Yi-King Choi

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Blue noise point sampling is one of the core algorithms in computer graphics. In this paper, we present a new and versatile variational framework for generating point distributions with high-quality blue noise characteristics while precisely adapting to given density functions. Different from previous approaches based on discrete settings of(More)
We propose a variational approach to computing an optimal segmentation of a 3D shape for computing a union of tight bounding volumes. Based on an affine invariant measure of e-tightness, the resemblance to ellipsoid, a novel functional is formulated that governs an optimization process to obtain a partition with multiple components. Refinement of(More)
We present a new method for modeling discrete constant mean curvature (CMC) surfaces, which arise frequently in nature and are highly demanded in architecture and other engineering applications. Our method is based on a novel use of the CVT (<i>centroidal Voronoi tessellation</i>) optimization framework. We devise a CVT-CMC energy function defined as a(More)
In this paper, we propose a novel edge prior for image interpolation which assumes that the variation of image intensity away from an edge is locally similar along the edge. Based on this edge prior, our method first approximates the gradient of the HR image which is then refined by diffusion. The unknown HR pixels are estimated by a weighted average of(More)
Collision detection and avoidance are important in robotics. Compared with commonly used circular disks, elliptic disks provide a more compact shape representation for robots or other vehicles confined to move in the plane. Furthermore, elliptic disks allow a simpler analytic representation than rectangular boxes, which makes it easier to perform continuous(More)
The area coverage problem of mobile sensor networks has attracted much attention recently, as mobile sensors find many important applications in remote and hostile environments. However, the deployment of mobile sensors in a non-convex domain is nontrivial due to the more general shape of the domain and the attenuation of sensing capabilities caused by the(More)
Given two convex polyhedra P and Q and a direction s, the minimum directional distance (MDD) is defined to be the shortest translational distance along the direction s that is required to make P and Q just in contact. In this paper we propose a novel method, called MDD-DUAL , for computing the MDD between two convex polyhedra. The MDD is equivalent to the(More)
A new index is proposed for describing the degree of folding of a planar curve segment. Based on a basic concept from integral geometry, the Curve Folding Index (CFI) of a curve segment is defined to be the expected number of intersections that a random line has with the curve. The CFI provides a simple measure to characterize planar curves in terms of the(More)
We present an accurate and efficient algorithm for continuous collision detection between two moving ellipsoids. We start with a highly optimized implementation of interference testing between two stationary ellipsoids based on an algebraic condition described in terms of the signs of roots of the characteristic equation of two ellipsoids. Then we derive a(More)