Bernal S D_2010.pdf - University of Plymouth

5.2. FEEDBACK'MEDIATED ILLUSORY CONTOUR COMPLETION
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Figure 5.25: S1. CI and .S2 model responses lo a Kanizsa square input image while the topdown
feedback from C2. Ti{S2]. is clamped to a square represeniaiion. The 2D
SI and CI maps represent the prohabitity value for the hori/omal stale across all
locations of scale band 2 and I. respectively. The S2 rcpresemauon corresponds
to the CI reconsUTJciion using the CI features of the maximum S2 prototypes at
each location, as described in Section 'i.l. For each layer, the temporal evolution
of the response from lime t= I loi=4 is shown, excepl for A (.S'I) and Jl{S2), whose
responses are fixed over lime. Arrows indicale feedforward (green) and feedback
(red) propagation of evidence. Note that in this case feedback does not arise
directly from the belief in the C2 layer, Bel{C2), because as illustrated in the
previous subsection, it is difficult to obtain a good 7i{S2) square reconstruction
via the S2-C2 weight mairix. Instead, the ;r(.V2) is fixed lo an ideal S2 square
representation in order In lesl ibe capacity of the model lo combine feedback
infomiaiion hypodteiically generated from the C2 layer.
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