• Title/Summary/Keyword: camera lens

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Compact Zoom Lens Design for a 5x Mobile Camera Using Prism

  • Park, Sung-Chan;Lee, Sang-Hun;Kim, Jong-Gyu
    • Journal of the Optical Society of Korea
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    • v.13 no.2
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    • pp.206-212
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    • 2009
  • This study presents the compact zoom lens with a zoom ratio of 5x for a mobile camera by using a prism. The lens modules and aberrations are applied to the initial design for a four-group inner-focus zoom system. An initial design with a focal length range of 4.4 to 22.0 mm is derived by assigning the first-order quantities and third-order aberrations to each module along with the constraints required for optimum solutions. We separately designed a real lens for each group and then combined them to establish an actual zoom system. The combination of the separately designed groups results in a system that satisfies the basic properties of the zoom system consisting of the original lens modules. In order to have a slim system, we directly inserted the right-angle prism in front of the first group. This configuration resulted in a more compact zoom system with a depth of 8 mm. The finally designed zoom lens has an f-number of 3.5 to 4.5 and is expected to fulfill the requirements for a slim mobile zoom camera having high zoom ratio of 5x.

Design of Cluster Type Assembly System for Lens Module of Phone Camera (폰 카메라 렌즈모듈의 Cluster Type 조립시스템 설계)

  • Song J.Y.;Lee C.W.;Jung Y.W.;Kim Y.G.
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2005.06a
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    • pp.974-977
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    • 2005
  • Automatic lens assembly system is used for automatically assembling the lens module of phone camera. In this paper, we are trying to develop the cluster type automatic lens assembly with standard tray for applying for assembly field directly. This paper proposes the principle of cluster type lens assembly system and the related assembly production line concept for optimal automatic lens production line.

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Robust Optimization of a Lens System for a Mobile Phone Camera (휴대폰 카메라용 렌즈 시스템의 강건최적설계)

  • Jung, Sang-Jin;Min, Jun-Hong;Choi, Dong-Hoon;Kim, Ju-Ho
    • Korean Journal of Computational Design and Engineering
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    • v.15 no.5
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    • pp.325-332
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    • 2010
  • A lens system for mobile phone cameras is comprised of various lenses and designed so as to satisfy design requirements for responses such as a modular transfer function (MTF). However, it is difficult to manufacture and assemble camera modules to maintain the same performance compared with the designed camera modules, because of uncertainty. We should always design a lens system by considering uncertainty that can be caused by errors in the manufacturing and assembly process of mobile phone cameras. The robust optimization offers tools of making robust decisions with the consideration of design parameters, uncontrollable parameters, and the variance of the system. Using an efficient reliability analysis method and an optimization algorithm, we obtained robust optimization results that maximize the mean of MTF and minimize the standard deviation and proposed a new robust design process for a lens system.

A Defocus Technique based Depth from Lens Translation using Sequential SVD Factorization

  • Kim, Jong-Il;Ahn, Hyun-Sik;Jeong, Gu-Min;Kim, Do-Hyun
    • 제어로봇시스템학회:학술대회논문집
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    • 2005.06a
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    • pp.383-388
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    • 2005
  • Depth recovery in robot vision is an essential problem to infer the three dimensional geometry of scenes from a sequence of the two dimensional images. In the past, many studies have been proposed for the depth estimation such as stereopsis, motion parallax and blurring phenomena. Among cues for depth estimation, depth from lens translation is based on shape from motion by using feature points. This approach is derived from the correspondence of feature points detected in images and performs the depth estimation that uses information on the motion of feature points. The approaches using motion vectors suffer from the occlusion or missing part problem, and the image blur is ignored in the feature point detection. This paper presents a novel approach to the defocus technique based depth from lens translation using sequential SVD factorization. Solving such the problems requires modeling of mutual relationship between the light and optics until reaching the image plane. For this mutuality, we first discuss the optical properties of a camera system, because the image blur varies according to camera parameter settings. The camera system accounts for the camera model integrating a thin lens based camera model to explain the light and optical properties and a perspective projection camera model to explain the depth from lens translation. Then, depth from lens translation is proposed to use the feature points detected in edges of the image blur. The feature points contain the depth information derived from an amount of blur of width. The shape and motion can be estimated from the motion of feature points. This method uses the sequential SVD factorization to represent the orthogonal matrices that are singular value decomposition. Some experiments have been performed with a sequence of real and synthetic images comparing the presented method with the depth from lens translation. Experimental results have demonstrated the validity and shown the applicability of the proposed method to the depth estimation.

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Feasibility of Using an Automatic Lens Distortion Correction (ALDC) Camera in a Photogrammetric UAV System

  • Jeong, Hohyun;Ahn, Hoyong;Park, Jinwoo;Kim, Hyungwoo;Kim, Sangseok;Lee, Yangwon;Choi, Chuluong
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.33 no.6
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    • pp.475-483
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    • 2015
  • This study examined the feasibility of using an automatic lens distortion correction (ALDC) camera as the payload for a photogrammetric unmanned aerial vehicle (UAV) system. First, lens distortion for the interior orientation (IO) parameters was estimated. Although previous studies have largely ignored decentering distortion, this study revealed that more than 50% of the distortion of the ALDC camera was caused by decentering distortion. Second, we compared the accuracy of bundle adjustment for camera calibration using three image types: raw imagery without the ALDC option; imagery corrected using lens profiles; and imagery with the ALDC option. The results of image triangulation, the digital terrain model (DTM), and the orthoimage using the IO parameters for the ALDC camera were similar to or slightly better than the results using self-calibration. These results confirm that the ALDC camera can be used in a photogrammetric UAV system using only self-calibration.

A Study on the Camera Calibration Using Lens Distortion Model (렌즈의 왜곡 모델을 이용한 카메라 보정에 관한 연구)

  • Dong Min Woo
    • Journal of the Korean Institute of Telematics and Electronics B
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    • v.31B no.2
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    • pp.56-68
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    • 1994
  • The objective of camera calibration is to determine the internal optical characteristics of camera and the three-dimensional position and orientation of camera with respect to the real world. Calibration procedure for computer vision should be automatical, accurate and applicable to general purpose cameras and lenses. In this paper, we present camera calibration method which meets the above requirements. The algorithm is based on the two-stage method which takes into account lens distortion in the second stage. In this paper, the overdetermined nonlinear system is established in terms of the constraints to all directions and our calibration algorithm is proposed which is constructed by using Marquardt iterations and our calibration algorithm is proposed which is constructed by using Marquardt iteration method in solving nonlinear equations. Experimental results indicate that lens distortion should be taken into consideration for the calibration of the general-purpose lens. With 24 calibration points acquired out of 512$\times$512 image, the proposed algorithm came up with average error of less than 1 pixel and showed a higher accuracy over the conventional two-stage method.

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Estimation of Rotation of Camera Direction and Distance Between Two Camera Positions by Using Fisheye Lens System

  • Aregawi, Tewodros A.;Kwon, Oh-Yeol;Park, Soon-Yong;Chien, Sung-Il
    • Journal of Sensor Science and Technology
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    • v.22 no.6
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    • pp.393-399
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    • 2013
  • We propose a method of sensing the rotation and distance of a camera by using a fisheye lens system as a vision sensor. We estimate the rotation angle of a camera with a modified correlation method by clipping similar regions to avoid symmetry problems and suppressing highlight areas. In order to eliminate the rectification process of the distorted points of a fisheye lens image, we introduce an offline process using the normalized focal length, which does not require the image sensor size. We also formulate an equation for calculating the distance of a camera movement by matching the feature points of the test image with those of the reference image.

HTF Algorithm for Evaluation of Lenses (렌즈 평가를 위한 MTF 알고리즘)

  • Song, Pil-Jae;Lee, Jong-Kue
    • Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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    • 2006.05a
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    • pp.403-406
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    • 2006
  • Various cameras that is included digitial camera and portable individual terminal are supplied rapidly. Therefore, is trying for quality sophistication of camera that buy each camera manufacture. However, is selecting sample test way because there is no correct lens measurement method in mass production. This paper presents method to measure performance of lens to improve performance of camera. This paper presents method to measure performance of lens to improve performance of camera. As automation public prosecutor lens quality is correct and did quantification so that done measuring is possible. And processing designed possible MTF with high steed.

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Performance Evaluation and Design of Zoom Lens Systems (Zoom Lens계의 성능 평가 및 설계)

  • Ji, Taek Sang
    • Journal of Korean Ophthalmic Optics Society
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    • v.7 no.2
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    • pp.113-121
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    • 2002
  • Nowadays, developed camera, camcorder, CCTV and copier system accept a wide angle and a telephoto lens, and have an excellent capacity. Also, it is small as using aspheric surface. In this paper, after we evaluate and analyze two-group zoom lens system and three-group zoom lens system for camera, we refer to it, and design three-group zoom lens system for camera. Therefore, when we design a zoom lens system for camera, we use a symmetrical system. As using an aspheric surface, we can try to a miniaturization and an efficient improvement. We use optical valuable measure methods, a ray intercept plot, MTF and Seidel coefficient. So, we can confirm to have a similar level to compare with reference model.

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Auto detect inspection system for single lens product of mobile phone camera (휴대폰 카메라용 렌즈단품 이물 자동검사장비)

  • Song C.H.;Jung Y.W.;Bae S.S.;Song J.Y.;Kim Y.G.
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2005.10a
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    • pp.432-435
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    • 2005
  • The Mega-pixel camera phones become main trends in mobile phone market. The lens modules used in mesa-pixel camera phones need high resolution. One of the main factors of resolution drop is the defects of bare lens. Though there are many advantages in auto-inspection of defects of bare lens, high technical problems take the defect inspections to be done with manual process. In this paper, the type and the source of defects were described and bare lens defect auto-inspection system design was explained. The designed auto-inspection system is composed of illumination optics part, focusing optics part and auto-moving system. With the proposed auto-inspection system, fast and uniform inspection of bare lens can be achieved.

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