Skip to main content
. Author manuscript; available in PMC: 2012 May 10.
Published in final edited form as: Vision Res. 2011 Feb 26;51(9):1086–1098. doi: 10.1016/j.visres.2011.02.022

Figure 1.

Figure 1

(A) Natural scene containing 1st- and 2nd-order contours. The boundary between the two pedestrians and walkway in the lower right is defined by a change in luminance, hence it is 1st-order. The texture-defined boundaries between the different regions of the walkway are 2nd-order. (B) A typical model of visual processing with parallel pathways for 1st- and 2nd-order stimuli. In the top path, luminance-defined stimuli are signaled by a linear filter. The bottom path is a filter-rectify-filter cascade sensitive to 2nd-order stimuli. Both 1st- and 2nd-order information are combined in a later decision stage (Baker & Mareschal, 2001).