• Journal of the Institute of Electronics and Information Engineers
• /
• v.53 no.3
• /
• pp.99-106
• /
• 2016

In this paper, we will discuss about correction method of missing data on noisy observation matrix and uncertainty analysis for the potential noise. In situations without missing data in an observation matrix, this solution is known to be accurately induced by SVD (Singular Value Decomposition). However, usually the several entries of observation matrix have not been observed and other entries have been perturbed by the influence of noise. In this case, it is difficult to find the solution as well as cause the 3D reconstruction error. Therefore, in order to minimize the 3D reconstruction error, above all things, it is necessary to correct reliably the missing data under noise distribution and to give a quantitative evaluation for the corrected results. This paper focuses on a method for correcting missing data using geometrical properties between 2D projected object and 3D reconstructed shape and for estimating a noise level of the observation matrix using ranks of SVD in order to quantitatively evaluate the performance of the correction algorithm.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.22 no.4
• /
• pp.157-163
• /
• 2022

Recently, with the development of automation in the industrial field, research on anomaly detection is being actively conducted. An application for anomaly detection used in factory automation is camera-based defect inspection. Vision camera inspection shows high performance and efficiency in factory automation, but it is difficult to overcome the instability of lighting and environmental conditions. Although camera inspection using deep learning can solve the problem of vision camera inspection with much higher performance, it is difficult to apply to actual industrial fields because it requires a huge amount of normal and abnormal data for learning. Therefore, in this study, we propose a network that overcomes the problem of collecting abnormal data with 72 geometric transformation deep learning methods using only normal data and adds an outlier exposure method for performance improvement. By applying and verifying this to the MVTec data set, which is a database for auto-mobile parts data and outlier detection, it is shown that it can be applied in actual industrial sites.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.44 no.11
• /
• pp.941-948
• /
• 2016

Textile composite materials have been widely applied in aerospace structures due to their various advantages such as high specific stiffnesses and strengths, better out-of-plane performances, impact and delamination resistances, and net shape fabrications. In this paper, a modified geometric model of repeating unit cell (RUC) is suggested based on the Naik's model for 2D plain weave textile composites. The RUC geometry is defined by various parameters. The proposed model considers another parameter which is a gap length between adjacent yarns. The effective stiffnesses are predicted by using the yarn slicing technique and stress averaging technique based on iso-strain assumption. And the stiffnesses of RUC are evaluated by adjusting the gap ratio and verified by comparing with Naik's model and experimental data for 2D plain weave composite specimens.

• Science of Emotion and Sensibility
• /
• v.12 no.1
• /
• pp.129-136
• /
• 2009

Unlike former researches, this study for developing the caricature generator began observing the methods that other caricature experts have adopted. According to the observation, it seemed that experts tried to exaggerate characteristics of the target shape from other similar objects. When we are saying "This is similar to that," we give salience to their difference among the identical form groups. This study was to find the most similar geometry form to the target shape and then to transform its form through exaggeration. The research scope was restricted to exaggerate the outline shape of two-dimensional looped curve as a caricature form. For this, the author discussed the following: (a) organization method of four kinds of similar geometry form database, (b) search method to find the pertinent similar geometry form, (c) arrangement method for those searched data, and (d) method to exaggerate the target shape. Human faces and cars were selected as research categories to make the database. According to the survey over the transformed results, it was proved its possibility.

• KIISE Transactions on Computing Practices
• /
• v.21 no.7
• /
• pp.452-457
• /
• 2015

In this paper, we propose a spatial query processor, SQUERY, which can derive rich query results through spatial reasoning on the initial knowledge base, as well as, process both qualitative and quantitative queries about the topological and directional relationships between spatial objects. In order to derive richer query results, the query processor expands the knowledge base by applying forward spatial reasoning into the initial knowledge base in a preprocessing step. The proposed query processor uses not only qualitative spatial knowledge describing topological/directional relationship between spatial objects, but also utilizes quantitative spatial knowledge including geometric data of individual spatial objects through geometric computation. The results of an experiment with the OSM(Open Street Map) spatial knowledge base demonstrates the high performance of our spatial query processing system.

• Journal of Aerospace System Engineering
• /
• v.17 no.2
• /
• pp.62-70
• /
• 2023

We proposed a technique for predicting Stress-Life (S-N) curve or fatigue life using geometric features of a ply-overlap joint structure in which plies of two composite materials are partially or wholly laminated and bonded. Geometric features that could affect fatigue properties of a structure were selected as variables. By analyzing relationships between geometric variables and material constants of the Epaarachchi-Clausen model, a fatigue model for composites, relational expressions of these two factors were proposed. To verify the prediction accuracy of the proposed method, fatigue life of a CFRP/GFRP ply-overlap joint was predicted. Predicted life and life obtained by test data-based model were compared to actual life. High prediction accuracy was confirmed by calculating the coefficient of determination of the predicted S-N curve.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.24 no.10B
• /
• pp.1946-1952
• /
• 1999

A new image compression method to preserve edge characteristics in reconstructed images using an unsupervised learning neural is proposed in this paper. By the unsupervised competitive learning which generalizes previously proposed Centroid Neural Network(CNN) algorithm with the geometric characteristics of edge area and statistical characteristics of image data, more codevectors are allocated in the edge areas to provide the more accurate edges in reconstructed image. Experimental results show that the proposed method gives improved edge in reconstructed images when compared with SOM, Modified SOM and M/R-CNN.

• Korean Journal of Optics and Photonics
• /
• v.15 no.2
• /
• pp.123-129
• /
• 2004

This paper concerns auto vergence control of a parallel stereoscopic camera through geometrical analysis. In the construction of a parallel stereoscopic camera, we experimentally demonstrated linear relationship between the key object distance and the amount of vergence control. And we proposed a vergence control system for the stereoscopic camera using binocular disparity information. For the real-time calculation of disparity information, the Hybrid Cepstral filter algorithm, with input data acquired from the vertical projection data and from the down sampling data from the source images, was proposed for precision and high speed processing. With the disparity information algorithm and the vergence control of the parallel stereoscopic camera system, the stereoscopic images become more like those of the human eye.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2002.11a
• /
• pp.348-351
• /
• 2002

Recently, the medical imaging field has been digitalized by the development of computer science and digitization of the medical devices. There are needs of the medical imaging database service and long term storage today because of the installation of PACS system following DICOM standards, telemedicine and etc. and ,also, the illegal distortion of the medical information, data authentication and copyright are being happened. In this paper, we propose watermarking technique as a method which can protect private informations and medical imaging from geometric distortion. Because many watermarks for images are sensitive to geometric distortion, we present a algorithm that is insensitive to RST distortion in medical image. we observed the robustness against several of the signal processing and attacks in medical imaging field by embedding watermark after making a region which is insensitive to RST distortion by using FFT and LPM transformation.

• Proceedings of the Korean Association of Geographic Inforamtion Studies Conference
• /
• 2008.06a
• /
• pp.387-390
• /
• 2008

소음지도는 공간의 소음값을 3차원적으로 분석하여 GIS 데이터에 소음분석결과값을 RGB 값으로 표현한 것이다. 현재의 GIS는 2차원 데이터이므로 3차원 소음분석결과값을 표현하고 사용자들에게 제공하는 것에 효과적이지 못하다. 따라서 본 연구에서는 소음분석결과값을 보다 효과적으로 사용자들에게 제공하기 위하여 3차원 소음지도를 제작하고자 한다. 3차원 소음지도는 도시공간모델의 지형과 건물을 각각 소음분석결과값을 이용하여 texturing하여 가시화한 후 통합하여 완성한다. 지형의 경우, 지형의 기하학적 가시화완 지형의 texturing의 두 단계를 거쳐 완성하고 건물의 경우, 건물의 기하학적 3차원 가시화와 건물의 texturing의 두 단계를 거쳐 생성한다. 건물과 지형의 texturing의 단계에서 texture file은 소음분석결과값을 RGB코드로 변환하여 jpg파일로 생성한다. 생성된 3차원 소음지도는 영등포구 전체 영역을 대상지로 하였고 web기반의 VRML파일이다. 가시화의 효율성을 고려하여 영등포구 영역을 $200m{\times}200m$로 구역을 설정 607개의 구역으로 나누어 가시화하였다. 도시공간 모델을 이용하여 3차원 소음지도를 제작함으로써 도시공간모델을 이용하는 응용분야에서 3차원 공간분석의 가시화를 위한 방법을 제시할 수 있었다. 이를 통하여 공간 문제들의 결과를 사용자들에게 보다 효율적으로 제공할 수 있을 것이다.