Evaluation of the accuracy of the Leap Motion controller for measurements of grip aperture

The Leap Motion controller allows for a mouse-free alternative to general computing. With 200 frames/second infrared cameras, a 150 field of view and an 8 ft2 umbrella of interactive space, the Leap Motion has many potential practical applications. The device is advertised as aiming to be placed in new cars, laptops and hospitals, for example, to provide contact-free device control, while reducing the need for attentive button pressing and averting eye focus

Ordinal judgments of depth in monocularly- and stereoscopically-viewed photographs of complex natural scenes

This study investigated the contribution of stereoscopic depth cues to the reliability of ordinal depth judgments in complex natural scenes. Participants viewed photographs of cluttered natural scenes, either monocularly or stereoscopically. On each trial, they judged which of two indicated points in the scene was closer in depth. We assessed the reliability of these judgments over repeated trials, and how well they correlated with the actual disparities of the points between the left and right eyes' views. The reliability of judgments increased as their depth separation increased, was higher when the points were on separate objects, and deteriorated for point pairs that were more widely separated in the image plane. Stereoscopic viewing improved sensitivity to depth for points on the same surface, but not for points on separate objects. Stereoscopic viewing thus provides depth information that is complementary to that available from monocular occlusion cues

Quality, quantity and precision of depth perception in stereoscopic displays

Stereoscopic 3D viewing (S3D) can create a clear and compelling improvement in the quality of the 3D experience compared with 2D displays. This improvement is distinct from any change in the amount of depth perceived, or the apparent 3D shapes of objects and the distances between them. It has been suggested instead that the enhanced feeling of realness is associated more with the precision with which we see depth. We measured the contribution of stereoscopic cues to the quality of depth perception in simple abstract images and complex natural scenes. We varied the amount of disparity present in the simple scenes in order to dissociate the magnitude and precision of perceived depth. We show that the qualitative enhancement of perceived depth in stereoscopic displays can be readily quantified, and that it is more closely related to the precision than to the magnitude of apparent depth. It is thus possible to make a distinction between scenes that contain more depth, and those that contain better depth

Distance mis-estimations can be reduced with specific shadow locations

Shadows in physical space are copious, yet the impact of specific shadow placement and their abundance is yet to be determined in virtual environments. This experiment aimed to identify whether a target’s shadow was used as a distance indicator in the presence of binocular distance cues. Six lighting conditions were created and presented in virtual reality for participants to perform a perceptual matching task. The task was repeated in a cluttered and sparse environment, where the number of cast shadows (and their placement) varied. Performance in this task was measured by the directional bias of distance estimates and variability of responses. No significant difference was found between the sparse and cluttered environments, however due to the large amount of variance, one explanation is that some participants utilised the clutter objects as anchors to aid them, while others found them distracting. Under-setting of distances was found in all conditions and environments, as predicted. Having an ambient light source produced the most variable and inaccurate estimates of distance, whereas lighting positioned above the target reduced the mis-estimation of distances perceived

Luminance contrast provides metric depth information

The perception of depth from retinal images depends on information from multiple visual cues. One potential depth cue is the statistical relationship between luminance and distance; darker points in a local region of an image tend to be farther away than brighter points. We establish that this statistical relationship acts as a quantitative cue to depth. We show that luminance variations affect depth in naturalistic scenes containing multiple cues to depth. This occurred when the correlation between variations of luminance and depth was manipulated within an object, but not between objects. This is consistent with the local nature of the statistical relationship in natural scenes. We also showed that perceived depth increases as contrast is increased, but only when the depth signalled by luminance and binocular disparity are consistent. Our results show that the negative correlation between luminance and distance, as found under diffuse lighting, provides a depth cue that is combined with depth from binocular disparity, in a way that is consistent with the simultaneous estimation of surface depth and reflectance variations. Adopting more complex lighting models such as ambient occlusion in computer rendering will thus contribute to the accuracy as well as the aesthetic appearance of three-dimensional graphics

Supplementary material from "Luminance contrast provides metric depth information"

The perception of depth from retinal images depends on information from multiple visual cues. One potential depth cue is the statistical relationship between luminance and distance; darker points in a local region of an image tend to be farther away than brighter points. We establish that this statistical relationship acts as a quantitative cue to depth. We show that luminance variations affect depth in naturalistic scenes containing multiple cues to depth. This occurred when the correlation between variations of luminance and depth was manipulated within an object, but not between objects. This is consistent with the local nature of the statistical relationship in natural scenes. We also showed that perceived depth increases as contrast is increased, but only when the depth signalled by luminance and binocular disparity are consistent. Our results show that the negative correlation between luminance and distance, as found under diffuse lighting, provides a depth cue that is combined with depth from binocular disparity, in a way that is consistent with the simultaneous estimation of surface depth and reflectance variations. Adopting more complex lighting models such as ambient occlusion in computer rendering will thus contribute to the accuracy as well as the aesthetic appearance of three-dimensional graphics

3D Perception of Complex Naturalistic Scenes in Consumer Virtual Reality

Vision research has progressed from simple experimental setups, to the immersive capabilities of virtual reality. This thesis will first introduce the reader to key concepts and background literature used throughout the text; a methodological chapter then outlines the practice and reasoning behind how software can be created for experimental studies in virtual reality. The first experimental chapter assesses 3D perception is two virtual reality headsets. Underestimation of distance in simple visual environments was found. Following this up, the second experimental chapter focusses on overcoming this issue using established methods: separating visual cues to determine which are most valuable and worthy of the host PC's processing power. Variability in distance estimation was found to be reduced by the addition of binocular cues, although an environment utilising all pictorial cues produced an equal sense of distance as binocular disparity alone. The third experimental chapter tests of the influence lighting, shadows, and clutter have on perception of virtual surroundings. Here it is shown that additional reference objects within an environment do not enhance distance perception, and visible cast shadows enhanced the precision of estimates. The penultimate chapter, an exploratory online experiment, is then presented which investigated perceptions surrounding immersive technologies. User experiences and impressions were investigated with both qualitative and quantitative data. Finally, a discussion on the results obtained through each stage of research, implications of these findings, and suggestions for future research is presented. Continuous advances in technology cause for continuous adjustments to be made, not only to the type of research being conducted, but also the type of equipment being used. This thesis supports the use of virtual reality as a means of gathering data in scientific research investigation, and also identifies specific visual cues that are vital in creating a realistic sense of depth within virtual scenes

The Evaluation of Externalities

This bachelor thesis focuses on problem of externalities of manufacturing company which should influence a surrounding of company in positive or negative way. The main issue of this thesis is an emergence of externalities in process of production and consumption. This thesis describes a types of those externalities and a ways of solutions. The externalities and their evaluation are presented on specific company, thermal power station in Hodonín. This thesis also contains a results of questionnaire survey among residents of city Hodonín

Salience difference calculations for our surface stimuli.

<p>The lines show the results for three differences in target disparity, plotted against the disparity of the central bump or dip. Salience was calculated using Eqs <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0165932#pone.0165932.e001" target="_blank">1</a>–<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0165932#pone.0165932.e003" target="_blank">3</a>, based on the positions and disparities of all the dots in the stimuli.</p