Perception of Local Surface Patches Using Shape From Shading

Perception of local shape from shading.

Theoretically, metric solid shape is not determined uniquely by shading. Consequently, human vision has difficulty in categorizing shape when shading is the only cue. In the present research, subjects were required to categorize shaded quadric surfaces. We found that they were rather poor at this task; they confused hyperbolic and elliptic (both convex and concave) shapes easily. When a cast sh...

Human perception of local shape from shading under variable lighting

It is commonly believed that humans exhibit lighting invariant object recognition. Here we present psychophysical evidence to the contrary. We examine the perception of qualitative local shape from shading and find that significant variations occur as a function of the lighting. These variations have two logically distinct causes: first, there are inherent ambiguities between shape and shading ...

Surface topography using shape-from-shading,

This paper demonstrates how a recently reported shape-from-shading scheme can be used to extract topographic information from 2D intensity imagery (Worthington and Hancock, IEEE Trans. Pattern Anal. Mach. Intell. 21 (1999) 1250}1267). The shape-from-shading scheme has two important features which enhance the recovered surface description. Firstly, it uses a geometric update procedure which allo...

On the perception of shape from shading.

The extraction of three-dimensional shape from shading is one of the most perceptually compelling, yet poorly understood, aspects of visual perception. In this paper, we report several new experiments on the manner in which the perception of shape from shading interacts with other visual processes such as perceptual grouping, preattentive search ("pop-out"), and motion perception. Our specific ...

Shape from Shading 1 1 The perception of shape