• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.284-287
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• 2003

Previous stereo methods doesn't deal effectively with depth discontinuity due to inevitable window-based problems, and so give inaccurate and noisy matching results in areas with steep disparity variations. In this paper. a variable window approach is presented to estimate accurate, detailed and smooth disparities with three-dimensional disparity space. It makes the smoothing of depth discontinuity reduced by evaluating corresponding correlation values and intensity gradient-based similarity in the space. In addition, it devises the novel arbitrarily-shaped variable window to treat with disparity variations of various structure shapes. We show how our results improve on those of closely related techniques for accuracy, robustness. matching density and computing speed.

• Economic and Environmental Geology
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• v.31 no.4
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• pp.339-347
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• 1998

The purpose of this study is to find P-wave crustal velocity structure and the Moho characteristics beneath Seoul (SEO) and Inchon (INCN) stations using broadband teleseismic records. The use of broadband receiver function analysis is increasing to estimate the fine-scale velocity structure of the lithosphere. The broadband receiver functions are developed from teleseismic events of P waveforms recorded at Seoul (SEO) and Inchon (INCN) stations, and are analyzed to examine the crustal structure beneath the stations. The teleseismic receiver functions are inverted in the time domain of the vertical P wave velocity structures beneath the stations. The crustal velocity structures beneath the stations are estimated using the receiver function inversion method (Ammon et al., 1990). The general features of inversion results are as follows: (1) For the Seoul station, the Conrad and Moho discontinuities exist at 22 km and 30 km depth in the south ($BAZ=180^{\circ}$) direction. (2) For the Inchon station, the Conrad discontinuity exists at 22 km depth in the direction of SE ($BAZ=145^{\circ}$) and the Moho discontinuity exists at 30~34 km depth with a 4 km thick, which consists of a laminated velocity transition layers with thickness, whereas a crust-mantle boundary beneath the Seoul station consists of a more sharp boundary compared with the Moho shape of INCN station.

• Korean Journal of Optics and Photonics
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• v.30 no.3
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• pp.106-113
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• 2019

When elemental images are remapped to solve the depth conversion in integral imaging, the integrated image is inevitably accompanied by discontinuity. This paper analyzes the discontinuity factor caused by elemental-image remapping, to validate the reduction of the discontinuity through converging pick-up and reconstruction of the three-dimensional image in real and virtual modes simultaneously. The validity of the proposed method is quantitatively verified when compared with the conventional parallel pick-up.

• The Journal of Engineering Geology
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• v.18 no.2
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• pp.159-166
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• 2008

We have a question about the changing possibility of orientation of discontinuities through the depth of under-ground. To know this, the data from Honam coalfield composed of shale, sandstone and coal and Suwon area which crops out mica schist, were analyzed the discontinuities measured by BIPS and Televiewer. In Honam coalfield the orientations of joints are changed at 30-40 m depth of underground and in Suwon area they are changed around 20 m depth. To compared the results from Honanam coalfield and Suwon area, there are different rock type and geologic structure. However, the attitude of the discontinuities are changing at 20-30 m depth of underground.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.10a
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• pp.706-709
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• 2005

A hybrid focus method with multiple laser slits has been newly proposed and it is based on the integration of DFD and DFF Rough depth information is estimated using DFD equipped with multiple laser slits, and then DFF is applied to only each specific depth range using the depth information resulting from DFD. The proposed hybrid method gives more accurate results than DFD and DFF, and faster measurement than DFF. Its performance has been verified through experiments of calibration blocks with sharp depth discontinuity.

• Proceedings of the KIEE Conference
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• 1987.07b
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• pp.1069-1072
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• 1987

In this paper, we drive useful data from 3-D depth information as input using discontinuity boundary or clustering. And using magnitude and direction of z-gradient we classify the data into adaptable primitive types through intrinsic and stochastical processing. After these processing information is reconstructed for forming data base. And make relationship and standard view position for matching.

• Journal of the Korean Society of Hazard Mitigation
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• v.4 no.4 s.15
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• pp.43-54
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• 2004

The broadband receiver functions are developed from teleseismic P waveforms recorded at Wonju(KSRS), Inchon(IRIS), and Pohang(PHN), and are analyzed to examine the crustal structure beneath these stations. The teleseismic receiver functions are inverted in the time domain of the vertical P wave velocity structures beneath the stations. Clear P-to-S converted phases from the Moho interface are observed in teleseismic seismograms recorded at these stations. The crustal velocity structures beneath the stations are estimated by using the receiver function inversion method(Ammon et al., 1990). The general features of inversion results are as follows: (1) For the Inchon station, the Conrad discontinuity exists at 17.5 Km(SW) deep and the Moho discontinuity exists at 29.5 Km(NW) and 30.5 Km(SE, SW) deep. (2) The shallow crustal structure beneath Wonju station may be covered with a sedimentary rock of a 3 Km thickness. The average Moho depth is assumed about 33.0 Km, and the Conrad discontinuity may exist at 17.0 Km(NE) and 21.0 Km(NW) deep. (3) For Pohang station, the thickness of shallow sedimentary layer is a 3.0 Km in the direction of NE and NW. The Moho depth is 28.0 Km in the direction of the NE and NW. The Conrad discontinuity can be estimated to be existed at 21.0 Km deep for the NE and NW directions.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37C no.9
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• pp.751-756
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• 2012

In this paper, we propose a foreground extraction and depth map generation method using a time-of-flight (TOF) depth camera. Although, the TOF depth camera captures the scene's depth information in real-time, it has a built-in noise and distortion. Therefore, we perform several preprocessing steps such as image enhancement, segmentation, and 3D warping, and then use the TOF depth data to generate the depth-discontinuity regions. Then, we extract the foreground object and generate the depth map as of the color image. The experimental results show that the proposed method efficiently generates the depth map even for the object boundary and textureless regions.

• Economic and Environmental Geology
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• v.33 no.6
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• pp.537-545
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• 2000

Shipborne gravity data are analyzed to investigate crustal structure under Dok Island and its surrounding seamounts located in border of Ulleung Basin and Oki Bank in the East Sea. Relatively low free-air gravity anomaly compared with the volume of seamounts may be explainable by isostatic compensation. From 1 st to 3rd Dokdo Seamounts, the decrease of free-air and Bouguer gravity anomalies implies the different degree of isostatic compensation, crustal thickness or/and density contrast. 3-D gravity modelling shows that seamounts have the mirror roots for regional Airy isostatic compensation, and from Ulleung Basin to Oki Bank, Moho discontinuity deepens and the density of crust is decreases. The results infer that study area is transitional zone from thin oceanic to thick continental crust. The depth of Moho discontinuity is about 15∼16 km, which may be interpreted as an uplifting of Mantle to shallow depth comparing with other borders of the Ulleung Basin.

• Journal of the Korean Society for Precision Engineering
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• v.22 no.9 s.174
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• pp.115-122
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• 2005

Errors resulting from magnification variations of a optical system are largely generated in three-dimensional shape measurements based on depth-from-focus. In the case of measuring the surface morphology of tiny objects based on DFF, images are acquired with a very small interval so that magnification changes can be minimized. However, the magnification variations are actually existed in the acquired images and so focus measures are wrongly or ambiguously extracted. In this paper, a methodology with linear magnification calibrations, based on DFF, is proposed to make more accurate measurement in surface morphology with high depth discontinuity, compared with previous ones. Several experiments show that the proposed method outperforms existing ones without magnification calibrations.