Perceived Shift Of The Centres Of Contracting And Expanding Optic Flow Fields:Visual Quadrant-based Analyses

One of the essential operations carried out by our visual system is the localization of the edges of objects and surfaces in a complex scene.However,we will locate the location of the object wrongly while the object is moving or nearby motion signal.The illusion divided into two categories by the origin: the first illusion is caused by self-motion, such as Flash-lag effect;the second illusion is caused by nearby motion signals,such as Motion aftereffect.The current research is belonged to the second illusion.We studied differences in localizing the centre of flow in radially expanding and contracting patterns in different regions of the visual field by Fan(2010) model. The specific purpose:(1) determine differences of sensitivity to optic flow in different quadrants;(2) Explore differences of the centre of flow in the upper visual field and in the lower visual field;(3) Integrate the results of the experiment and analyze the applications and limitations in the real scene.Study1demonstrates the perceived centre of a peripherally viewed expanding pattern and the differences of sensitivity to optic flow in different quadrants by4(the visual quadrants:,Up-Left(UL)VS Up-Right(UP)VS Low-Right(LR)VS Low-Left(LL))×2(direction of optical flow motion:radial expansion VS radial contraction) within subject design.The result find that there is a significant shift in the lower right visual quadrant,while there is not a significant difference in the discrimination of centre of flow in different quadrants.Study2explores difference of the discrimination of centre of flow in different quadrants4(the visual quadrants:Up-Left(UL) VS Up-Right(UP) VS Low-Right (LR) VS Low-Left(LL))×2(direction of optical flow motion:EXP-EXP V S CON-CON) within subject design.The result find that the discrimination thresholds of the contracting patterns are higher than that of the expanding patterns,especially in low vision quadrants.Study3demonstrates the true displacement of the perceived location of centre of radically expanding and contracting patterns and whether there is different in discrimination thresholds of the contracting patterns and the expanding patterns.The results showed that the discrimination of flow is more precise for contracting than expanding patterns.