Two topics intimately linked to active vision are spacevariant vision and mechanical devices. On the one hand, log-polar images is a biologically inspired space-variant imaging model featuring very attractive properties. On the other hand, pan-tilt heads are a common platform in active vision, allowing the observer to dynamically perceive the environment. In order to relate motor commands (for ...

The electroclinic (EC) effect is the tilt of the optical axis of a liquid crystal in the plane perpendicular to an applied electric field. Chirality plays a key role for its emergence. Based on the molecular and phase symmetry we derive a molecular expression for the EC coefficient, the material property that quantifies the linear coupling between tilt and electric field, in nematic liquid crys...

A prototype active surveillance system is presented. The system has two cameras, one of which is rigidly xed & has a wide angle lenses while the other is mounted on a pan-tilt head & has a zoomed lenses. The images from the wide angle camera are analyzed using dynamic background subtraction together with normalized cross correlation in order to identify moving people within the scene. An approx...

The quenched Kardar-Parisi-Zhang equation with negative nonlinear term shows a first order pinningdepinning ~PD! transition as the driving force F is varied. We study the substrate-tilt dependence of the dynamic transition properties in 111 dimensions. At the PD transition, the pinned surfaces form a facet with a characteristic slope sc as long as the substrate tilt m is less than sc . When m,s...

BACKGROUND Congenital Brown syndrome is characterized by limited elevation particularly during adduction. The pathogenesis of congenital Brown syndrome is still controversial. CASE PRESENTATION A 6-year-old boy had been tilting his head to the left since infancy. He showed right hypertropia (RHT) of 2 prism diopters (Δ) in the primary position. He showed RHT 6Δ in right gaze, RHT 2Δ in left g...

By presenting oriented Gabor patches either monocularly or binocularly, we dissociated retinal orientation from perceived tilt and perceived slant. After adapting to binocular patches, with zero apparent tilt and non-zero slant, small tilt after-effects (TAEs) and large slant after-effects (SAE) were measured. Adapting to monocular patches with non-zero tilt and zero slant produced large TAEs a...

This paper describes a method for calibrating a pan-tilt camera head. The key feature of the method is that the camera, the pan-tilt unit, and the relationship between the camera and the pan-tilt unit, are calibrated independently. This paper develops a geometric model of the pan-tilt camera head and presents procedures to estimate the values of the unknown model parameters. Target image reposi...

Low back dysfunction is associated in many cases with lumbar lordosis, and tilting the pelvis posteriorly is often recommended for therapeutic purposes. The influence of pelvic tilt on the spinal curves has not been studied. The purpose of this study was to use an objective noninvasive method to determine the effect of the pelvic tilt on the spinal curves in the sagittal plane. Thirty-two healt...

AIMS To compare the responses between clomipramine, a centrally acting substance, and nitroglycerin, with mainly peripheral action, when each drug is used during tilt test for the induction of vasovagal syncope (VVS). METHODS AND RESULTS Hundred patients with recurrent episodes of classical VVS underwent two tilt tests in a randomized sequence. One test included 20 min of tilt at 60 degrees w...