• Journal of the Korean Society for Precision Engineering
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• v.23 no.9 s.186
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• pp.111-118
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• 2006

A hybrid focus method with multiple laser slits is newly proposed for the measurement of surface morphology with depth discontinuity, and it is based on the integration of DFB and DFF. Rough depth information is estimated through calibration tables which are constructed by DFD with multiple laser slits, and then DFF is applied to only each specific depth range using the rough depth information resulting from DFD. The proposed hybrid method gives more accurate results than DFD and DFF, and faster measurement than DFF in the vicinity of depth discontinuity Its performance is verified through experiments of calibration blocks with sharp depth discontinuity.

• IEIE Transactions on Smart Processing and Computing
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• v.6 no.3
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• pp.175-182
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• 2017

In this paper, we present a multi-depth generation method using a time-of-flight (ToF) fusion camera system. Multi-view color cameras in the parallel type and ToF depth sensors are used for 3D scene capturing. Although each ToF depth sensor can measure the depth information of the scene in real-time, it has several problems to overcome. Therefore, after we capture low-resolution depth images by ToF depth sensors, we perform a post-processing to solve the problems. Then, the depth information of the depth sensor is warped to color image positions and used as initial disparity values. In addition, the warped depth data is used to generate a depth-discontinuity map for efficient stereo matching. By applying the stereo matching using belief propagation with the depth-discontinuity map and the initial disparity information, we have obtained more accurate and stable multi-view disparity maps in reduced time.

• Korean Journal of Cognitive Science
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• v.21 no.1
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• pp.1-24
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• 2010

The stationary image appears to move after we view a moving stimulus for a long time. The motion aftereffect(MAE) can spread to an adjacent region if there is no contrast discontinuity between two regions. In this study, it is investigated whether a phenomenon of MAE spreading to an adjacent non adapting area is affected by the depth discontinuity defined by binocular disparity. In the first experiment a disparity defined slanted pattern was presented in an unadapted region, and in the second experiment, a disparity defined pattern with a different depth was presented on the fronto-parallel plane. Although MAE duration in the condition with slanted pattern was not different from that in the non-slanted pattern condition, MAE durations in the pattern presented on pronto-parallel plane was vividly reduced, but not completely disappeared. These results suggest that a phenomenon of MAE spreading might be affected by depth discontinuity, and could be occurred after binocular information converges.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38C no.10
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• pp.875-880
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• 2013

When we generate 3D video that provides immersive and realistic feeling to users, depth information of the scene is essential. Since the resolution of the depth map captured by a depth sensor is lower than of the color image, we need to upsample the low-resolution depth map for high-resolution 3D video generation. In this paper, we propose a depth upsampling method using depth-discontinuity information. Using the high-resolution color image and the low-resolution depth map, we detect depth-discontinuity regions. Then, we define an energy function for the depth map upsampling and optimize it using the belief propagation method. Experimental results show that the proposed method outperforms other depth upsampling methods in terms of the bad pixel rate.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2009.01a
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• pp.583-587
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• 2009

In this paper we propose a new method of Depth-Image-Based Rendering (DIBR) for Free-viewpoint TV (FTV). In the proposed method, virtual viewpoint images are rendered with 3D warping instead of estimating the view-dependent depth since depth estimation is usually costly and it is desirable to eliminate it from the rendering process. However, 3D warping causes some problems that do not occur in the method with view-dependent depth estimation; for example, the appearance of holes on the rendered image, and the occurrence of depth discontinuity on the surface of the object at virtual image plane. Depth discontinuity causes artifacts on the rendered image. In this paper, these problems are solved by reconstructing disparity information at virtual camera position from neighboring two real cameras. In the experiments, high quality arbitrary viewpoint images were obtained.

• Ocean and Polar Research
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• v.32 no.3
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• pp.331-336
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• 2010

The CREAMS (Circulation Research of the East Asian Marginal Sea) survey in 1999 revealed a sharp mid-depth discontinuity of the phosphate:silicate ratio in all basins of the East/Japan Sea. Incidentally, this discontinuity layer corresponds to the oxygen minimum layer. Directly below the discontinuity layer, oxygen concentration is increased. This increase in oxygen concentration is interpreted as a proof of intermediate water formation. Oxygen minimum indicates that the water parcel is old and stable against mixing. So it seems be an efficient barrier to vertical exchange of materials. This means that, once materials enter the lower domain, they rarely return to the upper domain. Therefore, the biogeochemistry of the East/Japan Sea depends heavily on material input through the Korea Strait, and flux is expected to be sensitive to the climate change. As a result, the East/Japan Sea ecosystem seems vulnerable to tipping (regime shift), which occurred on a decadal time scale.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.13 no.3
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• pp.254-261
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• 2001

It is well known that when long waves propagate from deep ocean onto a continental shelf with a very steep continental slope, the waves reflected from the shore can not propagate offshore and are re-reflected from the continental slope so that large water level fluctuations are induced near the shore. Liu(1986) has analyzed this phenomenon by assuming a topography which has a depth discontinuity along a semicircular offshore boundary, but his solution is erroneous. In the present paper, we correct his analytical solutions for a straight shoreline and a rectangular harbor. The corrected solution is then compared with the numerical results of the Galerkin finite element model of Jeong et al.(1998), which is based on the extended mild-slope equation.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2003.03a
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• pp.45-49
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• 2003

The velocity structure beneath the CHNB broadband station is determined by receiver function analysis using by from teleseismic P waveforms. The detailed broadband receiver functions are obtained by stacking method for source-equalized vertical, radial and tangential components of teleseismic P waveforms. A time domain inversion uses the stacked radial receiver function to determine vertical P wave velocity structure beneath the station. The crustal velocity structures beneath the stations are estimated using the receiver function inversion method in the case at the crustal model parameterized by many thin, flat-tying, homogeneous layers. The result of crust at model inversion shows the crustal velocity structure beneath the CHNB station varies smoothly with increasing depth, and there are six discontinuity around 2.5km, 6.25km, 12.5km, 22.5km and 27.5km depth, with Moho discontinuity at about 32.5km depth.

• 한국지구물리탐사학회:학술대회논문집
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• 2007.12a
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• pp.43-51
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• 2007

In order to investigate the velocity structure of the southern part of the Korean peninsula, exploded seismic signals were recorded for 120 s along a 294-km WNW-ESE line and 150 s along a 335-km NNW-SSE line in 2002 and 2004, respectively. Velocity tomograms were derived from inverting P-wave and S-wave first arrival times. The raypaths indicate several midcrust interfaces. The shallowest one is at the approximate depth of $2{\sim}3\;km$ with refraction velocities of approximately Vp=6.0 and Vs=3.5 km/s, respectively. The second one of $15{\sim}17\;km$ depth has refraction velocities of approximately Vp=7.1 and Vs=3.7 km/s, respectively. The deepest significant interface varies in depth from 30.8 km to 36.1 km. The critically refracting Vp of $7.8{\sim}8.1\;km/s$ and Vs of $4.2{\sim}4.6\;km/s$ along this interface which may correspond to the Moho discontinuity. The velocity tomograms show (1) existence of a low-velocity zone centered at $6{\sim}7\;km$ depth under the Okchon fold belt and the Yeongnam massif, (2) extension of the Yeongdon fault down to greater than 10 km, and (3) existence of high-velocity materials under the Gyeongsan basin less than 4.2 km thick.

• Economic and Environmental Geology
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• v.18 no.4
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• pp.321-329
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• 1985

The gravity measurement has been conducted at 113 stations with an interval of about 1km along the national road of about 120km running from Busangdong to Pohang through Waekwan, Daegu, Youngchun and Aankang. The subsurface geology and structure along the survey line is interpreted from Bouguer anomaly by applying Fourier method and Talwani method for two dimensional body. The mean depth of Moho discontinuity is 31.4km, and the depth decreases very slowly from inner continent toward east coast. The depth of Conrad discontinuity increases from 11km at the east coastal area to 17km at the inner continental area, and especially increases rapidly in the area between Waekwan to Busangdong. The depth of basement of Kyoungsang Basin inereases from near Waekwan toward Daegu upto about 4. 8km, and increases rapidly to reach the maximum depth of about 8.5km at 8km east of Daegu. But it starts to decrease from the place of 10km west of Youngchun, and is about 7.2km at Youngchun and about 6km at 6km east of Youngchun. The depth starts to increase smoothly beyond this point, and is 7km at 15km east of Youngchun. From this point, the depth starts to decrease again, and is about 3.8km at Ankang. The depth of basement of Pohang Basin is 500m at Pohang and about 650m at 5km west of Pohang. A massive granite body which is considered to be a part of Palgongsan Granite exposed at the depth of 1. 5km at 9km west of Youngchun. Another massive granite body is situated underneath the Pohang Basin at depth of 1.5 to 2km, and sedimentary rocks of Kyoungsang Group and volcanic rocks are distributed between Pohang Basin and this granite body. Finally, Yangsan Fault is identified at about 2.5km east of Ankang.