Multispace behavioral model for face-based affective social agents

This paper describes a behavioral model for affective social agents based on three independent but interacting parameter spaces: knowledge, personality, andmood. These spaces control a lower-level geometry space that provides parameters at the facial feature level. Personality and mood use findings in behavioral psychology to relate the perception of personality types and emotional states to the facial actions and expressions through two-dimensional models for personality and emotion. Knowledge encapsulates the tasks to be performed and the decision-making process using a specially designed XML-based language. While the geometry space provides an MPEG-4 compatible set of parameters for low-level control, the behavioral extensions available through the triple spaces provide flexible means of designing complicated personality types, facial expression, and dynamic interactive scenarios

Easy Generation of Facial Animation Using Motion Graphs

Facial animation is a time-consuming and cumbersome task that requires years of experience and/or a complex and expensive set-up. This becomes an issue, especially when animating the multitude of secondary characters required, e.g. in films or video-games. We address this problem with a novel technique that relies on motion graphs to represent a landmarked database. Separate graphs are created for different facial regions, allowing a reduced memory footprint compared to the original data. The common poses are identified using a Euclidean-based similarity metric and merged into the same node. This process traditionally requires a manually chosen threshold, however, we simplify it by optimizing for the desired graph compression. Motion synthesis occurs by traversing the graph using Dijkstra's algorithm, and coherent noise is introduced by swapping some path nodes with their neighbours. Expression labels, extracted from the database, provide the control mechanism for animation. We present a way of creating facial animation with reduced input that automatically controls timing and pose detail. Our technique easily fits within video-game and crowd animation contexts, allowing the characters to be more expressive with less effort. Furthermore, it provides a starting point for content creators aiming to bring more life into their characters.<br/

Enhanced facial expression using oxygenation absorption of facial skin

Facial skin appearance is affected by physical and physiological state of the skin. The facial expression especially the skin appearances are in constant mutability and dynamically changed as human behave, talk and stress. The color of skin is considered to be one of the key indicators for these symptoms. The skin color resolution is highly determined by the scattering and absorption of light within the skin layers. The concentration of chromophores in melanin and hemoglobin oxygenation in the blood plays a pivotal role. An improvement work on prior model to create a realistic textured three-dimensional (3D) facial model for animation is proposed. This thesis considers both surface and subsurface scattering capable of simulating the interaction of light with the human skin. Furthermore, six parameters are used in this research which are the amount of oxygenation, de-oxygenation, hemoglobin, melanin, oil and blend factor for different types of melanin in the skin to generate a perfect match to specific skin types. The proposed model is associated with Blend Shape Interpolation and Facial Action Coding System to create five basic facial emotional expressions namely anger, happy, neutral, sad and fear. Meanwhile, the correlation between blood oxygenation in changing facial skin color for basic natural emotional expressions are measured using the Pulse Oximetry and 3D skin analyzer. The data from different subjects with male and female under different number of partially extreme facial expressions are fed in the model for simulation. The multi-pole method for layered materials is used to calculate the spectral diffusion profiles of two-layered skin which are further utilized to simulate the subsurface scattering of light within the skin. While the subsurface scattering is further combined with the Torrance-Sparrow Bidirectional Reflectance Distribution Function (BRDF) model to simulate the interaction of light with an oily layer at the skin surface. The result is validated by an evaluation procedure for measuring the accountability of a facial model via expressions and skin color of proposed model to the real human. The facial expressions evaluation is verified by calculating Euclidean distance between the facial markers of the real human and the avatar. The second assessment validates the skin color of facial expressions for the proposed avatar via the extraction of Histogram Color Features and Color Coherence Vector of each image with the real human and the previous work. The experimental result shows around 5.12 percent improvement compared to previous work. In achieving the realistic facial expression for virtual human based on facial skin color, texture and oxygenation of hemoglobin, the result demonstrates that the proposed model is beneficial to the development of virtual reality and game environment of computer aided graphics animation systems

Expresión de emociones de alegría para personajes virtuales mediante la risa y la sonrisa

La animación facial es uno de los tópicos todavía no resueltos tanto en el campo de la interacción hombre máquina como en el de la informática gráfica. Las expresiones de alegría asociadas a risa y sonrisa son por su significado e importancia, parte fundamental de estos campos. En esta tesis se hace una aproximación a la representación de los diferentes tipos de risa en animación facial a la vez que se presenta un nuevo método capaz de reproducir todos estos tipos. El método se valida mediante la recreación de secuencias cinematográficas y mediante la utilización de bases de datos de expresiones faciales genéricas y específicas de sonrisa. Adicionalmente se crea una base de datos propia que recopila los diferentes tipos de risas clasificados y generados en este trabajo. De acuerdo a esta base de datos propia se generan las expresiones más representativas de cada una de las risas y sonrisas consideradas en el estudio.L'animació facial és un dels tòpics encara no resolts tant en el camp de la interacció home màquina com en el de la informàtica gràfica. Les expressions d'alegria associades a riure i somriure són pel seu significat i importància, part fonamental d'aquests camps. En aquesta tesi es fa una aproximació a la representació dels diferents tipus de riure en animació facial alhora que es presenta un nou mètode capaç de reproduir tots aquests tipus. El mètode es valida mitjançant la recreació de seqüències cinematogràfiques i mitjançant la utilització de bases de dades d'expressions facials genèriques i específiques de somriure. Addicionalment es crea una base de dades pròpia que recull els diferents tipus de rialles classificats i generats en aquest treball. D'acord a aquesta base de dades pròpia es generen les expressions més representatives de cadascuna de les rialles i somriures considerades en l'estudi.Nowadays, facial animation is one of the most relevant research topics still unresolved both in the field of human machine interaction and in the computer graphics. Expressions of joy associated with laughter and smiling are a key part of these fields mainly due to its meaning and importance. In this thesis an approach to the representation of different types of laughter in facial animation is done while a new method to reproduce all these types is proposed. The method is validated by recreating movie sequences and using databases of generic and specific facial smile expressions. Additionally, a proprietary database that lists the different types of classified and generated laughs in this work is created. According to this proprietary database the most representative of every smile expression considered in the study is generated