• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2009.10a
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• pp.181-184
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• 2009

Authoring AR(augmented-reality) contents not only takes too much time and cost, but also needs the help of professionals in the areas of computer science, VR(virtual reality), AR, 3D computer graphics, computer vision, etc. This paper proposes an authoring tool to allow non-programmers as content creators to author AR contents easily and quickly. An ideal AR authoring tool, which is the goal of our research, faces four major challenges from a technical point of view: (1) easy and quick authoring, (2) strong power of expression, (3) ease of verification and validation, (4) interactive authoring and debugging. To tackle with the challenges, we employ the interactive framework approach using formal and visual specification techniques.

• Journal of the Korea Computer Graphics Society
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• v.21 no.5
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• pp.21-27
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• 2015

In this paper, we presents visual effect(water, fire, smoke) simulation and interaction system for TV virtual studio. TV virtual studio seamlessly synthesizes CG background and a live performer standing on a TV green studio. Previous virtual studios focus on the registration of CG background and a performer in real world. In contrast to the previous systems, we can afford to make new types of TV scenes more easily by simulating interactive visual effects according to a performer. This requires the extraction of the performer motion to be transformed 3D vector field and simulate fluids by applying the vector field to Navier Stokes equation. To add realism to water VFX simulation and interaction, we also simulate the dynamic behavior of splashing fluids on the water surface. To provide real-time recording of TV programs, real-time VFX simulation and interaction is presented through a GPU programming. Experimental results show this system can be used practically for realizing water, fire, smoke VFX simulation and the dynamic behavior simulation of fish flocks inside ocean.

• 한국HCI학회:학술대회논문집
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• 2007.02c
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• pp.306-317
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• 2007

We present an interactive and accurate collision detection algorithm for deformable, polygonal objects based on the streaming computational model. Our algorithm can detect all possible pairwise primitive-level intersections between two severely deforming models at highly interactive rates. In our streaming computational model, we consider a set of axis aligned bounding boxes (AABBs) that bound each of the given deformable objects as an input stream and perform massively-parallel pairwise, overlapping tests onto the incoming streams. As a result, we are able to prevent performance stalls in the streaming pipeline that can be caused by expensive indexing mechanism required by bounding volume hierarchy-based streaming algorithms. At run-time, as the underlying models deform over time, we employ a novel, streaming algorithm to update the geometric changes in the AABB streams. Moreover, in order to get only the computed result (i.e., collision results between AABBs) without reading back the entire output streams, we propose a streaming en/decoding strategy that can be performed in a hierarchical fashion. After determining overlapped AABBs, we perform a primitive-level (e.g., triangle) intersection checking on a serial computational model such as CPUs. We implemented the entire pipeline of our algorithm using off-the-shelf graphics processors (GPUs), such as nVIDIA GeForce 7800 GTX, for streaming computations, and Intel Dual Core 3.4G processors for serial computations. We benchmarked our algorithm with different models of varying complexities, ranging from 15K up to 50K triangles, under various deformation motions, and the timings were obtained as 30~100 FPS depending on the complexity of models and their relative configurations. Finally, we made comparisons with a well-known GPU-based collision detection algorithm, CULLIDE [4] and observed about three times performance improvement over the earlier approach. We also made comparisons with a SW-based AABB culling algorithm [2] and observed about two times improvement.

• Journal of the Korea Computer Graphics Society
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• v.28 no.2
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• pp.29-41
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• 2022

In this paper, we introduce a novel real-time, interactive animation system which uses real-time motion inputs from a low-cost motion-sensing device Kinect. Our system generates interaction motions between the user character and the counterpart character in real-time. While the motion of the user character is generated mimicking the user's input motion, the other character's motion is decided to react to the user avatar's motion. During a pre-processing step, our system analyzes the reference motion data and generates mapping model in advance. At run-time, our system first generates initial poses of two characters and then modifies them so that it could provide plausible interacting behavior. Our experimental results show plausible interacting animations in that the user character performs a modified motion of user input and the counterpart character properly reacts against the user character. The proposed method will be useful for developing real-time interactive animation systems which provide a better immersive experience for users.

• Journal of the Korea Computer Graphics Society
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• v.21 no.2
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• pp.11-20
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• 2015

We present a new interactive technique for directing the motion sequences of an animated character by dragging its specific body part to a desired location in the three-dimensional virtual environment via a hand motion tracking device. The motion sequences of our character is synthesized by reordering subsequences of captured motion data based on a well-known graph representation. For each new input location, our system samples the space of possible future states by unrolling the graph into a spatial search tree, and retrieves one of the states at which the dragged body part of the character gets closer to the input location. We minimize the difference between each pair of successively retrieved states, so that the user is able to anticipate which states will be found by varying the input location, and resultantly, to quickly reach the desired states. The usefulness of our method is demonstrated through experiments with breakdance, boxing, and basketball motion data.

• Journal of the Korea Computer Graphics Society
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• v.7 no.3
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• pp.9-18
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• 2001

Feature detection is important in various mesh processing techniques, such as mesh editing, mesh morphing, mesh compression, and mesh signal processing. In this paper, we propose a geometric snake as an interactive tool for feature detection on a 3D triangular mesh. A geometric snake is an extension of an image snake, which is an active contour model that slithers from its initial position specified by the user to a nearby feature while minimizing an energy functional. To constrain the movement of a geometric snake onto the surface of a mesh, we use the parameterization of the surrounding region of a geometric snake. Although the definition of a feature may vary among applications, we use the normal changes of faces to detect features on a mesh.

• Journal of the Korea Computer Graphics Society
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• v.25 no.2
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• pp.31-41
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• 2019

Extended Reality (XR), such as virtual and augmented reality, has huge potential for immersive data visualization and analysis. In XR, users can interact with data and other users realistically by navigating the shared virtual space, allowing for more intuitive data analysis. However, creating a visualization in XR also poses a challenge because complicated, low-level programming is required, which hinders broad adaptation in visual analytics. This paper proposes an interactive visualization authoring tool based on hand gesture for immersive data visualization-Gadget Arms. The proposed system provides a novel user interaction to create and place visualization in the 3D virtual world. This simple, but intuitive, user interaction enables user designs the entire visualization space in the XR without using a host computer and low-level programming. Our user study also confirmed that the proposed user interaction significantly improves the usability of the visualization authoring tool.

• Journal of the Korean Society of Costume
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• v.51 no.3
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• pp.99-109
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• 2001

The purpose of this study is to propose the effective development a fashion coordination website by computer graphics and web animation programs. Today, the internet fashion shopping malls come into the spotlight as the way of marketing. The amount of clothing products sold on the internet shopping mall and interest in the website design is increasing. This means many people consider that the web site design is one of the most important thing to lead customers to purchasing. For this reasons, this study develop fashion coordination items which was designed by the computer graphics software named 'photoshop 6.0'and propose the more visual effect of fashion coordination web image which was designed by animation software named 'flash 4.0'. As a result of this study. 1 It can accumulate a database of trend garment. 2. It can help designers save a time, expenses and tries to treat design also make correction and transform their work more freely. 3. It can help develop a new textile through the various image adjustment. 4. It can give more visual and interesting effect to website by animation and multimedia. 5. It can able to communicate interactive with each other by website.

• Journal of the Korea Computer Graphics Society
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• v.8 no.1
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• pp.1-11
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• 2002

In order to widely use volume rendering technology in practical fields, a user should be able to control the classification parameter interactively and extract a meaningful information easily from the 3D data as fast as it can be. Previous work on an accelerating volume rendering reconstructs an isotropic volume from an anisotropic one and classifies in pre-processing time and then renders the classified volume rapidly in run time. But, this traditional step may result in long pre-processing time and no real-time feedback. In this paper, we present an efficient classification and rendering method that allows a user to set the opacity transfer function interactively at rendering time on a personal computer without special-purpose hardware.

• Journal of the Korea Computer Graphics Society
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• v.13 no.2
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• pp.1-15
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• 2007

In this paper, we review relevant technologies of MR (Mixed Reality) and show important components of perspective that can overcome technical limitations of the current MR. An MR technology combines real and virtual objects in a real environment, and runs interactive in real time, and is regarded as an emerging technology in a large part of the future of IT (Information Technology). We've grouped the major obstacles limiting the wider use of MR technologies into three themes: technological limitations (i,e., tracking, rendering, authoring, and registration), user interface limitations(i.e. UI metaphor for MR interaction), and social acceptance Issues.