The display of space filling data is still a challenge for the community of visualization. Direct volume rendering (DVR) is one of the most important techniques developed to achieve direct perception of such volumetri...
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The display of space filling data is still a challenge for the community of visualization. Direct volume rendering (DVR) is one of the most important techniques developed to achieve direct perception of such volumetric data. It is based on semitransparent representations, where the data are accumulated in a depth-dependent order. However, it produces images that may be difficult to understand, and thus several techniques have been proposed so as to improve its effectiveness, using for instance lighting models or simpler representations (e.g., maximum intensity projection). In this article, we present three perceptual studies that examine how DVR meets its goals, in either static or dynamic context. We show that a static representation is highly ambiguous, even in simple cases, but this can be counterbalanced by use of dynamic cues (i.e., motion parallax) provided that the rendering parameters are correctly tuned. In addition, perspective projections are demonstrated to provide relevant information to disambiguate depth perception in dynamic displays.
In this paper, our aim is to determine factors that influence the perceived sex of virtual characters. In Experiment 1, four different model types were used: highly realistic male and female models, an androgynous cha...
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In this paper, our aim is to determine factors that influence the perceived sex of virtual characters. In Experiment 1, four different model types were used: highly realistic male and female models, an androgynous character, and a point light walker. Three different types of motion were applied to all models: motion captured male and female walks, and neutral synthetic walks. We found that both form and motion influence sex perception for these characters: for neutral synthetic motions, form determines perceived sex, whereas natural motion affects the perceived sex of both androgynous and realistic forms. These results indicate that the use of neutral walks is better than creating ambiguity by assigning an incongruent motion. In Experiment 2 we investigated further the influence of body shape and motion on realistic male and female models and found that adding stereotypical indicators of sex to the body shapes influenced sex perception. Also, that exaggerated female body shapes influences sex judgements more than exaggerated male shapes. These results have implications for variety and realism when simulating large crowds of virtual characters.
The proceedings contain 25 papers. The topics discussed include: hybrid image-/model-based gaze-contingent rendering;psychophysics for perception of (In)determinate art;psychophysical investigation of facial expressio...
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ISBN:
(纸本)159593670X
The proceedings contain 25 papers. The topics discussed include: hybrid image-/model-based gaze-contingent rendering;psychophysics for perception of (In)determinate art;psychophysical investigation of facial expressions using computer animated faces;a statistical approach for image difficulty estimation in X-ray screening using image measurements;redesign of classic information visualization techniques in an artistic computing perspective;simulation and optimization of display visibility;cognitive evaluation of uncertainty visualization methods for decision making;incorporating visual attention into mesh simplification techniques;action-based slant perception in real and virtual environments;redundancy reduction in 3D facial motion capture data for animation;perceptual uniformity of contrast scaling in complex images;3D facial expression analysis and deformation;and spatial properties of light fields in natural scenes.
This study was inspired by the task of revealing similarity in the development of financial indicators. We use a simplified analogy of animated scatterplots for time-dependent financial data and focus on perceptual as...
ISBN:
(纸本)9781595939814
This study was inspired by the task of revealing similarity in the development of financial indicators. We use a simplified analogy of animated scatterplots for time-dependent financial data and focus on perceptual aspects of animated data visualization. We are interested in the parameters of item coherent motion that affect detection of direction change in an item subset. The motion velocity and the angular difference in the subset motion were varied consistently. The rate of correct responses and reaction times (RTs) served as performance measures. Our results provide guidance for designing motion-based information visualization tools.
In a correctly constructed computer graphic image, usually one may still recognize the shape of the objects despite their (from a mathematical viewpoint correct) perspective distortion. Our perception accepts distorti...
ISBN:
(纸本)9781595939814
In a correctly constructed computer graphic image, usually one may still recognize the shape of the objects despite their (from a mathematical viewpoint correct) perspective distortion. Our perception accepts distortions and interprets, for example, an object as a proper circle, although it looks like a distorted ellipse. However, based on the scientific common sense, one should question the "infinity" of such perception tolerance. Where do its limits lie? Which perspective distortion would still be acceptable, before our perception "fails" to recognize an object because of its strong distortion?
The proceedings contain 29 papers. The topics discussed include: the effects of virtual reality, augmented reality and motion parallax on egocentric depth perception;HMD calibration and its effects on distance judgmen...
ISBN:
(纸本)9781595939814
The proceedings contain 29 papers. The topics discussed include: the effects of virtual reality, augmented reality and motion parallax on egocentric depth perception;HMD calibration and its effects on distance judgments;fixation-identification in dynamic scenes: comparing an automated algorithm to manual coding;perceptual evaluation of position and orientation context rules for pedestrian formations;effect of scenario on perceptual sensitivity to errors in animation;ensemble-space visualization improves perception of 3D state of molecular dynamics simulation;effects of horizontal field-of-view restriction on maneuvering performance through complex structured environments;tricking people into feeling like they are moving when they are not paying attention;joint and individual walking in an immersive collaborative virtual environment;and a full-body avatar improves egocentric distance judgments in an immersive virtual environment.
In order to analyze the emotional content of motions portrayed by different characters, we created real and virtual replicas of an actor exhibiting six basic emotions: sadness, happiness, surprise, fear, anger and dis...
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ISBN:
(纸本)9781595939814
In order to analyze the emotional content of motions portrayed by different characters, we created real and virtual replicas of an actor exhibiting six basic emotions: sadness, happiness, surprise, fear, anger and disgust. In addition to the video of the real actor, his actions were applied to five virtual body shapes: a low and high resolution virtual counterpart, a cartoon-like character, a wooden mannequin, and a zombie-like character (Figure 1). Participants were asked to rate the actions based on a list of 41 more complex emotions. We found that the perception of emotional actions is highly robust and to the most part independent of the character's body.
It has been previously proposed that understanding the mechanisms of contour perception can provide a theory for why some flow rendering methods allow for better judgments of advection pathways than others. In the pre...
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ISBN:
(纸本)9781595939814
It has been previously proposed that understanding the mechanisms of contour perception can provide a theory for why some flow rendering methods allow for better judgments of advection pathways than others. In the present paper we develop this theory through a numerical model of the primary visual cortex of the brain (Visual Area 1) where contour enhancement is understood to occur according to most neurological theories. We apply a two-stage model of contour perception to various visual representations of flow fields evaluated by Laidlaw et al [2001]. In the first stage, contour enhancement is modeled based on Li's [1998] cortical model. In the second stage, a model of contour integration is proposed designed to support the task of advection path tracing. The model yields insights into the relative strengths of different flow visualization methods for the task of visualizing advection pathways.
In this paper, we evaluate the effects of position and orientation on the plausibility of pedestrian formations. In a perceptual study we investigated how humans perceive characteristics of virtual crowds in static sc...
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ISBN:
(纸本)9781595939814
In this paper, we evaluate the effects of position and orientation on the plausibility of pedestrian formations. In a perceptual study we investigated how humans perceive characteristics of virtual crowds in static scenes reconstructed from annotated still images where the orientations and positions of the individuals have been modified. We found that by applying rules based on the contextual information of the scene, such as the type of scene being portrayed, the presence of nearby individuals and objects and the constraints of the walking areas in the scene, we improved the perceived realism of the crowd formations. Results from this study can help in the creation of virtual crowds, such as computer graphics pedestrian models or architectural scenes.
Understanding the shape of 3D objects is particularly significant in scientific visualization and CAD/CAM applications, however objective measurements of how various rendering techniques affect object perception has n...
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ISBN:
(纸本)9781595939814
Understanding the shape of 3D objects is particularly significant in scientific visualization and CAD/CAM applications, however objective measurements of how various rendering techniques affect object perception has not received enough attention. We propose a methodology which uses the Vandenberg and Kuse [1978] mental rotation paradigm as a mechanism for evaluating how well viewers are able to encode and match novel shapes presented in a computer graphics display. The established methodology and body of research on mental rotation provides a basis for its use to probe the influence of rendering on 3D shape perception. Our approach is complementary to techniques that evaluate perception of local shape properties and the adjustment of gauge figures to match local surface orientation [Koenderink et al. 1992]. We demonstrate the methodology with an experiment showing that at least in some circumstances, subjects are more accurate at shape perception with Blinn-style rendering than with Lambertian-style rendering.
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