• Journal of the Optical Society of Korea
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• v.10 no.1
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• pp.37-41
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• 2006

This paper discusses a method for precise depth detection in stereoscopic images. The geometry of a stereoscopic camera and a display system is presented. It was found that there exists a difference between the calculated depth and the perceived depth of objects. For precise depth detection, the proposed registration method is investigated and proved by experiment in stable condition.

• Proceedings of the Optical Society of Korea Conference
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• 2006.02a
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• pp.201-202
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• 2006

• Proceedings of the Optical Society of Korea Conference
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• 2006.07a
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• pp.473-474
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• 2006

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.11 no.3
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• pp.129-135
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• 2011

In this paper, we propose the algorithm using optical flow and machine learning-based segmentation for the 3D conversion of 2D video. For the segmentation allowing the successful 3D conversion, we design a new energy function, where color/texture features are included through machine learning method and the optical flow is also introduced in order to focus on the regions with the motion. The depth map are then calculated according to the optical flow of segmented regions, and left/right images for the 3D conversion are produced. Experiment on various video shows that the proposed method yields the reliable segmentation result and depth map for the 3D conversion of 2D video.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.61 no.4
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• pp.639-642
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• 2012

Optical coherence tomography(OCT) can provide real-time and non-invasive subsurface imaging with ultra-high resolution of micrometer scale. However, conventional OCT systems generally have a limited imaging depth range within a depth of only 1-2 mm. To overcome the limitation, we have proposed an active surface tracking algorithm used in common-path Fourier-domain OCT system in order to extend the imaging depth range. The surface tracking algorithm based on the threshold and Savitzky-Golay filter of A-scan data was applied to real-time tracking. The algorithm has controlled a moving stage according to the sample's surface variance in real time. An OCT image obtained by the algorithm clearly show an extended imaging depth range. Consequently, the proposed algorithm demonstrated the potential for improving the conventional OCT systems with limitary depth range.

• Korean Journal of Optics and Photonics
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• v.18 no.4
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• pp.246-255
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• 2007

The floating image system (FIS) is a device to display input source in the space between fast surface of the display and an observer and it provides pseudo 3D depth to an observer when input source as real object or 2D image was displayed through the optical lens system in the FIS. The Advanced floating image system (AFIS) was designed to give more effective 3D depth than existing FIS by adding front and rear depth cues to the displayed stereogram, which it was used as input source. The magnitude of disparity and size of stereogram were strongly related each other and they have been optimized for presenting 3D depths in a non-optical lens systems. Thus, if they were used in optical lens system, they will have reduced or magnified parameters, leading to problem such as providing incorrect 3D depth cues to an observer. Although the size of stereogram and disparity were demagnified by total magnifying power of optical system, the viewing distance (VD) from the display to an observer and base distance (BD) for the gap between the eyes were fixed. For this reason, the quantity of disparity in displayed stereogram through the existing FIS has not kept the magnifying power to the total optical system. Therefore, we proposed the methods to provide correct 3D depth to an observer by compensating quantity of disparity in stereogram which was satisfied to keep total magnifying power of optical lenses system by AFIS. Consequently, the AFIS provides a good floating depth (pseudo 3D) with correct front and rear 3D depth cues to an observer.

• Proceedings of the KSRS Conference
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• 2003.11a
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• pp.959-961
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• 2003

Cirrus clouds observation was conducted using a lidar system in order to measure their height, thickness and optical depth at Kwangju (35$^{\circ}$10'N, 126$^{\circ}$53'), Korea in winter, December 2002, and spring March and April 2003. Cirrus clouds at high altitude can be distinguished from atmospheric aerosols location by high depolarization ratio and high altitude. Cirrus clouds were observed at 5${\sim}$12km altitudes with a high depolarization ratio from 0.2 to 0.5. Optical depth of cirrus clouds had varied from 0.28 to 1.81. Radiative effect of observed cirrus cloud on climate system was estimated to be negative net flux from ?0.24 to ?31.04 W/m$^{2}$.

• Journal of the korean academy of Pediatric Dentistry
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• v.26 no.1
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• pp.109-118
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• 1999

The aim of this study was to evaluate the optical density of laser fluorescence for detection of incipient caries. Prepared and polished bovine enamel specimens were demineralized in a STPP solution for varying periods of time between 3 hrs. and 60 hrs. with an area of sound enamel retained on each specimen. The randomized specimens were analyzed for optical density of enamel demineralization using laser fluorescence. The specimens were sectioned and examined lesion depth by polarizing light microscope. Results were analyzed statistically with SAS program. The results from this study can be summarized as follows: 1. Optical density measured by laser fluorescence and lesion depth measured by polarizing light microscope was increased as demineralization time was increased(p<0.001). 2. Between optical density measured by laser fluorescence and lesion depth measured by polarizing light microscope was correlated highly(${\gamma}{\geq}0.74956$, p<0.001). 3. Regressive equation was obtained in this study as follows. Y=[X-0.260851]/0.000271(R-square:0.5618, p<0.001) (X:DENSITY, Y:DEPTH) In summary, optical density measured by laser fluorescence would be within the range of possibility to quantitatively presume demineralization amount of incipient caries lesion

• Journal of the Optical Society of Korea
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• v.17 no.6
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• pp.500-505
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• 2013

In this paper, we propose a novel framework to evaluate the depth resolution of axially distributed stereo sensing (ADSS) under fixed resource constraints. The proposed framework can evaluate the performance of ADSS systems based on various sensing parameters such as the number of cameras, the number of total pixels, pixel size and so on. The Monte Carlo simulations for the proposed framework are performed and the evaluation results are presented.

• Fire Science and Engineering
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• v.30 no.2
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• pp.62-67
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• 2016

In this study, the optical depth is analyzed with the effects of droplet size distribution of the water curtain nozzle to attenuate the radiative heat transfer. The HELOS/VARIO equipment is used for the measurement of the droplet size distributions. The spray characteristics are quantified by the investigation of Deirmenjian's modified gamma distribution function. The distribution constant of the nozzle can be obtained as ${\alpha}=1$ and ${\gamma}=5.2$. The generalized equation of the optical depth related with the droplet size distribution is introduced. These results will be applicable to the analysis of the design condition of the water curtain nozzle.