• Title/Summary/Keyword: camera lens

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Camera Calibration And Lens of Distortion Model Constitution for Using Artificial Neural Networks (신경망을 이용한 렌즈의 왜곡모델 구성 및 카메라 보정)

  • Kim, Min-Suk;Nam, Chang-Woo;Woo, Dong-Min
    • Proceedings of the KIEE Conference
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    • 1999.07g
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    • pp.2923-2925
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    • 1999
  • The objective of camera calibration is to determine the internal optical characteristics of camera and 3D position and orientation of camera with respect to the real world. Calibration procedure applicable to general purpose cameras and lenses. The general method to revise the accuracy rate of calibration is using mathematical distortion of lens. The effective og calibration show big difference in proportion to distortion of camera lens. In this paper, we propose the method which calibration distortion model by using neural network. The neural network model implicity contains all the distortion model. We can predict the high accuracy of calibration method proposed in this paper. Neural network can set properly the distortion model which has difficulty to estimate exactly in general method. The performance of the proposed neural network approach is compared with the well-known Tsai's two stage method in terms of calibration errors. The results show that the proposed approach gives much more stable and acceptabke calibration error over Tsai's two stage method regardless of camera resolution and camera angle.

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Accurate Camera Calibration Using GMDH Algorithm (GMDH 알고리즘을 이용한 정확한 카메라의 보정기법)

  • Kim, Myoung-Hwan;Do, Yong-Tae
    • Proceedings of the KIEE Conference
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    • 2004.11c
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    • pp.592-594
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    • 2004
  • Camera calibration is an important problem to determine the relationship between 3D real world and 2D camera image. The existing calibration methods can be classified into linear and non-linear models. The linear methods are simple and robust against noise, but the accuracy expectation is generally poor. In comparison, if the non-linearity, which is due mainly to lens distortion, is corrected, the accuracy can be better. However, as the optical features of lens are diverse, no non-linear method can be always effective for diverse vision systems. In this paper, we propose a new approach to correct the calibration error of a linear method using GMDH algorithm. The proposed technique is simple in concept and showed improved accuracy in various cases.

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Automatic Focus Control for Assembly Alignment in a Lens Module Process (렌즈 모듈 생산 공정에서 조립 정렬을 위한 자동 초점 제어)

  • Kim, Hyung-Tae;Kang, Sung-Bok;Kang, Heui-Seok;Cho, Young-Joon;Park, Nam-Gue;Kim, Jin-Oh
    • Journal of the Korean Society for Precision Engineering
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    • v.27 no.2
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    • pp.70-77
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    • 2010
  • This study proposed an auto focusing method for a multi-focus image in assembling lens modules in digital camera phones. A camera module in a camera phone is composed of a lens barrel, an IR glass, a lens mount, a PCB board and aspheric lenses. Alignment among the components is one of the important factors in product quality. Auto-focus is essential to adjust image quality of an IR glass in a lens holder, but there are two focal points in the captured image due to thickness of IR glass. So, sharpness, probability and a scale factor are defined to find desired focus from a multi-focus image. The sharpness is defined as clarity of an image. Probability and a scale factors are calculated using pattern matching with a registered image. The presented algorithm was applied to a lens assembly machine which has 5 axes, two vacuum chucks and an inspection system. The desired focus can be determined on the local maximum of the sharpness, the probability and the scale factor in the experiment.

A Method for Estimating the Distance Using the Stereo Zoom Lens Module (양안 줌 렌즈 모듈을 이용한 깊이 추정 방법)

  • Hwang, Eun-Seop;Lee, Seung-U;Gwon, Gi-Cheol;Gil, Sang-Geun;Kim, Nam
    • Proceedings of the Optical Society of Korea Conference
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    • 2007.02a
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    • pp.125-126
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    • 2007
  • This paper discussed a method for estimating the distance using the stereo zoom lens module. A method for estimating the distance using single zoom lens is limited in convergence angle. So, we composed horizontal moving camera and estimated the distance. In the experiment, we get the wider convergence angle and more precise distance than single camera's.

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Design and Implementation of Convergence Point Adjustment Method for Zoom-In (줌인을 위한 컨버전스포인트 조정 기법의 설계 및 구현)

  • Ha, Jong-Soo;Kim, Dae-Woong
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.17 no.6
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    • pp.1383-1388
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    • 2013
  • Even though a dual lens stereoscopic camera allows for convenient stereoscopic photography, the necessity for the research comes up, since the dual lens stereoscopic camera can cause visual discomfort during zoom-in due to the fixed convergence point. We propose a method based on which a convergence point can be adjusted to prevent visual discomfort during zoom-in for a dual lens stereoscopic camera. First, the relational model is classified into nine kinds and defined, depending on locations of focus, object, and convergence point. And then, the method to minimize visual discomfort is suggested by adjusting convergence point on the given model. We also implement the suggested methods with anaglyph computer graphic and demonstrate the superiority of them.

Design and Implementation of Convergence Point Adjustment Method for Zoom-In (줌인을 위한 컨버전스포인트 조정 기법의 설계 및 구현)

  • Ha, Jong-soo;Kim, Dae-woong
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2013.05a
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    • pp.456-459
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    • 2013
  • Even though a dual lens stereoscopic camera allows for convenient stereoscopic photography, the necessity for the research comes up, since the dual lens stereoscopic camera can cause visual discomfort during zoom-in due to the fixed convergence point. We propose a method based on which a convergence point can be adjusted to prevent visual discomfort during zoom-in for a dual lens stereoscopic camera. First, the relational model is classified into nine kinds and defined, depending on locations of focus, object, and convergence point. And then, the method to minimize visual discomfort is suggested by adjusting convergence point on the given model. We also implement the suggested methods with anaglyph computer graphic and demonstrate the superiority of them.

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Fish-eye camera calibration and artificial landmarks detection for the self-charging of a mobile robot (이동로봇의 자동충전을 위한 어안렌즈 카메라의 보정 및 인공표지의 검출)

  • Kwon, Oh-Sang
    • Journal of Sensor Science and Technology
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    • v.14 no.4
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    • pp.278-285
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    • 2005
  • This paper describes techniques of camera calibration and artificial landmarks detection for the automatic charging of a mobile robot, equipped with a fish-eye camera in the direction of its operation for movement or surveillance purposes. For its identification from the surrounding environments, three landmarks employed with infrared LEDs, were installed at the charging station. When the robot reaches a certain point, a signal is sent to the LEDs for activation, which allows the robot to easily detect the landmarks using its vision camera. To eliminate the effects of the outside light interference during the process, a difference image was generated by comparing the two images taken when the LEDs are on and off respectively. A fish-eye lens was used for the vision camera of the robot but the wide-angle lens resulted in a significant image distortion. The radial lens distortion was corrected after linear perspective projection transformation based on the pin-hole model. In the experiment, the designed system showed sensing accuracy of ${\pm}10$ mm in position and ${\pm}1^{\circ}$ in orientation at the distance of 550 mm.

Virtual portraits from rotating selfies

  • Yongsik Lee;Jinhyuk Jang;SeungjoonYang
    • ETRI Journal
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    • v.45 no.2
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    • pp.291-303
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    • 2023
  • Selfies are a popular form of photography. However, due to physical constraints, the compositions of selfies are limited. We present algorithms for creating virtual portraits with interesting compositions from a set of selfies. The selfies are taken at the same location while the user spins around. The scene is analyzed using multiple selfies to determine the locations of the camera, subject, and background. Then, a view from a virtual camera is synthesized. We present two use cases. After rearranging the distances between the camera, subject, and background, we render a virtual view from a camera with a longer focal length. Following that, changes in perspective and lens characteristics caused by new compositions and focal lengths are simulated. Second, a virtual panoramic view with a larger field of view is rendered, with the user's image placed in a preferred location. In our experiments, virtual portraits with a wide range of focal lengths were obtained using a device equipped with a lens that has only one focal length. The rendered portraits included compositions that would be photographed with actual lenses. Our proposed algorithms can provide new use cases in which selfie compositions are not limited by a camera's focal length or distance from the camera.

The Aspheric Analysis through the Optical Capacity of 35mm Camera with an Aspheric Zoom Lens System (35mm 카메라 비구면 줌 렌즈계의 광학적 성능을 통한 비구면 분석)

  • Ji, Taek Sang;Lim, Hyeon Seon;Kim, Bong Hwan
    • Journal of Korean Ophthalmic Optics Society
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    • v.6 no.1
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    • pp.93-100
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    • 2001
  • We analyzed aspheric patterns after we investigated zoom lens' constructions and optical capacities of a ordinary designed 35mm camera with an aspheric zoom lens system in this research. As this lens system was the zoom lens system about infinite object point, it was made to get a short back focal length, be able to use a lens unit more close to the image plane, and be used the compact camera which got a viewing system. The zoom ratio of the system was 1 : 2 and it got a positive and negative power's distribution. As it was determined the 35~70 mm focal length range which the most common people used, it might be called economic optical system considered universality. As it was used two aspheric surface, it was used just three lens, compensated the aberration and schemed lens' miniaturization, lightweightization, and the decrease effect of the unit cost of production.

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