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. Author manuscript; available in PMC: 2007 Mar 2.
Published in final edited form as: J Opt Soc Am A Opt Image Sci Vis. 2005 Oct;22(10):2230–2238. doi: 10.1364/josaa.22.002230

Fig 2.

Fig 2

Examples of stimuli used in the experiments. Note that the centers are slightly different either in spatial frequency or orientation from the surround. This difference has been greatly exaggerated for the figure, and therefore apparent contours or phase shifts are visible here, but not in the actual experiment. Examples are for spatial frequency judgments. Only one of the pair to be discriminated is shown in each case. Panel A: control pattern with unmodulated surround. Panel B: Same as A but with an example of a lower-contrast surround. Panel C: Same as A but with same-contrast surround. Panel D: Same as A but with an example of a higher-contrast surround.