• Title/Summary/Keyword: Rotating Scanning Mechanism

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Airborne Infrared Scanning Imaging System with Rotating Drum for Fire Detection

  • Song, c;Chang, Jun;Cao, Jiao;Zhang, Lifei;Wen, Yao;Wei, Aman;Li, Jiang
    • Journal of the Optical Society of Korea
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    • v.15 no.4
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    • pp.340-344
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    • 2011
  • Airborne infrared techniques have been used in wild land fire management for decades. This paper describes a kind of infrared scanning system based on a rotating drum with a tilted porthole underside the plane nose. This design increases the stability of the mechanism system, reduces air resistance and protects inner parts. Aberration characteristics of a tilted ellipsoid porthole are analyzed and an effective solution is invented which makes the system achieve $30^{\circ}$ field of regard. The system's ultimate value of modulation transfer function is near the diffraction limit, which indicates that the performance of the rotating optical system meets the imaging requirements.

Coercivity Enhancement in Nd2Fe14B Permanent Magnetic Powders through Rotating Diffusion Process with DyHx Powders

  • Choi, Moon-Hee;Yu, Ji-Hun;Kim, Dong-Hwan;Kim, In-Bae;Kim, Yang-Do
    • Journal of Magnetics
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    • v.16 no.4
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    • pp.342-349
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    • 2011
  • [ $Nd_2Fe_{14}B$ ]permanent magnetic powders ($_iH_c$ = 9.2 kOe, $B_r$ = 12.2 kG) were produced by HDDR process. Their coercivity was enhanced to 12.6 kOe through the grain boundary diffusion process with dysprosium hydride ($DyH_x$). $DyH_x$ diffusion process was optimized through rotating diffusion process, resulting in distinct phases rich in Nd and Dy observable by field emission scanning microscopy and transmission electron microscopy. The mechanism of coercivity enhancement that resulted in restrain the coupling effect between $Nd_2Fe_{14}B$ grains is also discussed.

One Idea on a Three Dimensional Measuring System Using Light Intensity Modulation

  • Fujimoto Ikumatsu;Cho In-Ho;Pak Jeong-Hyeon;Pyoun Young-Sik
    • International Journal of Control, Automation, and Systems
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    • v.3 no.1
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    • pp.130-136
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    • 2005
  • A new optical digitizing system for determining the position of a cursor in three dimensions(3D) and an experimental device for its measurement are presented. A semi-passive system using light intensity modulation, a technology that is well known in radar ranging, is employed in order to overcome precision limitations imposed by background light. This system consists of a charge-coupled device camera placed before a rotating mirror and a light-emitting diode whose intensity is modulated. Using a Fresnel pattern for light modulation, it is verified that a substantial improvement of the signal to noise ratio is realized for the background noise and that a resolution of less than a single pixel can be achieved. This opens the doorway to the realization of high precision 3D digitized measurement. We further propose that a 3D position measurement with a monocular optical system can be realized by a numerical experiment if a linear-period modulated waveform is adopted as the light-modulating one.

Simulation of Elastohydrodynamic Phenomena of Thin Foil in Magnetic Recording Device (자기기록장치에서의 박막탄성체의 탄성유체윤활현상에 관한 수치해석)

  • 권해성;민옥기;김수경
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.18 no.6
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    • pp.1355-1364
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    • 1994
  • This paper analyzes the running mechanism of flexible and thin foil above rotating protrusion through a numerical simulation. The scope of analysis is confined to the phenomena of elastohy-drodynamic lubrication between the stationary and rotary drums with a running protrusion and thin foil. This mathematical model is based on the modified Reynolds equation and the equation of plate, considering the geometry of protrusion, running direction of protrusion, and the effect of geometric nonlinearity. Finite element method is adopted as a numerical simulation technique to solve the avobe coupled nonlinear equations. In numerical analysis, the effects of the scanning angle in Reynolds equation and the nonlinear term in plate equation are evaluated. Furthermore, the simulation is applied to the situation that thin foil is located in the entire drums (stationary and rotary drums).

Basic Examination on 3D Measuring System Using Pulse-Compression

  • Fujimoto Ikumatsu;Ando Shigeru
    • International Journal of Precision Engineering and Manufacturing
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    • v.6 no.4
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    • pp.60-66
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    • 2005
  • In this paper, we propose the basic measurement method of a 3D digitizer using a CCD camera in detail. In the localization measurement with a CCD camera, the effect of the background light and the sensitivity consideration are always problems in realizing a high precision. In this research, a new measurement principle is proposed in which the pulse compression technique known in radar is used to eliminate the effect of background light even under a low intensity light source, and the coordinate values on the CCD camera image plane are determined accurately. From the quantitative evaluation of the S/N ratio improvement and the fundamental experiment, it is verified that a substantial improvement in the S/N ratio is realized for both the background noise and the pixel noise and that a resolution of less than the pixel is sufficiently possible.