Unformatted text preview: Vision as unconscious inference Thursday, September 9th 2010
Thursday, September 9, 2010 Thursday, September 9, 2010 Thursday, September 9, 2010 Thursday, September 9, 2010 Retinal
changes conformation when light hits Thursday, September 9, 2010 Inner screen? Thursday, September 9, 2010 Where’s the homunculus? Thursday, September 9, 2010 Rod Cone Amacrine cell Horizontal cell Bipolar cell Ganglion cell Optic nerve Light
Thursday, September 9, 2010 Explicit Thursday, September 9, 2010 © 1984 SCIENTIFIC AMERICAN, INC Inverse problem Thursday, September 9, 2010 Helmholtz’s unconscious inference The psychic activities that lead us to infer that there in front of us at a certain place there is a certain object of a certain character are generally not conscious activities, but unconscious ones. In their result they are equivalent to a conclusion
Herman von Helmholtz Treatise on Physiological Optics (1866) translated by JPC Southall
Thursday, September 9, 2010 Helmholtz’s unconscious inference Thursday, September 9, 2010 Helmholtz’s unconscious inference http://psych.hanover.edu/krantz/SizeConstancy/
Thursday, September 9, 2010 Necker illusion
reverses in depth Thursday, September 9, 2010 Thursday, September 9, 2010 Thursday, September 9, 2010 Thursday, September 9, 2010 Hans Vredman de Vries (c. 1604) “Perspective”
Thursday, September 9, 2010 Thursday, September 9, 2010 Thursday, September 9, 2010 Thursday, September 9, 2010 made of wood Thursday, September 9, 2010 general viewpoint Thursday, September 9, 2010 otograph on be a triangle photograph phed object is included se in which al parts (the , rather than y (1971) inexplorations
Thursday, September 9, 2010 Escher’s Belvedere Thursday, September 9, 2010 Thursday, September 9, 2010 Thursday, September 9, 2010 Blocksworld ﬁgure 21.1
Thursday, September 9, 2010 trihedral Thursday, September 9, 2010 junction types Thursday, September 9, 2010 8 octants Thursday, September 9, 2010 ways of ﬁllingout octants Thursday, September 9, 2010 ways of ﬁllingout octants Thursday, September 9, 2010 concave vs convex Thursday, September 9, 2010 ways of ﬁllingout octants Thursday, September 9, 2010 ways of ﬁllingout octants Thursday, September 9, 2010 viewpoints Thursday, September 9, 2010 boundary vs interior Thursday, September 9, 2010 Thursday, September 9, 2010 junction dictionary L Y T Y
Thursday, September 9, 2010 Norvig’s
implementation
http://norvig.com/paip.html L Y T Y (defun possiblelabelings (vertextype) "The list of possible labelings for a given vertex type." ;; In these labelings, R means an arrow pointing away from ;; the vertex, L means an arrow pointing towards it. (case vertextype ((L) '((R L) (L R) (+ R) (L +) ( L) (R ))) ((Y) '((+ + +) (  ) (L R ) ( L R) (R  L))) ((T) '((R L +) (R L ) (R L L) (R L R))) ((W) '((L R +) (  +) (+ + )))))
Thursday, September 9, 2010 starts off with all possible labels at every vertex Thursday, September 9, 2010 starts off with all possible labels at every vertex Thursday, September 9, 2010 Thursday, September 9, 2010 Thursday, September 9, 2010 Marr levels
‣computational level
the task is to ﬁnd a consistent assignment of junction labels to vertices keep eliminating possible labels from vertices connected by lines, if they are inconsistent. stop when nothing else can be eliminated ‣algorithmic/representational level Thursday, September 9, 2010 For next time.... do the Coglab visual search experiment ‣create your Coglab account ‣follow instructions posted
on Blackboard Thursday, September 9, 2010 For next time.... read excerpt from Wolfe a el r x & le ve a la or f er t read in prep for Tuesday
Thursday, September 9, 2010 ...
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 Fall '07
 SPIVEY,M
 Cognitive Science, Hermann von Helmholtz, Thursday, ganglion cell, Bipolar cell of the retina, Helmholtz Treatise on Physiological Optics

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