• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.24 no.12
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• pp.122-130
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• 2010

This paper presents an active ranging system based on laser structured-light image. The structured-light image processing is computationally efficient in comparison with the conventional stereo image processing, since the burdensome correspondence problem is avoidable. In order to achieve robustness against environmental illumination noise, an efficient image processing algorithm, i.e., integration of difference images with structured-light modulation is proposed. Distance equation from the measured structured light pixel distance and system parameter calibration are addressed in this paper. Experiments and analysis are carried out to verify performance of the proposed ranging system.

• Proceedings of the KIEE Conference
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• 1987.07b
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• pp.1077-1080
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• 1987

Images are 2-dimensional projection of 3-dimensional scenes and many problems of scene analysis arise due to inherent depth ambiguities in a monocular 2-D image. Therefore, depth recovery is a crucial problem in image understanding. This paper proposes modified algorithm which is focused on accurate correspondnce in stereo vision. The feature we use is zero-crossing points and the similarity measure with two property evaluation function is used to estimate initial probability. And we introduce relaxation technique for accurate and global correspondence.

• Proceedings of the IEEK Conference
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• 1999.06a
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• pp.763-768
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• 1999

The space variant imaging system which mimics the human beings visual system has some merits such as wide field-of-view, the low computational cost and the high accuracy in matching of correspondence points of stereo images. In this presentation, a visual servoing system based on the space variant imaging technique is proposed for the control of the rehabilitation robot arm. The position information of an object obtained by space variant imaging techniques is used for the visual servoing. According to the empirical data, the degree of correlation extracted by the space variant imaging technique is more accurate than that of the space invariant imaging technique.

• Journal of Institute of Control, Robotics and Systems
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• v.16 no.1
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• pp.18-24
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• 2010

In this paper, we address an active ranging system based on laser structured light image for mobile robot application. Since the burdensome correspondence problem is avoidable, the structured light image processing has efficient computation in comparison with the conventional stereo image processing. By using a cylindrical lens in the laser generation, it is possible to convert a point laser into a stripe laser without motorized scan in the proposed system. In order to achieve robustness against environmental illumination noise, we propose an efficient integro-differential image processing algorithm. The proposed system has embedded image processing module and transmits distance data to reduce the computational burden in main control system.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.5C
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• pp.530-535
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• 2007

Disparity space image (DSI) technique is a method of establishing correspondence between a pair of images. It has a merit of generating a dense disparity map for each pixel. DSI has a cost function to be minimized, and it needs empirical weighting factors for occlusion penalty and match reward. This paper provides theoretical basis for the weighting factors, which depend on image noise and contrast between an object and background.

• The Journal of the Korea institute of electronic communication sciences
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• v.8 no.8
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• pp.1187-1193
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• 2013

In this paper, we present realistic 3D head modeling and facial expression systems. For 3D head modeling, we perform generic model fitting to make individual head shape and texture mapping. To calculate the deformation function in the generic model fitting, we determine correspondence between individual heads and the generic model. Then, we reconstruct the feature points to 3D with simultaneously captured images from calibrated stereo camera. For texture mapping, we project the fitted generic model to image and map the texture in the predefined triangle mesh to generic model. To prevent extracting the wrong texture, we propose a simple method using a modified interpolation function. For generating 3D facial expression, we use the vector muscle based algorithm. For more realistic facial expression, we add the deformation of the skin according to the jaw rotation to basic vector muscle model and apply mass spring model. Finally, several 3D facial expression results are shown at the end of the paper.

• Journal of Broadcast Engineering
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• v.17 no.2
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• pp.305-315
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• 2012

Color correction between two or multiple images is very crucial for the development of subsequent algorithms and stereoscopic 3D camera system. Even though various color correction methods are proposed recently, there are few methods for measuring the performance of these methods. In addition, when two images have view variation by camera positions, previous methods for the performance measurement may not be appropriate. In this paper, we propose a method of measuring color difference between corresponding images for color correction. This method finds matching points that have the same colors between two scenes to consider the view variation by correspondence searches. Then, we calculate statistics from neighbor regions of these matching points to measure color difference. From this approach, we can consider misalignment of corresponding points contrary to conventional geometric transformation by a single homography. To handle the case that matching points cannot cover the whole regions, we calculate statistics of color difference from the whole image regions. Finally, the color difference is computed by the weighted summation between correspondence based and the whole region based approaches. This weight is determined by calculating the ratio of occupying regions by correspondence based color comparison.

• 제어로봇시스템학회:학술대회논문집
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• 1993.10b
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• pp.70-75
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• 1993

We represent a method of 3-D object recognition using multi images in this paper. The recognition process is executed as follows. Object models as prior knowledgement are generated and stored on a computer. To extract features of a recognized object, three CCD cameras are set at vertices of a regular triangle and take images of an object to be recognized. By comparing extracted features with generated models, the object is recognized. In general, it is difficult to recognize 3-D objects because there are the following problems such as how to make the correspondence to both stereo images, generate and store an object model according to a recognition process, and effectively collate information gotten from input images. We resolve these problems using the method that the collation on the basis of features independent on the viewpoint, the generation of object models as enumerating some candidate models in an early recognition level, the execution a tight cooperative process among results gained by analyzing each image. We have made experiments based on real images in which polyhedral objects are used as objects to be recognized. Some of results reveal the usefulness of the proposed method.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2012.11a
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• pp.33-36
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• 2012

변이 탐색 범위는 스테레오 정합을 위한 변이 추정 알고리즘의 성능에 가장 큰 영향을 줄 수 있는 변수 중 하나이다. 일반적으로 이러한 변이 탐색 범위는 영상 전체의 최소 변이 값과 최대 변이 값의 범위로 정의된 전역적인 탐색 범위를 사용하게 된다. 이러한 전역적인 탐색 범위는 픽셀에 따라서 불필요한 범위에까지 탐색하게 하며, 이는 변이 추정의 성능적, 속도적 측면에서 좋지 않은 영향을 미치게 된다. 본 논문에서는 픽셀에 따라 변이 탐색 범위를 제한시키는 방법을 제안한다. 낮은 계산 복잡도를 갖는 간단한 변이 추정 알고리즘을 통해 먼저 변이 지도를 생성하여 각 픽셀 당 윈도우를 대응하여 변이 히스토그램을 만든다. 변이 히스토그램에 적응적인 임계 값을 적용하여 픽셀당 변이 후보군을 결정한다. 전역적인 변이 탐색 범위와 제안하는 방법으로 제한된 변이 탐색 범위를 각각 동일한 변이 추정 알고리즘에 적용해 보는 실험을 통해 제안하는 방법의 성능을 분석하였다. 실험 결과로부터 제안하는 방식은 변이 추정 알고리즘의 정확도 측면의 성능을 향상시켰고, 알고리즘의 속도를 평균 5배 이상 향상시켜주는 결과를 보여주었다.

• Journal of Satellite, Information and Communications
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• v.9 no.4
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• pp.32-37
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• 2014

The panorama is a good alternative to overcome narrow FOV under study in robot vision, stereo camera and panorama image registration and modeling. The panorama can materialize view with angles wider than human view and provide realistic space which make feeling of being on the scene based on realism. If we use all correspondence, it is too difficult to find strong features and correspondences and assume accurate homography matrix in geographic changes in images as load of calculation increases. Accordingly, we used SURF algorithm to estimate overlapping areas with high similarity by comparing and analyzing the input images' histograms and to detect features. And we solved the problem of input order so we can make panorama by input images without order.