• Journal of Digital Contents Society
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• v.5 no.4
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• pp.257-263
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• 2004

This paper is related to the object-based stereo matching algorithm which makes it possible to estimate inner-region disparities for each segmented region. First, several sample points are selected for effectively representing the segmented region, Next, stereo matching is applied to the small area within segmented region which existed in the neighborhood or each sample point. Finally, inner-region disparities are interpolated using a plane equation with disparity of each selected sample. According to the proposed method, the problem of feature-based method that the depth estimation is possible only in the feature points can be solved through the propagation of the disparity in the sample point into the inside of the region. Also, as selecting sample points in contour of segmented region we can effectively suppress obscurity which is occurred in the depth estimation of the monotone region in area-based methods.

• 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.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 1996.06b
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• pp.35-40
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• 1996

In this paper, a method for 3-D surface reconstruction with two real cameras is presented. The method, which combines the extraction of binocular disparity and its interpolation can be applied to the synthesis of images from virtual viewpoints. The synthesized virtual images are as natural as the real images even when we observe the images as stereoscopic images. The method opens up many applications, such as synthesizing input images for multi-viewpoint 3-D displays, enhancing the depth impression in 2-D images and so on. We also have developed a video-rate stereo machine able to obtain binocular disparity in 1/30 sec with two cameras. We show the performance of the machine.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.38 no.5
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• pp.498-508
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• 2001

In this paper, we propose an efficient coding algorithm for the zoom images to find the optimal depth and texture information. The proposed algorithm is the area-based method consisting of two consecutive steps, i) the depth extraction step and ii) the texture extraction step. The X-Y plane of the object space is divided into triangular patches and the depth value of the node is determined in the first step and then the texture of the each patch is extracted in the second step. In the depth extraction step, the depth of the node is determined by applying the block-based disparity compensation method to the windowed area centered at the node. In the second step, the texture of the triangular patches is extracted from the zoom images by applying the affine transformation based disparity compensation method to the triangular patches with the depth value extracted from the first step. To improve the quality of image, the interpolation is peformed on the object space instead of the interpolation on the image plane.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.48 no.3
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• pp.21-29
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• 2011

This paper presents a method that estimates distance and velocity of an object with reliability regardless of maneuver status of the target in stereo vision system. A stereo vision system can calculate a distance with disparity from left and right images. However, the distance estimation error may occur due to quantization error of image pixel. A sub-pixel interpolation method minimizes the quantization error and estimates accurate disparity with real value. Extended Kalman filter (EKF) was used to minimize the error covariance and estimate the object's velocity. However, divergence problem occurs due to model uncertainty when a target maneuvers highly, which makes the estimation error increase. In this paper, we propose a virtual model extended Kalman filter (VMEKF) method that minimizes the processing time and provides reliable estimation ability regardless of maneuver status. Computer simulations and experimental results in real road environments demonstrate that the proposed method gives a reliable estimation performance and reduces processing time under various maneuver status while comparing other estimation filters.

• Journal of the Korea Computer Graphics Society
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• v.16 no.4
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• pp.1-10
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• 2010

We present a method to reproduce in-between views from captured stereo images to control depth feeling that a user can perceive on a 3D display. The stereo images captured from a pair of cameras have a fixed viewpoint and a screen parallax which depend on the physical position and the distance between the cameras. In this paper, we produce stereo images of an intermediate viewpoint between two original cameras by a view interpolation on the input stereo images. Furthermore, the camera separation of the reproduced stereo images can be controlled by a linear interpolation coefficient used by the view interpolation. By using the proposed method, stereo images can be reproduced where the depth feeling and a three dimensional effect is suitable for the individual's eye separation or the characteristic of an application.

• Phonetics and Speech Sciences
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• v.3 no.2
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• pp.37-52
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• 2011

This study investigates patterns of the alignment of the accentual peaks in bisyllabic words of the CVNCV, CVNV, and CVNNV structures in North Kyungsang Korean. Based on the tonal alignment, patterns of the F0 pitch excursion are discussed relative to one another. Issues are addressed concerning how the tonal targets are aligned, and how the tonal specifications of nasals in postvocalic, intervocalic, and prevocalic environments are supplied in the LH, HL, and HH classes. Tonal specification of nasals in various environments is accounted for by extension of the L target, displacement of the pitch peak, and interpolation between two tonal targets, depending on the tonal class. The results in this study provide preliminary evidence that the categorical alignment of the tonal targets is implemented by simply checking the presence or absence of a nasal before or after the nucleus vowel on the segmental string, without reference to the constituency of the nasal in the syllable structure. However, the prosodic structure has a key role to play in explaining speaker-dependent variations in the tonal alignment. Sensitivity to tautosyllabicity has an effect on the shape of the F0 contour, and disparity in the patterns of the pitch excursion is represented as a function of syllable structure correlated with segmental composition of the nasal.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.1C
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• pp.55-64
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• 2006

In this paper, a new web-based remote 3D imaging communication system employing an adaptive matching algorithm is suggested. In the proposed method, feature values are extracted from the stereo image pair through estimation of the disparity and similarities between each pixel of the stereo image. And then, the matching window size for disparity estimation is adaptively selected depending on the magnitude of this feature value. Finally, the detected disparity map and the left image is transmitted into the client region through the network channel. And then, in the client region, right image is reconstructed and intermediate views be synthesized by a linear combination of the left and right images using interpolation in real-time. From some experiments on web based-transmission in real-time and synthesis of the intermediate views by using two kinds of stereo images of 'Joo' & 'Hoon' captured by real camera, it is analyzed that PSNRs of the intermediate views reconstructed by using the proposed transmission scheme are highly measured by 30dB for 'Joo', 27dB for 'Hoon' and the delay time required to obtain the intermediate image of 4 view is also kept to be very fast value of 67.2ms on average, respectively.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.46 no.6
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• pp.28-37
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• 2009

In this paper, we propose an obstacle localization method using a road feature based on a V-disparity map binarized by a maximum frequency value. In a conventional method, the detection performance is severely affected by the size, number and type of obstacles. It's especially difficult to extract a large obstacle or a continuous obstacle like a median strip. So we use a road feature as a new decision standard to localize obstacles irrespective of external environments. A road feature is proper to be a new decision standard because it keeps its rough feature very well in V-disparity under environments where many obstacles exist. And first of all, we create a binary V-disparity map using a maximum frequency value to extract a road feature easily. And then we compare the binary V-disparity map with a median value to remove noises. Finally, we use a linear interpolation for rows which have no value. Comparing this road feature with each column value in disparity map, we can localize obstacles robustly. We also propose a post-processing technique to remove noises made in obstacle localization stage. The results in real road tests show that the proposed algorithm has a better performance than a conventional method.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 1998.06a
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• pp.13-16
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• 1998

본 논문에서는 입체 영상 시스템 중 전송단에서의 영상의 입체감 분석을 위한 변이추정 방식에 대해 중점적으로 연구하였다. 변이추정은 기본적으로 MAE(mean absolute error)를 최소가 되도록 하는 동시에 변이를 각 방향에서의 경계값의 크기에 반비례한 정도로 평활화하는 반복적 블록 매칭 방식을 적용하였다. 수신단에서는 복원된 영상과 변이 정보를 이용하여 IVR(Intermediate View Reconstruction)을 수행하였으며, 보간법(interpolation)을 사용하는 동시에 occlusion 영역에서의 좌우 영상중 한 영상에서 외삽법(extrapolation)을 택하였다. 이 알고리즘으로 영상의 smooth 영역에서 일정하게 평활화된 변이를 추정하였고, 경계부분에서는 평활화방식에서 흔히 발생하는 oversmoothing 문제를 해결하였다. 또한 IVR에서는 다른 알고리즘에 비해 영상의 경계 부분을 살리며, occlusion 영역을 잘 보존하는 특성을 보였다.