Examples of patterns used to study complex (second-order, non-Fourier) channels

(to top of Complex-Channels Page)

NOTE: These are all monochromatic patterns although on some browsers they sometimes appear tinted.

Example of element-arrangement pattern used to study the orientation bandwidth of the first stage of complex channels

This pattern also used in demonstration of how complex channels respond.

Example of competing-paths pattern used to study the spatial-frequency bandwidth of the first stage of complex channels

Task: Are the downward-and-to-the-right paths more salient than the downward-and-to-the-left paths?

(Ignore the black bar at the top of the pattern - it does not occur in the experimental stimuli.)

 

Return to bandwidth question on Complex Channels page

 

Examples of element-arrangement patterns used to study spatial summation in simple channels (square-elements pattern on top) and in complex channels (grating-elements pattern on bottom).

With square-element patterns, approximately linear spatial summation is seen (the tradeoff between area and contrast is approximately linear).

 

The nonlinear spatial summation that is seen between area and contrast (nonlinear tradeoff between area and contrast) in patterns with gratings elements (example below) can be explained by an intermediate nonlinearity in complex channels that is a (rectified) power function with an exponent of 3 or 4.

(Ignore the black bar at the top of the pattern - it does not occur in the experimental stimuli.)

Return to area-contrast tradeoff experiments (in question about intermediate nonlinearity) on Complex Channels page