Properties of second-order spatial frequency channels

摘要: The segregation of texture patterns may be carried out by a set linear spatial filters (to enhance one the constituent textures), nonlinearity convert higher contrast response to that mean response), and finally subsequent (‘‘second-order’’) provide strong texture-defined edge itself). In this paper, properties such second-order are characterized. Observers were required detect or discriminate textures modulated between predominantly horizontally oriented vertically noise patterns. Spatial summation for these reached asymptote stimulus size 15 � deg. Modulation sensitivity was nearly flat over five-octave range frequency, but bandpass when stated as efficiency (relative an idealized observer confronted with same task). Increment threshold showed improved performance sub-threshold pedestal seen in ‘‘dipper effect’’, typical Weber’s law behavior at contrasts not observed highest modulation achievable our stimuli. Sub-threshold experiments indicate have moderate bandwidth. 2002 Elsevier Science Ltd. All rights reserved.