Li and Zaidi (Li, A., and Zaidi, Q. (2000) Vision Research, 40, 217-242) showed that the veridical perception of the 3-dimensional (3D) shape of a corrugated surface from texture cues is entirely dependent on the visibility of critical patterns of oriented energy. These patterns are created by perspective projection of surface markings oriented along lines of maximum 3D curvature. In images mis...

Several recent studies have used radial frequency patterns to investigate intermediate-level shape perception, a critical precursor to object recognition. Here, we developed the first neural model of RF perception based on known V4 properties that exhibits many of the characteristics of human RF perception. The model is composed of two main parts: (1) recovery of object position using large-sca...

A refined version of the strong maximum principle is proven for a class second order ordinary differential equations with possibly discontinuous non-monotone nonlinearities. Then, exploiting this tool, some optimal regularity results, recently established by López-Gómez and Omari in [15] , [16] [17] bounded variation solutions non-autonomous quasilinear driven one-dimensional curvature operator...

On the circular curve, lateral acceleration affects comfort. On the spiral, both lateral acceleration and jerk affect comfort.  The determination of maximum curving speed on the basis of lateral acceleration only is not critical because the lateral acceleration is proportional to the square of speed whereas jerk is proportional to cubic power of speed. The maximum speed on a curve is thus signi...

In this paper, we propose two Maple procedures and some related utilities to determine the maximum curvature of a cubic Bézier-spline curve that interpolates an ordered set points in R2 or R3. The are designed from closed-form formulas for such open closed curves.

A very recent observation on the membrane mediated attraction and ordered aggregation of colloidal particles bound to giant phospholipid vesicles (I. Koltover, J. O. Rädler, C. R. Safinya, Phys. Rev. Lett. 82, 1991(1999)) is investigated theoretically within the frame of Helfrich curvature elasticity theory of lipid bilayer fluid membrane. Since the concave or waist regions of the vesicle posse...

This paper describes a terrain-aided navigation system that employs points of maximum curvature extracted from laser scan data as primary landmarks. A scale space method is used to extract points of maximum curvature from laser range scans of unmodified outdoor environments. This information is then fused with odometric information to provide localization information for an outdoor vehicle. The...

on the circular curve, lateral acceleration affects comfort. on the spiral, both lateral acceleration and jerk affect comfort.  the determination of maximum curving speed on the basis of lateral acceleration only is not critical because the lateral acceleration is proportional to the square of speed whereas jerk is proportional to cubic power of speed. the maximum speed on a curve is thus signi...

Patients with right unilateral cerebral stroke, four of which showed acute hemispatial neglect, and healthy aged-matched controls were tested for their ability to grasp objects located in either right or left space at near or far distances. Reaches were performed either in free vision or without visual feedback from the hand or target object. It was found that the patient group showed normal gr...

Recently, we have shown that the differential properties of the surfaces represented by 3D volumic images can be recovered using their partial derivatives. For instance, the crest lines can be characterized by the first, second and third partial derivatives of the grey levrl function I(x,y,z) . This paper deals with the following points : the computation of the partial derivatives of an image c...