• Korean Journal of Optics and Photonics
• /
• v.23 no.4
• /
• pp.147-153
• /
• 2012

Multi-view 3D displays based on a limited number of pixels have the problem that the stereo-scopic image has a low resolution because of increasing view number. To solve the problem of low resolution, we propose an optical approaching method that focuses the width of a unit pixel by using a commercial spherical shape lenticular lens sheet and increases the effective resolution by increasing the number of sources of light in the multi-view 3D display system based on projection type. The method was performed in such an order that several main derivable parameters were defined, and, through the theoretical and experimental result, the value of the contractible unit pixel width and the scalable effective resolution was derived in a given system environment. As a result, for the case that the ray of light from the projector transmitted the 25 LPI lenticular lens sheet which has the pitch size 1.016 mm, the focused unit pixel width was 0.19 mm and the scalable effective resolution was, at most, 5 times wider than the original one. In addition, the range of depth of focus was 1.496 mm, which shows us the range of thickness tolerances of commercial spherical shape lenticular lens sheet and sufficient optical alignment tolerances.

• Proceedings of the KSRS Conference
• /
• 2005.10a
• /
• pp.225-228
• /
• 2005

Telescope structure based on Korsch type optical layout was suggested for a large aperture optical system. Korsch type optical layout is regarded as providing wide field of view and no color aberration for which high resolution space cameras greatly demand. For the suggested Korsch type telescope structure, two folding mirrors are adopted, firstly to provide for the refocusing device mounting plane on the second fold mirror assembly, secondly by double folding the light path to concisely confine focal plane assembly within the perimeter of the tube. Optical layput design and corresponding support structure design were attained.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
• /
• 2003.10a
• /
• pp.385-389
• /
• 2003

To make high speed spindle system work properly, sensors with outstanding resolution and dynamic characteristics are essential. An optical fiber displacement sensor is based on simple principles. Electrical signal responds to the optical flux change due to the displacement change between a target and a sensor probe. In this paper, the performance of optical fiber displacement sensor has been investigated according to properties of optical fiber Firstly, optical loss has been measured before and after polishing optical fiber endface. Secondly, allowance of optical fiber bending has been tested. thirdly sensitivity and linear range of the sensor has been found out according to the shape of cross section of optical fiber.

• Korean Journal of Remote Sensing
• /
• v.33 no.6_1
• /
• pp.961-970
• /
• 2017

Despite of large demand for high spatial resolution products of aerosol properties from satellite remote sensing, it has been very difficult due to the weak signal by a single pixel and higher noise from clouds. In this study, aerosol retrieval algorithm with the high spatial resolution ($500m{\times}500m$) was developed using Geostationary Ocean Color Imager (GOCI) data during the Korea-US Air Quality (KORUS-AQ) period in May-June, 2016.Currently, conventional GOCI Yonsei aerosol retrieval(YAER) algorithm provides $6km{\times}6km$ spatial resolution product. The algorithm was tested for its best possible resolution of 500 m product based on GOCI YAER version 2 algorithm. With the new additional cloud masking, aerosol optical depth (AOD) is retrieved using the inversion method, aerosol model, and lookup table as in the GOCI YAER algorithm. In some cases, 500 m AOD shows consistent horizontal distribution and magnitude of AOD compared to the 6 km AOD. However, the 500 m AOD has more retrieved pixels than 6 km AOD because of its higher spatial resolution. As a result, the 500 m AOD exists around small clouds and shows finer features of AOD. To validate the accuracy of 500 m AOD, we used dataset from ground-based Aerosol Robotic Network (AERONET) sunphotometer over Korea. Even with the spatial resolution of 500 m, 500 m AOD shows the correlation coefficient of 0.76 against AERONET, and the ratio within Expected Error (EE) of 51.1%, which are comparable to the results of 6 km AOD.

• The Journal of the Acoustical Society of Korea
• /
• v.37 no.1
• /
• pp.12-20
• /
• 2018

Efforts have been made to reconstruct low-resolution underwater images to high-resolution ones by using the image SR (Super-Resolution) method, all to improve efficiency when acquiring side-scan sonar images. As side-scan sonar images are similar with the optical images with respect to exploiting 2-dimensional signals, conventional image restoration methods for optical images can be considered as a solution. One of the most typical super-resolution methods for optical image is a sparse coding and there are studies for verifying applicability of sparse coding method for underwater images by analyzing sparsity of underwater images. Sparse coding is a method that obtains recovered signal from input signal by linear combination of dictionary and sparse coefficients. However, it requires huge computational load to accurately estimate sparse coefficients. In this study, a sparse coding based underwater image super-resolution method is applied while a selective reconstruction method for object region is suggested to reduce the processing time. For this method, this paper proposes an edge detection and object and non object region classification method for underwater images and combine it with sparse coding based image super-resolution method. Effectiveness of the proposed method is verified by reducing the processing time for image reconstruction over 32 % while preserving same level of PSNR (Peak Signal-to-Noise Ratio) compared with conventional method.

• Proceedings of the Optical Society of Korea Conference
• /
• 2009.02a
• /
• pp.359-360
• /
• 2009

• Bulletin of the Korean Space Science Society
• /
• 1997.04a
• /
• pp.20.2-20
• /
• 1997

No Abstract.See Full-text

• Proceedings of the Optical Society of Korea Conference
• /
• 2005.02a
• /
• pp.254-255
• /
• 2005

• Proceedings of the Optical Society of Korea Conference
• /
• 1991.07a
• /
• pp.67-70
• /
• 1991

종펌핑 Littman 공진기에서 선폭 500 MHz 이하의 단일 종모드 색소레이저를 발진켰으며, 에탈론 간섭무늬를 이용하여 단일종모드 색소레이저의 주파수를 안정화시켰다. 아울러 이들 레이저의 여러 특성을 조사하였으며, 최대효율은 2%, 문턱에너지는 130uJ이었다.

• Proceedings of the Optical Society of Korea Conference
• /
• 2004.07a
• /
• pp.198-199
• /
• 2004