• Title, Summary, Keyword: Scanning Method

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Adaptive Scanning for H.264/AVC Intra Coding

  • Lee, Yung-Lyul;Han, Ki-Hun;Sim, Dong-Gyu;Seo, Jeong-Il
    • ETRI Journal
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    • v.28 no.5
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    • pp.668-671
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    • 2006
  • In this letter, an adaptive scanning that improves intra coding efficiency in the H.264/AVC standard is proposed. The proposed adaptive scanning utilizes the prediction directions (modes) that include the horizontal and vertical edge information in a block. Depending on the prediction directions, the proposed method uses three scanning methods: zigzag scanning, horizontal scanning, and vertical scanning. In the proposed method, horizontal and vertical scanning are used in vertical and horizontal prediction modes, respectively, and the normal zigzag scanning in the H.264 standard is used in all other intra prediction modes. The proposed method reduces the bit rate by approximately 2.5% compared with H.264/AVC, without the degradation of video quality.

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Signal increasing method in confocal scanning microscopy in fluorescence mode using curved mirror

  • Kang, Dong-kyun;Seo, Jung-woo;Gweon, Dae-gab
    • 제어로봇시스템학회:학술대회논문집
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    • pp.99.3-99
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    • 2001
  • In fluorescence mode confocal scanning microscope, level of detected signal is very low. In object scanning type confocal scanning microscope, the additional optical system with objective lens and plane mirror was proposed to increase signal intensity, but there was none for beam scanning type confocal scanning microscope. We propose reflecting optical systems which improve signal intensity in beam scanning type confocal scanning microscope. We choose one of the proposed optical systems and design the optical system, i.e., select optical components and assign distances between the selected components. To design the optical system, we use finite ray tracing method and make cost function to be minimized.

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A Pilot Study of the Scanning Beam Quality Assurance Using Machine Log Files in Proton Beam Therapy

  • Chung, Kwangzoo
    • Progress in Medical Physics
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    • v.28 no.3
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    • pp.129-133
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    • 2017
  • The machine log files recorded by a scanning control unit in proton beam therapy system have been studied to be used as a quality assurance method of scanning beam deliveries. The accuracy of the data in the log files have been evaluated with a standard calibration beam scan pattern. The proton beam scan pattern has been delivered on a gafchromic film located at the isocenter plane of the proton beam treatment nozzle and found to agree within ${\pm}1.0mm$. The machine data accumulated for the scanning beam proton therapy of five different cases have been analyzed using a statistical method to estimate any systematic error in the data. The high-precision scanning beam log files in line scanning proton therapy system have been validated to be used for off-line scanning beam monitoring and thus as a patient-specific quality assurance method. The use of the machine log files for patient-specific quality assurance would simplify the quality assurance procedure with accurate scanning beam data.

Continuous Scanning Method for Improvement of Precision and Fabrication Efficiency of Two-Photon Stereolithography (연속적 스캐닝 방법을 이용한 이광자 광중합 공정의 제작 속도 및 정밀도 개선에 관한 연구)

  • Lim, Tae-Woo;Son, Yong;Yang, Dong-Yol;Kong, Hong-Jin;Lee, Kwang-Sup;Park, Sang-Hu
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.32 no.5
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    • pp.396-401
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    • 2008
  • Minimization of processing time in two-photon stereolithography (TPS) has been one of important issues. Generally, a voxel scanning method (VSM) has been used in TPS because the method is very profitable for the stable fabrication irrespective of jittering and response time of scanning equipments such as a stage and a galvano-scanner. However, supplementary processing time due to the on/off control of a shutter for the generation of each voxel is required inevitably in VSM; by this reason, much processing time takes to fabricate largescale micropatterns and three-dimensional patterns. In this work, a continuous scanning method (CSM), generating patterns by movement of beam focus with a constant speed, is proposed for the improvements of scanning speed and precision in TPS. Some line patterns are fabricated by each scanning method to demonstrate the usefulness of CSM with viewpoints of scanning speed and precision.

Pattern Shape Modulation by Scanning Methods in E-Beam Lithography (전자빔 리소그래피를 이용한 주사기법에 따른 패턴형상 조정)

  • Oh, Se-Kyu;Kim, Seoung-Jae;Kim, Dong-Hwan;Park, Keun;Jang, Dong-Young
    • Journal of The Korean Society of Manufacturing Technology Engineers
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    • v.18 no.6
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    • pp.558-564
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    • 2009
  • To aim at obtaining a correct and fine small pattern by an electron beam lithography several conditions and methods affecting a real pattern shape needs to be investigated. A micro/nano sized pattern shape is sometimes dependent on the scanning method. In this work, four types of scanning methods are implemented and their characteristics are investigated. For a $11\times11um$ pattern, a Zigzag scanning method proves a precise pattern generation. The other ways such as SEM scanning and swirl in-out scanning method result in some distorted pattern shape. It is proved that abrupt change in the pattern generation limits to obtaining a fine and small pattern.

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Evaluation of Scanning Methods for Target Detection (표적 검출을 위한 주사방법들의 성능평가)

  • Lee, Moon-Kyu
    • Journal of Institute of Control, Robotics and Systems
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    • v.19 no.1
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    • pp.72-79
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    • 2013
  • Different scanning methods can be used to detect targets of interest in an image. In this paper, four scanning methods, generalized raster scanning, radial scanning, corner scanning, and random scanning, are considered for the evaluation of their scanning performances. The scanning performance is defined here as the ratio of the average scanning area required to detect a single target to the whole image area. Analytic expressions for the performance of each scanning method are derived. Computational results are given to illustrate the usage and validity of the expressions for the performance comparison.

A Study on Generation of Laser Scanning Path and Scanning Control (레이저 주사 경로 생성 및 주사 제어에 관한 연구)

  • 최경현;최재원;김대현;도양회;이석희;김성종;김동수
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • pp.1295-1298
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    • 2004
  • Selective Laser Sintering(SLS) method is one of Rapid Prototyping(RP) technologies. It is used to fabricate desirable part to sinter powder and stack the fabricated layer. To develop this SLS machine, it needs effective scanning path and the development of scanning device. This paper shows how to make fast scanning path with respect to scan spacing, laser beam size and scanning direction from 2-dimensional sliced file generated in commercial CAD/CAM software. Also, we develop the scanning device and its control algorithm to precisely follow the generated scanning path. Scanning path affects precision and total machining time of the final fabricated part. Sintering occurs using infrared laser which has high thermal energy. As a result, shrinkage and curling of the fabricated part occurs according to thermal distribution. Therefore, fast scanning path generation is needed to eliminate the factors of quality deterioration. It highly affects machining efficiency and prevents shrinkage and curling by relatively lessening the thermal distribution of the surface of sintering layer. To generate this fast scanning path, adaptive path generation is needed with respect to the shape of each layer, and not simply x, y scanning, but the scanning of arbitrary direction must be enabled. This paper addresses path generation method to focus on fast scanning, and development of scanning system and control algorithm to precisely follow generated path.

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Development of single optical axis scanning PIV method (단일 광경로 스캔PIV기법의 개발)

  • Kim Hyoung-Bum;Jeong In-Young;Lee Sang-Hyuk;Ryu Chung-Hwan;Jean Hertzberg
    • 한국가시화정보학회:학술대회논문집
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    • pp.6-10
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    • 2005
  • PIV(Particle image velocimetry) presents the flow velocity of whole flow fields in a fraction of a second. Conventional PIV method uses two optical axis configuration during the image grabbing process. That is, the illumination plane and the recording plane must be parallel. This configuration is very natural to grab the whole field without the image distortion. In the real problem, it is often to meet the situation which this configuration is hard to be fulfilled. In this study, we developed new PIV method which only uses single optical axis to grab the particle images. This new PIV method become possible by utilizing the scanning method similar to echo PIV technique. One particle image of scanning PIV consists of scanned several line images and by repeating this scanning process, two particle images were grabbed and processed to produce the velocity vectors.

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Development of the Scanning PIV Method with Single Optical Axis (단일 광경로 스캐닝 PIV기법 개발)

  • Kim, Hyoung-Bum
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.31 no.2
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    • pp.181-187
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    • 2007
  • Conventional PIV method uses two optical axis configuration during the image grabbing process. That is, the illumination plane and the recording plane must be parallel. This configuration is very natural to grab the whole field without the image distortion. In the real problem, it is often to meet the situation when this configuration is hard to be fulfilled. In the present study, the new PIV method which uses only single optical axis to grab the particle images is developed. This new PIV method becomes possible by utilizing the scanning method similar to the echo PIV technique. One particle image of the scanning PIV consists of scanned several line images and by repeating this scanning process, two particle images were grabbed and processed to produce the velocity vectors. An optimization study was performed to find parameters which minimize the measurement errors. The effects of particle diameter, beam overlap ratio and particle number density were investigated.

Adaptive Coefficient Scanning Based on the Intra Prediction Mode

  • Choi, Byeong-Doo;Kim, Jin-Hyung;Ko, Sung-Jea
    • ETRI Journal
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    • v.29 no.5
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    • pp.694-696
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    • 2007
  • This letter presents an adaptive coefficient scanning method for intra mode coding in H.264. The proposed adaptive scanning uses six alternative scanning orders based on the intra prediction mode. Experimental results show that the proposed method improves the coding efficiency up to 3% compared to conventional scanning methods without additional computations.

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