Selective rendering for efficient ray traced stereoscopic images

Depth-related visual effects are a key feature of many virtual environments. In stereo-based systems, the depth effect can be produced by delivering frames of disparate image pairs, while in monocular environments, the viewer has to extract this depth information from a single image by examining details such as perspective and shadows. This paper investigates via a number of psychophysical experiments, whether we can reduce computational effort and still achieve perceptually high-quality rendering for stereo imagery. We examined selectively rendering the image pairs by exploiting the fusing capability and depth perception underlying human stereo vision. In ray-tracing-based global illumination systems, a higher image resolution introduces more computation to the rendering process since many more rays need to be traced. We first investigated whether we could utilise the human binocular fusing ability and significantly reduce the resolution of one of the image pairs and yet retain a high perceptual quality under stereo viewing condition. Secondly, we evaluated subjects' performance on a specific visual task that required accurate depth perception. We found that subjects required far fewer rendered depth cues in the stereo viewing environment to perform the task well. Avoiding rendering these detailed cues saved significant computational time. In fact it was possible to achieve a better task performance in the stereo viewing condition at a combined rendering time for the image pairs less than that required for the single monocular image. The outcome of this study suggests that we can produce more efficient stereo images for depth-related visual tasks by selective rendering and exploiting inherent features of human stereo vision

E-topia: Utopia after the Mediated Body

open access journalA custom-made media installation, diplorasis, will be used to explore the body in digital media. This mediated body attempts to re-think how the Deleuzian time-image is translated from its cinematic confinement to the space of new media. In diplorasis the digitized time-image becomes more directly incorporated with-in the bodily schema. Consequently, the thinking of the virtual and actual space of the body in diplorasis enables a questioning of bodily space-time, and particularly the relation between self and digitized self-image. It is thus crucial to re-frame how this digitized mediated body is distinct from a conventional notion of a metric and habitual space—one that is reinforced by, for example, the medium of linear perspective. The articulation of the mediated body will be used to in-form and extend Elizabeth Grosz’s paradoxical reading of embodiment and utopia, by revisiting the notions of utopia as eu-topic/ou-topic. The spatio-temporality of the topos must be re-considered before utopia. Foucault’s analogy of the mirror will then serve to superimpose the dual and slippery relations between utopia and the heterotopic. The digitized mediated body will thus seek to explore emerging ways by which to consider the utopic by conflating embodiment, time and space within an electronic topos. It is argued that as the sensing and cognitive body becomes increasingly pliable in relation to technological mediations, our very understanding of space-time is changing

Perspectival generation in/within the Sala della Pace: broadening the viewfield of spatialised images

It is everyday experience to look at a picture on a wall, (or on a computer screen) from a position that is out of alignment with its perspective, and then make a mental adjustment so as to allow for and ignore the distortion which results. To understand the limits and problem of this compensation it is necessary to look at works where there is an explicit attempt to relate the space of an image and the space in which the image exists. One such exemplar is the Sala della Pace, painted by Ambrogio Lorenzetti in 1338-40. The Sala della Pace may be of particular value today in helping us understand and evaluate the rapidly developing capacity of digital technology to represent dense visual and spatial information. Through Lorenzetti’s amalgam of multiple zones of extromissive generation within the images of the Sala della Pace, Lorenzetti‘s work suggests a potential compositional technique that subverts the reduction of spatial representation to a singular point of perspectival generation by broadening the viewfield in which to receive and construct multiple spatialised images. It is the aim of this paper to explore spatial concepts in Lorenzetti’s painting that may inform the way in which we conceptualise the spatial representation of both real and fictive space in/within images

What do we perceive in a glance of a real-world scene?

What do we see when we glance at a natural scene and how does it change as the glance becomes longer? We asked naive subjects to report in a free-form format what they saw when looking at briefly presented real-life photographs. Our subjects received no specific information as to the content of each stimulus. Thus, our paradigm differs from previous studies where subjects were cued before a picture was presented and/or were probed with multiple-choice questions. In the first stage, 90 novel grayscale photographs were foveally shown to a group of 22 native-English-speaking subjects. The presentation time was chosen at random from a set of seven possible times (from 27 to 500 ms). A perceptual mask followed each photograph immediately. After each presentation, subjects reported what they had just seen as completely and truthfully as possible. In the second stage, another group of naive individuals was instructed to score each of the descriptions produced by the subjects in the first stage. Individual scores were assigned to more than a hundred different attributes. We show that within a single glance, much object- and scene-level information is perceived by human subjects. The richness of our perception, though, seems asymmetrical. Subjects tend to have a propensity toward perceiving natural scenes as being outdoor rather than indoor. The reporting of sensory- or feature-level information of a scene (such as shading and shape) consistently precedes the reporting of the semantic-level information. But once subjects recognize more semantic-level components of a scene, there is little evidence suggesting any bias toward either scene-level or object-level recognition

Autoscopic Space: Re-thinking the Limits Between Self and Self-Image

open access journalAn experimental installation project of my own making, the diplorasis, aims to re-think the human sensorium by considering the bodily perceptual boundaries that are induced by visual media processes. Within the installation space the participant will, unexpectedly, encounter stereoscopic projections of himself/herself from previous instances and multiple perspectives. The photographic cameras within the device that are attached to sensors have been programmed to capture different views of the moving participant, and then to digitally split (and in some cases manipulate) the images before sending them to screens that project the image for the participant’s view. These stereoscopic images induce an illusionistic three-dimensional projection of the subject. The reduplicated, projected, and three-dimensionally simulated self in the diplorasis begins to trigger a questioning of how the body is understood within visual media. During the visual experience one has a solipsistic perception of oneself. The participant views himself both from outside and inside his body. The out-of-body experience of observing oneself from the multiple points of view of another (as a simulated object) is somehow countered to the embodied operation of the physical binocular eyes. The uncanny closeness of a neutral image “out there” (e.g. of a house) evoked by the original stereoscopes is now subverted, as the digitization of the stereoscope allows for unexpected self projections of the viewer. The diplorasis brings to the fore a particular reading of a sensory body that veers between, on the one hand, a projected image generated by electronic information, and on the other, the embodied response to this projected spectral other. As electronic processes are changing the perceptual and cognitive limits of the body, how do these shift our understanding of inside/outside

A systematic review of protocol studies on conceptual design cognition: design as search and exploration

This paper reports findings from the first systematic review of protocol studies focusing specifically on conceptual design cognition, aiming to answer the following research question: What is our current understanding of the cognitive processes involved in conceptual design tasks carried out by individual designers? We reviewed 47 studies on architectural design, engineering design and product design engineering. This paper reports 24 cognitive processes investigated in a subset of 33 studies aligning with two viewpoints on the nature of designing: (V1) design as search (10 processes, 41.7%); and (V2) design as exploration (14 processes, 58.3%). Studies on search focused on solution search and problem structuring, involving: long-term memory retrieval; working memory; operators and reasoning processes. Studies on exploration investigated: co-evolutionary design; visual reasoning; cognitive actions; and unexpected discovery and situated requirements invention. Overall, considerable conceptual and terminological differences were observed among the studies. Nonetheless, a common focus on memory, semantic, associative, visual perceptual and mental imagery processes was observed to an extent. We suggest three challenges for future research to advance the field: (i) developing general models/theories; (ii) testing protocol study findings using objective methods conducive to larger samples and (iii) developing a shared ontology of cognitive processes in design