We designed and implemented a magnetically levitated stage with large planar motion capability. This planar magnetic levitator employs four novel permanent-magnet linear motors. Each motor generates vertical force for suspension against gravity, as well as horizontal force for drive. These linear levitation motors can be used as building blocks in the general class of multi-degree-of-freedom mo...

The effects of surface markings on perceived motion direction were examined for a rotating sphere in a structure-from-motion display. The markings were dot patterns representing separate line segments or intersecting line segments (crosses) covering the surface of the sphere. The orientation of the surface markings and their intersection angles affected the perceived direction of motion, sugges...

Nyquist ghosts are an inherent artifact in echo planar imaging acquisitions. An approach to robustly eliminate Nyquist ghosts is presented that integrates two previous Nyquist ghost correction techniques: temporal domain encoding (phase labeling for additional coordinate encoding: PLACE and spatial domain encoding (phased array ghost elimination: PAGE). Temporal encoding modulates the echo plan...

We propose a vision-based registration method for Augmented Reality (AR) that uses real scenes containing multiple planar structures. Our method provides users with an enhanced view of a real scene by overlaying computer-generated virtual objects onto images captured with a movable camera. The virtual objects are associated with a 3D planar structure and appeared to move with that structure. To...

This paper presents the design and multivariable feedback control of a compact precision positioner. The moving stage that has a total mass of 1.52 kg can generate all 6-axis motions with a single frame. Aerostatic bearings levitate the positioner and three 3-phase synchronous permanent-magnet planar motors (SPMPMs) generate electromagnetic forces over the concentrated-field permanent-magnet ma...

A vision sensor calibration method based on flexible three-dimensional (3d) target and invariance of cross ratio is proposed. Flexible 3d target is obtained by moving planar target to different positions. According to the relative position relationship of planar targets in the different positions, unify target points to the base coordinate frame of the flexible 3d target. Using the invariance o...

The FanGrower algorithm proposed here segments a manifold triangle mesh into regions (called caps), which may each be closely approximated by a triangle-fan. Once the caps are formed, their rims, which form the inter-cap boundaries, are simplified, replacing each fan by its frame—a fan with the same apex but fewer triangles. The resulting collection of frames is an approximation of the original...

This paper studies the problem of sequence-to-sequence alignment, namely establishing correspondences in time and in space between two di erent video sequences of the same dynamic scene. The sequences are recorded by uncalibrated video cameras, which are either stationary or jointly moving, with xed (but unknown) internal parameters and relative inter-camera external parameters. Temporal variat...

This paper studies the problem of designing a rational Bézier developable surface pencil with a common isogeodesic, and provides an algorithm for the representation of complicated geometric models in industrial applications which need to satisfy that the shape surface can be developed and a given curve is geodesic. By employing the local Frenet orthonormal frame, the explicit expression of the ...

Real-time rendering of recursive reflections have previously been done using different techniques. However, a fast unified approach for capturing recursive reflections on both planar and curved surfaces, as well as glossy reflections and interreflections between such primitives, have not been described. This paper describes a framework for efficient simulation of recursive specular reflections ...