{"id":39834,"date":"2018-11-05T13:37:18","date_gmt":"2018-11-05T13:37:18","guid":{"rendered":"http:\/\/www.labri.fr\/perso\/barla\/blog\/?p=39834"},"modified":"2019-08-14T16:37:57","modified_gmt":"2019-08-14T16:37:57","slug":"visit-in-giessen-2018","status":"publish","type":"post","link":"https:\/\/www.labri.fr\/perso\/barla\/blog\/?p=39834","title":{"rendered":"Visit in Giessen, 2018"},"content":{"rendered":"<p id=\"top\" \/><h3>Alex Schmid: object dynamics<\/h3>\n<p>Look at whether the basic engine at the heart of a dynamic simulation may explain the ability of velocity disparities to be robust visual cues to fluidness, sponginess, heaviness, etc.\u00a0There might be more <strong>structured local motion dynamic patterns<\/strong> that are inherent to specific classes of materials and substances, which cause such global disparities in velocities. Point-light cloud stimuli permit to focus on these motion patterns; however, by bypassing both geometry and shading, they reveal information that might not directly be available. A good example is a water surface: with point-light clouds the stimuli look like objects floating on the surface, whereas it is only observed through reflection off its surface in reality.<\/p>\n<p><strong>Swarms of animals<\/strong> (schools of fishes, flocks of birds) exhibit special motion dynamics patterns due to local relationships between (visible) neighbor individuals.\u00a0Despite knowing that each element is an individual, we cannot help but perceive 3D deforming shapes; I suggest these are due to similarities with motion dynamics patterns due to deforming objects.<\/p>\n<p>How are the physical properties of common (rigid, elastic, plastic) objects related to <strong>potential<\/strong> motion patterns? Is there anything in the formula that can hint to things like inertia?\u00a0How can these motion dynamics pattern characteristic of a material or substance be <strong>effectively<\/strong> conveyed in a given scene? What is the role of interacting objects (ex: ground, walls)?\u00a0What happens to these 3D motion patterns once they get projected onto the image plane? How are effective 2D motion patterns related to them?\u00a0What explains the unintentional illusory motion dynamics produced by swarms of animals? How do professional 2D animators manipulate these illusions on purpose?<\/p>\n<h3>Katja Doershner: specular motion<\/h3>\n<p>Design experiments to evaluate whether observers are <strong>capable<\/strong>\u00a0to perceive shape relief (bumpiness) chiefly through specular flow.\u00a0An extreme case would be that of an object that is roughly invariant by a global transformation, but with a relief that is revealed by the motion of reflections off the surface.\u00a0A slightly bumpy tile is one example (invariant by translation); an engraved\/embossed vase is another (invariant by rotation around the axis of revolution).\u00a0But in general, specular flow should complement other cues; so we should also try objects with shapes\/silhouettes revealed through motion (e.g., using texture?).<\/p>\n<p>Introduce the idea of <strong>potential<\/strong> specular flow, and use it to predict both perceived shape and motion properties with a reflective object.\u00a0For shape, focus on curvature anisotropy, maybe with a dedicated gauge probe, and predict regions where shape features are ambiguously perceived.\u00a0For motion, use direction of minimal curvature in 3D to produce votes for a perceived rotation axis in 3D, with an additional confidence evaluation (whether votes are focused or spread).\u00a0In both cases, vary features of the lighting as well as their orientation, and observe impact on results: this permits to make a first distinction with <strong>effective\u00a0<\/strong>specular flow.<\/p>\n<h3>Philip Schmidt: deformed shapes<\/h3>\n<p>The tasks given to observers were to detect geometric deformations that are supposed to have been applied to 3D objects, distinguishing the magnitude of the deformation.\u00a0Humans seem very well able to do such tasks, even localizing deformations directly; however, not all deformations are distinguished equally, and some non-deformed parts of an object are sometimes perceived as deformed&#8230;<\/p>\n<p>It seems that shape features at a few salient scales could explain these differences in discrimination.\u00a0Some deformation processes might add features at scales that were not previously present or they might remove features at a specific existing scale; in these cases, it would be easy for an observer to point to the modifications.\u00a0Other deformations essentially modify shape features at their own scale, which makes distinction much less obvious to an observer.<\/p>\n<p>The very notion of shape feature may thus (at least in part) be characterized by pertinent scales in a 3D model, which constitutes <strong>potential<\/strong> sources of shape deformation information.\u00a0Whether these sources are <strong>effectively<\/strong> available might depend on their distribution of modifications over the object: inhomogeneous distributions hint to deformations through growth or alteration processes.<\/p>\n<h3>Jacob Cheeseman: optical materials<\/h3>\n<p>Study of perceptual differences between different (high-)gloss BRDFs for industrial applications, using Just-Noticeable Differences (JNDs).\u00a0Start with analytical BSDF models (from Mitsuba), but the goal is to get an end-to-end characterization of material sensitivity.<\/p>\n<p>One may find <strong>potential<\/strong> sources of difference in BSDF space; however, whether these are <strong>effectively<\/strong> available to visual perception depends on both shape and lighting.\u00a0To maximize similarities of effectively available cues to potential differences, one may resort to lighting design: find the environment that shows these differences as mhc as possible, for a given shape.<\/p>\n\n\n<p><\/p>\n","protected":false},"excerpt":{"rendered":"<p>Alex Schmid: object dynamics Look at whether the basic engine at the heart of a dynamic simulation may explain the ability of velocity disparities to be robust visual cues to fluidness, sponginess, heaviness, etc.\u00a0There might be more structured local motion dynamic patterns that are inherent to specific classes of materials and substances, which cause such &#8230; <a title=\"Visit in Giessen, 2018\" class=\"read-more\" href=\"https:\/\/www.labri.fr\/perso\/barla\/blog\/?p=39834\" aria-label=\"Read more about Visit in Giessen, 2018\">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":[21],"tags":[],"class_list":["post-39834","post","type-post","status-publish","format-standard","hentry","category-discuss"],"_links":{"self":[{"href":"https:\/\/www.labri.fr\/perso\/barla\/blog\/index.php?rest_route=\/wp\/v2\/posts\/39834","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=39834"}],"version-history":[{"count":9,"href":"https:\/\/www.labri.fr\/perso\/barla\/blog\/index.php?rest_route=\/wp\/v2\/posts\/39834\/revisions"}],"predecessor-version":[{"id":40139,"href":"https:\/\/www.labri.fr\/perso\/barla\/blog\/index.php?rest_route=\/wp\/v2\/posts\/39834\/revisions\/40139"}],"wp:attachment":[{"href":"https:\/\/www.labri.fr\/perso\/barla\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=39834"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.labri.fr\/perso\/barla\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=39834"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.labri.fr\/perso\/barla\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=39834"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}