• Proceedings of the Optical Society of Korea Conference
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• 2005.02a
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• pp.250-251
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• 2005

• Proceedings of the Optical Society of Korea Conference
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• 2008.02a
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• pp.135-136
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• 2008

• 정보저장시스템학회:학술대회논문집
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• 2005.10a
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• pp.4-11
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• 2005

In this paper, we propose novel optics design for media inside near-field recording (NFR) using hemispherical solid immersion lens (HMS). To obtain strong advantage of data protection and high data capacity simultaneously, HMS based near field optics using aplanatic position of super hemisphere is designed. In this design, to improve small optical tolerance of this aplanatic position, additional aspheric lens surface is added on top of the HMS and it is combined with zoom optics which composed of two single lenses having low numerical aperture (NA). Also, to compensate chromatic aberration which happens seriously in optics using blue laser diode, diffractive optical element is used. Using zoom optics, additional aspheric lens surface, and diffractive optical element together, wavefront aberration and chromatic aberration are effectively reduced in broad range of cover layer thickness and wavelength variation. In addition, In this paper, effect of gap induced aberration is investigated by analyzing different behavior of each TM and TE wave for designed media inside dual-layer NFR optics.

• Transactions of the Society of Information Storage Systems
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• v.2 no.1
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• pp.13-20
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• 2006

In this paper, we propose novel optics design for media inside near-field recording(NFR) using hemispherical solid immersion lens(HMS). To obtain strong advantage of data protection and high data capacity simultaneously, HMS based near field optics using aplanatic position of super hemisphere is designed. In this design, to improve small optical tolerance of this aplanatic position, additional aspheric lens surface is added on top of the HMS and it is combined with zoom optics which composed of two single lenses having low numerical aperture(NA). Also, to compensate chromatic aberration which happens seriously in optics using blue laser diode, diffractive optical element is used. Using zoom optics, additional aspheric lens surface, and diffractive optical element together, wavefront aberration and chromatic aberration are effectively reduced in broad range of cover layer thickness and wavelength variation. In addition, in this paper, effect of gap induced aberration is investigated by analyzing different behavior of each TM and TE wave for designed media inside dual-layer NFR optics.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 1999.06a
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• pp.125-131
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• 1999

In this paper, we address practical methods for calculating camera lens distortion for real time applications. Although the lens distortion problem can be easily ignored for constant-parameter lenses, in the field of real-time camera calibrations, for zoom lenses a large number of calculations are needed to calculate the distortion. However, if the distortion can be calculated independently of the other camera parameter, we can easily calibrate a camera without the need for a large number of calculations. Based on Tsai's camera model, we propose two different methods for calculating lens distortion. These methods are so simple and require so few calculations that the lens distortion can be rapidly calculated even in real-time applications. The first method is to refer to the focal length - lens distortion Look Up Table(LUT), which is constructed in the initialization process. The second method is to use the relationship between the feature points found in the image. Experiments were carried out for both methods, results of which show that the proposed methods are favorably comparable in performance with non-real full optimization method.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.18 no.1
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• pp.11-19
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• 2008

This paper proposes small VCM(voice coil motor) type, auto-focusing and zoom actuators for mobile information devices. In order to meet the large output displacement within small height restriction, the proposed auto-focusing actuator adopts curved suspensions, which are similar to a leaf-spring type suspension of optical disk drives. The sensitivity of design parameters on output displacement and dynamic performance is implemented using ANSYS (3D FEM tool) to determine the optimal geometry and stiffness of the curved suspensions. This paper also investigates a new zoom actuator without a suspension supporting a bobbin. The zoom actuator uses a moving rail and a stoper mechanism by generating rotational force at lens holder. Magnetic flux density of the zoom actuator are calculated by both the FEM and permeance method. Experiments using prototypes of the proposed focusing and zoom models show that both actuators meet the required displacement and performance.

• The Journal of the Convergence on Culture Technology
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• v.8 no.5
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• pp.713-721
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• 2022

In order to use the LED video wall in the broadcasting studio, there are a few things to be aware of. First, since the pixels are closely arranged, a moire phenomenon may occur due to a short arrangement period, and second, the distance between pixels (pixel pitch) may be recorded on the image sensor of the broadcasting camera. When moire occurs or pixel pitch is observed, viewers feel uncomfortable. Moire effect can be reduced by adjusting the shooting distance or angle of the camera, but in order to prevent the pixel pitch from being recorded on the image sensor, secure a sufficient distance between the LED video wall and camera. even when the distance secured, the zoom lens used in the broadcasting studio must be operated by appropriately changing the magnification. If the focal length is changed by changing the magnification to obtain a desired angle of view, the pixel pitch may be unintentionally recorded. In this study we propose the range that the pixel pitch is not observed while changing the magnification ratio of the zoom lens when the distance from the video wall is sufficiently secured. The content was played back on the LED video wall and the LED video wall was recorded on the server using an HD camera equipped with a B4 mount zoom lens

• Korean Journal of Cognitive Science
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• v.16 no.4
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• pp.333-349
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• 2005

In this paper, we propose a real tine moving object tracking system based on block-based image processing technique and human visual processing. The system has two nun features. First, to take advantage of the merit of the biological mechanism of human retina, the system has two cameras, a CCD(Charge-Coupled Device) camera equipped with wide angle lens for more wide scope vision and a Pan-Tilt-Zoon tamers. Second, the system divides the input image into a numbers of blocks and processes coarsely to reduce the rate of tracking error and the processing time. Tn an experiment, the system showed satisfactory performances coping with almost every noisy image, detecting moving objects very int and controlling the Pan-Tilt-Zoom camera precisely.

• Journal of Korea Society of Industrial Information Systems
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• v.12 no.3
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• pp.124-131
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• 2007

Aspheric glass lenses was fabricated by glass molding press(GMP), which is a plano-aspheric convox shape and intended for use as an optical design of 3 megapixel and 2.5 magnifications zoom in a camera phone module. Transcription ratio of form accuracy (PV) as well as resolution properties was measured for evaluation the molded lens. Form accuracy (PV) of the mold surface was $0.127\;{\mu}m$ in an aspheric and $0.168\;{\mu}m$ in a plano, in case of the molded lens it shows $0.205\;{\mu}m$ and $0.223\;{\mu}m$, respectively. Resolution of the molded lens was measured as a MTF[Contrast]. The molded lens shows contrast of 32.9% at 80 1p/mm and the value is similar with contrast of 33% obtained simulation.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.169-172
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• 2005

Tiny camera module using in modern cellular phone requires precise assembly processes. Higher camera resolution and more functions such as zoom lens make the number of camera parts bigger. As market grows rapidly, automatic assembly process is required. However, diverse product line and short life cycle make it difficult. To attack this, a flexible and expandable lens assembly system is proposed. For the fast manufacturing line formation, modular concept is adopted. Also each module is designed to have intelligence to save system formation time. The assembly system is built up on the standard flat-form which provides vibration free base, air and electric supply, controllers, etc. Futhermore, the assembly cell has the capability of handling tiny, thin, or transparent parts which are very difficult to align with vision.