Texture Segmentation in 3D

M.J. Bravo and H. Farid

Investigative Opthalmology and Visual Science (ARVO), Fort Lauderdale, FL, 1999

Purpose: Observers can readily discriminate two textures with different orientations when both are presented on a planar surface. In this case the discontinuity in the image coincides with the discontinuity in the world. But if the surface is folded the image it produces may contain additional discontinuities. Can observers differentiate between texture discontinuities that are due only to changes in surface slant versus those that reflect a change in both surface slant and surface texture?

Methods: Our stimulus was a rendered three-panel surface. The texture on the center panel was oriented bandpass noise, the texture on one side panel was the same (in the world, not the image), while the texture on the other side panel was rotated by a variable amount. The stimuli were presented stereoscopically and all observers reported having a vivid 3D percept. The observer's task was to indicate which side panel had the rotated texture.

Results: Performance levels varied with the orientation of the surface texture. Observers performed best with textures that were oriented horizontally on two of the surfaces but they performed near chance with some diagonal textures.

Conclusions: Observers generally have difficulty determining whether a change in image texture is due solely to a change in surface slant or if it also reflects a change in the intrinsic surface texture. While humans are quite adept at detecting texture discontinuities in an image, they are limited in their ability to interpret them.