• Title/Summary/Keyword: invariant

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A partially occluded object recognition technique using a probabilistic analysis in the feature space (특징 공간상에서 의 확률적 해석에 기반한 부분 인식 기법에 관한 연구)

  • 박보건;이경무;이상욱;이진학
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.26 no.11A
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    • pp.1946-1956
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    • 2001
  • In this paper, we propose a novel 2-D partial matching algorithm based on model-based stochastic analysis of feature correspondences in a relation vector space, which is quite robust to shape variations as well as invariant to geometric transformations. We represent an object using the ARG (Attributed Relational Graph) model with features of a set of relation vectors. In addition, we statistically model the partial occlusion or noise as the distortion of the relation vector distribution in the relation vector space. Our partial matching algorithm consists of two-phases. First, a finite number of candidate sets areselected by using logical constraint embedding local and structural consistency Second, the feature loss detection is done iteratively by error detection and voting scheme thorough the error analysis of relation vector space. Experimental results on real images demonstrate that the proposed algorithm is quite robust to noise and localize target objects correctly even inseverely noisy and occluded scenes.

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Slab Region Localization for Text Extraction using SIFT Features (문자열 검출을 위한 슬라브 영역 추정)

  • Choi, Jong-Hyun;Choi, Sung-Hoo;Yun, Jong-Pil;Koo, Keun-Hwi;Kim, Sang-Woo
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.58 no.5
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    • pp.1025-1034
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    • 2009
  • In steel making production line, steel slabs are given a unique identification number. This identification number, Slab management number(SMN), gives information about the use of the slab. Identification of SMN has been done by humans for several years, but this is expensive and not accurate and it has been a heavy burden on the workers. Consequently, to improve efficiency, automatic recognition system is desirable. Generally, a recognition system consists of text localization, text extraction, character segmentation, and character recognition. For exact SMN identification, all the stage of the recognition system must be successful. In particular, the text localization is great important stage and difficult to process. However, because of many text-like patterns in a complex background and high fuzziness between the slab and background, directly extracting text region is difficult to process. If the slab region including SMN can be detected precisely, text localization algorithm will be able to be developed on the more simple method and the processing time of the overall recognition system will be reduced. This paper describes about the slab region localization using SIFT(Scale Invariant Feature Transform) features in the image. First, SIFT algorithm is applied the captured background and slab image, then features of two images are matched by Nearest Neighbor(NN) algorithm. However, correct matching rate can be low when two images are matched. Thus, to remove incorrect match between the features of two images, geometric locations of the matched two feature points are used. Finally, search rectangle method is performed in correct matching features, and then the top boundary and side boundaries of the slab region are determined. For this processes, we can reduce search region for extraction of SMN from the slab image. Most cases, to extract text region, search region is heuristically fixed [1][2]. However, the proposed algorithm is more analytic than other algorithms, because the search region is not fixed and the slab region is searched in the whole image. Experimental results show that the proposed algorithm has a good performance.

Principal Component Analysis as a Preprocessing Method for Protein Structure Comparison (단백질 구조 비교를 위한 전처리 기법으로서의 주성분 분석)

  • Park Sung Hee;Park Chan Yong;Kim Dae Hee;Park Soo-Jun;Park Seon Hee
    • Proceedings of the Korea Information Processing Society Conference
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    • 2004.11a
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    • pp.805-808
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    • 2004
  • 본 논문에서는 두 단백질의 구조적 유사성을 기반으로 한 단백질 비교를 위해서 전처리 기법으로서의 주성분분석기법을 소개한다. 기존의 백본 및 알파탄소 간의 거리행렬(distance matrix), 2차 구조 비교기법, 구역(segment)단위의 비교 기법과 같은 단백질 비교 기법들은 위치이동(translation)와 회전(rotation)에 불변한(invariant) 차이를 구하기 위하여 거리행렬을 이용하였다. 그리고, 난 다음 이들의 최적화 과정을 거쳤다. 그러나, 본 논문에서 제시하는 전처리 기법으로서의 주성분분석기법은 단백질 구조를 전체적인 구조 관점에서 위치를 정렬시킨 후에 단백질 간의 구조를 비교하는 방식이다. 단백질의 구조의 방향성(Orientation)을 맞춘 다음에는 다양한 단백질 표현으로 구를 비교할 수 있다. 본 논문에서는 두 단백질의 구조의 유사성을 측정하기 위한 간결한 단백질 표현(representation)으로 3 차원 에지 히스토그램을 사용하였다. 이 기법은 방향성을 정렬하기 위하여 기존의 방법에서 사용되었던 반복적인 거리계산을 통한 최적화하는 과정을 없앰으로써 단백질 구조 비교 시간을 단축할 수 있는 새로운 단백질 구조 비교 패러다임을 가능하게 한다. 따라서, 이 패러다임을 통하여 적절한 단백질 구조 방향성 정렬과 단백질 구조 표현을 이용한 단백질 구조 비교 검색 시스템은 많은 양의 단백질 구조 정보로부터 원하는 형태의 단백질 구조를 빠른 시간에 검색할 수 있는 장점을 가질 수 있다.

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Vision-Based Self-Localization of Autonomous Guided Vehicle Using Landmarks of Colored Pentagons (컬러 오각형을 이정표로 사용한 무인자동차의 위치 인식)

  • Kim Youngsam;Park Eunjong;Kim Joonchoel;Lee Joonwhoan
    • The KIPS Transactions:PartB
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    • v.12B no.4 s.100
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    • pp.387-394
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    • 2005
  • This paper describes an idea for determining self-localization using visual landmark. The critical geometric dimensions of a pentagon are used here to locate the relative position of the mobile robot with respect to the pattern. This method has the advantages of simplicity and flexibility. This pentagon is also provided nth a unique identification, using invariant features and colors that enable the system to find the absolute location of the patterns. This algorithm determines both the correspondence between observed landmarks and a stored sequence, computes the absolute location of the observer using those correspondences, and calculates relative position from a pentagon using its (ive vortices. The algorithm has been implemented and tested. In several trials it computes location accurate to within 5 centimeters in less than 0.3 second.

The Extraction of Camera Parameters using Projective Invariance for Virtual Studio (가상 스튜디오를 위한 카메라 파라메터의 추출)

  • Han, Seo-Won;Eom, Gyeong-Bae;Lee, Jun-Hwan
    • The Transactions of the Korea Information Processing Society
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    • v.6 no.9
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    • pp.2540-2547
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    • 1999
  • Chromakey method is one of key technologies for realizing virtual studio, and the blue portions of a captured image in virtual studio, are replaced with a computer generated or real image. The replaced image must be changed according to the camera parameter of studio for natural merging with the non-blue portions of a captured image. This paper proposes a novel method to extract camera parameters using the recognition of pentagonal patterns that are painted on a blue screen. We extract corresponding points between a blue screen. We extract corresponding points between a blue screen and a captured image using the projective invariant features of a pentagon. Then, calculate camera parameters using corresponding points by the modification of Tsai's method. Experimental results indicate that the proposed method is more accurate compared to conventional method and can process about twelve frames of video per a second in Pentium-MMX processor with CPU clock of 166MHz.

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A Study on the Rule for Creation of the Pattern Language of Christopher Alexander (크리스토퍼 알렉산더의 패턴언어 생성규칙에 관한 연구)

  • Jung, Sung-Wook;Kim, Moon-Duck
    • Korean Institute of Interior Design Journal
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    • v.26 no.1
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    • pp.75-82
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    • 2017
  • This study reviews the process of creating the patterns through the Christopher Alexander's books to discover the fundamental rules for creation of the pattern language. The essential ideas of 11 rules describing the characteristics of the pattern language are organized by keyword depending on the characteristics of each rule. Then, this study analyzes which keyword was applied importantly and how it had been developed chronologically in the Alexander's books. As a result, 5 keywords - reflection of cultural difference, reflection of human desires, solving the repeated problem, function suitable for principal purpose, and network structure - are applied to his early books in which the pattern language was theoretically developed, the pattern of traditional society was discovered and the network structure was developed. Another 5 keywords - user participation method, new problem solving, structure preserving transformation, post-mechanization method, and central invariant structure - are applied to the books in his mid-term after completion of the pattern theory which discover new pattern for contemporary society and apply the pattern language to time and space. In his later books which organize the theory of pattern language and suggest the direction for using the pattern language, 5 keywords - wholeness, post-mechanization method, user participation method, new problem solving, and structure preserving transformation - are applied. Users may use the pattern language more precisely if he/she considers the keywords of the early period in searching the patterns of existing environment, the keywords of the intermediate period in searching the patterns of new environment or in regard to time and space, and the keywords of the later period in considering direction of the application of the pattern language.

LMI Design of Multi-Objective$ Η_2/Η_\infty$Controllers for an Inverted Pendulum on the Cart Using Polytope Models (폴리토프 모델을 이용한 도립진자의 다목적$ Η_2/Η_\infty$ 제어기의 LMI 설계)

  • 이상철
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.6 no.1
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    • pp.6-13
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    • 2002
  • This paper deals with the linear matrix inequality (LMI) design procedures for multi-objective Η$_2$$_{\infty}$ controllers with pole-placement constraints for an inverted pendulum system modeled as convex polytopes to ensure the stabilizing regulator and tracking performances. Polytopic models with multiple linear time-invariant models linearized at some operating points are derived to design controllers overcoming the conservativeness such as a controller may have when it is designed for a model linearized at a single operating point. Multi-objective controllers are designed for polytopic models by the LMT design technique with convex algorithms. It is observed that the inverted pendulum controlled by any controller designed for each polytopic model is stabilizingly restored to the vertical angle position for initial values of larger tilt anlges.

Recognition of Online Handwritten Digit using Zernike Moment and Neural Network (Zerinke 모멘트와 신경망을 이용한 온라인 필기체 숫자 인식)

  • Mun, Won-Ho;Choi, Yeon-Suk;Cha, Eui-Young
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2010.05a
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    • pp.205-208
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    • 2010
  • We introduce a novel feature extraction scheme for online handwritten digit based on utilizing Zernike moment and angulation feature. The time sequential signal from mouse movement on the writing pad is described as a sequence of consecutive points on the x-y plane. So, we can create data-set which are successive and time-sequential pixel position data by preprocessing. Data preprocessed is used for Zernike moment and angulation feature extraction. this feature is scale-, translation-, and rotation-invariant. The extracted specific feature is fed to a BP(backpropagation) neural network, which in turn classifies it as one of the nine digits. In this paper, proposed method not noly show high recognition rate but also need less learning data for 200 handwritten digit data.

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Rotation and Scale Invariant Face Detection Using Log-polar Mapping and Face Features (Log-polar변환과 얼굴특징추출을 이용한 크기 및 회전불변 얼굴인식)

  • Go Gi-Young;Kim Doo-Young
    • Journal of the Institute of Convergence Signal Processing
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    • v.6 no.1
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    • pp.15-22
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    • 2005
  • In this paper, we propose a face recognition system by using the CCD color image. We first get the face candidate image by using YCbCr color model and adaptive skin color information. And we use it initial curve of active contour model to extract face region. We use the Eye map and mouth map using color information for extracting facial feature from the face image. To obtain center point of Log-polar image, we use extracted facial feature from the face image. In order to obtain feature vectors, we use extracted coefficients from DCT and wavelet transform. To show the validity of the proposed method, we performed a face recognition using neural network with BP learning algorithm. Experimental results show that the proposed method is robuster with higher recogntion rate than the conventional method for the rotation and scale variant.

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Facial Expression Recognition Using SIFT Descriptor (SIFT 기술자를 이용한 얼굴 표정인식)

  • Kim, Dong-Ju;Lee, Sang-Heon;Sohn, Myoung-Kyu
    • KIPS Transactions on Software and Data Engineering
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    • v.5 no.2
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    • pp.89-94
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    • 2016
  • This paper proposed a facial expression recognition approach using SIFT feature and SVM classifier. The SIFT was generally employed as feature descriptor at key-points in object recognition fields. However, this paper applied the SIFT descriptor as feature vector for facial expression recognition. In this paper, the facial feature was extracted by applying SIFT descriptor at each sub-block image without key-point detection procedure, and the facial expression recognition was performed using SVM classifier. The performance evaluation was carried out through comparison with binary pattern feature-based approaches such as LBP and LDP, and the CK facial expression database and the JAFFE facial expression database were used in the experiments. From the experimental results, the proposed method using SIFT descriptor showed performance improvements of 6.06% and 3.87% compared to previous approaches for CK database and JAFFE database, respectively.