• Title/Summary/Keyword: Multi-resolution representation

Search Result 38, Processing Time 0.024 seconds

Multi-Resolution Representation of Solid Models using the Selective Boolean Operations (선택적 불리안 연산자를 이용한 솔리드 모델의 다중해상도 구현)

  • 이상헌;이강수;박상근
    • Proceedings of the Korean Society of Precision Engineering Conference
    • /
    • 2002.05a
    • /
    • pp.833-835
    • /
    • 2002
  • In this paper, we propose multi-resolutional representation of B-rep solid models using the selective Boolean operations on non-manifold geometric models. Since the union and subtraction operations of the selective Boolean operations are commutative, the integrity of the model is guaranteed for reordering design features. A multi-resolution representation is established using a non-manifold merged set model and a feature modeling tree reordered according to some criterion of level of detail (LOD). Then, a solid model for a specified LOD can be extracted from this multi-resolution model using the selective Boolean operations.

  • PDF

Multi-resolutional Representation of B-rep Model Using Feature Conversion (특징형상 변환을 이용한 B-rep모델의 다중해상도 구현)

  • 최동혁;김태완;이건우
    • Korean Journal of Computational Design and Engineering
    • /
    • v.7 no.2
    • /
    • pp.121-130
    • /
    • 2002
  • The concept of Level Of Detail (LOD) was introduced and has been used to enhance display performance and to carry out certain engineering analysis effectively. We would like to use an adequate complexity level for each geometric model depending on specific engineering needs and purposes. Solid modeling systems are widely used in industry, and are applied to advanced applications such as virtual assembly. In addition, as the demand to share these engineering tasks through networks is emerging, the problem of building a solid model of an appropriate resolution to a given application becomes a matter of great necessity. However, current researches are mostly focused on triangular mesh models and various operators to reduce the number of triangles. So we are working on the multi-resolution of the solid model itself, rather than that of the triangular mesh model. In this paper, we propose multi-resolution representation of B-rep model by reordering and converting design features into an enclosing volume and subtractive features.

Feature-Based Multi-Resolution Modeling of Solids Using History-Based Boolean Operations - Part II : Implementation Using a Non-Manifold Modeling System -

  • Lee Sang Hun;Lee Kyu-Yeul;Woo Yoonwhan;Lee Kang-Soo
    • Journal of Mechanical Science and Technology
    • /
    • v.19 no.2
    • /
    • pp.558-566
    • /
    • 2005
  • We propose a feature-based multi-resolution representation of B-rep solid models using history-based Boolean operations based on the merge-and-select algorithm. Because union and subtraction are commutative in the history-based Boolean operations, the integrity of the models at various levels of detail (LOD) is guaranteed for the reordered features regardless of whether the features are subtractive or additive. The multi-resolution solid representation proposed in this paper includes a non-manifold topological merged-set model of all feature primitives as well as a feature-modeling tree reordered consistently with a given LOD criterion. As a result, a B-rep solid model for a given LOD can be provided quickly, because the boundary of the model is evaluated without any geometric calculation and extracted from the merged set by selecting the entities contributing to the LOD model shape.

Multi- Resolution MSS Image Fusion

  • Ghassemian, Hassan;Amidian, Asghar
    • Proceedings of the KSRS Conference
    • /
    • 2003.11a
    • /
    • pp.648-650
    • /
    • 2003
  • Efficient multi-resolution image fusion aims to take advantage of the high spectral resolution of Landsat TM images and high spatial resolution of SPOT panchromatic images simultaneously. This paper presents a multi-resolution data fusion scheme, based on multirate image representation. Motivated by analytical results obtained from high-resolution multispectral image data analysis: the energy packing the spectral features are distributed in the lower frequency bands, and the spatial features, edges, are distributed in the higher frequency bands. This allows to spatially enhancing the multispectral images, by adding the high-resolution spatial features to them, by a multirate filtering procedure. The proposed method is compared with some conventional methods. Results show it preserves more spectral features with less spatial distortion.

  • PDF

Multi-task learning with contextual hierarchical attention for Korean coreference resolution

  • Cheoneum Park
    • ETRI Journal
    • /
    • v.45 no.1
    • /
    • pp.93-104
    • /
    • 2023
  • Coreference resolution is a task in discourse analysis that links several headwords used in any document object. We suggest pointer networks-based coreference resolution for Korean using multi-task learning (MTL) with an attention mechanism for a hierarchical structure. As Korean is a head-final language, the head can easily be found. Our model learns the distribution by referring to the same entity position and utilizes a pointer network to conduct coreference resolution depending on the input headword. As the input is a document, the input sequence is very long. Thus, the core idea is to learn the word- and sentence-level distributions in parallel with MTL, while using a shared representation to address the long sequence problem. The suggested technique is used to generate word representations for Korean based on contextual information using pre-trained language models for Korean. In the same experimental conditions, our model performed roughly 1.8% better on CoNLL F1 than previous research without hierarchical structure.

Multi-resolution Representation of 2D Point Data (2차원 점 데이터의 다중해상도 표현)

  • Yun, Seong-Min;Lee, Mun-Bae;Park, Sang-Hun
    • Journal of KIISE:Computing Practices and Letters
    • /
    • v.16 no.7
    • /
    • pp.768-774
    • /
    • 2010
  • Reconstruction of implicit surfaces from scattered point data sets have been developed in various engineering and scientific studies. In this paper, we represent a method to construct functions of 2D point data using multi-scale kernels and show it can be applied to graphics applications needed to access data in real-time. Our approach is similar to previous work in that a set of coefficients of the functions are calculated and stored in the preprocessing stage and function values at arbitrary positions are evaluated for real-time applications, however, it is different from others in that users can choose detail levels freely in real-time processing stage. The reason why the functions implicitly supports multi-resolution results from the mathematical properties of multi-scale kernels, and proposed method can be expanded to represent multi-resolution functions of n-dimensional data.

Embedding a Signature to Pictures under Wavelet Transformation (웨이브렛변환을 이용한 영상으로의 서명데이터 삽입)

  • Do, Jae-Su
    • Convergence Security Journal
    • /
    • v.7 no.1
    • /
    • pp.83-89
    • /
    • 2007
  • This paper is to suggest the method of embedding a signature to pictures secretly under the orthogonal wavelet transform which represents pictures as multi-resolution representations. As it is focused upon the differential output under the multi-resolution representation of pictures, this method can embed bit series to pictures. In doing so, it can compound approximately 6K byte of information with gray-level image $256{\times}256$. The method can include not only the database which designates copyright of pictures but also the author and usage of pictures, and the information of the picture itself. Therefore, this method can easily discriminate the inspection of picture database.

  • PDF

Structuring Element Representation of an Image and Its Applications

  • Oh, Jin-Sung
    • International Journal of Control, Automation, and Systems
    • /
    • v.2 no.4
    • /
    • pp.509-515
    • /
    • 2004
  • In this paper we present the linear combination of a fuzzy opening and closing filter with locally adaptive structuring elements that can preserve the geometrical features of an image. Based on the adaptation algorithm of linear combination of the fuzzy opening and closing filter, the optimal structuring element for image representation is obtained. The optimal structuring element is an indicator of the shape and direction of an object's image, which is useful in filtering, multi resolution, segmentation, and recognition of an image.

Similarity Comparison of Mechanical Parts (다중해상도 개념을 이용한 기계 부품의 유사성 비교)

  • Hong, T.S.;Lee, K.W.;Kim, S.C.
    • Korean Journal of Computational Design and Engineering
    • /
    • v.11 no.4
    • /
    • pp.315-325
    • /
    • 2006
  • It is very often necessary to search for similar parts during designing a new product because its parts are often easily designed by modifying existing similar parts. In this way, the design time and cost can be reduced. Thus it would be nice to have an efficient similarity comparison algorithm that can be used anytime in the design process. There have been many approaches to compare shape similarity between two solids. In this paper, two parts represented in B-Rep is compared in two steps: one for overall appearances and the other for detail features. In the first step, geometric information is used in low level of detail for easy and fast pre-classification by the overall appearance. In the second step, feature information is used to compare the detail shape in high level of detail to find more similar design. To realize the idea above, a multi resolution algorithm is proposed so that a given solid is described by an overall appearance in a low resolution and by detail features in high resolution. Using this multi-resolution representation, parts can be compared based on the overall appearance first so that the number of parts to be compared in high resolution is reduced, and then detail features are investigated to retrieve the most similar part. In this way, computational time can be reduced by the fast classification in the first step while reliability can be preserved by detail comparison in the second step.

NETWORK DESIGN AND PREPROCESSING FOR MULTI-SCALE SPHERICAL BASIS FUNCTION REPRESENTATION

  • Oh, Hee-Seok;Kim, Dong-Hoh
    • Journal of the Korean Statistical Society
    • /
    • v.36 no.2
    • /
    • pp.209-228
    • /
    • 2007
  • Given scattered surface air temperatures observed by a network of weather stations, it is an important problem to estimate the entire temperature field for every location on the globe. Recently, a multi-scale spherical basis function (SBF) representation was proposed by Li (1999) for representing scattered data on the sphere. However, for a successful application of Li (1999)'s method, some practical issues such as network design, bandwidth selection of SBFs and initial coefficients are to be resolved. This paper proposes automatic procedures to design network and to select bandwidths. This paper also considers a preprocessing problem to obtain a stable initial coefficients from scattered data. Experiments with real temperature data demonstrate the promising empirical properties of the proposed approaches.