Relative flattening between velvet and matte 3D shapes: Evidence for similar shape-from-shading computations

Relative flattening between velvet and matte 3D shapes: Evidence for similar shape-from-shading computations

Wijntjes, W.A.
Doerschner, K.
Kucukoglu, G.
Pont, S.C.

Industrial Design Engineering

2011-11-03

Among other cues, the visual system uses shading to infer the 3D shape of objects. The shading pattern depends on the illumination and reflectance properties (BRDF). In this study, we compared 3D shape perception between identical shapes with different BRDFs. The stimuli were photographed 3D printed random smooth shapes that were either painted matte gray or had a gray velvet layer. We used the gauge figure task (J. J. Koenderink, A. J. van Doorn, & A. M. L. Kappers, 1992) to quantify 3D shape perception. We found that the shape of velvet objects was systematically perceived to be flatter than the matte objects. Furthermore, observers' judgments were more similar for matte shapes than for velvet shapes. Lastly, we compared subjective with veridical reliefs and found large systematic differences: Both matte and velvet shapes were perceived more flat than the actual shape. The isophote pattern of a flattened Lambertian shape resembles the isophote pattern of an unflattened velvet shape. We argue that the visual system uses a similar shape-from-shading computation for matte and velvet objects that partly discounts material properties

3D surface and shape perception
shading
ecological optics

http://resolver.tudelft.nl/uuid:3f45394a-23b6-459a-bede-746fe9e836d2

https://doi.org/10.1167/12.1.2

ARVO

1534-7362

Journal of Vision, 12 (1), 2012

Institutional Repository

journal article

(c) 2012 The Author(s)