Parallax

Parallax is a live contemporary dance work that incorporates 3D animation, stereoscopic illusions and dance. This work was performed within the Melbourne Fringe Festival at the Substation, Newport. Within this work the stereoscopic illusion creates a new choreographic palette that can be used to manipulate human physicality via animated bodies that appear within the performance space. The stereoscopic image is released from the wall and placed within the dancing environment the image becomes another body within the dance space that can be manipulated in ways that would be impossible for a real physical body. In turn, the dancing body is positioned within the digital environment. The performer’s abilities have not changed, but the space around the dancer can be manipulated with imagery that transforms the place of the dancer within time and space. The stereoscopic illusion and live dance are melded creating a new experience of choreography one that takes the infinite possibilities of 3D animation and places them directly within choreography. Thematically this performance draws on the historical events revolving around the development of the stereoscope in the 1830s and the seminal ideas of the virtual that surfaced at this time. In the early 1830s Charles Wheatstone drew on the ideas and writings of Euclid and Leonardo da Vinci and discovered binocular vision through the use of his stereoscope box. It was this box that became the entertainment sensation of this time becoming a standard parlour entertainment. Unlike now where imagery of people are everywhere in the 1830s these types of imagery were novel. The stereoscopic pictures often showed content of people doing ordinary tasks such as chopping wood, doing the washing or simply standing in front of their house. In Parallax a Victorian woman is transported from her hallway to virtual worlds where she encounters, Euclid’s ancient Greek column, a di Vinci sphere and one of the first stereoscopic images drawn by Charles Wheatstone’s a stick figure cube.

Hyperstereopsis in helmet-mounted NVDs : slope perception

Modern helmet-mounted night vision devices, such as the Thales TopOwl helmet, project imagery from intensifiers mounted on the sides of the helmet onto the helmet faceplate. This produces a situation of hyperstereopsis in which binocular disparities are magnified. This has the potential to distort the perception of slope in depth (an important cue to landing), because the slope cue provided by binocular disparity conflicts with veridical cues to slope, such as texture gradients and motion parallax. In the experiments, eight observers viewed sparse and dense textured surfaces tilted in depth under three viewing conditions: normal stereo hyper-stereo (4 times magnification), and hypostereo (1 / 4 magnification). The surfaces were either stationary, or rotated slowly around a central vertical axis. Stimuli were projected at 6 metres to minimise conflict between accommodation and convergence, and stereo viewing was provided by a Z-screen and passive polarised glasses. Observers matched perceived visual slope using a small tilt table set by hand. We found that slope estimates were distorted by hyperstereopsis, but to a much lesser degree than predicted by disparity magnification. The distortion was almost completely eliminated when motion parallax was present.