• Title/Summary/Keyword: Wide angle

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Pretilt Angle Dependent Electro-Optic Characteristics of the Fringe-Field Switching mode using the Liquid Crystal with Positive Dielectric Anisotropy (유전율 이방성이 양인 액정을 이용한 프린지 필드 구동형 모드에서 프리틸트각 변화에 따른 전기-광학 특성)

  • 정태봉;임영진;안명환;이승희
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.17 no.3
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    • pp.311-318
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    • 2004
  • We have studied electro-optic characteristics as a function of pretilt angle ($\theta$$_{p}$) in the fringe-field switching (FFS) mode using the LC with positive dielectric anisotropy. When $\theta$$_{p}$ is increased from 0$^{\circ}$ to 20$^{\circ}$, a maximum transmittance and an operating voltage are obviously decreased. In the viewing angle characteristics, the cell with low pretilt angle has a wide region for the contrast ratio greater than 5 and has a best luminance uniformity. Therefore, in the FFS device, a low pretilt angle is favored for high transmittance and wide viewing angle.gle.

Viewing Angle Switching of Vertical Alignment Liquid Crystal Display (수직배향 액정 디스플레이의 시야각 스위칭)

  • Lim, Young-Jin;Jeong, Eun;Choi, Min-Oh;Lee, Seung-Hee
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2006.11a
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    • pp.49-50
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    • 2006
  • We have developed vertical alignment liquid crystal display (VA-LCD), of which the viewing angle can be controlled. The VA-LCD has the function of switching between the wide viewing mode and narrow viewing angle mode using one homogeneous aligned (HA) LC layer and one compensation film with a negative C-plate. The retardation of the HA layer at off axis can be controlled by applying an electric field while keeping the retardation value to be zero at normal direction. Consequently, the device exhibits a viewing mode over $170^{\circ}$ in terms of CR = 10 in wide viewing mode and about $60^{\circ}$ in terms of CR = 2 in narrow viewing angle mode m horizontal direction.

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Viewing angle control of TN-LCD using optical compensation of two LC layers (두 액정 층의 광학적 보상을 이용한 비틀린 네마틱 액정 셀의 시야각 조절)

  • Choi, Min-Oh;Lim, Young-Jin;Jeong, Eun;Lee, Seung-Hee
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2006.06a
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    • pp.479-480
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    • 2006
  • We have studied the viewing angle control of a twist nematic liquid crystal display (TN-LCD). The TN-LCD exhibits a bad image quality along vertical direction, due to characteristics such as low contrast ratio and gray scale inversion. The proposed new TN-LCD has the function of switching between the wide viewing mode and narrow viewing angle mode using two tilted LC layers at both sides of a TN-cell. Tilt angles of the two LC layers, $14^{\circ}$ and $60^{\circ}$ were required in both wide viewing angle and narrow viewing angle modes, respectively.

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Control of Off-axis Viewing Quality using Two Additional Homogeneous LC Layers in Twisted Nematic mode (두개의 수평 배향된 액정층을 이용한 비틀린 네마틱 액정 셀의 시야각 화질 조절)

  • Choi, Min-Oh;Lim, Young-Jin;Jeong, Eun;Lee, Seung-Hee
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2006.11a
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    • pp.53-54
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    • 2006
  • We have studied the viewing angle control of a twist nematic liquid crystal display (TN-LCD). The TN-LCD exhibits a bad image quality along vertical direction, due to characteristics such as low contrast ratio and grey scale inversion. The proposed new TN-LCD has the function of switching between the wide viewing mode and narrow viewing angle mode using two tilted LC layers at both sides of a TN-cell Tilt angles of the two LC layers, $14^{\circ}$ and $60^{\circ}$ were required in both wide viewing angle and narrow viewing angle modes, respectively.

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Distortion in Visual Memory for Wide-angle Image (광각 이미지에 대한 시각적 기억의 왜곡)

  • Jang, Phil-Sik
    • Journal of the Ergonomics Society of Korea
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    • v.26 no.3
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    • pp.11-16
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    • 2007
  • Viewers remember seeing more of the scene than was present in the physical input: an illusion known as boundary extension. This study examined the aspects of the distortion by presenting 69 subjects with wide-angle views of four scenes. Results of recognition and reproduction test showed that the boundary extension is not a unidirectional phenomenon. On the contrary, boundary restriction and foreground extension were observed with extreme wide-angle views of scenes. Results support the hypothesis that boundary restriction and foreground extension were mediated by the activation of a memory schema during picture perception.

Rendezvous Mission to Apophis: V. Wide-Angle Camera Science

  • JeongAhn, Youngmin;Lee, Hee-Jae;Jeong, Minsup;Kim, Myung-Jin;Choi, Jin;Moon, Hong-Kyu;Choi, Young-Jun
    • The Bulletin of The Korean Astronomical Society
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    • v.46 no.2
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    • pp.59.1-59.1
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    • 2021
  • The Korean spacecraft for the exploration of Apophis will be equipped with an optical navigation camera with a wide-angle lens. The major purpose of the wide-angle camera is to capture imagery during the rendezvous phase in order to determine the spacecraft's position and the pointing direction relative to the asteroid Apophis. Two potential sciences, however, can be achieved by the wide-angle camera: (1) to measure the high-order gravity terms, and (2) to capture possible ejecting small particles. In this presentation, we will discuss instrument specification and operation scenario required to accomplish the given science objectives.

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Study on Effective Visual Surveillance System using Dual-mode(Fixed+Pan/Tilt/Zoom) Camera (듀얼 모드(고정형+PTZ 카메라) 감시 카메라를 이용한 효과적인 화상 감시 시스템에 관한 연구)

  • Kim, Gi-Seok;Lee, Saac;Park, Jong-Seop;Cho, Jae-Soo
    • Journal of Institute of Control, Robotics and Systems
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    • v.18 no.7
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    • pp.650-657
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    • 2012
  • An effective dual-mode camera system(a passive wide-angle camera and a pan-tilt-zoom camera) is proposed in order to improve the performance of visual surveillance. The fixed wide-angle camera is used to monitor large open areas, but the moving objects on the images are too small to view in detail. And, the PTZ camera is capable of increasing the monitoring area and enhancing the image quality by tracking and zooming in on a specific moving target. However, its FOV (Field of View) is limited when zooming in on a specific target. Therefore, the cooperation of wide-angle and PTZ cameras is complementary. In this paper, we propose an automatic initial set-up algorithm and coordinate transform method from the wide-angle camera coordinate to the PTZ one, which are necessary to achieve the cooperation. The automatic initial set-up algorithm is able to synchronize the views of two cameras. When a moving object appears on the image plane of a wide-angle camera after the initial set-up positioning, the obtained values of the wide-angle camera should be transformed to the PTZ values based on the coordinate transform method. We also develope the PTZ control method. Various in-door and out-door experiments show that the proposed dual-camera system is feasible for the effective visual surveillance.

The Research for the Wide-Angle Lens Distortion Correction by Photogrammetry Techniques (사진측량 기법을 사용한 광각렌즈 왜곡보정에 관한 연구)

  • Kang, Jin-A;Park, Jae-Min;Kim, Byung-Guk
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.26 no.2
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    • pp.103-110
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    • 2008
  • General lens, widely using in Photogrammetry, has narrow view, and have to adjust "Image-Registration Method" after obtain images and it need cost; economic, period of time. Recent days, there is various study that use wide-angle lens, usually for robotics field, put to practical use in photogrammetry instead of general lens. In this studies, distortion tendency of wide-angle lens and utilize the correction techniques suitable to wide-angle lens by the existing photographic survey methods. After carrying out the calibration of the wide-angle lens, we calculated the correction parameters, and then developed the method that convert the original image-point to new image-point correcting distortion. For authorization the developed algorithm, we had inspection about shape and position; there are approximately 2D RMSE of 3 pixel, cx = 2, and cy = 3 different.

Exposure Filter Design for Wide Angle CRT (CRT 편향각 증가를 위한 노광필터 설계)

  • Kim, Ryo-Hyang;Lee, Tae-Yong;Choi, Sie-Young
    • Journal of the Institute of Electronics Engineers of Korea SD
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    • v.45 no.9
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    • pp.14-20
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    • 2008
  • In recent days, a wide angle for slim depth in CRT(Cathode ray tube) is required to meet other rapidly growing slim FPD such as LCD and PDP. However, in making the CRT with a wide angle screen, problems, such as a difficulty in forming black matrix, and excessive formation of black matrix, can be occurred. In this work, we designed a new exposure filter systm to avoid these problems for a wide angle CRT. We changed the design concept from a filter-to-Panel method to a Panel-to-fater control method, which can control the Black Matrix to easily satisfy the user's request. This study suggests new filter design method for a wide angle CRT which has good screen qualify.

Design of Off-axis Wide Angle Lens for the Automobile Application

  • Kim, Tae Young;Shin, Min-Ho;Kim, Young-Joo
    • Journal of the Optical Society of Korea
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    • v.17 no.4
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    • pp.336-343
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    • 2013
  • Recently various types of driver assistance systems have been used for automobiles. In 2008, the U.S Congress passed a law which required that most cars be equipped with devices to warn objects behind the vehicle. Because of that, market of rear view cameras is expected to rise dramatically. Therefore many suppliers try to provide a wide angle camera for car makers. But a high distortion is caused by the wide angle might result in lower image quality. In order to improve the image quality, normally we use an algorithm to correct a distortion. Though we can improve the distorted image by correction algorithm, we must pay more cost to use it. In this paper, we propose a new optical system reducing a distortion in contrast to a conventional lens without cost. In other words, we can see only an area of interest. That is similar to reducing a field of view. Using a new optical system, we can get a less distorted image. In order to view an area of interest, we introduce an off axis optical system having refractive surfaces and reflective surfaces. In this paper, we describe the results of design and, evaluation of an off axis wide angle compact imaging system. In comparison to conventional wide angle lens, we can get the improvement of MTF, distortion, and lateral color aberrations. And we also can reduce a total cost because we don't need the outer apparatus or bracket to mount on the car.