• Journal of Broadcast Engineering
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• v.24 no.5
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• pp.765-774
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• 2019

In this paper, we propose a point cloud matching algorithm for multiple RGB-D cameras. In general, computer vision is concerned with the problem of precisely estimating camera position. Existing 3D model generation methods require a large number of cameras or expensive 3D cameras. In addition, the conventional method of obtaining the camera external parameters through the two-dimensional image has a large estimation error. In this paper, we propose a method to obtain coordinate transformation parameters with an error within a valid range by using depth image and function optimization method to generate omni-directional three-dimensional model using 8 low-cost RGB-D cameras.

• Journal of The Korean Society of Agricultural Engineers
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• v.49 no.3
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• pp.63-68
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• 2007

The LRA(Logistic Regression Analysis) conducts a quantitative analysis by collecting a lot of samples and the AHP(Analytic Hierarchy Program) makes use of expert decision influenced by subjective judgment to a certain degree. This study is to suggest a combination method in mapping landslide hazard by giving equal weight for the result of LRA and AHP. Topographic factors(slope, aspect, elevation), soil dram, soil depth and land use were adopted to classify landslide hazard areas. The three methods(LRA, AHP, the combined approach) was applied to a $520km^2$ region located in the middle of South Korea which have occurred 39 landslides during 1999 and 2003. The suggested method showed 58.9% matching rate for the real landslide sites comparing with the classified areas of high-risk landslide While LRA and AHP Showed 46.1% and 48.7% matching rates respectively. Further studies are recommended to find the optimal combining weight of LRA and AHP with more landslide data.

• The KSFM Journal of Fluid Machinery
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• v.9 no.2 s.35
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• pp.30-38
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• 2006

An aerodynamic design for centrifugal compressor which was applied to medium speed diesel engine has been done. First of all, exact compressor specifications must be defined by accurate engine system matching. This matching program has been developed. Using the meanline prediction method, geometric design and performance curves for compressor were established and verified by comparing three dimensional viscous CFD results. The deviation at the design point was about 2.3%. Combustor has been designed and manufactured for the performance test of medium speed diesel engine turbocharger. Fuel nozzle of combustor was designed and its characteristics was analyzed by PIV and PDPA test equipment. Through these results, spray characteristics were studied and flow coefficient equation was deduced.

• Proceedings of the KOSOMBE Conference
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• v.1996 no.05
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• pp.31-35
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• 1996

This paper presents a real time algorithm for monitoring of the arrythmia of ECG signal. A real time monitoring, following by detecting a QRS complex, is the most important. Using 2-dimensional time-delay coordinates which are reconstructed by the phase portrait plotting special trajectory, we detect QRS complexes. In this study, arrythmias are detected by matching the past standard template with tile present pattern when changing abruptly In order to matching with each other, we propose modified chain coding algorithm which applies vetor table consisting of eight orthonormal code(=binary code) to the phase portraits. This algorithm using logical function increases the weight if exceeding to the threshold determinded by correlation value and the distance from a straight line(y=x). Evaluating the performance of the proposed algorithm, we use standard MIT/BIH database. The results are fellowing, 1) Improve the speed of matching template than that of cross-correlation ever has been used. 2) Because the proposed algorithm is robust to varing fiducial point, it is possible to monitor the ECG signal with irregular RR interval. 3) In spite of baseline wandering owing to the low frequency noise, monitoring performance is not reduced.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.32 no.6
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• pp.625-635
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• 2014

Multiple strips are required for large area mapping using ALS (Airborne Laser Scanner) system. LiDAR (Light Detection And Ranging) data collected from the ALS system has discrepancies between strips due to systematic errors of on-board laser scanner and GPS/INS, inaccurate processing of the system calibration as well as boresight misalignments. Such discrepancies deteriorate the overall geometric quality of the end products such as DEM (Digital Elevation Model), building models, and digital maps. Therefore, strip adjustment for minimizing discrepancies between overlapping strips is one of the most essential tasks to create seamless point cloud data. This study implemented area-based matching (ABM) to determine conjugate features for computing 3D transformation parameters. ABM is a well-known method and easily implemented for this purpose. It is obvious that the exact same LiDAR points do not exist in the overlapping strips. Therefore, the term "conjugate point" means that the location of occurring maximum similarity within the overlapping strips. Coordinates of the conjugate locations were determined with sub-pixel accuracy. The major drawbacks of the ABM are sensitive to scale change and rotation. However, there is almost no scale change and the rotation angles are quite small between adjacent strips to apply AMB. Experimental results from this study using both simulated and real datasets demonstrate validity of the proposed scheme.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.8 no.2
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• pp.338-343
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• 2004

In Block Matching Algorithm (BMA), a search pattern has a very important affect on the search time and the output quality. In this paper, we propose the HDS( Half Diamond Search) pattern based on the cross center-biased distribution property of a motion vector. At lust, the 4 points in the above, below, left, and right around the search center is calculated to decide the point of the MBD (Minimum Block Distortion). And an above point of the MBD is checked to calculate the SAD. If the SAD is less than the previous MBD, this process is repeated. Otherwise, the left and right points of MBD are calculated to decide the points that have the MBD between two points. These processes are repeated to the predicted direction for motion estimation. Experiments show that the speedup improvement of the proposed algorithm can be up to 23% while maintaining similar image quality.

• Journal of Korea Multimedia Society
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• v.22 no.7
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• pp.780-789
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• 2019

In this paper, we propose a new indoor localization method for indoor mobile robots using LiDAR. The indoor mobile robots operating in limited areas usually require high-precision localization to provide high level services. The performance of the widely used localization methods based on radio waves or computer vision are highly dependent on their usage environment. Therefore, the reproducibility of the localization is insufficient to provide high level services. To overcome this problem, we propose a new localization method based on the comparison between ceiling shape information obtained from LiDAR measurement and the blueprint. Specifically, the method includes a reliable segmentation method to classify point clouds into connected planes, an effective comparison method to estimate position by matching 3D point clouds and 2D blueprint information. Since the ceiling shape information is rarely changed, the proposed localization method is robust to its usage environment. Simulation results prove that the position error of the proposed localization method is less than 10 cm.

• Nonlinear Functional Analysis and Applications
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• v.28 no.2
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• pp.497-520
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• 2023

Numerous problems in science and engineering defined by nonlinear functional equations can be solved by reducing them to an equivalent fixed point problem. Fixed point theory provides essential tools for solving problems arising in various branches of mathematical analysis, such as split feasibility problems, variational inequality problems, nonlinear optimization problems, equilibrium problems, complementarity problems, selection and matching problems, and problems of proving the existence of solution of integral and differential equations.The theory of fixed is known to find its applications in many fields of science and technology. For instance, the whole world has been profoundly impacted by the novel Coronavirus since 2019 and it is imperative to depict the spread of the coronavirus. Panda et al. [24] applied fractional derivatives to improve the 2019-nCoV/SARS-CoV-2 models, and by means of fixed point theory, existence and uniqueness of solutions of the models were proved. For more information on applications of fixed point theory to real life problems, authors should (see [6, 13, 24] and the references contained in).

• Journal of Broadcast Engineering
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• v.17 no.2
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• pp.363-373
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• 2012

This paper proposes a method to generate a depth image at an arbitrary intermediate view-point, which is targeting a video service for free-view, auto-stereoscopy, holography, etc. It assumes that the leftmost and the rightmost depth images are given and they both have been camera-calibrated and image-rectified. This method calculates and uses a disparity increment per depth value. In this paper, it is obtained by stereo matching for the given two depth image by considering more general cases. The disparity increment is used to find the location in the intermediate view-point depth image (IVPD) for each depth in the given images. Thus, this paper finds two IVPDs, from left image and from right image. Noises are removed and holes are filled in each IVPDs and the two results are combined to get the final IVPD. The proposed method was implemented and applied to several test sequences. The results revealed that the quality of the generated IVPD corresponds to 33.84dB of PSNR in average and it takes about 1 second to generate a HD IVPD. We evaluate that this image quality is quite good by considering the low correspondency among the left images, intermediate images, and the right images in the test sequences. If the execution speed is improved, the proposed method can be a very useful method to generate an IVPD at an arbitrary view-point, we believe.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.6 no.10
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• pp.2663-2678
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• 2012

Due to sharp depth transition, big holes may be found in the novel view that is synthesized by depth-image-based rendering (DIBR). A hole-filling method based on disparity map is proposed. One important aspect of the method is that the disparity map of destination image is used for hole-filling, instead of the depth image of reference image. Firstly, the big hole detection based on disparity map is conducted, and the start point and the end point of the hole are recorded. Then foreground pixels and background pixels are distinguished for hole-dilating according to disparity map, so that areas with matching errors can be determined and eliminated. In addition, parallaxes of pixels in the area with holes and matching errors are changed to new values. Finally, holes are filled with background pixels from reference image according to these new parallaxes. Experimental results show that the quality of the new view after hole-filling is quite well; and geometric distortions are avoided in destination image, in contrast to the virtual view generated by depth-smoothing methods and image inpainting methods. Moreover, this method is easy for hardware implementation.