Han Kyun Choi

Feature detection of triangular meshes based on tensor voting theory

Abstract This paper presents n -dimensional feature recognition of triangular meshes that can handle both geometric properties and additional attributes such as color information of a physical object. Our method is based on a tensor voting technique for classifying features and integrates a clustering and region growing methodology for segmenting a mesh into sub-patches. We classify a feature into a corner, a sharp edge and a face. Then, finally we detect features via region merging and cleaning processes. Our feature detection shows good performance with efficiency for various dimensional models.

Immersive modeling system (IMMS) for personal electronic products using a multi-modal interface

In developing new personal electronic products, the development time has shortened to a few months due to high competition in the market. Now it has become very hard to meet the time to market by evaluating products by making physical prototypes. To overcome this problem, we propose an immersive modeling system (IMMS) that enables us to interact with a digital product model in the augmented virtual environment using a multi-modal interface. The IMMS allows the user to evaluate the product model realistically using visual, auditory, and tactile/force senses. The architecture and main modules of the system are described in detail. The integration problems encountered during the development of the test bed are discussed. Application examples to personal electronic products are also included.

Mesh simplification with vertex color

In a resource-constrained computing environment, it is essential to simplify complex meshes of a huge 3D model for visualization, storing and transmission. Over the past few decades, quadric error metric (QEM) has been the most popular error evaluation method for mesh simplification because of its fast computation time and good quality of approximation. However, quadric based simplification often suffers from its large memory consumption. Since recent 3D scanning systems can acquire both geometry and color data simultaneously, the size of model and memory overhead of quadric increases rapidly due to the additional color attribute. This paper proposes a new error estimation method based on QEM and half-edge collapse for simplifying a triangular mesh model which includes vertex color. Our method calculates geometric error by the original QEM, but reduces the required memory for maintaining color attributes by a new memory-efficient color error evaluation method.

Physics Based Deformation Using Shape Matching in Augmented Reality Environments

The importance of the deformation and physics based deformation methods are continuously increasing in computer graphics area. However, the user interaction and reality using them is still insufficient for the various applications such as modeling process and game industry. In this paper, we propose physics based deformation technology under AR (augmented reality) environments to improve the effectiveness of the model manipulation. In the proposed method, free form deformation and lattice shape matching method are combined first for the stable and fast deformation of the polygonal model. Then dynamics of the lattice shape matching region is applied for the physics based deformation. Finally those algorithms are implemented under AR environment. For the various physics based simulations, the adjustment of the material properties such as elasticity and damping ratio are also enable.

Deformation and Simulation of 3D Contents for the Digilog Book

Recently the use of e-book has been rapidly increased due to the development of portable electronic devices taking advantage of their portability and storage. The e-book can contain various multimedia contents which cannot be expressed in a traditional text-book such as movie clips, music and flash games. However, physical presence and analog sensibility of a traditional book cannot be described in the e-book. To overcome these limitations, the concept of digilog book has been proposed, which combines analog sensibility and digitized contents. In this research, we propose 3D contents deformation and simulation techniques in the Augmented Reality(AR) environments that can be utilized in the digilog book. Furthermore, the deformation technique is extended to dynamic simulation and user specified simulation using a physics engine and deformation paths.

A mesh simplification method using noble optimal positioning

This paper proposes a mesh simplification method by finding the optimal positions of vertices. It generates a Bezier patch around the collapsed edge and finds the optimal position based on visual importance and curvature. It successfully maintains the geometry and topology of the model even when the size of the model is reduced to less than 5 % of the original model. Our method uses QEM for the error measure. It can be applied to usual mesh simplification but also to mesh parameterization and remeshing.

A deformable model of soap film considering physical properties

Modeling of the soap film for a given boundary curve, called Plateaus problem, is identical with constructing the surface of minimal area. Since mathematicians have dealt with this topic in 19th century, two methods have been widely used to solve the minimal surface problem. The first algorithm originated with solving the linear Dirichlet problem in [Pinkall and Polthier 1993], and another approach in [M. Desbrun 1999] was to evolve the surface via mean curvature flow. In order to describe the deformation of soap film based on dynamics, however, it is required to consider its physical properties as well as geometric properties. In this paper, we propose a physics-based model for the deformation of soap film through discrete differential geometry. It shows robust results for given boundaries as inputs.