A selective rendering algorithm based on memory schemas

Summarization: In order to economize on rendering computation, selective rendering guides high level of detail to specific regions of a synthetic scene and lower quality to the remaining scene, without compromising the level of information transmitted. Scene regions that have been rendered in low and high quality can be combined to form one complete scene. We propose a novel selective rendering approach which is task and gaze-independent, simulating cognitive creation of spatial hypotheses. Scene objects are rendered in varying quality (polygon count) according to how they are associated with the context (schema) of the scene.Παρουσιάστηκε στο: SIGGRAP

Selective rendering based on perceptual importance of scene regions

Summarization: Computer graphics algorithms have for long dealt with simulation of physics: simulation of the geometry of a real-world space, simulation of the light propagation in a real environment and simulation of motor actions with appropriate tracking. Perception principles have subsequently been incorporated into rendering algorithms in order to save rendering computation and produce photo realistic images from a human rather than a machine point of view. Spatial memory tasks are often incorporated in benchmarking processes when assessing fidelity of a VE simulation, since spatial awareness is crucial for human performance efficiency of any task that entails awareness of space. This paper is exploring the exploitation of visual perception principles towards efficient selective rendering techniques. In order to economize on rendering computation, selective rendering guides a high level of detail to appropriate regions of a synthetic scene. Such decisions are based on predictive attention modeling, gaze or even cognitive information. Experimental studies presented will show that it is possible to produce scenes from a human rather than a physics point of view.Παρουσιάστηκε στο: IEEE International Conference on Systems, Man and Cybernetic

Assessing functional realism

This research presents an innovative method for assessing ‘functional realism’ of interactive Virtual Environments (VEs) in which the same information is transmitted in real and synthetic scenes. The basic premise is that an individual’s prior experience will influence how one perceives, comprehends and remembers information in a scene. 120 participants across two conditions of varying rendering quality of a space including varied ratios of objects’ association to the scene context, are being exposed to the VE and complete an object-based memory recognition task. The results of this study could have significant implications while identifying areas of an interactive computer graphics scene that require varying quality of rendering

Human-centered fidelity metrics for virtual environment simulations

Summarization: It is increasingly important to provide fidelity mecrics for rendered images and interactive virtual environments (VEs) targeting transfer of training in real-world task situations. Computational metrics which aim to predict the degree of fidelity of a rendered image can be based on psychophysical observations. For interactive simulations, psychophysical investigations can be carried out into the degree of similarity between the original and a synthetic simulation. Psychophysics comprises a collection of methods used to conduct non-invasive experiments on humans, the purpose of which is to study mappings between events in an environment and levels of sensory responses to those events. This tutorial will present the techniques and principles towards conducting psychophysical studies, for assessing image quality as well as fidelity of a VE simulation and how results from such studies contribute to VE system design as well as to computational image quality metrics. Methods based on experiments for measuring the perceptual equivalence between a real scene and a computer simulation of the same scene will be reported. These methods are presented through the study of human vision and include using photorealistic computer graphics to depict complex environments and works of art. In addition, physical and psychophysical fidelity issues in the assessment of virtual environments will be emphasised. Specifications for correct matching between the psychophysical characteristics of the displays and the human users’ sensory and motor systems will he discussed as well as some examples of the consequences when systems fail to be physically well matched to their users. Complete experimental cycles will be described from the initial idea and design, to pilot study, experimental redesign, data collection, analysis and post-experiment lessons learned. Examples will include research on spatial orientation in Virtual Reality, assessing fidelity of flight simulators, fidelity of simulation of humans and clothing and measuring perceptual sensitivity to latency. This tutorial requires no fundamental prerequisites. It would help if the attendee had some knowledge of experimental design, and of some personal experience of computer graphics and simulation systems. However, the course will be self-contained.Παρουσιάστηκε στο: IEEE Conference on Virtual Realit

Memory for objects in virtual environments

Summarization: Schema theory proposes that memory for objects in scenes depends on the degree to which the objects appear to belong to a particular scene (consistent objects) or not (inconsistent objects). However, the degree to which an object will be consistent with a scene is likely to depend on whether the perception of the scene is itself consistent with our previous experience. Thus, for example, if a familiar scene is presented in an unfamiliar manner, the effect of object consistency on memory is likely to change. We wished to see whether this kind of effect can be used to investigate the degree to which a virtual environment (VE) is perceived as “normal”, i.e. consistent with our usual experience of similar environments, or “abnormal”, i.e. markedly different from our previous experience. Two initial studies measured the effect of rendering quality on memory for consistent and inconsistent objects in conditions of varying quality of radiosity (Experiment 1) and polygon count (Experiment 2). Participants interacted with the scenes wearing VGA resolution, head-tracked HMDs. They were then tested for memory for inconsistent and consistent objects. There was little effect of rendering quality except in one condition in which individual objects were hard to recognize. Experiment 3 therefore used a more extreme set of rendering types: wireframe with added color, and full radiosity. The proportion of inconsistent/consistent objects was varied, and object recognition tests ensured that all objects were easily recognized in all conditions. The results showed a significant interaction between rendering type, object type, and consistency ratio. This suggests that inconsistent objects are only preferentially remembered if the scene looks “normal” or if there are many such objects in an “abnormal” scene. We conclude that memory for objects can be used to assess the degree to which the context of a VE appears normal.Presented on: Journal of Visio