• Geophysics and Geophysical Exploration
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• v.1 no.1
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• pp.57-63
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• 1998

The electrical resistivity method, one of old and widely used geophysical prospecting methods, has extended its scope to civil & environmental engineering areas. The electrical resistivity imaging technique was performed at the waste disposal site located in Junju to verify the applicability to the environmental engineering area. The dipole-dipole array, with the dipole spacing of 10 m, was applied along eight survey lines. The field data were obtained under the control of automatic acquisition softwares and topographic effects were corrected during processing stage. The processed resistivity images show that very low resistivity develops inside the disposal site and the distribution of low resistivity is exactly in accord with the boundary of the site except the river side. The depth of low resistivity zones is deeper toward the river side, which is interpreted that there is a high possibility for contaminants to be scattered to the river. From resistivity images, it was feasible to deduce the depth of waste disposal as well as the horizontal/vertical distribution of the contaminated zone, which proved the applicability of the electrical resistivity imaging technique to the environmental engineering area.

• Proceedings of the Korea Water Resources Association Conference
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• 2006.05a
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• pp.1201-1205
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• 2006

본 연구의 목적은 낙동강 권역을 대상으로 가뭄지역을 검출하고 부족수분량을 산정하는 방법을 개발하는 것이다. 위성자료는 임의 지점에 대하여 지속적이고 반복적인 관측 자료를 제공하므로 가뭄 감시를 위해 유용하게 사용될 수 있다. 본 연구에서는 증발산량과 정규식생지수(Normalized Difference Vegetation Index: NDVI)가 밀접한 상관성이 있는 점에 착안하여 MODIS 영상으로부터 얻어진 NDVI와 기상자료 중 기온자료를 이용하여 증발산량을 산정하는 간편법을 제안하였다. 또한, 가뭄 분석을 위해 위성자료로부터 얻어진 증발산량 자료를 이용하여 기후학적 물수지 모형에 의해 부족수분량을 산정하여 물부족의 심도를 파악하였다. 본 연구의 결과로서 가뭄 분석에 있어서 위성영상의 활용이 대단히 유용하다는 것을 보여주고 있다.

• Journal of the Ergonomics Society of Korea
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• v.10 no.1
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• pp.11-22
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• 1991

This paper aims to examine experimentally the difference of subjectively measured degree of depth between two dimensional (2D) and three dimensional (3D) images. For this paper, two experiments were conducted; in the first experiment, the subjects were asked to estimate the distance between two objects presented with different depths, while in the second experiment, the subjects' role was to rank three objects in the order of distance from the screen. In both experiments, the objects were presented either in 2D or 3D images. The results of the experiments show that the use of 3D images can induce more accurate and more stable estimates of distance than the use of 2D images. However, it is also noted that the absolute degree of depth is not the unique criteria utilized by the subjects for the distinction of small differences of depth.

• Proceedings of the Korean Society of Computer Information Conference
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• 2023.01a
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• pp.93-95
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• 2023

본 논문에서는 장편의 드라마나 영화에서 스토리 기반의 축약된 요약본을 자동으로 제작하기 위해 미디엄 숏(medium shot) 크기의 숏(shot)들을 추출하기 위한 방법을 고려한다. 미디엄 숏 정도의 크기는 보통 인물에 중심을 둔 숏들로 인물들 간의 관계에서 특히 대사나 표정으로 내용을 전달하기 위한 목적으로 적극 권장된다. 비디오 검색을 위한 인덱싱에서 신(scene) 전환 검출 및 숏 경계 검출, 그리고 이미지에서 심도와 초점기반의 화질 및 피사체 추출 등을 위해 전통적인 신호/영상처리 기법의 활용에서부터 최근의 기계학습 접목 등 다양한 연구들이 진행되고 있다. 영상문법에 근거하여 편집된 영상물에서 미디엄 숏 정도 크기의 숏들을 추출하여 배열한다면 어느 정도 원본 내용을 충실히 전달할 수 있는 축약된 요약본을 제작할 수 있다는 가정하에 해당 샷들을 블러(blur) 기반으로 검출하기 위해 이와 관련된 키워드들을 기반으로 기존 연구들을 살펴보고 적용 방법을 모색한다.

• Tunnel and Underground Space
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• v.18 no.3
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• pp.185-193
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• 2008

We have carried out Pearson-type chi-square tests on the orientation data of joints from different depths in order to estimate the homogeneity of joint orientations obtained from a borehole. The orientation data of joints were collected from two non-foliated massive rocks of granitic gneisses in South Korea since orientations of joints in folded metamorphic rocks, for example, are controlled by foliation and also changes as the orientations of foliation change by folding. Borehole images were used for the analysis of the orientations of individual joints. The orientation data were subdivided into the upper level data and lower level data. The data from these two levels are plotted on the patch net consisting of 21 orientation patches. Then, the two patterns on the patch net were analyzed using a contingency table. From the chi-square test on the data collected from two sites, we found that some data sets show statistically meaningful differences in orientations of joints. Since joints are one of the important parameters in determining the physical properties of rock masses, in situ investigation of joints are desirable in the geotechnical investigation and also in design of subsurface structures (e.g. tunnels and underground storages).

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2011.07a
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• pp.188-191
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• 2011

본 논문에서는 시간적 움직임 벡터 성분 값을 절삭하여 시간적 움직임 벡터를 저장하는데 필요한 메모리 요구량을 감소하는 방법에 대해서 제안한다. HEVC 에서 시간적 움직임 벡터는 움직임 병합 모드와 향상된 움직임 벡터 예측 방법에서 부호화 효율 향상을 위해서 사용되고 있다. 하지만 부호화해야 할 원본 영상의 공간적 해상도 및 비트 심도가 증가함에 따라 메모리에 저장할 시간적 움직임 벡터의 데이터뿐만 아니라 메모리 접근 대역폭도 크게 증가한다. 따라서 본 논문에서는 시간적 움직임 벡터 성분의 비트 심도를 조절한 후 메모리에 저장하는 방법에 대해서 제안한다. 제안하는 방법을 HM 2.0 에 구현하고 HEVC 표준화에서 사용되는 임의접근 및 저지연 실험 조건에서 실험했을 때, 평균 0.2%의 비트율 손실을 보이지만, 필요한 메모리 요구량을 약 반 정도 줄일 수 있다.

• Journal of Korean Ophthalmic Optics Society
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• v.17 no.2
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• pp.165-170
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• 2012

Purpose: The aim of this study was to measure and evaluate changes of visual responses in viewing a 2D and 3D (three-dimensional) image. Methods: The subjects were 44 college students aged 19 to 25 years with normal binocular vision. The visual responses measured were CA/C (convergence accommodation/convergence) ratio, convergence-induced PD(interpupillary distance), accommodative responses, perceived distance in viewing a 3D image. Results: Convergence and accommodative responses in viewing the 3D image were significantly larger (p<0.05) than in 2D. A moderate positive correction was found between CA/C ratio and accommodative response (r = 0.477, p = 0.001). It was indicated that smaller PD had larger depth perception. Convergence in viewing the 3D image was significantly larger (p<0.05) than that at cognitive distance. Conclusions: The visual fatigue may be more intense in larger CA/C ratio and smaller PD when viewing 3D images.

• Journal of Broadcast Engineering
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• v.18 no.4
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• pp.647-650
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• 2013

HEVC RExt(High Efficiency Video Coding Range Extension) set a goal to support RGB/YUV 4:2:2 4:4:4 color sampling and over 10 bit-depth images. Unlike the previous 4:2:0 color sampling images, RGB images have the high correlation in inter-color planes. Using this characteristic, some methods which are contributed in JCT-VC standardization meetings estimate the pixel values of inter-color plane. But when we use the estimation of inter-color plane in RGB images, high frequency components of RGB images are caused to reduce the coding efficiency because they usually have the low inter-color plane correlation. Therefore, in this paper, we propose an adaptive low pass filtering method in the inter-color plane estimation. Using this method, we can improve the estimation efficiency of inter-color plane in RGB images. The experimental results with HEVC RExt RGB test sequences show that the proposed method has 0.6% BD(Bjontegaard Distortion)-rate gain and some increased complexity compared to the previous inter-color plane estimation method.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.44 no.6
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• pp.1-8
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• 2007

In this paper, research on joint optimization of the image spatial registration and the exposure compensation is conducted. The exposure compensation is performed in a frame work of the intensity compensation based on the polynomial approximation of the relationship between images. This compensation is jointly combined with the registration problem employing the Gauss-Newton nonlinear optimization method. In this paper, to perform for a simple and stable optimization, the block-coordinate method is combined with the Gauss-Newton optimization and extensively compared with the traditional approaches. Furthermore, regression analysis is considered in the compensation part for a better stable performance. By combining the block-coordinate method with the Gauss-Newton optimization, we can obtain a compatible performance reducing the computational complexity and stabilizing the performance. In the numerical result for a particular image, we obtain a satisfactory result for 10 repeats of the iteration, which implies a 50% reduction of the computational complexity. The error is also further reduced by 1.5dB compared to the ordinary method.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.23 no.11
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• pp.1377-1383
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• 2019

Histogram equalization is the most frequently used algorithm for image enhancement. Its hardware implementation significantly outperforms in time its software version. The overall performance of FPGA-based implementation of histogram equalization can be improved by applying pipelining in the design and by exploiting the multipliers and a lot of SRAM blocks which are embedded in recent FPGAs. This work proposes how to implement a fast histogram equalization circuit for 8-bit gray level images. The proposed design contains a FIFO to perform equalization on an image while the histogram for next image is being calculated. Because of some overlap in time for histogram equalization, embedded multipliers and pipelined design, the proposed design can perform histogram equalization on a pixel nearly at a clock. And its dual parallel version outperforms in time almost two times over the original one.