• The Mathematical Education
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• v.48 no.2
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• pp.183-190
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• 2009

This is a following study of the preceding study, Flexibility of mind and divergent thinking in problem solving process that was performed by Choi & Do in 2005. In this paper, we discuss the relationship between ability to shift a viewpoint and insight into invariance, another major consideration in mathematical creativity, in the process of mathematical problem solving.

• Proceedings of the KSR Conference
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• 1998.05a
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• pp.291-298
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• 1998

The object of this study is to investigate the effect of elastic wheel from the viewpoint of noise and vibration of railway vehicle. The vibration reduction was predicted from the FRF difference between elastic wheel and solid wheel by FEM simulation. The elastic wheel and solid wheel were compared in viewpoint of carbody vibration and car interior noise level. The effect of elastic wheel on the noise and vibration of subway vehicle was obtained. But, the application of elastic wheel must be reviewed in some aspect.

• Journal of Institute of Control, Robotics and Systems
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• v.18 no.1
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• pp.7-12
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• 2012

In this paper, we present an effective viewpoint estimation algorithm for the Moving parallax barrier method of 3D display mobile device. Moving parallax barrier is designed to overcome the biggest problem, the limited view angle. To accomplish it, the position of the viewer's eyes or face should be estimated with strong stability and no latency. We focus on these requirements in the poor performance of mobile processors. We used a pre-processing algorithm in order to overcome the various illumination changes. And, we combined the conventional Viola-Jones face detection method and Optical-flow algorithm for robust and stable viewpoint estimation. Various computer simulations prove the effectiveness of the proposed method.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2009.01a
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• pp.583-587
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• 2009

In this paper we propose a new method of Depth-Image-Based Rendering (DIBR) for Free-viewpoint TV (FTV). In the proposed method, virtual viewpoint images are rendered with 3D warping instead of estimating the view-dependent depth since depth estimation is usually costly and it is desirable to eliminate it from the rendering process. However, 3D warping causes some problems that do not occur in the method with view-dependent depth estimation; for example, the appearance of holes on the rendered image, and the occurrence of depth discontinuity on the surface of the object at virtual image plane. Depth discontinuity causes artifacts on the rendered image. In this paper, these problems are solved by reconstructing disparity information at virtual camera position from neighboring two real cameras. In the experiments, high quality arbitrary viewpoint images were obtained.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2009.01a
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• pp.751-754
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• 2009

This paper deals with the Cell-based distributed processing for generating free viewpoint images by merging multiple differently focused images. We previously proposed the method of generating free viewpoint images without any depth estimation. However, it is not so easy to realize real-time image reconstruction based on our previous method. In this paper, we discuss the method to reduce the processing time by dimension reduction for image filtering and Cell-based distributed processing. Especially, the method of high-speed image reconstruction by the Cell processor on SONY PLAYSTATION3(PS3) is described in detail. We show some experimental results by using real images and we discuss the possibility of real-time free viewpoint image reconstruction.

• Journal of Information Processing Systems
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• v.11 no.4
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• pp.643-654
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• 2015

Face recognition under controlled settings, such as limited viewpoint and illumination change, can achieve good performance nowadays. However, real world application for face recognition is still challenging. In this paper, we propose using the combination of Affine Scale Invariant Feature Transform (SIFT) and Probabilistic Similarity for face recognition under a large viewpoint change. Affine SIFT is an extension of SIFT algorithm to detect affine invariant local descriptors. Affine SIFT generates a series of different viewpoints using affine transformation. In this way, it allows for a viewpoint difference between the gallery face and probe face. However, the human face is not planar as it contains significant 3D depth. Affine SIFT does not work well for significant change in pose. To complement this, we combined it with probabilistic similarity, which gets the log likelihood between the probe and gallery face based on sum of squared difference (SSD) distribution in an offline learning process. Our experiment results show that our framework achieves impressive better recognition accuracy than other algorithms compared on the FERET database.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.40 no.12
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• pp.2363-2371
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• 2015

In this paper, we propose a new feature matching algorithm which is robust to the viewpoint change by using the FAST(Features from Accelerated Segment Test) feature detector and the SIFT(Scale Invariant Feature Transform) feature descriptor. The original FAST algorithm unnecessarily results in many feature points along the edges in the image. To solve this problem, we apply the principal curvatures for refining it. We use the SIFT descriptor to describe the extracted feature points and calculate the homography matrix through the RANSAC(RANdom SAmple Consensus) with the matching pairs obtained from the two different viewpoint images. To make feature matching robust to the viewpoint change, we classify the matching pairs by calculating the Euclidean distance between the transformed coordinates by the homography transformation with feature points in the reference image and the coordinates of the feature points in the different viewpoint image. Through the experimental results, it is shown that the proposed algorithm has better performance than the conventional feature matching algorithms even though it has much less computational load.

• 한국HCI학회:학술대회논문집
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• 2008.02a
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• pp.772-774
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• 2008

A navigation system for virtual environments using low-quality HMD(head mounted display)must quantize images when the system presents true-color image with restricted number of colors. Such navigation system quantizes an image by using fixed palette. If the system represents an image by using a variable palette which is made considering a region around the viewpoint then user can perceive a virtual environments more vividly because human visual system is sensitive to the colors variation in the region around the viewpoint. In this paper we propose a color quantization algorithm that quantize a region around the viewpoint more finely than other regions at each variation of viewpoint for virtual environments navigation system and compose virtual environments navigation system using proposed algorithm. The system quantizes an image at each variation of viewpoint and shows a quantized image to user through HMD. We tested user preferences for our proposed system and the results show that users preferred our system.

• Proceeding of Spring/Autumn Annual Conference of KHA
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• 2009.04a
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• pp.243-246
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• 2009

Housing distribution rate in our country has been continuously increased with economic growth, but residential plans satisfying the demands of residents are still not perfect yet. The demands of residents can be predicted by analyzing the housing viewpoint of residents. And also, the housing viewpoint can change according to various environmental changes, so it's important for us to understand the trend of change. Therefore, the housing viewpoints of university students who will be subjective residents of houses in future were analyzed by observing change due to trend of time. Target for this study is female university students in 20s. A portion of previously presented material (Korean Home Economics Association 37,1, 67-78) was used as data for 1998 and a questionnaire with 171 female university students was conducted on December 2008 for data for 2008. The following result was drawn from examination of change in the housing viewpoint due to trend of time by comparing the housing viewpoint of university students between 1998 and 2008. First, importance of was decreased and importance of was increased in functions of residence. Second, Most students thought and regardless of the time passage as their opinions on housing. And also, most students considered a living room as the most important space inside of a house regardless of the time passage and the ratio of considering a living room as the most important space was more increased.

• Journal of Korea Game Society
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• v.16 no.6
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• pp.49-58
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• 2016

This paper proposes three schemes of one-hand control that can be used in the First-Person Viewpoint mobile games and evaluates them. Displaying virtual controllers on the screen, the existing mobile games use schema that allows users use both hands. In the First-Person Viewpoint mobile games, however, one-hand control is possible because smaller number of functions for viewpoint movement is required. This research proposes three one-hand control schemes for First-Person Viewpoint movement and rotation, and evaluates them using AHP. The experiment results prove that one-hand control schemes are more useful than both-hands control schemes for the mobile game users.