• Title/Summary/Keyword: geometrical relationship

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Evaluating Correlation between Geometrical Relationship and Dose Difference Caused by Respiratory Motion Using Statistical Analysis

  • Shin, Dong-Seok;Kang, Seong-Hee;Kim, Dong-Su;Kim, Tae-Ho;Kim, Kyeong-Hyeon;Cho, Min-Seok;Noh, Yu-Yoon;Yoon, Do-Kun;Suh, Tae Suk
    • Progress in Medical Physics
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    • v.27 no.4
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    • pp.203-212
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    • 2016
  • Dose differences between three-dimensional (3D) and four-dimensional (4D) doses could be varied according to the geometrical relationship between a planning target volume (PTV) and an organ at risk (OAR). The purpose of this study is to evaluate the correlation between the overlap volume histogram (OVH), which quantitatively shows the geometrical relationship between the PTV and OAR, and the dose differences. 4D computed tomography (4DCT) images were acquired for 10 liver cancer patients. Internal target volume-based treatment planning was performed. A 3D dose was calculated on a reference phase (end-exhalation). A 4D dose was accumulated using deformation vector fields between the reference and other phase images of 4DCT from deformable image registration, and dose differences between the 3D and 4D doses were calculated. An OVH between the PTV and selected OAR (duodenum) was calculated and quantified on the basis of specific overlap volumes that corresponded to 10%, 20%, 30%, 40%, and 50% of the OAR volume overlapped with the expanded PTV. Statistical analysis was performed to verify the correlation with the OVH and dose difference for the OAR. The minimum mean dose difference was 0.50 Gy from case 3, and the maximum mean dose difference was 4.96 Gy from case 2. The calculated range of the correlation coefficients between the OVH and dose difference was from -0.720 to -0.712, and the R-square range for regression analysis was from 0.506 to 0.518 (p-value <0.05). However, when the 10% overlap volume was applied in the six cases that had OVH value ${\leq}2$, the average percent mean dose differences were $34.80{\pm}12.42%$. Cases with quantified OVH values of 2 or more had mean dose differences of $29.16{\pm}11.36%$. In conclusion, no significant statistical correlation was found between the OVH and dose differences. However, it was confirmed that a higher difference between the 3D and 4D doses could occur in cases that have smaller OVH value.

Target Identification using the Mahalanobis Distance and Geometric Parameters (마할라노비스 거리와 기하학적 파라메터에 의한 표적의 인식)

  • 이준웅;권인소
    • Journal of Institute of Control, Robotics and Systems
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    • v.5 no.7
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    • pp.814-820
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    • 1999
  • We propose a target identification algorithm for visual tracking. Target identification is realized by finding out corresponding line segments to the hypothesized model segments of the target. The key idea is the combination of the Mahalanobis distance with the geometrical relationship between model segments and extracted line segments.

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Eye Gaze Interface in Wearable System (웨어러블 시스템에서 눈동자의 움직임을 이용한 인터페이스)

  • 권기문;이정준;박강령;김재희
    • Proceedings of the IEEK Conference
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    • 2003.07e
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    • pp.2124-2127
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    • 2003
  • This paper suggests user interface method with wearable computer by means of detecting gaze under HMD, head mounted display, environment. System is derived as follows; firstly, calibrate a camera in HMD, which determines geometrical relationship between monitor and captured image. Second, detect the center of pupil using ellipse fitting algorithm and represent a gazing position on the computer screen. If user blinks or stares at a certain position for a while, message is sent to wearable computer. Experimental results show ellipse fitting is robust against glint effects, and detecting error was 6.5%, and 4.25% in vertical and horizontal direction, respectively.

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Target identification for visual tracking

  • Lee, Joon-Woong;Yun, Joo-Seop;Kweon, In-So
    • 제어로봇시스템학회:학술대회논문집
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    • 1996.10a
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    • pp.145-148
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    • 1996
  • In moving object tracking based on the visual sensory feedback, a prerequisite is to determine which feature or which object is to be tracked and then the feature or the object identification precedes the tracking. In this paper, we focus on the object identification not image feature identification. The target identification is realized by finding out corresponding line segments to the hypothesized model segments of the target. The key idea is the combination of the Mahalanobis distance with the geometrica relationship between model segments and extracted line segments. We demonstrate the robustness and feasibility of the proposed target identification algorithm by a moving vehicle identification and tracking in the video traffic surveillance system over images of a road scene.

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Localization for Mobile Robot Using Vertical Line Features (수직선 특징을 이용한 이동 로봇의 자기 위치 추정)

  • 강창훈;안현식
    • Journal of Institute of Control, Robotics and Systems
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    • v.9 no.11
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    • pp.937-942
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    • 2003
  • We present a self-localization method for mobile robots using vertical line features of indoor environment. When a 2D map including feature points and color information is given, a mobile robot moves to the destination, and acquires images from the surroundings having vertical line edges by one camera. From the image, vertical line edges are detected, and pattern vectors meaning averaged color values of the left and right regions of the each line are computed by using the properties of the line and a region growing method. The pattern vectors are matched with the feature points of the map by comparing the color information and the geometrical relationship. From the perspective transformation and rigid transformation of the corresponded points, nonlinear equations are derived. Localization is carried out from solving the equations by using Newton's method. Experimental results show that the proposed method using mono view is simple and applicable to indoor environment.

Localization for Mobile Robot Using Vertical Lines

  • Kang, Chang-Hun;Ahn, Hyun-Sik
    • 제어로봇시스템학회:학술대회논문집
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    • 2003.10a
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    • pp.793-797
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    • 2003
  • In this paper, we present a self-localization method for mobile robots using vertical line features of indoor environment. When a 2D map including feature points and color information is given, a mobile robot moves to the destination, and acquires images by one camera from the surroundings having vertical line edges. From the image, vertical line edges are detected, and pattern vectors meaning averaged color values of the left and right region of each line segment are computed. The pattern vectors are matched with the feature points of the map using the color information and the geometrical relationship of the points. From the perspective transformation of the corresponded points, nonlinear equations are derived. Localization is carried out from solving the equations by using Newton's method. Experimental results show that the proposed method using mono view is simple and applicable to indoor environment.

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Human Head Mouse System Based on Facial Gesture Recognition

  • Wei, Li;Lee, Eung-Joo
    • Journal of Korea Multimedia Society
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    • v.10 no.12
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    • pp.1591-1600
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    • 2007
  • Camera position information from 2D face image is very important for that make the virtual 3D face model synchronize to the real face at view point, and it is also very important for any other uses such as: human computer interface (face mouth), automatic camera control etc. We present an algorithm to detect human face region and mouth, based on special color features of face and mouth in $YC_bC_r$ color space. The algorithm constructs a mouth feature image based on $C_b\;and\;C_r$ values, and use pattern method to detect the mouth position. And then we use the geometrical relationship between mouth position information and face side boundary information to determine the camera position. Experimental results demonstrate the validity of the proposed algorithm and the Correct Determination Rate is accredited for applying it into practice.

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Development of train/bridge interaction Analysis program Consideration braking (열차 제동하중을 고려한 차량/교량 상호 작용 해석기법 개발)

  • Yun hee sub;Kim Man-Cheol;Han sang chel
    • Proceedings of the KSR Conference
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    • 2005.11a
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    • pp.1177-1183
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    • 2005
  • This paper presents the effects of dynamic response of the railway bridge through the suspension system when the train is moving with uniform speed and non-uniform speed Railway bridges are subjected to dynamic loads generated by the interaction between moving vehicles and the bridge structures. these dynamic loads result in response fluctuation in bridge members. To investigate the real dynamic behavior of the bridge, a number of analytical and experimental investigation should be carried out. This paper, a train/bridge interaction analysis program considerate braking action. New scheme consideration of braking action on the bridge using speed-dependent braking function is presented. This program also used torsional degree of freedom and constraint equation based on geometrical relationship in order to take into consideration three-dimensional eccentricity effect due to the operation on double track through quasi three-dimensional analysis.

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Optimization of Build Parameters in SLS Process (SLS의 공정 파라미터 최적화에 관한 연구)

  • Heo, Seong-Min;O, Do-Geun;Choe, Gyeong-Hyeon;Lee, Seok-Hui
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.24 no.3 s.174
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    • pp.769-776
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    • 2000
  • RP(Rapid Prototyping) technology is gaining its popularity in building a prototype in all industries. SLS(Slective Laser Sintering) is one of RP technologies, which is focused on tooling processes as well as three dimension solid model. There are several factors, the length and the cross-sectional area of a part, that have an effect on build setup in SLS process. In this paper, the computation on geometrical relationship is used to slice STL file and to estimate these factors. Based on these values, the build setup parameters such as the heating temperature, the laser power, and the powder cartridge feed rate are determined by neural network approaches. The test results show that the computation time is saved and the neural network approach is able to apply to get the optimal parameters of build process within an acceptable error rate.

Eye Gaze toy Human Computer Interaction (눈동자의 움직임을 이용한 휴먼 컴퓨터 인터랙션)

  • 권기문;이정준;박강령;김재희
    • Proceedings of the IEEK Conference
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    • 2003.11b
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    • pp.83-86
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    • 2003
  • This paper suggests user's interface with computer by means of detecting gaze under HMD, head mounted display, environment. System is derived as follows; firstly, calibrate a camera in HMD, which determines geometrical relationship between monitor and captured image. Second, detect the center of pupil using algorithm of the center of mass and represent a gazing position on the computer screen. If user blinks or stares at a certain position for a while, message is sent to computer. Experimental results show the center of mass is robust against glint effects, and detecting error was 7.1%. and 4.85% in vertical and horizontal direction, respectively. To adjust detailed movement of a mouse takes 0.8 sec more. The 98% of blinking is detected successfully and 94% of clicking detection is resulted.

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