• Proceedings of the Korean Society of Computer Information Conference
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• 2022.01a
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• pp.353-355
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• 2022

본 논문에서는 외력에 의해 헤어가 움직일 때, 전체가 아닌 변형률이 큰 부분에 입자 제어점을 추가하여 베지에 곡선을 그리는 적응형 헤어 시뮬레이션 기법을 제안한다. 일반적인 정규화 샘플링을 통한 물리 시뮬레이션은 헤어의 움직임에 대한 정확도가 높은 반면, 계산량이 증가하고 메모리를 많이 차지하기 때문에 비효율적이다. 이 문제는 굽힘이 일어나는 특정 부분만 활용한 적응형 샘플링을 통해 해결할 수 있으며, 메모리뿐만 아니라 속도 측면에서도 모두 우수한 성능을 보인다. 본 논문에서 제안하는 방법을 이용한 굽힘 샘플링 기법은 헤어의 굽힘 패턴에 따라 실시간으로 표현되며 자연스럽고 부드러운 실제 헤어와 유사한 결과를 보여준다.

• Proceedings of the Korean Society of Computer Information Conference
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• 2022.07a
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• pp.559-562
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• 2022

본 논문에서는 젖은 머리카락의 응집력을 효율적으로 표현할 수 있는 적응형 샘플링 기법을 제안한다. 젖은 헤어는 인접 머리카락과 달라붙어 머리카락 하단으로 뭉치는 응집력 형태를 지닌다. 헤어 동역학은 수많은 입자 구조로 연결되어있으며 머리카락의 상호작용을 고려하는 젖은 헤어의 경우 응집력 계산이 개별적인 머리카락 단위로 표현되기 때문에, 이를 위한 계산과정을 효율적으로 풀어내는 것은 중요하다. 본 논문에서는 젖은 헤어의 시뮬레이션을 효율적으로 계산하기 위해 밀도와 각도, 그리고 포화도를 고려한 적응형 샘플링 기법을 제안한다. 이는 속도와 메모리 측면에서 최적화가 가능하며 헤어 입자의 추가와 삭제를 통해 사실적인 젖은 머리카락의 응집력 표현을 실시간으로 표현할 수 있다. 본 논문에서 제안하는 방법은 실제 젖은 헤어와 유사한 결과를 보여주며, 실시간 프로그램에서 사람의 젖은 모발 또는 동물의 젖은 털의 특징 등을 표현하는데 응용할 수 있다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.12 no.5
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• pp.466-477
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• 1987

본 논문에서는 NTSC칼라 TV합성신호를 프레임내에서 색도신호와 명도신호성분으로 분리하기 위한 두 종류의 적응 필터링 방식을 제시하였다. 적응 필터링 방식에 있어서 합성신호는 수직필터와 수평필터에 의하여 필터링 되어 지고 화상의 국부적인 특성에 따라 필터의 출력이 선택되어 진다. 첫번째 방식에서는 조건형 스위칭 알고리즘에 의하여 수직필터 또는 수평필터의 출력이 최종단의 출력으로 결정되어 진다. 두번째 방식에서는 선형 조합 검출 알고리즘에 의하여 수직필터와 수평필터의 출력의 가중치합이 최종단의 출력이 된다. 사용된 필터들은 NTSC 칼라 TV 합성신호를 4fsc로 샘플한 경우에 대하여 설계되어졌다. 몇가지 정량적인 기준을 이용하여 여러가지 방식들을 컴퓨터 시뮬레이션에 의하여 비교평가하였다.

• KIPS Transactions on Software and Data Engineering
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• v.5 no.9
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• pp.401-410
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• 2016

3D registration is a computer vision technique of aligning multi-view range images with respect to a reference coordinate system. Various 3D registration algorithms have been introduced in the past few decades. Iterative Closest Point (ICP) is one of the widely used 3D registration algorithms, where various modifications are available nowadays. In the ICP-based algorithms, the closest points are considered as the corresponding points. However, this assumption fails to find matching points accurately when the initial pose between point clouds is not sufficiently close. In this paper, we propose a new method to solve this problem using the 6D distance (3D color space and 3D Euclidean distances). Moreover, a color segmentation-based adaptive sampling technique is used to reduce the computational time and improve the registration accuracy. Several experiments are performed to evaluate the proposed method. Experimental results show that the proposed method yields better performance compared to the conventional methods.

• Journal of Convergence for Information Technology
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• v.8 no.1
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• pp.201-206
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• 2018

Recently, as technologies for realizing artificial intelligence have become more common, machine learning is widely used. Machine learning provides insight into collecting large amounts of data, batch processing, and taking final action, but the effects of the work are not immediately integrated into the learning process. In this paper proposed an adaptive learning model to improve the performance of real-time stream analysis as a big business issue. Adaptive learning generates the ensemble by adapting to the complexity of the data set, and the algorithm uses the data needed to determine the optimal data point to sample. In an experiment for six standard data sets, the adaptive learning model outperformed the simple machine learning model for classification at the learning time and accuracy. In particular, the support vector machine showed excellent performance at the end of all ensembles. Adaptive learning is expected to be applicable to a wide range of problems that need to be adaptively updated in the inference of changes in various parameters over time.

• Journal of the Korea Society of Computer and Information
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• v.27 no.3
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• pp.63-69
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• 2022

In this paper, we propose a new GPU-based framework for quickly calculating adaptive and continuous SDF(Signed distance fields), and examine cases related to rendering/collision processing using them. The quadtree constructed from the triangle mesh is transferred to the GPU memory, and the Euclidean distance to the triangle is processed in parallel for each thread by using it to find the shortest continuous distance without discontinuity in the adaptive grid space. In this process, it is shown through experiments that the cut-off view of the adaptive distance field, the distance value inquiry at a specific location, real-time raytracing, and collision handling can be performed quickly and efficiently. Using the proposed method, the adaptive sign distance field can be calculated quickly in about 1 second even on a high polygon mesh, so it is a method that can be fully utilized not only for rigid bodies but also for deformable bodies. It shows the stability of the algorithm through various experimental results whether it can accurately sample and represent distance values in various models.

• Journal of KIISE:Software and Applications
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• v.29 no.11
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• pp.809-817
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• 2002

This paper describes a new face detection method that is a pre-processing algorithm for on-line face recognition. To complement the weakness of using only edge or rotor features from previous face detection method, we propose the two types of face detection method. The one is a combined method with edge and color features and the other is a center area color sampling method. To prevent connecting the people's face area and the background area, which have same colors, we propose a new adaptive edge detection algorithm firstly. The adaptive edge detection algorithm is robust to illumination variance so that it extracts lots of edges and breakouts edges steadily in border between background and face areas. Because of strong edge detection, face area appears one or multi regions. We can merge these isolated regions using color information and get the final face area as a MBR (Minimum Bounding Rectangle) form. If the size of final face area is under or upper threshold, color sampling method in center area from input image is used to detect new face area. To evaluate the proposed method, we have experimented with 2,100 face images. A high face detection rate of 96.3% has been obtained.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.19 no.2
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• pp.211-224
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• 1994

In this paper, a multi-level adaptive intraframe method has been proposed to separate the luminance and chominance components in NTSC composite signal. The control signals are generated by detecting the vertical correlation and transition in the horizontal and diagonal directions. The chrominance component is adaptively processed through vertical and horizontal filters according to the control signals and the luminance component is processed by subtracting the chrominance component from the composite video signal. The several filters have been used at the sampling rate of four times the color subcarrier frequency and computer simulation and SVP(Serial Video Processing) system have been introduced to compare the performance of the conventional methods and that of proposed one.

• Journal of KIISE
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• v.43 no.4
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• pp.399-403
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• 2016

Deferred Shading is a shading technique that postprocesses pixels in the screen space, following geometry-only rendering passes with depth buffering. Unlike typical shadow mapping techniques, this technique allows us to render shadows from multiple light sources without changing the structure of the rendering pipelines. This paper presents a deferred shadow mapping technique and its extension to soft shadows using mipmapping. Our technique first generates visibility maps from light sources, and blurs the visibility maps for deferred shading. This strategy leads to efficient soft-edged shadows, but does not incorporate depth variation, producing light bleeding to some extent. In order to suppress the light-bleeding artifacts, we also propose a depth-adaptive mipmap sampling technique in the screen space.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.3A
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• pp.317-324
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• 2000

In this paper, we propose an interpolation technique to rain attenuation data which represents dynamic characteristics by time variations. By using this technique, it is possible to sample the rain attenuation data at an arbitrary time interval, and thus it would play an important role in developing adaptive transmission scheme for countermeasuring rain attenuation. We propose the interpolation technique which can synthesizes rain attenuation data by extracting the most proper parameters required to emulate the dynamic characteristics of rain attenuation. Interpolation results to measured data of I minute time interval will be demonstrated, and it is shown that more exact performance evaluation of adaptive transmission scheme to countermeasure rain attenuation can be achieved.