• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1993년도 추계학술대회 논문집
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• pp.550-555
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• 1993

The aim of this paper is to present the development of visual seam tracking system equipped with visual range finder. The visual range finder, which consists of a CCD camera and a diode laser system with line generating optics, developed to recognize the types of weld joints and detect the location of weld joints. In practical applications, however, images of the weld joints are often degraded due to spatters, are flares, surface specularity, and welding smoke. To overcome the problem, this paper proposes a syntactic approach which is a class of artificial intelligence techniques. In the approach, the type of weld joint is inferred based upon the production rules which are linguiques grammars consisting of a set of line and junction primitives of laser strip image projected on weld joint. The production rules eliminate several noisy primitives to create new primitives through the merging process of primitives. After the recognition of weld joint, arc welding is started and the location of weld joints is repeatedly detected using a spring model-based template matching in which the template model is a by-product of the recognition process of weld joint. To show the effectiveness of the proposed approach a series of experiments-identification and robotic tracking-are conducted for four different types of weld joints.

• 대한원격탐사학회지
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• 제17권4호
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• pp.319-334
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• 2001

Extracting primitives from imagery plays an important task in visual information processing since the primitives provide useful information about characteristics of the objects and patterns. The human visual system utilizes features without difficulty for image interpretation, scene analysis and object recognition. However, to extract and to analyze feature are difficult processing. The ultimate goal of digital image processing is to extract information and reconstruct objects automatically. The objective of this study is to develop robust method to achieve the goal of the image processing. In this study, an adaptive strategy was developed by implementing Gabor filters in order to extract feature information and to segment images. The Gabor filters are conceived as hypothetical structures of the retinal receptive fields in human vision system. Therefore, to develop a method which resembles the performance of human visual perception is possible using the Gabor filters. A method to compute appropriate parameters of the Gabor filters without human visual inspection is proposed. The entire framework is based on the theory of human visual perception. Digital images were used to evaluate the performance of the proposed strategy. The results show that the proposed adaptive approach improves performance of the Gabor filters for feature extraction and segmentation.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2009년도 추계학술대회
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• pp.285-288
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• 2009

동영상에서 물체를 추적하기 위한 많은 방법들은 각 방법마다 다양한 요소들을 이용한다. 하지만 다양한 요소들은 그 관계를 명확히 나타낼 수 없다. 본 논문에서는 동영상에서 물체 추적을 위해 시각적 기본 요소의 동일성을 나타내고 설명하기 위한 방법을 제안한다. 시각적 기본 요소란 이미지에서 얻을 수 있는 순수한 시각적 기본 요소들인 색상, 명암, 윤곽선 정보를 말하며 이 정보를 이용하여 연속된 프레임을 비교해 동일한 물체인지를 판단한다. 그리하여 판단된 정보를 가지고 추적에 사용되는 요소들의 지속적인 갱신을 통해 대상을 모델 없이 추적하고 인식 과정에 대하여 제어가 가능하도록 한다.

• 한국멀티미디어학회논문지
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• 제19권11호
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• pp.1900-1908
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• 2016

Recent times have seen the introduction of modeling technologies using implicit surface and marching cubes algorithm in the field of computer graphics. Implicit surface modeling is used to express characters or fluid. This study presents a calculation method for the density of curve skeletal primitives using parametric curve and implements an implicit surface modeling tool by utilizing Maya API. Skeletal primitives can be assembled and utilized in character modeling using the implemented modeling tool. Results could be obtained more effectively compared to existing particle-based methods.

• 생물환경조절학회지
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• 제3권1호
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• pp.42-51
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• 1994

대다수 농산물과 마찬가지로 건조표고의 등급판정은 외관특징에 주로 의존한다. 표고 갓의 전후면에 걸친 복잡하고 다양한 외관특징들로 인하여 표고의 등급판정은 임의로 추출한 표고샘플에 대하여 전문가가 수작업으로 판정하고 있으며, 선별작업 역시 전적으로 수작업에 의존하고 있다. 단순한 반복작업으로 보이는 농산물의 등급판정은 사실 시각과 촉각을 위시한 고도의 감각신경계를 통하여 상호 복잡하게 얽혀 들어오는 정보를 지능적으로 처리하는 고기능의 작업이다. 농산물의 경우, 외관특성을 비롯한 물성은 종류별로 그 경계치를 일괄적으로 명확하게 규정할 수 없기 때문에 대개는 오차를 포함한 통계적 접근에 의하여 규정하고 있다. 따라서 농산작업에 있어서는 농산물 물성이 갖는 모호성을 효율적으로 처리할 수 있는 가변적인 작업구조 및 정보처리가 필수적으로 요구된다. 본 연구에서는 인간 뇌의 정보처리 기능을 부분적으로 구현할 수 있는 인공신경회로망을 컴퓨터 시각 시스템에 적용하여 단순 기하도형의 분류 및 표고의 등급판정을 성공적으로 수행하였다. 회로망 입력으로는 컴퓨터시각 시스템을 이용하여 건조표고의 정성적 외관특징을 자동으로 추출한 후 정량화한 특징점 값들을 이용하였다. 신경회로망의 학습은 표본 추출한 등급표고와 이들의 정량적 특징점 값들을 입출력 쌍으로 하여 수행하였다. 학습한 회로망의 등급판정 성능시험은 표본추출한 미지의 표고에 대한 컴퓨터 영상 특징점 값들을 입력하여 수행하였다.

• 한국컴퓨터그래픽스학회논문지
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• 제4권1호
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• pp.55-66
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• 1998

This paper presents a simple method for relieving the ambiguity problems within the sub-voxel based surface-fitting approach for the surface construction. ECB algorithm is proposed to avoid the ambiguity problem which is the root of the holes within the resulting polygon based approximation. The basic idea of our disambiguation strategy is the use of a set of predefined modeling primitives (we call SMP) which guarantees the topological consistency of resulted surface polygons. 20 SMPs are derived from the extension of the concept of the elementary modeling primitives in the CB algorithm [3], and fit one to five faces of them to the iso-surface crossing a cell with no further processing. A look-up table which has a surface triangle list is pre-calculated using these 20 SMPs. All of surface triangles in the table are from the faces of SMPs and are stored in the form of edge list on which vertices of each surface triangle are located. The resulted polygon based approximation is unique at every threshold value and its validity is guaranteed without considering the complicated problems such as average of density and postprocessing. ECB algorithm could be free from the need for the time consuming post-processing, which eliminates holes by revisiting every boundary cell. Through three experiments of surface construction from volume data, its capability of hole avoidance is showed.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제13권4호
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• pp.2129-2147
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• 2019

This paper introduces an adaptive face recognition method based on a Novel Incremental Kernel Nonparametric Discriminant Analysis (IKNDA) that is able to learn through time. More precisely, the IKNDA has the advantage of incrementally reducing data dimension, in a discriminative manner, as new samples are added asynchronously. Thus, it handles dynamic and large data in a better way. In order to perform face recognition effectively, we combine the Gabor features and the ordinal measures to extract the facial features that are coded across local parts, as visual primitives. The variegated ordinal measures are extraught from Gabor filtering responses. Then, the histogram of these primitives, across a variety of facial zones, is intermingled to procure a feature vector. This latter's dimension is slimmed down using PCA. Finally, the latter is treated as a facial vector input for the advanced IKNDA. A comparative evaluation of the IKNDA is performed for face recognition, besides, for other classification endeavors, in a decontextualized evaluation schemes. In such a scheme, we compare the IKNDA model to some relevant state-of-the-art incremental and batch discriminant models. Experimental results show that the IKNDA outperforms these discriminant models and is better tool to improve face recognition performance.

• 한국정보과학회논문지:소프트웨어및응용
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• 제26권1호
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• pp.157-157
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• 1999

Researches on the gesture recognition have become a very interesting topic in the computer vision area, Gesture recognition from visual images has a number of potential applicationssuch as HCI (Human Computer Interaction), VR(Virtual Reality), machine vision. To overcome thetechnical barriers in visual processing, conventional approaches have employed cumbersome devicessuch as datagloves or color marked gloves. In this research, we capture gesture images without usingexternal devices and generate a gesture trajectery composed of point-tokens. The trajectory Is spottedusing phase-based velocity constraints and recognized using the discrete left-right HMM. Inputvectors to the HMM are obtained by using the LBG clustering algorithm on a polar-coordinate spacewhere point-tokens on the Cartesian space .are converted. A gesture vocabulary is composed oftwenty-two dynamic hand gestures for editing drawing elements. In our experiment, one hundred dataper gesture are collected from twenty persons, Fifty data are used for training and another fifty datafor recognition experiment. The recognition result shows about 95% recognition rate and also thepossibility that these results can be applied to several potential systems operated by gestures. Thedeveloped system is running in real time for editing basic graphic primitives in the hardwareenvironments of a Pentium-pro (200 MHz), a Matrox Meteor graphic board and a CCD camera, anda Window95 and Visual C++ software environment.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2001년도 춘계학술대회 논문집
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• pp.37-40
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• 2001

This paper describes the selection and evaluation of RP processes. Major rapid prototyping processes such as SLS, SLA, FDM and LOM, which are wide spread in use are selected. A test part, which includes various primitives, is designed in order to evaluate these RP processes. Measurement of the test part is automated by using a CMN program. To visualize and analyze measured data, Microsoft Access and Visual C++ are used. Also, from measured data obtained, TOPSIS, one of the decision making methods, and Shannon Entropy is used to select an appropriate RP process for specific application.

• 한국정보과학회논문지:컴퓨팅의 실제 및 레터
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• 제5권4호
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• pp.385-394
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• 1999

제품을 설계하는 디자이너나 엔지니어는 많은 시간과 노력을 들이지 않고서 그들이 설계한 3차원 제품 모델에 대한 사실적인 이미지를 원한다. 디자인 프로세스의 초기인 개념 설계에서부터 설계검증, 그리고 가공 과정에서 사실적인 이미지가 매우 유용하므로, 대부분의 주요 CAD 제작사는 그들의 CAD 소프트웨어에 고급 렌더링 기능을 추가하고 있다. 상용의 CAD/CAM 모델러에서는 NURB 곡면을 기초로 모델링을 수행하므로, NURB 곡면을 렌더링할 수 있는 패키지가 필요하다. VIF(Visual InterFace) 렌더링 라이브러리는 A-buffer 방식과 Ray tracing 방식의 두 가지 고급 렌더링 모드를 제공한다. 다각형은 물론 NURB 곡면을 입력으로 받아 사용자가 설정한 표면의 각종 계수, 원하는 view와 설정된 광원에 따라 이미지를 만들고 다양한 형태로 출력시킬 수 있는 다양한 기능을 제공한다. 본 논문에서는 VIF 렌더링 라이브러리에 대한 구조와 기능별로 분류된 함수에 대하여 설명하며, 실제로 CAD/CAM 시스템과 통합되어 구상설계에서부터 3차원 설계 모델링에 이르기까지의 제조공정에서 설계검증 툴로써 어떻게 활용되고 있는가에 대하여 기술한다.Abstract Engineers and industrial designers want to produce a realistic-looking images of a 3D model without spending a lot of time and money. Photo-realistic images are so useful from the conceptual design, through its verification, to the machining, that most major CAD venders offer built-in as well as add-on photo-realistic rendering capability to their core CAD software. Since 3D model is consists of a set of NURB surfaces in commercial CAD packages, we need a renderer which handles NURB surface as well as other primitives.A new rendering library called VIF (Visual InterFace) provides two photo-realistic rendering modes: A-buffer and Ray tracing. As an input data it takes NURB surfaces as well as polygonal data and produces images in accordance with the surface parameters, view and lights set by user and outputs image with different formats. This paper describes the overall architecture of VIF and its library functions classified by their functionalities, and discusses how VIF is used as a graphical verification tool in manufacturing processes from the conceptual design to 3D modeling.