File:The-venetian-blind-effect-a-preference-for-zero-disparity-or-zero-slant-Movie1.ogv

English: Demonstration of Venetian-blind effect as a function of frequency ratio. Top: Two spatial frequency gratings are initially presented with a frequency ratio of one. The spatial frequencies of the gratings change in opposite sign until the frequency ratio is equal to 0.67. The frequencies of the gratings then converge until the ratio returns to one. Bottom: The cross correlation output is shown for each frame of the video. Green regions represent high correlation while black regions represent low correlation. Azimuth is shown in the abscissa and corresponds to azimuth in the gratings above; high correlation is computed for all disparities beyond the edge of the gratings because there are no unique features to constrain matching. The ordinate of the correlation output represents disparity and changes from crossed disparity (in front of the screen) at the bottom of the correlation output to uncrossed disparity (behind the screen) at the top of the correlation output; zero disparity is denoted by the white line.