Recent experiments have revealed that the opening and closing of the channel is controlled by concertedly rotating and tilting the ends of the alpha-helices in the KcsA ion channels. We recognize these transmembrane alpha-helices as the generating lines of the ruled surface: the hyperboloid of one sheet. The twist-to-shrink feature of the hyperboloid is adopted by KcsA channels in gating the po...

Both texture and motion can be strong cues to depth, and estimating slant from texture cues can be considered analogous to calculating slant from motion parallax (Malik and Rosenholtz 1994, report UCB/CSD 93/775, University of California, Berkeley, CA). A series of experiments was conducted to determine the relative weight of texture and motion cues in the perception of planar-surface slant whe...

Pictorial depth cues such as perspective projection, aspect ratio, and texture gradients can specify mathematically the slant of a planar surface. We performed experiments to measure the accuracy of human perception of surface slant from these cues. We calculated the perceived slant from judgments of the relative lengths of a pair of orthogonal lines embedded in the surface. Our results indicat...

Across many scenes, local contrast provides a valid cue to surface reflectance, but it is not the only such cue. To generalize beyond theories of lightness that rely exclusively on local contrast, we need to know which other potential cues matter. We had observers make lightness matches between two scene locations, and varied the surface slant and local surround reflectance of one of the locati...

This paper [5] implements and compares six well-known shape from shading (SFS) techniques. They analyse the performance on a set of synthetic and real images. The common goal for SFS methods is to recover the depth of the scene at all pixel locations . Furthermore the surface normal , the surface gradient or the surface slant and tilt can be determined at each pixel. The gradient is consists of...

This pa.per propc.)ses a method for estimat.ing surface 1oca.tion of a testurecl pla~le using spect.ra1 momeI1t.s. 13'hen a test.urec1 plane approaches a camera and sla~lt,s, tlle 2-D power spectrum concentrates around lower frecluencies and espancls to the slant direction. The sl>ectral ~nonlents also make clmnge correspc.)nclingly. The tlistance from camera, slant a,ngle a.ncl the slant, clir...