• 전자공학회논문지S
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• 제35S권7호
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• pp.53-61
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• 1998

In this paper, we propose an efficient multi-view images coding algorithm to find the optimal depth and texture from the set of multi-view images. The proposed algorithm consists of two consecutive steps, i) the depth estraction step, and ii) the texture extraction step, comparedwith the traditional algorithem which finds the depth and texture concurrently. The X-Y plane of the normalized object space is divided into traingular paatches and the Z 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 traingular patches is extracted from the multi-view images by applying the affine transformation based disparity compensation method to the traingular pateches with the depth extracted from the first step. Experimental results show that the SNR(Singnal-to- Noise Ratio) of images enconded by our algorithm is better than that of images encoded by the traditional algorithm by the amount about 4dB for for the test sets of multi-view images called dragon, kid, city and santa.

• 한국통신학회논문지
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• 제33권12C호
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• pp.1029-1038
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• 2008

본 논문에서는 다시점 동영상에서 임의시점영상을 생성하기 위한 기법과 생성된 영상 내에 존재하는 미처리 영역을 보상하기 위한 전처리 및 후처리 기법을 제안한다. 임의시점영상을 생성하기 위한 방법으로는 카메라의 기하학적 특성을 이용하는 방법을 사용한다. 다시점 영상의 깊이정보와 카메라의 파라미터 정보를 이용하여 텍스쳐 영상 내 화소들의 실제 3차원 좌표를 얻어낼 수 있고, 산출된 3차원 좌표를 다른 시점 카메라의 2차원 영상면으로 재 배치함으로써 원하는 시점의 영상을 생성할 수 있다. 하지만 생성된 영상 내에는 다수의 미처리 영역이 존재한다. 본 논문에서는 영상의 시간적인 중복성, 공간적인 방향성, 획득된 다시점 영상 또는 깊이정보의 오차의 특징을 고려하여 미처리 영역을 보상하는 방법을 제안한다. 제안한 방법을 적용한 결과 30dB 이상의 PSNR과 3.5이상의 DSCQS(double stimulus continuous quality scale method) 점수를 얻음으로써 객관적, 주관적 평가에서 모두 신뢰도가 높은 임의시점 영상을 생성할 수 있었다.

• Journal of Multimedia Information System
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• 제1권1호
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• pp.45-53
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• 2014

This article describes a two wheelers detection system riding on people based on modified histogram of oriented gradients (HOG) for vision based intelligent vehicles. These features used correlation coefficient parameter are able to classify variable and complicated shapes of a two wheelers according to different viewpoints as well as human appearance. Also our system maintains the simplicity of evaluation of traditional formulation while being more discriminative. In this paper, we propose an evolutionary method trained part-based models to classify multiple view-based detection: frontal, rear and side view (within $60^{\circ}C$). Our experimental results show that a two wheelers riding on people detection system based on proposed approach leads to higher detection accuracy rate than traditional features.

• Journal of Information Display
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• 제5권4호
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• pp.38-44
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• 2004

In this paper, a server and client simulator for the web-based multi-view 3D image communication system is implemented by using the IEEE 1394 digital cameras, Intel Xeon server computer and Microsoft's DirectShow programming library. In the proposed system, two-view image is initially captured by using the IEEE 1394 stereo camera and then, this data is compressed through extraction of its disparity information in the Intel Xeon server computer and transmitted to the client system, in which multi-view images are generated through the intermediate views reconstruction method and finally display on the 3D display monitor. Through some experiments it is found that the proposed system can display 8-view image having a grey level of 8 bits with a frame rate of 15 fps.

• ETRI Journal
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• 제37권6호
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• pp.1251-1258
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• 2015

We investigate an image recovery method for sparse-view computed tomography (CT) using an iterative shrinkage algorithm based on a second-order approach. The two-step iterative shrinkage-thresholding (TwIST) algorithm including a total variation regularization technique is elucidated to be more robust than other first-order methods; it enables a perfect restoration of an original image even if given only a few projection views of a parallel-beam geometry. We find that the incoherency of a projection system matrix in CT geometry sufficiently satisfies the exact reconstruction principle even when the matrix itself has a large condition number. Image reconstruction from fan-beam CT can be well carried out, but the retrieval performance is very low when compared to a parallel-beam geometry. This is considered to be due to the matrix complexity of the projection geometry. We also evaluate the image retrieval performance of the TwIST algorithm -sing measured projection data.

• 한국소음진동공학회논문집
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• 제15권9호
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• pp.1108-1117
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• 2005

A robust damage detection method using short-time Fourier transform and beating phenomena is presented as an estimating tool of the healthiness of large structures. The present technique makes use of beating phenomena that manifest themselves when two signals of similar frequencies are added or subtracted. Unlike most existing methods based on vibration signals, the present approach does not require an analytic model for target structures. Furthermore, the main advantage of the proposed method compared to the competing diagnostic method using vibration data is its robustness. The proposed method is not affected by the amplitude of exciting signals and the location of exciting points. From a measuring view point. the location of sensing point have no influence on the performance of the present method. With a view to verifying the effectiveness of this method. a series of experiments are made and the results show its possibility as a robust damage diagnostic method.

• 한국멀티미디어학회논문지
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• 제11권12호
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• pp.1676-1687
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• 2008

In this paper, we proposed a new multi-view human recognition method based on face and gait features detection algorithm. For getting the position of moving object, we used the different of two consecutive frames. And then, base on the extracted object, the first important characteristic, walking direction, will be determined by using the contour of head and shoulder region. If this individual appears in camera with frontal direction, we will use the face features for recognition. The face detection technique is based on the combination of skin color and Haar-like feature whereas eigen-images and PCA are used in the recognition stage. In the other case, if the walking direction is frontal view, gait features will be used. To evaluate the effect of this proposed and compare with another method, we also present some simulation results which are performed in indoor and outdoor environment. Experimental result shows that the proposed algorithm has better recognition efficiency than the conventional sing]e view recognition method.

• 대한안전경영과학회지
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• 제12권2호
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• pp.55-64
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• 2010

This study tried to focus on nontraditional job that has not been studied in terms of the subjects associated with MSDs(Musculoskeletal Disorders). Specifically, dental procedure was the job to be analyzed in this study. An alternative method as well as a traditional method for viewing teeth while performing simulated dental procedures. Four graduated students did both methods(direct view and indirect view) as the subjects in this study. The method based on indirect view used a video camera and monitor to view the teeth. The experiment was conducted five times for each subject. The major findings in this study were as follows; 1) Job speed was increased with the repetitions for both methods, 2) Difference of Neck flexion between direct and indirect methods was statistically siginificant(Neck flexion for indirect method was dramatically decreased), 3) Difference of job speed between direct and indirect methods was statistically significant(Job speed for direct method was faster than that of indirect method), 4) Difference of error rate between direct and indirect methods was statistically significant(error rate for direct method was lower than that of indirect method), 5) Even though indirect method did not provide better performance in terms of job speed and error rate yet, it seemed to need a trade-off between two methods in the future since indirect method provided better working postures than that of direct method.

• 방송공학회논문지
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• 제17권2호
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• pp.363-373
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• 2012

본 논문에서는 자유시점 또는 오토스테레오스코픽 비디오나 홀로그래픽 비디오 서비스 등을 목표로 중간시점 깊이영상을 생성하는 방법을 제안한다. 이 방법에서 좌/우 깊이영상이 주어졌다고 가정하고, 이 깊이영상들은 카메라 보정과 영상보정이 수행되었다고 가정한다. 제안한 방법은 깊이 당 변위증분을 계산하여 사용하며, 이 변위증분은 일반적인 상황을 고려하여 좌/우 깊이영상을 스테레오 정합하여 계산한다. 계산된 변위증분을 사용하여 해당 깊이값의 위치를 원하는 중간시점 깊이영상에서 찾는다. 중간시점 깊이영상은 좌영상과 우영상으로부터 각각 생성하며, 잡음을 제거하고 홀 필링을 수행한 후 두 영상을 결합하여 최종 중간시점 깊이영상을 생성한다. 제안한 방법을 구현하여 여러 테스트 시퀀스에 적용한 결과, 생성된 중간시점 깊이영상의 화질은 평균 PSNR 33.84dB이었으며, HD급 중간시점 깊이영상을 초당 한 프레임 정도 생성하는 속도를 보였다. 이 화질은 테스트 시퀀스들의 비균질성을 고려할 때 상당히 좋은 화질이라 판단되며, 향후 수행속도를 더욱 향상시키면 제안한 방법은 중간시점 깊이영상을 생성하는 좋은 방법이 될 것으로 사료된다.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2005년도 추계종합학술대회
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• pp.549-552
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• 2005

This paper presents a 3D video content generation technique and system that uses the multi-view images and the depth map. The proposed uses 3-view video and depth inputs from the 3-view video camera and depth camera for the 3D video content production. Each camera is calibrated using Tsai's calibration method, and its parameters are used to rectify multi-view images for the multi-view stereo matching. The depth and disparity maps for the center-view are obtained from both the depth camera and the multi-view stereo matching technique. These two maps are fused to obtain more reliable depth map. Obtained depth map is not only used to insert a virtual object to the scene based on the depth key, but is also used to synthesize virtual viewpoint images. Some preliminary test results are given to show the functionality of the proposed technique.