Investigating Macroexpressions and Microexpressions in Computer Graphics Animated Faces

Due to varied personal, social, or even cultural situations, people sometimes conceal or mask their true emotions. These suppressed emotions can be expressed in a very subtle way by brief movements called microexpressions. We investigate human subjects’ perception of hidden emotions in virtual faces, inspired by recent psychological experiments. We created animations with virtual faces showing some facial expressions and inserted brief secondary expressions in some sequences, in order to try to convey a subtle second emotion in the character. Our evaluation methodology consists of two sets of experiments, with three different sets of questions. The first experiment verifies that the accuracy and concordance of the participant’s responses with synthetic faces matches the empirical results done with photos of real people in the paper by X.-b. Shen, Q. Wu, and X.-l. Fu, 2012, “Effects of the duration of expressions on the recognition of microexpressions,” Journal of Zhejiang University Science B, 13(3), 221–230. The second experiment verifies whether participants could perceive and identify primary and secondary emotions in virtual faces. The third experiment tries to evaluate the participant’s perception of realism, deceit, and valence of the emotions. Our results show that most of the participants recognized the foreground (macro) emotion and most of the time they perceived the presence of the second (micro) emotion in the animations, although they did not identify it correctly in some samples. This experiment exposes the benefits of conveying microexpressions in computer graphics characters, as they may visually enhance a character’s emotional depth through subliminal microexpression cues, and consequently increase the perceived social complexity and believabilit

Can gender categorization influence the perception of animated virtual humans?

Animations have become increasingly realistic with the evolution of Computer Graphics (CG). In particular, human models and behaviors were represented through animated virtual humans, sometimes with a high level of realism. In particular, gender is a characteristic that is related to human identification, so that virtual humans assigned to a specific gender have, in general, stereotyped representations through movements, clothes, hair and colors, in order to be understood by users as desired by designers. An important area of study is finding out whether participants' perceptions change depending on how a virtual human is visually presented. Findings in this area can help the industry to guide the modeling and animation of virtual humans to deliver the expected impact to the audience. In this paper, we reproduce, through CG, a perceptual study that aims to assess gender bias in relation to a simulated baby. In the original study, two groups of people watched the same video of a baby reacting to the same stimuli, but one group was told the baby was female and the other group was told the same baby was male, producing different perceptions. The results of our study with virtual babies were similar to the findings with real babies. First, it shows that people's emotional response change depending on the character gender attribute, in this case the only difference was the baby's name. Our research indicates that by just informing the name of a virtual human can be enough to create a gender perception that impact the participant emotional answer.Comment: 8 pages, 1 figure, 2 table

Hierarchical model for real time simulation of virtual human crowds

This paper describes a model for simulating crowds of humans in real time. We deal with a hierarchy composed of virtual crowds, groups, and individuals. The groups are the most complex structure that can be controlled in different degrees of autonomy. This autonomy refers to the extent to which the virtual agents are independent of user intervention and also the amount of information needed to simulate crowds. Thus, depending on the complexity of the simulation, simple behaviors can be sufficient to simulate crowds. Otherwise, more complicated behavioral rules can be necessary and, in this case, it can be included in the simulation data in order to improve the realism of the animation. We present three different ways for controlling crowd behaviors: 1) by using innate and scripted behaviors, 2) by defining behavioral rules, using events and reactions, and 3) by providing an external control to guide crowd behaviors in real time. The two main contributions of our approach are: The possibility of increasing the complexity of group/agent behaviors according to the problem to be simulated and the hierarchical structure based on groups to compose a crowd

Evaluating Perceived Trust From Procedurally Animated Gaze

Adventure role playing games (RPGs) provide players with increasingly expansive worlds, compelling storylines, and meaningful fictional character interactions. Despite the fast-growing richness of these worlds, the majority of interactions between the player and non-player characters (NPCs) still remain scripted. In this paper we propose using an NPC’s animations to reflect how they feel towards the player and as a proof of concept, investigate the potential for a straightforward gaze model to convey trust. Through two perceptual experiments, we find that viewers can distinguish between high and low trust animations, that viewers associate the gaze differences specifically with trust and not with an unrelated attitude (aggression), and that the effect can hold for different facial expressions and scene contexts, even when viewed by participants for a short (five second) clip length. With an additional experiment, we explore the extent that trust is uniquely conveyed over other attitudes associated with gaze, such as interest, unfriendliness, and admiration

Modelagem e simulação do tráfego de veículos e controle semafórico em um ambiente virtual

Simulate urban traffic realistically in a virtual environment is a complex task to implement, since many characteristics need to be developed. In this paper, we propose the use of different techniques to model and control the interaction of the elements of a simulation. In particular, we present a model physics-based for the vehicles to collisions avoid, an access control policy based on reserves and a model of synchronization of traffic signals using Petri net. The results show that the proposed model reproduces the behavior expected for the simulated contexts.Simular o trânsito de áreas urbanas de maneira realista em um ambiente virtual é uma tarefa complexa de ser implementada, pois muitas características precisam ser desenvolvidas. Neste trabalho, propomos a utilização de diversas técnicas para modelar e controlar a interação dos elementos constituintes de uma simulação. Em particular, apresentamos um modelo baseado em Física para que os veículos evitem colisões, uma política de controle de acesso a cruzamentos baseada em reservas e um modelo de sincronização de semáforos utilizando rede de Petri. Os resultados apresentados demonstram que os modelos propostos reproduzem os comportamentos esperados para os contextos simulados

Baseline data of four insecticides with different modes of action for Anastrepha fraterculus and Ceratitis capitata (Diptera: Tephritidae)

La mosca de la fruta del Mediterráneo, Ceratitis capitata (Wiedemann), y la mosca sudamericana de los frutos, Anastrepha fraterculus (Wiedemann) son plagas de gran importancia económica en Argentina y el mundo. Una de las formas de control es el uso de insecticidas en pulverizaciones totales o en cebos. El uso reiterado de un determinado producto ejerce una fuerte presión de selección, pudiendo ocasionar la aparición de resistencia. El objetivo de este trabajo fue determinar el dato de nivel básico de cuatro insecticidas con diferentes mecanismos de acción mediante bioensayos en laboratorio. Los productos utilizados fueron formulaciones comerciales de ciantraniliprol, clorpirifos, lambdacialotrina y spinosad. La concentración letal media se estimó mediante un análisis de la curva dosis-respuesta. Para ciantraniliprol y clorpirifós los machos y las hembras de ambas especies fueron igualmente susceptibles. Para lambdacialotrina se detectaron diferencias entre las dos especies; la CL50 de A. fraterculus (0,058 y 0,074 para machos y hembras respectivamente) fue menor que la de C. capitata (0,523 y 0,624 para machos y hembras respectivamente). Para spinosad, los machos de A. fraterculus fueron igualmente susceptibles que los machos y las hembras de C. capitata. Estos resultados generan valores de referencia para Argentina y evidencian la necesidad de completar este tipo de estudios con evaluaciones de poblaciones naturales sobre las cuales se ejerce control químico así como con ensayos en campo y semi-campo. Asimismo muestran la necesidad de completar este tipo de estudios con evaluaciones de los niveles de ingesta en las distintas concentraciones.The Mediterranean fruit fly, Ceratitis capitata (Wiedemann), and the South American fruit fly, Anastrepha fraterculus (Wiedemann) are pests of major economic importance in Argentina and worldwide. One way to control them is the use of insecticide in sprays or baits. The repeated use of a particular product exerts a strong selection pressure and can lead to development of resistance. The aim of this study was to determine baseline data of four insecticides with different mechanisms of action through laboratory bioassays. The products used were commercial formulations of cyantraniliprole, chlorpyrifos, lambdacyalothrin and spinosad. The mean lethal concentration was estimated by a dose-response curve analysis. Cyantraniliprole and chlorpyrifos were equally susceptible for males and females of both species. For lambdacyalothrin differences between the two species were detected; LC50 of A. fraterculus (0.058 and 0.074 for males and females respectively) was lower than that of C. capitata (0.523 and 0.624 for males and females respectively). For spinosad, A. fraterculus males were equally susceptible than males and females of C. capitata. These results generate reference values for Argentina and demonstrate the need to complete these studies with field evaluations of natural populations on which chemical control is exercised as well as with field and semi-field trials. It also shows the need to complete these studies in which the intake at different concentrations is measured.Fil: Paez Jerez, P. G.. Universidad Nacional de Tucumán. Facultad de Agronomía y Zootecnia. Cátedra. Terapéutica Vegetal; ArgentinaFil: Carrizo, B. N.. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Tucumán-Santiago del Estero. Estación Experimental Agropecuaria Famaillá; ArgentinaFil: Musse, R.. Universidad Nacional de Tucumán. Facultad de Agronomía y Zootecnia. Cátedra. Terapéutica Vegetal; ArgentinaFil: Varela, E.. Universidad Nacional de Tucumán. Facultad de Agronomía y Zootecnia. Cátedra. Terapéutica Vegetal; ArgentinaFil: Armiñana, A.. Universidad Nacional de Tucumán. Facultad de Agronomía y Zootecnia. Cátedra. Terapéutica Vegetal; ArgentinaFil: Milla, F.. Instituto Nacional de Tecnología Agropecuaria. Centro Nacional de Investigaciones Agropecuarias. Centro de Investigación de Ciencias Veterinarias y Agronómicas. Instituto de Genética; ArgentinaFil: Vera, Maria Teresa. Universidad Nacional de Tucumán. Facultad de Agronomía y Zootecnia. Cátedra. Terapéutica Vegetal; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: de la Vega, M. H.. Universidad Nacional de Tucumán. Facultad de Agronomía y Zootecnia. Cátedra. Terapéutica Vegetal; Argentin

A paradigm for controlling virtual humans in urban environment simulations

Presents a new architecture for simulating virtual humans in complex urban environments. The approach is based on the integration of six modules. Four key modules are used in order to manage environmental data, simulate human crowds, control interactions between virtual humans and objects, and generate tasks based on a rule-based behavioral model. The communication between these modules is made through a client/server system. Finally, all low-level virtual human actions are delegated to a single motion and behavioral control module. Our architecture combines various human and object simulation aspects, based on the coherent extraction and classification of information from a virtual city database. This architecture is discussed in this paper, together with a detailed case study exampl