• Proceedings of the Korean Society of Precision Engineering Conference
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• 1994.10a
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• pp.510-514
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• 1994

This paper deals with an application of neural network to camera calibration with wide angle lens and 2-D range finding. Wide angle lens has an advantage of having wide view angles for mobile environment recognition ans robot eye in hand system. But, it has severe radial distortion. Multilayer neural network is used for the calibration of the camera considering lens distortion, and is trained it by error back-propagation method. MLP can map between camera image plane and plane the made by structured light. In experiments, Calibration of camers was executed with calibration chart which was printed by using laser printer with 300 d.p.i. resolution. High distortion lens, COSMICAR 4.2mm, was used to see whether the neural network could effectively calibrate camera distortion. 2-D range of several objects well be measured with laser range finding system composed of camera, frame grabber and laser structured light. The performance of 3-D range finding system was evaluated through experiments and analysis of the results.

• Journal of Sensor Science and Technology
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• v.24 no.1
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• pp.54-61
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• 2015

In recent years, there has been increasing use of automatic surveillance and monitoring systems based on vision sensors. Humans are often the most important target in the systems, but processing human images is difficult due to the small sizes and flexible motions. Particularly, occlusion among pedestrians in camera images brings practical problems. In this paper, we propose a novel method to separate image regions of occluded pedestrians. A camera equipped with a wide angle lens is attached to the ceiling of a building corridor for sensing pedestrians with a wide field of view. The output images of the camera are processed for the human detection, tracking, identification, distortion correction, and occlusion handling. We resolve the occlusion problem adaptively depending on the angles and positions of their heads. Experimental results showed that the proposed method is more efficient and accurate compared with existing methods.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.11a
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• pp.107-107
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• 2004

• Proceedings of the IEEK Conference
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• 2003.07a
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• pp.629-632
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• 2003

This paper has been studied analysis and design of microstrip Rotman lens operating over wide band and wide steering angle by the contour integral method along with the segmentation method. All mutual coupling, internal reflections between ports with exponential taper are taken into account. Equally spaced ports are designed and realized which gives less amplitude ripple at array ports. The measured results of 12 input and 12 output lens show $\pm$1.8 dB insertion loss deviation over 6~18GHz wide frequency range and beam steering accuracy less than 1$^{\circ}$ over $\pm$53$^{\circ}$ angle and agrees well with the analysis results.

• 한국정보디스플레이학회:학술대회논문집
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• 2000.01a
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• pp.161-162
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• 2000

We propose multi-layer aspheric lenticular lens for rear projection screen to provide wide viewing angle. Each pitch of lenticular lens sheet is divided by three region and image light from projection optical system is propagated widely on each region due to different focal point. Besides, to improve vertical viewing angle of screen, we propose glass bead embedded screen on observer side of lenticular lens.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.30 no.4
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• pp.241-245
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• 2017

This paper proposes a private display that can adjust viewing angles by using an electric-field-driven (EFD) LC Lens. The EFD LC Lens design and simulation were analyzed by using the Extended Jones Matrix Method. The conventional method for attaching a private film to the display was difficult. In order to solve this problem, in this study, by using the EFD LC Lens, we devised a method that can view images more conveniently. We analyzed the luminance and illumination of the optical viewing distance by using the Extended Jones Matrix Method. We also measured the intensity of the viewing angles. The simulation attached the EFD LC Lens to the 14" Full HD RGB stripe wide panel. We calculated the relative luminance distribution and the luminance distribution on the viewing angle of the image at the optimum viewing distance of 60 cm, using the EFD LC Lens and the lenticular lens. The proposed method could be used to design private displays that can adjust the viewing angle of the EFD LC Lens.

• Korean Journal of Optics and Photonics
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• v.23 no.5
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• pp.179-188
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• 2012

Lenses with an ultra wide angle of view are usually called fisheye lenses since a fish can see an ultra wide panoramic view under water. As the angle of view for these kinds of lenses reaches a wide angle, the illumination on an image sensor is reduced by a rapid drop. In this paper, we discuss the causes and the ways to correct for a rapid drop. First, it is treated for the sign convention of directional cosine vectors and normal vectors on the curved surface by means of analytic geometry. And, from the fundamental discussion for these vectors, the rapid illumination drop is numerically analyzed for various kinds of causes by utilizing geometrical optics and radiometry as well as Fresnel equations derived from electromagnetic boundary conditions. As a result, we are able to get the full understanding for the rapid illumination drop and to propose ways to correct effects due to an wide angle of view.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.63 no.4
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• pp.570-574
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• 2014

This paper proposes a wireless digital endoscope with a ultra-wide-angle view. Two key components are implemented to demonstrate the feasibility of the proposed endoscope. First, a ultra-wide-angle lens module with the field of view of 144 degree and F-number of 2.2 is designed and manufactured. Second, a wireless module for a high-speed video transfer is implemented using a USB device server and wireless LAN router. The wireless module can directly transfer a streaming video to a computer with the resolution of 1920x1080, frame rate of 30 fps, and data rate of 53.3 Mbps without an internet connection. Since the wireless module supports two USB devices, two spots can be simultaneously observed using the proposed endoscope.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.14 no.7
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• pp.769-776
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• 2003

This paper presents analysis and design of microstrip Rotman lens operating over wide band and wide steering angle by the contour integral method along with the segmentation method. All mutual coupling, internal reflections between ports and the discontinuity at every junction are taken into account. Equally spaced ports are designed and realized, which make suppress output ripple through the array ports. Impedance matching and mutual coupling between ports are analyzed and optimized using 12 input and 12 output exponential tapers. The measured results of fabricated lens show ${\pm}$ 1.8 dB insertion loss deviation over 6∼18 GHz wide frequency range and beam steering accuracy less than 1$^{\circ}$over ${\pm}$53$^{\circ}$angle and agrees well with the analysis results.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2004.11a
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• pp.145-150
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• 2004

The LED lighting used spot-light illuminate the limited surface. So it is a key-point to condense wide emission angle of high power light emitting diodes (LEDs) to narrow that angle. In this paper, the secondary optics was designed by lens-makers formula for concentration rays of LED into specific region. So, it simulated the optics that designed by lens makers-formula in the optical design program, LightTools. And then, show the p propriety of lens design utilizing simulation result, luminous intensity, emission angle.