• Journal of the Korea Institute of Information and Communication Engineering
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• 제17권5호
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• pp.1119-1128
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• 2013

In this paper, we propose an algorithm to detect and track the human face with a GPU-based high speed. Basically the detection algorithm uses the existing Adaboost algorithm but the search area is dramatically reduced by detecting movement and skin color region. Differently from detection process, tracking algorithm uses only depth information. Basically it uses a template matching method such that it searches a matched block to the template. Also, In order to fast track the face, it was computed in parallel using GPU about the template matching. Experimental results show that the GPU speed when compared with the CPU has been increased to up to 49 times.

• Journal of Broadcast Engineering
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• 제13권5호
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• pp.596-601
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• 2008

In this paper, we propose a new scheme to generate region-of-interest (ROI) enhanced depth maps in the hybrid camera system, which is composed of a low-resolution depth camera and a high-resolution stereoscopic camera. The proposed method creates an ROI depth map for the left image by carrying out a three-dimensional (3-D) warping operation onto the depth information obtained from the depth camera. Then, we generate a background depth map for the left image by applying a stereo matching algorithm onto the left and right images captured by the stereoscopic camera. Finally, we merge the ROI map with the background one to create the final depth map. The proposed method provides higher quality depth information on ROI than the previous methods.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2001년도 ICCAS
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• pp.181.5-181
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• 2001

This paper presents the method of 3D reconstruction of the depth information from the endoscopic stereo scopic images. After camera modeling to find camera parameters, we performed feature-point based stereo matching to find depth information. Acquired some depth information is finally 3D reconstructed using the NURBS(Non Uniform Rational B-Spline) algorithm. The final result image is helpful for the understanding of depth information visually.

• Journal of Korea Multimedia Society
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• 제22권12호
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• pp.1356-1367
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• 2019

This paper proposes a novel active stereo matching technique using white auxiliary stripe pattern. The conventional active stereo matching techniques that uses two cameras and an active source such as projector can accurately estimate disparity information even in the areas with low texture compared to the passive ones. However, it is difficult that the conventional active stereo matching techniques using color code patterns acquire these patterns robustly if the object is composed of various colors or is exposed to complex lighting condition. To overcome this problem, the proposed method uses an additional white auxiliary stripe pattern to get and localize the color code patterns robustly. This paper proposes a process based on adaptive thresholding and thinning to obtain the auxiliary pattern accurately. Experimental results show that the proposed method more precisely measures the stepped sample whose depth is known in advance than the conventional method.

• Smart Media Journal
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• 제1권3호
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• pp.15-21
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• 2012

Depth information is necessary for various three dimensional contents generation. Depth acquisition techniques can be categorized broadly into two approaches: active, passive depth sensors depending on how to obtain depth information. In this paper, we take a look at several ways of depth acquirement. We present not only depth acquisition methods using discussed ways, but also hybrid methods which combine both approaches to compensate for drawbacks of each approach. Furthermore, we introduce several matching cost functions and post-processing techniques to enhance the temporal consistency and reduce flickering artifacts and discomforts of users caused by inaccurate depth estimation in 3D video.

• Journal of the Korean Institute of Telematics and Electronics B
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• 제32B권1호
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• pp.39-49
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• 1995

Stereo vision is useful to obtain three dimensional depth information from two images taken from different view points. In this paper, we reduce searching area for correspondence by using the intra-scanline constraint, and utilize the inter-scanline constraint and the property of disparity continuity among the neighboring pixels for relaxation. Nodes with 3-D stucture are located on the axes of two views, and have matching possibility of correspondent pixels of two images. A matching is accepted if a node at the intersection of the disparity axes has the greatest matching possibility. Otherwise, the matching possibility of the node is updated by relaxation with the cooperation of neighboring nodes. Further relaxation with competition of two views is applied to a matching possibility of randomly selected node. The consensus of two views increases the confidence of matching, and removes a blurring phenomenon on the discontinuity of object. This approach has been tested with various types of image such as random dot stereogram and aerial image, and the experimental results show good matching performance.

• Journal of the Korea Institute of Information and Communication Engineering
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• 제16권7호
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• pp.1437-1446
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• 2012

In this paper we propose a new stereo matching algorithm which is suitable for application to obtain depth information with high-speed in stereoscopic camera environment. For satisfying these condition we propose a new adaptive stereo matching technique using frequency information in discrete wavelet (DWT) domain and variable matching window. The size of the matching window is selected by analysis of the local property of the image in spatial domain and the feature and scaling factor of the matching window is selected by the frequency property in the frequency domain. For using frequency information we use local DWT and global DWT. We identified that the proposed technique has better peak noise to signal ratio (PSNR) than the fixed matching techniques with similar complexity.

• Journal of the Korea Institute of Information and Communication Engineering
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• 제13권6호
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• pp.1194-1199
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• 2009

Stereo vision system is useful method for inferring 3D depth information from two or more images. So it has been the focus of attention in this field for a long time. Stereo matching is the process of finding correspondence points in two or more images. A central problem in a stereo matching is that it is difficult to satisfy both the computation time problem and accuracy at the same time. To resolve this problem, we proposed a new stereo matching technique using weighted cost aggregation. To begin with, we extract the weight in given stereo images based on features. We compute the costs of the pixels in a given window using correlation of weighted color and brightness information. Then, we match pixels in a given window between the reference and target images of a stereo pair. To demonstrate the effectiveness of the algorithm, we provide experimental data from several synthetic and real scenes. The experimental results show the improved accuracy of the proposed method.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 한국해양정보통신학회 2009년도 춘계학술대회
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• pp.396-399
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• 2009

Stereo vision system is useful method for inferring 3D depth information from two or more images. So it has been the focus of attention in this field for a long time. Stereo matching is the process of finding correspondence points in two or more images. A central problem in a stereo matching is that it is difficult to satisfy both the computation time problem and accuracy at the same time. To resolve this problem, we proposed a new stereo matching technique using weighted cost aggregation. To begin with, we extract the weight in given stereo images based on features. We compute the costs of the pixels in a given window using correlation of weighted color, brightness and distance information. Then, we match pixels in a given window between the reference and target images of a stereo pair. To demonstrate the effectiveness of the algorithm, we provide experimental data from several synthetic and real scenes. The experimental results show the improved accuracy of the proposed method.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 한국방송공학회 1997년도 Proceedings International Workshop on New Video Media Technology
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• pp.131-136
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• 1997

We present a method to estimate a dense and sharp depth map using multiple cameras for the application to flexible video production. A key issue for obtaining sharp depth map is how to overcome the harmful influence of occlusion. Thus, we first propose to selectively use the depth information from multiple cameras. With a simple sort and discard technique, we resolve the occlusion problem considerably at a slight sacrifice of noise tolerance. However, boundary overreach of more textured area to less textured area at object boundaries still remains to be solved. We observed that the amount of boundary overreach is less than half the size of the matching window and, unlike usual stereo matching, the boundary overreach with the proposed occlusion-overcoming method shows very abrupt transition. Based on these observations, we propose a hierarchical estimation scheme that attempts to reduce boundary overreach such that edges of the depth map coincide with object boundaries on the one hand, and to reduce noisy estimates due to insufficient size of matching window on the other hand. We show the hierarchical method can produce a sharp depth map for a variety of images.