Magnitude, precision, and realism of depth perception in stereoscopic vision

Our perception of depth is substantially enhanced by the fact that we have binocular vision. This provides us with more precise and accurate estimates of depth and an improved qualitative appreciation of the three-dimensional (3D) shapes and positions of objects. We assessed the link between these quantitative and qualitative aspects of 3D vision. Specifically, we wished to determine whether the realism of apparent depth from binocular cues is associated with the magnitude or precision of perceived depth and the degree of binocular fusion. We presented participants with stereograms containing randomly positioned circles and measured how the magnitude, realism, and precision of depth perception varied with the size of the disparities presented. We found that as the size of the disparity increased, the magnitude of perceived depth increased, while the precision with which observers could make depth discrimination judgments decreased. Beyond an initial increase, depth realism decreased with increasing disparity magnitude. This decrease occurred well below the disparity limit required to ensure comfortable viewing

Affective ambiences created with lighting for older people

Item does not contain fulltextCurrent lighting technologies provide huge flexibility in creating ambiences that may be adapted to the needs of an occupant in a room. These ambiences not only satisfy visual needs, but may also improve people’s well-being. This paper describes one possible application of adaptable light ambiences, namely to counteract negative mood states that older people often experience in care centres. To this end, we wanted to create a pleasant, relaxing ambience to counteract anxiousness and a pleasant, activating ambience to counteract sadness. We asked 15 (relatively young) lighting designers to create these ambiences and averaged their input to create both ambiences in a real room. Subsequently, these ambiences were evaluated with the Atmosphere questionnaire by younger and older participants. The affective connotation of the ambiences in terms of the Atmosphere dimensions was well recognized by the younger participants but significantly less so by the older people. Hence, a photo interview with older people was used to make the ambiences more appropriate for them. A final validation experiment confirmed that the affective connotation of these new ambiences was well recognized by the older people.17 p

Quality measures of reconstruction filters for stereoscopic volume rendering

In direct volume rendering (DVR), the choice of reconstruction filter can have a significant effect on the visual appearance of the images produced and thus, on the perceived quality of a DVR rendered scene. This paper presents the results of a subjective experiment where participants stereoscopically viewed DVR rendered scenes and rated their subjective quality. The statistical analysis of the results focuses on the relationship between the quality of the stereoscopic scene and properties of the filters such as post-aliasing and smoothing, as well as the relationship between the quality of the stereoscopic scene and properties of the rendered images such as shape compactness. The experiment evaluated five reconstruction filters on four different volumetric datasets. Participants rated the stereoscopic scenes on four quality measures: depth quality, depth layout, lack of jaggyness, and sharpness. The results show that the correlation between the quality measures and post-aliasing and smoothing, which are properties associated with each reconstruction filter, is moderate and statistically insignificant. On the other hand, the correlation between the quality measures and compactness, which is a property specific to each rendered image, is strong and statistically significant