{"id":37791,"date":"2015-07-27T15:35:00","date_gmt":"2015-07-27T15:35:00","guid":{"rendered":"http:\/\/www.labri.fr\/perso\/barla\/blog\/?p=37791"},"modified":"2015-07-27T15:36:03","modified_gmt":"2015-07-27T15:36:03","slug":"perception-of-space","status":"publish","type":"post","link":"https:\/\/www.labri.fr\/perso\/barla\/blog\/?p=37791","title":{"rendered":"Perception of Space"},"content":{"rendered":"<p id=\"top\" \/>\n<h2><b>Layout<\/b><\/h2>\n<p><i>Perceiving layout and knowing distances: the integration, relative potency, and contextual use of different information about depth [Cutting1995]<\/i><\/p>\n<ul>\n<li>Adding information to a stimulus display generally increases the amount of depth seen, but also generally increases the consistency and accuracy with which judgments are made.<\/li>\n<li>For occlusion to yield ordinal information, one need make only four assumptions: the linearity of light rays, the general opacity of objects, the Gestalt quality of good continuation of boundary contours, and luminance contrast.<\/li>\n<li>The range over which occlusion works is extremely impressive. Quite simply, occlusion can be trusted at all distances in which visual perception holds.<\/li>\n<li>The effectiveness of aerial perspective increases as the logarithm of the distance.<\/li>\n<li>Motion perspective acuity declines below about 2m because of the difficulty in tracking and even seeing differences in rapid movement.<\/li>\n<li>The effectiveness of convergence alone as a source of information on depth is confined to a range up to about 2m, and accommodation a bit less so. Even when combined, their useful range still seems to be less than 3m.<\/li>\n<li>Clearly, disparities are most effective in the near field, and their relative effectiveness attenuates linearly with distance.<\/li>\n<li>Kinetic occlusion is simply occlusion as revealed through motion; it differs only in that it needs not assume any luminance contrast at the occluding edge.<\/li>\n<li>There are at least three kinds of spaces around each of us, each perceived by means of different combinations of different sources of information, each combination dependent on the context in which the information is presented.<\/li>\n<\/ul>\n<p><i>Detecting natural occlusion boundaries using local cues [DiMattina2012]<\/i><\/p>\n<ul>\n<li>Luminance differences are a local cue to occluding contours, being equally useful at all patch sizes. In contrast, texture cues are only useful for larger image patches<\/li>\n<li><i>There is always potential ambiguity in the identification of occlusion boundaries in a static image. However with just a little bit of motion or disparity, most of these boundaries become apparent. What is the connection between static and kinematic cues here ?<\/i><\/li>\n<\/ul>\n<p>&nbsp;<\/p>\n<h2><b>Motion<\/b><\/h2>\n<p><i>Visual space perception through motion [Johansson198?]<\/i><\/p>\n<ul>\n<li>Static perception in fact is generated by abstracting a common component in a flow analysis.<\/li>\n<li>Static perception is described as an aspect of motion perception, while traditionally motion perception was analyzed in terms of static images.<\/li>\n<li><i>Challenging question: what characterizes a static\u00a0 region (in 3D) in an ego-motion flow, only making use of properties of the flow itself?<\/i><\/li>\n<\/ul>\n<p><i>The how and why of what went where in Apparent Motion: modeling solutions to the motion correspondence problem [Dawson1991]<\/i><\/p>\n<ul>\n<li>Nearest neighbor principle: when 3D motion vectors are projected to 2D, their depth component is lost. As a result, slower 2D movements are much more likely to occur than are faster movements. Because a preference for the nearest neighbor is equivalent to a preference for the slowest 2D velocities, it may be that the HVS exploits this constraint. <i>This might be violated at occluding contours, hence requiring the identification of a clipped neighborhood.<\/i><\/li>\n<li>Relative velocity principle: it is defined as the difference between two motion correspondence matches (interpreted as motion vectors) after they have been centered at a common origin. <i>This sounds a lot like a differential analysis of motion flow\u2026<\/i><\/li>\n<li>Element integrity principle: The physical coherence of surfaces suggests that the splitting or the fusing of visual elements is unlikely. One-to-one mappings between elements over time will be correct everywhere except at surface discontinuities. <i>What about the matching and \u201csliding integrity\u201d of occluding contours themselves?<\/i><\/li>\n<\/ul>\n<p><i>Effects of surface reflectance and 3D shape on perceived rotation axis [Doershner2013]<\/i><\/p>\n<ul>\n<li>Observers tend to overestimate the rotation axis slant of shiny objects relative to other material categories, and the general underestimation of rotation axis slant was most pronounced for silhouette objects. <i>This will quite strongly depend on object shape though. It thus remains to explain what shape properties influence perceived rotation.<\/i><\/li>\n<\/ul>\n<p><i>Perception of physical stability and center of mass of 3D objects [Cholewiak2015]<\/i><\/p>\n<ul>\n<li>Although observers are able to localize the center of mass (COM), it does not appear to explain performance in a visual balancing task. Therefore, comparing the two sets of results, observers do not appear to use their perceived COM (at least not in the physically correct manner) when making judgments of object stability.<\/li>\n<\/ul>\n<p>&nbsp;<\/p>\n<h2><b>Light-field<\/b><\/h2>\n<p><i>Why the visual recognition system might encode the effects of illumination [Tarr1998]<\/i><\/p>\n<ul>\n<li>The representation of illumination may be tied to individual objects, or small portions of scenes, rather than to the scene as a whole. <i>Maybe the observation should be reversed: because the light-field varies in lumps throughout a 3D scene, it may constitute a good spatial cue (varying, for ex., with time of day).<\/i><\/li>\n<\/ul>\n<p><i>Perceiving illumination inconsistencies in scenes [Ostrovsky2001]<\/i><\/p>\n<ul>\n<li>The HVS is not very sensitive to main illumination direction anomalies in global settings.\u00a0 <i>Why would the HVS need to be sensitive to things that do not happen?<\/i><\/li>\n<li>This may originate from evolution in a single (sun-) lit world. <i>What about torch light in caves? Or reflections from water ponds?<\/i><\/li>\n<\/ul>\n","protected":false},"excerpt":{"rendered":"<p>Layout Perceiving layout and knowing distances: the integration, relative potency, and contextual use of different information about depth [Cutting1995] Adding information to a stimulus display generally increases the amount of depth seen, but also generally increases the consistency and accuracy with which judgments are made. For occlusion to yield ordinal information, one need make only &#8230; <a title=\"Perception of Space\" class=\"read-more\" href=\"https:\/\/www.labri.fr\/perso\/barla\/blog\/?p=37791\" aria-label=\"Read more about Perception of Space\">Read more<\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[761],"tags":[],"class_list":["post-37791","post","type-post","status-publish","format-standard","hentry","category-papers"],"_links":{"self":[{"href":"https:\/\/www.labri.fr\/perso\/barla\/blog\/index.php?rest_route=\/wp\/v2\/posts\/37791","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.labri.fr\/perso\/barla\/blog\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.labri.fr\/perso\/barla\/blog\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.labri.fr\/perso\/barla\/blog\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.labri.fr\/perso\/barla\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=37791"}],"version-history":[{"count":2,"href":"https:\/\/www.labri.fr\/perso\/barla\/blog\/index.php?rest_route=\/wp\/v2\/posts\/37791\/revisions"}],"predecessor-version":[{"id":37811,"href":"https:\/\/www.labri.fr\/perso\/barla\/blog\/index.php?rest_route=\/wp\/v2\/posts\/37791\/revisions\/37811"}],"wp:attachment":[{"href":"https:\/\/www.labri.fr\/perso\/barla\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=37791"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.labri.fr\/perso\/barla\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=37791"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.labri.fr\/perso\/barla\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=37791"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}