• Journal of Institute of Control, Robotics and Systems
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• v.19 no.4
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• pp.379-384
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• 2013

We propose a new global positioning method for the indoor mobile robots. The multiple indoor lights fixed in ceiling are used as the landmarks of positioning system. The ceiling images are acquired by the fisheye lens camera mounted on the moving robot. The position and orientation of the lights are extracted by binarization and labeling techniques. Also the boundary lines between ceiling and walls are extracted to identify the order of each light. The robot position is then calculated from the extracted position and known position of the lights. The proposed system can increase the accuracy and reduce the computation time comparing with the other positioning methods using natural landmark. Experimental results are presented to show the performance of the method.

• Journal of the Korean Society for Precision Engineering
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• v.17 no.5
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• pp.160-167
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• 2000

In this research, the fatigue behaviors of carbonitrided Cr-Mo(SCM415) steel are examined. From fatigue test results, we propose a modified fatigue strength evaluation model and modified formulae. That is, we develop improved models fur evaluating and predicting the fatigue strength of carbonitrided SCM415 by modifying specific terms in the Murakami and Endo's model which is the representative fatigue strength evaluation formulae fur high strength steel.

• Journal of the Korean housing association
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• v.14 no.5
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• pp.37-46
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• 2003

The quantitative analysis of view tells how surroundings and sky are showed, and requires understanding of visual perception and three dimensional information of buildings. The visual perception and the existing projection methods for view analysis are examined. The results of this study are as follows: The visual perception on the size is determined by the visual angle, which can be described as a solid angle. The analysis of view by planar projection can be narrow-sighted according to the size of the window and the location of the viewpoint, which will cause the obstacles in the normal direction of the window interfere the view. For the analysis of view by fisheye projection, the area around the focus point is calculated wider than other areas, and so the view ratio depends on the position of the focus point. When analyzing sky view by dividing the sky vault into the differential area, the distortion by projection can be minimized.

• Journal of the Korean Society for Precision Engineering
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• v.15 no.8
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• pp.135-144
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• 1998

In this research, the fatigue behaviors of Cr-Mo(SCM415) steel and carbonitrided CrMo(SCM415) steel are examined. The description of experiments in detail as follows. For SCM415 and carbonitried Cr-Mo(SCM415) steel, smooth specimens and hole defected specimens are fabricated and tested under a rotary bending tester, respectively. By performing the rotary bending fatigue test for smooth and hole defected specimens, the characteristics of the fatigue strength are examined for parameters such as tensile strength, hardness at surface, and residual stresses.

• Current Optics and Photonics
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• v.1 no.4
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• pp.378-388
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• 2017

We present a graphical method for determining a pair of optical materials and powers to design an achromatic and athermal lens system with corrected Petzval curvature. To graphically obtain the solutions, a three-dimensional (3D) glass chart is proposed. Even if a particular material combination is unavailable, we can select an element suitable for a specific lens and continuously change the element powers of an equivalent single lens for aberrations correction. Thus, we can iteratively identify the materials and powers on a 3D glass chart. By designing a fisheye lens using this method, an achromatic and athermal system with flat Petzval curvature is obtained, over the specified waveband and temperature ranges.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2001.05a
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• pp.357-362
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• 2001

The purpose of this study is to investigate the effect of nitriding on the fatigue strength and fatigue life of turbine rotor steel (ICr-lMo-0.25V), and acquire data on the fatigue strength of nitrided turbine rotor steel at high temperature (538$^{\circ}C$). Specimens were nitrided with various layer thicknesses (160$\mu$m, 270$\mu$m and 290$\mu$m) using the nitemper method. A microstructure analysis, microhardness test, surface roughness test, and fracture surface analysis were also carried out at room temperature in order to investigate the mechanical properties of the nitrided specimens.

• Proceedings of the Korea Information Processing Society Conference
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• 2004.05a
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• pp.1259-1262
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• 2004

Detecting environmental hazards and monitoring remote terrain are among many sensor network applications. In case of fire detection, it is significantly valuable to monitor fire-spot's shape and trend in time. Mobile ad hoc sensor nodes right round are responsible for sensoring, processing and networking packets, or even launching extinguisher. In this paper, we proposed a ring-oriented Multicast architecture based on "Fisheye State Routing" (MFSR) to organize a group of mobile ad hoc sensor nodes in a multicast way. It is familiar with traditional mesh-based multicast protocol [1] in mobile ad hoc network, trying to concentrates on efficiency and robustness simultaneously. Certain applications-based solution for hazards is proposed, quantitative results including architecture and recovery algorithms of MFSR are also investigated in this paper.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.13 no.4
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• pp.2148-2161
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• 2019

In this paper, we present a real-time cattle action recognition algorithm to detect the estrus phase of cattle from a live video stream. In order to classify cattle movement, specifically, to detect the mounting action, the most observable sign of the estrus phase, a simple yet effective feature description exploiting motion history images (MHI) is designed. By learning the proposed features using the support vector machine framework, various representative cattle actions, such as mounting, walking, tail wagging, and foot stamping, can be recognized robustly in complex scenes. Thanks to low complexity of the proposed action recognition algorithm, multiple cattle in three enclosures can be monitored simultaneously using a single fisheye camera. Through extensive experiments with real video streams, we confirmed that the proposed algorithm outperforms a conventional human action recognition algorithm by 18% in terms of recognition accuracy even with much smaller dimensional feature description.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2021.06a
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• pp.212-215
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• 2021

본 논문에서는 6 Fisheye lens 원본 영상에 대하여 Insta360 stitcher, AutoStitch[4], As-Projective-AsPossible(APAP)[5] 스티칭 방법으로 360 도 파노라마 영상을 생성하고 기하학적 왜곡과 컬러 왜곡을 비교 평가한다. 360 도 파노라마 Image Quality Assessment(IQA) 메트릭으로 Natural Image Quality Evaluator(NIQE)[6], Blind/Referenceless Image Spatial Quality Evaluator (BRISQUE)[7], Perception based Image Quality Evaluator(PIQE)[8], Feature Similarity(FSIM)[9] 그리고 high frequency feature 에 대한 Structural Similarity(SSIM)[10]을 측정하여 정량적 평가를 하며 정성적인 비교를 통하여 파노라마 영상의 품질과 평가 메트릭에 대한 벤치마크를 제공한다.

• Journal of the Semiconductor & Display Technology
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• v.23 no.1
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• pp.56-60
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• 2024

In this paper, we propose a SIFT feature-based dynamic stitching algorithm for image calibration and correction of a 360-degree surround view system. The existing surround view system requires a lot of processing time and money because in the process of image calibration and correction. The traditional marker patterns are placed around the vehicle and correction is performed manually. Therefore, in this study, images captured with four fisheye cameras mounted on the surround view system were distorted and then matched with the same feature points in adjacent images through SIFT-based feature point extraction to enable image stitching without a fixed marker pattern.