• Proceedings of the Korean Information Science Society Conference
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• 2011.06c
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• pp.440-442
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• 2011

본 논문에서는 객체 검출을 위한 지면가정에 기반한 스테레오 시차영상의 획득방법을 제안한다 지면과 좌우 영상간의 호모그라피를 사용하여 정합비용을 정의하고 지면기준의 시차에 대해서 4방향의 정합비용을 집계하여 시차를 결정한다. 또한 획득된 시차영상에서 나타나는 정합오류들은 중간값 필터와 연결성분 분석을 통하여 제거하고 이를 이진화하여 객체의 검출에 활용한다. 영상평면과 평행한 평면을 기준으로한 기존의 시차정합방법과는 달리 지면보다 아래에 대한 정합 비용이 고려되지 않으며 시차영상으로부터 거리 영상을 획득하여 처리하는 과정을 거치기 전에 객체를 검출할 수 있다는 장점이 있다.

• Proceedings of the Korea Information Processing Society Conference
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• 2021.11a
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• pp.868-871
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• 2021

기후, 경영, 경제 등 여러 분야의 회귀분석에서 설명변수가 반응변수에 일정 시차를 두고 영향을 미치는 경우들이 많다. 하지만 지금까지 대부분의 회귀분석은 설명변수가 반응변수에 즉각적으로 영향을 미치는 경우만을 가정하고 있으며, 설명변수와 반응변수 간에 존재하는 시차를 탐색하는 연구는 거의 이루어지지 않았다. 그러나 보다 정확한 회귀분석을 위해서는 설명변수와 반응변수 간에 존재하는 시차를 파악하는 것이 중요하다. 본 논문은 회귀분석 데이터가 주어졌을 때 설명변수와 반응변수 간에 존재하는 시차를 파악하는 딥러닝 모델을 제안한다. 제안하는 딥러닝 모델은 설명변수의 과거 값들 중 어떤 값이 현재 반응변수에 가장 큰 영향을 미치는지를 노드 간 가중치로 표현하고, 회귀모델의 오차를 최소화하는 가중치를 탐색한다. 훈련이 끝나면 이 가중치들을 사용하여 각 설명변수와 반응변수 간에 존재하는 시차를 파악한다. 실험을 통해 제안 방법은 시차를 고려하지 않는 기존 회귀모델에 비해 시차까지 고려함으로써 오차가 1/100 수준에 불과한 더 정확한 회귀모델을 찾을 수 있음을 확인하였다.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.48 no.6
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• pp.77-87
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• 2011

In this paper, we propose a disparity correction technique to reduce the inherent visual discomfort while watching stereoscopic videos. The visual discomfort must be solved for commercial 3D display systems to provide natural stereoscopic videos to human eyes. The proposed disparity correction technique consists of horizontal and vertical disparity corrections. The horizontal disparity correction is implemented by controlling the depth budget of stereoscopic video using the geometric relations of a stereoscopic camera system. In addition, the vertical disparity correction is implemented by using a feature-based stereo matching algorithm. Conventional vertical disparity corrections have been done by only using camera calibration parameters, which still cause systematic errors in vertical disparities. In this paper, we minimize the vertical disparity as small as possible by using a feature-based correction algorithm. Through the comparisons of conventional feature-based correction algorithms, we analyze the performance of the proposed technique.

• Journal of Korean Ophthalmic Optics Society
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• v.13 no.3
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• pp.79-87
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• 2008

Purpose: This study measured Y-intercept that means a fixation disparity, X-intercept that means a associated phoria and slope of a fixation disparity curve (FDC), which are variables of dissociated phoria and the FDC. We searched for the result value and examined the direction, distribution pattern and a variable that give an most affect on dissociated phoria and the FDC at distance and near. Also this study examined that there were statistically significant differences between distance and near, comparing the result value. Methods: We measured the dissociated phoria and the fixation disparity for 51 subjects at distance and near in June, 2007. All subjects ranged from 20 to 25 years of age (average 21.72${\pm}$1.88 years old) and had no eye disease. At distance the dissociated phoria measured with the distance MIM card (muscle imbalance measure card, Bernell co., USA), and the fixation disparity measured with the modified Mallett Far Unit (Bernell co., USA). At near the dissociated phoria measured with the near MIM card (muscle imbalance measure card, Bernell co., USA), and the fixation disparity measured with the Wesson fixation disparity card (American Optical co., USA). Results: The percentage distribution of types of fixation disparity curves was that at distance prevalence of Type I (74.6%) was the highest, followed by Type IV (17.6%) and Type II (3.9%), Type III (3.9%) and that at near prevalence of Type I (53.0%) was the highest, followed by Type III (29.4%), Type IV (13.7%) and Type II (3.9%). 2. There were significantly correlation in dissociated phoria, fixation disparity (Y-intercept) and associated phoria (X-intercept). 3. The fixation disparity at distance was most affected by associated phoria (X-intercept) (p=0.000). The distance dissociated phoria was most affected by fixation disparity (Y-intercept) (p=0.342), but the influence was weak. 4. The fixation disparity at near was most affected by associated phoria (X-intercept) (p=0.000). The near also dissociated phoria was most affected by associated phoria (X-intercept) (p=0.009). The result that compared the each variables with the same variables at distance and near had statistically significant on paired t-test for among dissociated phoria (t=7.529, p=0.000), X-intercept (t=5.860, p=0.000), the Y-intercept (t=4.640, p=0.000) but slope of the FDC did not differ significant (t=1.336 p=0.188). Conclusions: Relationship of fixation disparity and Heterophoria had close correlation at distance and near.

• 한국경영정보학회:학술대회논문집
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• 2008.06a
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• pp.827-832
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• 2008

IT성과는 정보시스템 구축 가동 후 상당기간이 경과되어야 제대로 나타나는 경우가 일반적이며, 아무리 근거리의 성과지표에 의한다 하더라도 단기적으로는 여전히 조직 내외의 다른 영향요인들에 의해 상쇄 효과(Smooting Effect)가 나타날 수 있다. 특히 IT 성과를 사후적으로 평가하고자 하는 방법론에서 시차를 고려하지 않고서는 정확한 IT 성과를 측정하기 어렵다. 본 연구에서는 정보화 성과평가에 있어 시차적 특성을 어떻게 효과적으로 분석할 수 있는지에 대해 알아보고자 한다. 이를 위해 시차의 개념이 도입된 정보화 성과평가 방법론을 토대로 성과평가를 실시한 공공 기관의 정보시스템 6개를 대상으로 시차분석에 대한 사례연구를 실시하였다.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2020.07a
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• pp.47-50
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• 2020

최근 Panorama와 360도 영상이 대표되는 몰입형(Immersive) 미디어 콘텐츠의 사용이 증가하고 있다. 몰입형 영상 콘텐츠는 사용자에게 현장감을 제공해야 하지만, 촬영 카메라 간의 시차(Parallax)로 인해 영상 콘텐츠에서 시차 왜곡이 발생할 수 있고, 이는 사용자의 콘텐츠 몰입을 제한하기 때문에 해당 영상 콘텐츠의 제작 기술인 영상 스티칭의 높은 정확도가 요구되고 있다. 지금까지 스티칭 영상의 시차 왜곡을 줄이기 위하여 다중 호모그래피 추정 방법과 Seam Optimization 방법이 제안되었지만, 영상 내 사물 배치에 따라 기술 적용이 제한될 수 있다. 이에 본 논문에서는 Mask R-CNN을 활용하여 사물을 세그먼트화하고, 사물의 종류에 따라 각각 다른 가중치 적용을 통해 시차 왜곡을 방지하며, 영상 내 사물의 배치에 따라 시차 왜곡이 발생할 상황에서는 사용자의 인지 중요도가 낮은 사물로 시차 왜곡을 유도하는 영상 스티칭 방법을 제안한다.

• Journal of the Institute of Electronics and Information Engineers
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• v.53 no.5
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• pp.132-140
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• 2016

In this paper, we propose boundary-preserving stereo matching method based on adaptive disparity adjustment using confidence region detection. To find the initial disparity map, we compute data cost using the color space (CIE Lab) combined with the gradient space and apply double cost aggregation. We perform left/right consistency checking to sort out the mismatched region. This consistency check typically fails for occluded and mismatched pixels. We mark a pixel in the left disparity map as "inconsistent", if the disparity value of its counterpart pixel differs by a value larger than one pixel. In order to distinguish errors caused by the disparity discontinuity, we first detect the confidence map using the Mean-shift segmentation in the initial disparity map. Using this confidence map, we then adjust the disparity map to reduce the errors in initial disparity map. Experimental results demonstrate that the proposed method produces higher quality disparity maps by successfully preserving disparity discontinuities compared to existing methods.

• Korean Journal of Cognitive Science
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• v.14 no.1
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• pp.17-28
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• 2003

In order to provide natural images with a specified depth through three-dimensional display system, the stereo images should be similar to those projected from real environment as much as possible. Even when two persons see an identical scene, the binocular Parallax between two images of an object varies as a function of one's inter-pupilary distance (IPD). In this study, we investigated whether individual differences, such as IPD and accommodative vergence, would affect the perception of three dimensional scene provided by stereo-images. Results showed that a person's IPD is correlated with the limit of screen and binocular parallax for single vision, and affects the perceived depth of an object on fixation. More specifically, with longer IPD the limit of screen and binocular parallax for single vision is decreased, and the perceived depth is reduced. These results suggest that the screen and binocular parallax of an object should be calibrated with regard to users IPD to provide natural stereo-images with a specified depth and to Prevent double vision.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.39 no.2
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• pp.107-115
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• 2002

In this paper, we describe a novel method to generate an intermediate scene using BDM (Bidirectional Disparity Morphing) from the parallel stereopair. Because an image is composed of several layers and each layer has a similar disparity, it is available to use the block based disparity estimation. In order to prevent the false correspondence, however, we closely investigate the corresponding block as we adaptively vary the block size according to the estimation error. Therefore, we can detect the occlusion because of larger estimation error of the occluded region. We define three occluding patterns, which ate derived from the peculiar property of the disparity map, in order to smooth the computed disparity map. The filtered disparity map using these patterns presents that the false disparities ate well corrected and the boundary between foreground and background becomes sharper. As a result, we can improve the quality of the intermediate scenes.

• Explosives and Blasting
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• v.32 no.3
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• pp.18-25
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• 2014

Ground vibration and noise from blasting operation are known to be the most representative constituents which can cause human and material damage. In this study, the effect of delay time on ground vibration is investigated by adopting seven different delay times in bench blasting. For each delay time, three blasting operations were performed. The prediction equations for blasting vibration are derived from 50 sets of measurement and the time theory of Langefors is evoked in the analysis of the blasting vibrations and frequencies. For the delay times of 8 ms and 28 ms, the average values of ground vibration are 5.76 cm/sec and 5.75 cm/sec, respectively, which are considerably low. Also the cyclic variation in the vibration measurements with the delay time confirms the interference effect. From the application of the measurements of blasting vibration and frequency to the time theory of Langefors, it is concluded that the optimum delay times are 8 ms and 24 ms for the test site.