sem histórico de traumas ou cirurgias faciais e sem anormalidades congênitas, tiveram pontos de referência marcados em suas faces por um mesmo examinador e foram fotografados em dois momentos, com intervalo de uma semana (T1 e T2), pelo sistema de estereofotogrametria digital Vectra M3® (Canfield Scientific, Fairfield, EUA). Trinta e oito pontos foram demarcados em cada captura. Identificou-se um total de 2280 pontos; 11 medidas foram feitas em cada imagem capturada e 330 medições foram realizadas. As imagens obtidas foram medidas em software próprio do sistema. A análise foi realizada a partir de um conjunto de nove medidas angulares (ângulos nasolabial, mentolabial, convexidade facial, convexidade facial total, nasal, maxilar, mandibular, nasofrontal, maxilofacial, e duas medidas lineares (altura facial média AFAM e altura facial inferior - AFAI), propostas para caracterizar a morfologia facial dos indivíduos da amostra. A repetibilidade intraexaminador na aquisição das medidas foi analisada pela Média Absoluta das diferenças (MAD), Magnitude Relativa do Erro (MRE), Erro Técnico de Medição (ETM), Coeficiente de Correlação Intraclasse (ICC) e análise de Bland-Altman. O teste t para amostras pareadas foi utilizado na identificação de erro sistemático entre T1-T2. O coeficiente de correlação de Pearson foi empregado para verificar a associação entre idade/IMC e o erro nas medições realizadas. Resultados: No cálculo do ETM e da MAD, apenas os ângulos nasolabial (2,17°) e mentolabial (2,88°) apresentaram valores maiores que 2 graus (limite clínico estabelecido para o presente estudo). Para a MRE, 9,1% das medidas foram consideradas moderadas (ângulo maxilofacial), 27,3% foram consideradas boas (ângulo nasal, ângulo maxilar, ângulo mandibular), 45,5% muito boas (ângulo nasolabial, ângulo mentolabial, ângulo nasofrontal, AFAM, AFAI) e 18,2% excelentes (ângulo da convexidade facial, ângulo da convexidade facial total.). Os ângulos nasolabial, mentolabial, convexidade facial, convexidade facial total, maxilofacial e nasofrontal apresentaram valores de ICC (R) classificados como excelentes. O ângulo nasal, e as medidas lineares de AFAI e AFAM tiveram um resultado satisfatório. Não ficou comprovada a relação entre idade/IMC e o erro encontrado entre as medições (diferença absoluta entre T1 e T2). As medidas para AFAM apresentaram um erro sistemático. As medições realizadas foram consideradas precisas dentro dos limites e referências estabelecidas para o presente estudo. Os ângulos nasolabial e mentolabial devem ser interpretados com critério pela variabilidade apresentada. O examinador apresentou boa repetibilidade nas medições realizadas. Os resultados obtidos no presente estudo acrescentam confiabilidade ao uso da estereofotogrametria digital na antropometria facial. Os parâmetros de precisão adequados a cada situação, em clínica ou em pesquisa, devem ser previamente estabelecidos. / Digital stereophotogrammetry systems represent a non-radioactive, safe, and accurate method to quantify the facial soft tissues dimensions. New equipment has emerged as viable alternative in the specialties that deal with the craniofacial complex. Stereophotogrammetry system has been highlighted by the complete absence of ionizing radiation, high-speed acquisition, large viewing angles, virtual image navigation and possibility of integration with others imaging systems. When a new method is proposed, it is necessary to assess its reliability in achieving results. The aim of this study was to analyze the intra-examiner repeatability on linear and angular facial measurements into a digital stereophotogrammetry system used to assess facial morphology. The final sample consisted of 30 Brazilian adults aged between 18 and 45 years, average of 26.71±6,53 years. Five men and twenty-five women, healthy, with no history of trauma or previous facial surgeries and without congenital abnormalities, had landmarks labeled on their faces by the same rater and were photographed in two stages (T1-T2), with an interval of one week, at stereophotogrammetry system digital Vectra M3® (Canfield Scientific, Fairfield, NJ). Thirty-eight points were labeled in each capture. 2280 points were identified; 11 distances were measured in each image, giving a total of 330 measurements. The images were measured by a dedicated software system. The analysis was performed from a set of nine angular measurements (nasolabial, mentolabial, facial convexity, full facial convexity, nasal, maxillary, mandibular, nasofrontal, maxillofacial angles, and two linear measurements (middle facial height - AFAM and lower facial height AFAI). Precision and intra-rater repeatability in the measurements acquisition were evaluated by the Mean Absolute Difference (MAD) Relative Error Magnitude (REM), Technical Error of Measurements (TEM), intra-class correlation coefficient (ICC) and Bland-Altman analysis. Test t for paired samples was used in the systematic error identification between T1-T2. The Pearson correlation coefficient was used to verify the association between age / BMI and measurement errors. Results: to the estimated TEM and MAD only nasolabial angles (2.17°), mentolabial (2.88°) had higher values than 2.0 degrees (clinical limit for this study). For MRE, 9.1% of the measures were considered moderate (maxillofacial angle), 27.3% were considered good (nasal angle, maxillary angle, mandibular angle), 45.5% very good (nasolabial angle, mentolabial angle, nasofrontal angle, AFAM, AFAI) and 18.2% excellent (facial convexity, full facial convexity.). The nasolabial, mentolabial, facial convexity, total facial convexity, maxillofacial and nasofrontal angles showed R values rated as excellent. The nasal angle, and the linear measurements of AFAI and AFAM had a satisfactory outcome. It was not proven the relation between age / body mass index and the error (absolute difference between T1 and T2). Measures to AFAM showed a systematic error. Conclusion: The measurements were considered accurate within the limits and references established for this study. The examiner showed good repeatability in identifying landmarks. The results presented on this study add reliability to the Digital stereophotogrammetry in clinical and research activities, provided there are previously established adequate precision parameters.

No description available.

No description available.

In this research we develop a Real-time face tracking system by single pan-tilt camera. The system includes face detection, deformable template tracking and motion control. We refer a method to search the facial features by using the genetic algorithm searching technique, the learning algorithm for face detector is based on AdaBoost. In the face tracking, we refer a tracking way to combine with detection and tracking. In the pan-tilt camera control part, two fuzzy logic controllers are designed to control the tracking and handling of moving face. We achieve a more robust tracking way than the single-template by renewing face-template continuously. Finally in our tests, the system can track the face of people in 30-frame per second under complex environment by using the personal computer.

Thesis (Ph.D.)--York University, 2008. Graduate Programme in Psychology. / Typescript. Includes bibliographical references (leaves 228-251). Also available on the Internet. MODE OF ACCESS via web browser by entering the following URL: http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&res_dat=xri:pqdiss&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&rft_dat=xri:pqdiss:NR39024

Thesis (M.S.)--Florida State University, 2003. / Advisor: Dr. Gordon Erlebacher, Florida State University, College of Arts and Sciences, Dept. of Computer Science. Title and description from dissertation home page (viewed Apr. 06, 2004). Includes bibliographical references.

When a witness views a crime, they are often asked to construct a facial likeness, or composite of the suspect. These composites are then used to stimulate recognition from someone who is familiar with the suspect. Facial composites are commonly used in large scale cases e. g. Jill Dando, Yorkshire Ripper, however a great deal of research has indicated that facial composites perform poorly and often do not portray an accurate likeness of the suspect. This thesis therefore examined methods of improving facial composites. In particular, it examined methods of increasing the likeness portrayed in composites, both during construction and at test. Experiments 1 to 3 examined the effectiveness of a new three-quarter-view database in PROfit. Experiment 1 examined whether the presentation of composites in a three-quarter- view composite will aid construction. Participant-witnesses were exposed to all views of a target and the results indicated that three-quarter-view composites performed as well as full-face composites but not better. Experiments 2 and 3 then examined whether the presentation of two composites (one in a full-face view and the other in a three-quarter-view) from the same participant-witness would increase performance above the level observed for a single composite. The results revealed that two views were better than one. In addition, experiment 3 examined the issue of encoding specificity and viewpoint dependency in composite construction. All participant-witnesses were exposed to either one view of a target (full-face or three-quarter) or all views and they were asked to construct both a full-face and a three-quarter- view composite. The results indicated that performance was better when all views of a face had been presented. When a target had been seen in a three-quarter-view, it was better to construct a three-quarter-view composite. However, when a target had been seen in a full-face view, performance for both full-face and three-quarter composites was poor. Experiments 4 to 8 examined whether the presentation of composites from multiple witnesses would increase performance. The results revealed that morphing composites from four different witnesses (4-Morphs) resulted in an image that performed as well as or better than the best single image. Further experimentation attempted to examine why multiple composites performed well. In particular, it was asked whether multiple composites performed well because they contained varied information or whether they performed well because they just contained more information. Multiple composites from both single and multiple witnesses using the same (PROfit) and different (PROfit, E-FIT, Sketch, EvoFIT) composite techniques were compared and the results revealed that multiple composites performed well because they contained different memorial representations. This combination of different memorial representations appeared to result in an image that was closer to the ideal, or prototypical image. Experiments 9 to 12 examined the relationship between verbal descriptions and composite quality. The results revealed that there was no clear relationship between the amount of description provided, the accuracy of the description and performance of the resulting composite. Further experimentation examined whether the presentation of a composite and a description would increase performance above the level observed for a single composite. The results revealed that the combination of a description and a composite from the same participant-witness did increase performance. This indicated that descriptions and composites might contain differing amounts and types of featural and configurational information. Both the theoretical and practical implications of these results are discussed. Experiments 1, 2 and 3 of this thesis have been submitted for publication. Ness, H., Hancock, P. J. B., Bowie, L. and Bruce, V. Are two views better than one? A study investigating recognition of full-face and three-quarter-view composites. Applied Cognitive Psychology. Experiment 4 of this thesis appears in Bruce, V., Ness, H., Hancock, P. J. B., Newman, C. and Rarity, J. (2002). Four heads are better than one: combining face composites results yields improvements in face likeness. Journal of Applied Psychology. 87 (5), 894-902. Other Publications Frowd, C. D., Carson, D., Ness, H., Richardson, J., Morrison, L., McLanaghan, S., Hancock, P. J. B. Evaluating Facial Composite Systems. Manuscript accepted for publication in Psychology, Crime and Law. Frowd, C. D., Carson, D., Ness, H., McQuiston, D., Richardson, J., Baldwin, H., Hancock, P. J. B. Contemporary Composite Techniques: The impact of a forensically relevant target delay. Manuscript accepted for publication in Legal and Criminological Psychology.