• Current Optics and Photonics
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• 제1권4호
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• pp.344-350
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• 2017

We present a new design approach and an example design for an image-space telecentric two-mirror system that has a fast f-number and a wide-field line image. The initial design of the telecentric mirror system is a conventional axially symmetric system, consisting of a flat primary mirror with fourth-order aspheric deformation and an oblate ellipsoidal secondary mirror to correct spherical aberration, coma, and field curvature. Even though in the optimized design the primary mirror is tilted, to avoid ray obstruction by the secondary mirror, the image-space telecentric two-mirror system shows quite good imaging performance, for a line imager.

• 한국광학회지
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• 제31권1호
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• pp.20-25
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• 2020

넓은 시야를 가지는 2반사광학계를 설계하기 위하여서는 제2거울에 의한 광선의 차폐와 시야 가림이 없도록 비축시야를 사용하여야 한다. 그러나 이러한 2반사경계에서는 설계변수가 적어 비축수차를 충분하게 보정할 수 없었다. 이 연구에서는 조리개를 편심시켜 보다 성능이 개선된 비축시야 2반사광학계를 설계하였다.

• Journal of the Optical Society of Korea
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• 제19권6호
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• pp.604-613
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• 2015

An unobstructed off-axis two-mirror system is presented in this paper. First a suitable initial configuration is established based on third-order aberration theory. In order to achieve a wide field of view (FOV) with high image quality , the diffractive mirror is adopted in the two-mirror system to increase the optimization freedom and the aberration relationship between diffractive phase coefficients and Zernike coefficients is derived. Furthermore, a complete comparison design example with a focal length of 1200 mm, F-number of 12, and FOV of 40° × 2° is given to verify the aberration correction ability of the diffractive mirror. The system average wavefront error is 0.007 λ (λ=0.6328 μm) developed from 0.061 λ when the system didn’t adopt the diffractive mirror. In this system the phase modulation function of the diffractive mirror is established as an even function of x, so we could obtain a symmetrical imaging quality about the tangential plane, and the symmetric aberration performance also brings considerable convenience to alignment and testing for the system.

• 한국광학회지
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• 제31권6호
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• pp.304-313
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• 2020

조리개가 제 2거울에 있는 inverse Cassegrain 광학계에서 비축시야를 사용하면, 이 2반사경계는 넓은 시야를 가지는 대물광학계로 사용할 수 있다. 하지만 이 전통적인 회전대칭 구조의 반사경계는 설계변수의 수가 너무 적기 때문에 수차보정에 한계가 있다. 이 연구에서는 조리개와 제 2거울을 별도로 횡이동시켜 성능을 개선한 새로운 2반사 광학계를 설계하였다. 새로운 설계변수를 사용하여 5차 코마와 비점수차에 대한 보정이 개선되었으며, 시야 전체에서 보다 좋은 수차균형을 얻을 수 있었다. 새로 설계된 비축시야 2반사경계는 회전대칭 구조의 통상적인 2반사경계와 비교하여 spot의 크기가 1/2 수준으로 줄어들었으며, 개선의 효과가 시야 전체에 고르게 나타나고 있다.

• Journal of the Optical Society of Korea
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• 제20권4호
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• pp.481-487
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• 2016

This study presents a new optical system for a combiner-type head-up display (HUD) with a cylindrical lens as an asymmetrical aberration corrector, instead of a freeform mirror. In the initial design process based on off-axial aberration analysis, we obtain an off-axis two-mirror system corrected for linear astigmatism and spherical aberration by adding a conic secondary mirror to an off-axis paraboloidal mirror. Thus, since the starting optical system for an HUD is corrected for dominant aberrations, it enables us to balance the residual asymmetrical aberrations with a simple optical surface such as a cylinder, not a complex freeform surface. From this design process, an optical system for an HUD having good performance is finally obtained. The size of the virtual image is 10 inches at 2 meters away from a combiner, and the area of the eye box is 130×50 mm².

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2000년도 제15차 학술회의논문집
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• pp.7-7
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• 2000

This paper describes a mirror control system that can adjust the location of side and room mirror of the vehicle automatically using 3D coordinates to monitor the location of driver's eyes. Through analysis of the image inputted by two B/W CCD camera and infrared lamps installed on top of the driver's dashboard, we can estimate the values of 3D coordinate of the driver's eyes. Using these values, this system can determine the absolute position of each mirror and activate each actuator to the appropriate position. The stereo vision system can detect the driver's eyes whether it is day or night by virtue of infrared Lamps. We have tested this system using 10 drivers who drive a car currently, and most of the drivers were satisfied with the convenience of this system.

• 한국광학회지
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• 제28권6호
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• pp.263-272
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• 2017

넓은 시야를 가지는 광학계에서는 전반부는 음의 굴절능, 후반부는 양의 굴절능을 가지는 inverted telephoto 구조가 일반적으로 사용되고 있고, 2반사광학계에서는 inverse Cassegrain system이 inverted telephoto 구조에 해당한다. 하지만 통상적인 회전대칭 구성의 inverse Cassegrain system에서는 시야가 가려지고 광선의 차폐가 심한 문제점이 있다. 이 연구에서는 이점을 고려하여 inverse Cassegrain system의 제2면에 조리개를 두어 시야를 넓히고, 광선의 차폐가 없는 비축시야만을 사용하는 광시야 비축 2반사광학계를 설계하였다.

• Current Optics and Photonics
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• 제5권6호
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• pp.660-671
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• 2021

We present a novel optical system for an augmented reality head-up display (AR HUD) with two virtual images at different conjugates by employing a confocal off-axis two-mirror and introducing the horopter circle. For a far virtual image with large asymmetrical aberrations, we initially obtain an off-axis two-mirror system corrected for these aberrations and compensated for the down angle by configuring its parameters to satisfy the confocal and Scheimpflug conditions, respectively. In addition, this system is designed to reduce the biocular parallax by matching Petzval surface into the longitudinal horopter circle in a near virtual image. This design approach enables us to easily balance the residual aberrations and biocular parallax when configuring the optical system with two different conjugates, which results in an AR HUD available for near and far virtual images together.

• Current Optics and Photonics
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• 제1권4호
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• pp.336-343
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• 2017

A wide field-of-view (FOV) image contains more visual information than a conventional image. This study proposes a new type of hyperbolic mirror for wide FOV image acquisition. The proposed mirror consists of a hyperbolic cylindrical section and a bowl-shaped hyperbolic omnidirectional section. Using an imaging system with this mirror, it is possible to achieve a $213.8^{\circ}$ horizontal and a $126.94^{\circ}$ vertical maximum FOV. Parameters of each section of the mirror are designed to be continuous at the junction of the two parts, and the resultant image is seamless. The image-acquisition model is obtained using ray-tracing optics. To rectify the geometrical distortion of the original image due to the mirror, an image-restoration algorithm based on conformal projection is presented in this study. The performance of the proposed imaging system with the hyperbolic mirror and its image-restoration algorithm are verified by experiments.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2005년도 ICCAS
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• pp.2435-2439
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• 2005

In case of visual sensing systems with multiple mirrors, systematic errors need to be reduced by the system calibration and the mirror position adjustment in order to enhance system measurement accuracy. In this paper, a self calibration method is presented for a visual sensing system designed to measure the three-dimensional information in deformable peg-in-hole tasks. It is composed of a CCD camera and a series of mirrors including two pyramidal mirrors. By using an image of the inner pyramidal mirror taken by the system, the error parameters of the inner pyramidal mirror could be calibrated or adjusted. Also the influence of the plane mirrors is investigated.