Abstract
Neon color spreading is a well established visual illusion in which a colored inducing figure evokes the impression of colored glow spreading through empty (achromatic) regions of space between the colored inducing lines, with a sharp color border around the edge of the induced figure. We asked whether there is a depth spreading effect analogous to the color spreading, whereby the perceived depth of the figure region would form a surface at the depth of the inducing lines with a sharp depth border along the perceived figure boundary. Two alternatives are possible. The inducing lines could be seen as isolated in depth with no effect on the surrounding space, or the lines could induce a smooth surface completion with the background, corresponding to smoothness constraint on stereoscopic depth reconstruction.
The perceived depth was estimated by selection of which of a set of points matched the perceived the perceived depth of the surrounding space at selected locations across the image. For a group of four subjects, the perceived depth showed strong adherence to the depth of the inducing lines, forming a sharp depth edge at the boundary of the induced figure (a disk) although it was running through empty space. The depth induction was not limited to frontoparallel surfaces, being equally compelling when the surface slanted horizontally in depth. There was no evidence of the operation of a smoothness constraint across the perceived depth edge, although the edge itself represents a form of anisotropic continuity constraint on the form of the induced depth structure. The results place strong constraints on the properties required models of depth reconstruction of object structures implied by sparse disparity cues.
Meeting abstract presented at VSS 2012