• Title/Summary/Keyword: geometric features

Search Result 504, Processing Time 0.021 seconds

A Design of Press Die Components by Use of 3D CAD Library (3차원 CAD라이브러리를 이용한 프레스 금형 부품의 설계)

  • Park C. H.;Lee S. S.
    • Korean Journal of Computational Design and Engineering
    • /
    • v.9 no.4
    • /
    • pp.373-381
    • /
    • 2004
  • Using standard components of a press die is recognized as a way for a cost reduction and a short lead time. It also provides a way for a quick maintenance of a die under repair. It is expected to contribute to integration of CAD/CAM system for manufacturing dies in the future. This paper presents a 3D CAD library which is constructed using the standard components and is used for designing a press die. This 3D CAD library is generated by a database system made of Microsoft Access for standard components and by CATIA V5 R10 API for geometric features. The library is implemented using Visual Basic 6.0 utility of CATIA API function in the Windows NT environment. It creates a 3D model of the standard components of press die easily when a die designer inputs numerical values of geometric features and the BOM of the completely assembled parts. It also generates automatically the assembly drawing of die set by using variables for standard values of die parts. Therefore users can save the cost of time to design the press die components, and even a beginner can use this program with ease. The test results of the 3D CAD library for designing shearing and bending dies verify its usefulness and feasibility.

A Face Recognition System using Geometric Image Processing (기하학적 영상처리를 이용한 얼굴인식 시스템)

  • 이항찬
    • Journal of Korea Multimedia Society
    • /
    • v.6 no.7
    • /
    • pp.1139-1148
    • /
    • 2003
  • Biometric system has been studied as an optimal solution for preventing or reducing the peculation or loss of ID. Nowadays, face recognition has been spot-lighted as a future biometric system because it is not forced to contact the part of human body with the specific input area of the system. However, there is some limitations to get the constant facial features because the size of face area is varied by the capturing distance or tilt of the face. In this paper, we can extract constant facial features within the predefined threshold using the simple geometric processing such as image scaling, transformation, and rotation for frontal face images. This face recognition system identifies faces with 92% of accuracy for the 400 images of 40 different people.

  • PDF

Surface Approximation Utilizing Orientation of Local Surface

  • Ko, Myeong-Cheol;Sohn, Won-Sung;Choy, Yoon-Chul
    • Journal of Korea Multimedia Society
    • /
    • v.6 no.4
    • /
    • pp.698-706
    • /
    • 2003
  • The primary goal of surface approximation is to reduce the degree of deviation of the simplified surface from the original surface. However it is difficult to define the metric that can measure the amount of deviation quantitatively. Many of the existing studies analogize it by using the change of the scalar quantity before and after simplification. This approach makes a lot of sense in the point that the local surfaces with small scalar are relatively less important since they make a low impact on the adjacent areas and thus can be removed from the current surface. However using scalar value alone there can exist many cases that cannot compute the degree of geometric importance of local surface. Especially the perceptual geometric features providing important clues to understand an object, in our observation, are generally constructed with small scalar value. This means that the distinguishing features can be removed in the earlier stage of the simplification process. In this paper, to resolve this problem, we present various factors and their combination as the metric for calculating the deviation error by introducing the orientation of local surfaces. Experimental results indicate that the surface orientation has an important influence on measuring deviation error and the proposed combined error metric works well retaining the relatively high curvature regions on the object's surface constructed with various and complex curvatures.

  • PDF

Using Geometry based Anomaly Detection to check the Integrity of IFC classifications in BIM Models (기하정보 기반 이상탐지분석을 이용한 BIM 개별 부재 IFC 분류 무결성 검토에 관한 연구)

  • Koo, Bonsang;Shin, Byungjin
    • Journal of KIBIM
    • /
    • v.7 no.1
    • /
    • pp.18-27
    • /
    • 2017
  • Although Industry Foundation Classes (IFC) provide standards for exchanging Building Information Modeling (BIM) data, authoring tools still require manual mapping between BIM entities and IFC classes. This leads to errors and omissions, which results in corrupted data exchanges that are unreliable and thus compromise the validity of IFC. This research explored precedent work by Krijnen and Tamke, who suggested ways to automate the mapping of IFC classes using a machine learning technique, namely anomaly detection. The technique incorporates geometric features of individual components to find outliers among entities in identical IFC classes. This research primarily focused on applying this approach on two architectural BIM models and determining its feasibility as well as limitations. Results indicated that the approach, while effective, misclassified outliers when an IFC class had several dissimilar entities. Another issue was the lack of entities for some specific IFC classes that prohibited the anomaly detection from comparing differences. Future research to improve these issues include the addition of geometric features, using novelty detection and the inclusion of a probabilistic graph model, to improve classification accuracy.

A Study on the New Simplicity in Contemporary Interior Space - Focused on the John Pawson's works - (현대 실내공간에서의 New Simplicity에 대한 연구 - 존 파우슨(John Pawson) 작품을 중심으로 -)

  • Koo, Man-Jae;Lee, Jung-Wook
    • Korean Institute of Interior Design Journal
    • /
    • v.22 no.1
    • /
    • pp.38-46
    • /
    • 2013
  • The change in radically changing era requires various interpretation of interior space and application according to it Minimalism shows simple and pure geometric structure and has been influencing to every aspect encompassing space till present. The features of minimalism in space is geometric structure and composition of simple and repetitive line, restrained simple space, pure and structural simplicity. When minimalism construction is discussed, the vocabulary of simplicity has been followed incidentally and has been discussed as concept of simplicity in new viewpoint through historical flow. The purpose of this study is analyzing basic features of John Pawson's ways of working and trying to define the semantics of the new simplicity concept in modern interior space. The new simplicity in John Pawson shows interactive relationship of eastern and western through basic consideration of fundamental elements such as space, light and materials. The relational simple in intermediation of the new simplicity expressed by amalgamation of eastern and western further from disparate interpretation for simplicity expressed in eastern and western is to review back the basic meaning of simplicity in minimalism. And I hope this study can offer various directions for new interior space accepting theory of the new simplicity and I think that new constructional alternative is required as physical space which can be matched with era of social, environmental chaos caused by this theory of the new simplicity.

Measuring Pattern Recognition from Decision Tree and Geometric Data Analysis of Industrial CR Images (산업용 CR영상의 기하학적 데이터 분석과 의사결정나무에 의한 측정 패턴인식)

  • Hwang, Jung-Won;Hwang, Jae-Ho
    • Journal of the Institute of Electronics Engineers of Korea CI
    • /
    • v.45 no.5
    • /
    • pp.56-62
    • /
    • 2008
  • This paper proposes the use of decision tree classification for the measuring pattern recognition from industrial Computed Radiography(CR) images used in nondestructive evaluation(NDE) of steel-tubes. It appears that NDE problems are naturally desired to have machine learning techniques identify patterns and their classification. The attributes of decision tree are taken from NDE test procedure. Geometric features, such as radiative angle, gradient and distance, are estimated from the analysis of input image data. These factors are used to make it easy and accurate to classify an input object to one of the pre-specified classes on decision tree. This algerian is to simplify the characterization of NDE results and to facilitate the determination of features. The experimental results verify the usefulness of proposed algorithm.

Automatic Road Lane Matching Using Aerial Images (항공사진을 이용한 도로차선 자동매칭)

  • 김진곤;한동엽;유기윤;김용일
    • Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
    • /
    • 2003.10a
    • /
    • pp.147-152
    • /
    • 2003
  • Aerial Images are usually used to extract 3-D coordinates of various urban features. In this process, the stereo matching of images should be performed precisely to extract these information from aerial Images. In this research, we proposed a matching technique based on geometric features of lanes. We extracted lanes from aerial images and grouped into 4 lane's types. They are lane lines, dotted lines, arrow lane, safety zone. After preprocessing, We will match them by spatial relationships, for example, the distance and orientation between the extracted features. In the future, we will obtain lane coordinates and reconstruct 3-d coordinates of roads.

  • PDF

Performance Analysis of Brightness-Combined LLAH (밝기 정보를 결합한 LLAH의 성능 분석)

  • Park, Hanhoon;Moon, Kwang-Seok
    • Journal of Korea Multimedia Society
    • /
    • v.19 no.2
    • /
    • pp.138-145
    • /
    • 2016
  • LLAH(Locally Likely Arrangement Hashing) is a method which describes image features by exploiting the geometric relationship between their neighbors. Inherently, it is more robust to large view change and poor scene texture than conventional texture-based feature description methods. However, LLAH strongly requires that image features should be detected with high repeatability. The problem is that such requirement is difficult to satisfy in real applications. To alleviate the problem, this paper proposes a method that improves the matching rate of LLAH by exploiting together the brightness of features. Then, it is verified that the matching rate is increased by about 5% in experiments with synthetic images in the presence of Gaussian noise.

Secure Biometric Hashing by Random Fusion of Global and Local Features

  • Ou, Yang;Rhee, Kyung-Hyune
    • Journal of Korea Multimedia Society
    • /
    • v.13 no.6
    • /
    • pp.875-883
    • /
    • 2010
  • In this paper, we present a secure biometric hashing scheme for face recognition by random fusion of global and local features. The Fourier-Mellin transform and Radon transform are adopted respectively to form specialized representation of global and local features, due to their invariance to geometric operations. The final biometric hash is securely generated by random weighting sum of both feature sets. A fourfold key is involved in our algorithm to ensure the security and privacy of biometric templates. The proposed biometric hash can be revocable and replaced by using a new key. Moreover, the attacker cannot obtain any information about the original biometric template without knowing the secret key. The experimental results confirm that our scheme has a satisfactory accuracy performance in terms of EER.

Global Feature Extraction and Recognition from Matrices of Gabor Feature Faces

  • Odoyo, Wilfred O.;Cho, Beom-Joon
    • Journal of information and communication convergence engineering
    • /
    • v.9 no.2
    • /
    • pp.207-211
    • /
    • 2011
  • This paper presents a method for facial feature representation and recognition from the Covariance Matrices of the Gabor-filtered images. Gabor filters are a very powerful tool for processing images that respond to different local orientations and wave numbers around points of interest, especially on the local features on the face. This is a very unique attribute needed to extract special features around the facial components like eyebrows, eyes, mouth and nose. The Covariance matrices computed on Gabor filtered faces are adopted as the feature representation for face recognition. Geodesic distance measure is used as a matching measure and is preferred for its global consistency over other methods. Geodesic measure takes into consideration the position of the data points in addition to the geometric structure of given face images. The proposed method is invariant and robust under rotation, pose, or boundary distortion. Tests run on random images and also on publicly available JAFFE and FRAV3D face recognition databases provide impressively high percentage of recognition.