• Title/Summary/Keyword: 기하학적 변환

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Geometric Correction of Lips Using Lip Information (입술정보를 이용한 입술모양의 기하학적 보정)

  • 황동국;박희정;전병민
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.29 no.6C
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    • pp.834-841
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    • 2004
  • There can be lips transformed geometrically in the lip images according to the location or the pose of camera and speaker. This transformation of the lip images changes geometric information of original lip phases. Therefore, for enhancing global lip information by using partial information of lips to correct lip phases transformed geometrically, in this paper we propose a method that can geometrically correct lips. The method is composed of two steps - the feature-deciding step and the correcting step. In the former, it is for us to extract key points and features of source image according to the its lip model and to create that of target image according to the its lip model. In the latter, we decide mapping relation after partition a source and target image based on information extracted in the previous step into each 4 regions. and then, after mapping, we unite corrected sub-images to a result image. As experiment image, we use fames that contain pronunciation on short vowels of the Korean language and use lip symmetry for evaluating the proposed algorithm. In experiment result, the correcting rate of the lower lip than the upper lip and that of lips moving largely than little was highly enhanced.

Robust Watermarking Scheme Against Geometrical Attacks Using Alignment of Image Features (영상특징 정렬을 이용한 기하학적 공격에 강인한 워터마킹 기법)

  • Ko Yun-Ho
    • Journal of Korea Multimedia Society
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    • v.9 no.5
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    • pp.624-634
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    • 2006
  • This paper presents a new watermarking scheme that is robust against geometrical attacks such as translation and rotation. The proposed method is based on the conventional PSADT(Polar Coordinates Shape Adaptive Discrete Transform) method which is an robust watermarking scheme for an arbitrarily-shaped image such as character images. The PSADT method shows perfect robustness against geometrical attack if there is no change in the shape of the image object. However, it cannot be utilized to watermark general rectangular images because of the missing alignment between the watermarked signals in the embedding and extracting side. To overcome this problem we propose a new watermarking scheme that aligns the watermark signal using the image inherent feature, especially corner. Namely the proposed method decides a consistent target region whose shape and position isn't changed by any malicious attack and then embeds the watermark in it using the PSADT method. Experimental results show the robustness of the proposed method against geometrical attacks as well as image compression.

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Image Watermarking Robust to Rotation, Scale and Translation Distortion (RST변환에 강인한 이미지 워터마킹 방법)

  • Choo, Hyon-Gon;Lim, Sam;Kim, Whoi-Yul
    • Proceedings of the IEEK Conference
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    • 2001.09a
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    • pp.209-212
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    • 2001
  • 오늘날, 디지털 워터마크에 대하여 기하학적 변환에 대한 강인성이 요구되고 있다. 본 논문에서는 회전, 이동 및 크기변화에 강인한 워터마킹 방법을 제안한다. 영상의 푸리에 변환 계수를 이용하여 이동에 대한 강인한 속성을 가지도록 하며, 입력 마스크의 상호 관계가 회전, 크기 변화에 강인하도록 워터마크 마스크를 생성한 후 영상에 삽입한다. 삽입된 워터마크의 검출은 영상의 주파수 영역의 radial projection 에 대한 워터마크 신호의 상관도를 이용하여 검출한다. 실험을 통하여 제안된 방법이 여러 가지 기하학적 변환에 강인함을 보여준다.

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Automated Geometric Correction based on Robust Estimation with Geostationary Weather Satellite Image (강인추정 기법에 기반한 정지궤도 기상위성영상의 자동 기하보정)

  • Lee, Tae-Yoon;Ahn, Myoung-Hwan;Oh, Hyun-Jong
    • Proceedings of the KSRS Conference
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    • 2007.03a
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    • pp.161-166
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    • 2007
  • Multi-functional Transport Satellite lR(MTSAT-lR)과 같은 정지궤도 기상위성의 지상 전처리 과정에는 영상위치보정(Image navigation and registration)이 포함된다. 영상위치보정은 위성 영상의 기하학적인 왜곡을 보정하는 과정이다. 랜드마크를 이용하는 영상위치보정 과정은 랜드마크 결정과 센서 모델 추정, 리샘플링(Resampling)의 세 가지 단계로 나눌 수 있다. MTSAT-1R의 High Resolution Image Data(HiRID)는 이미 영상위치보정이 수행되었지만, 기하학적인 오차가 남아있는 영상을 포함하기도 한다. 본 연구에서는 이런 기하학적인 오차를 제거하기 위해서 강인추정 기법에 기반한 기하보정을 수행하였다. 이태윤 등 (2005)은 강인추정 기법과 Direct Linear Transformation (DLT)에 기반한 오정합 판별 방법을 제안하였다. 이 판별 방법을 적용하여 추정된 DLT로 MTSAT-1R 영상의 기하보정을 수행한 결과에는 향상된 정확도로 기하보정 된 영상 뿐만 아니라 비교적 큰 오차를 포함하는 영상도 있었다. 이를 해결하기 위해서 본 연구에서는 강인추정 기법과 Affine 변환을 이용한 방법을 적용하였다. 본 연구에서는 기준 해안선에서 추출한 1,407개의 랜드마크와 8개의 MTSAT-1R 영상을 이용하였으며,강인추정 기법에 DLT를 적용한 방법과 Affine 변환을 적용한 방법으로 자동 기하보정을 수행하여 그 결과를 비교하였다. 또한 강인추정 기볍 중 RANSAC과 MSAC의 적용 결과를 비교하여 보았다. 그 결과,DLT로 기하보정 시,본 논문에서 제안된 방법이 강인추정 기법에 DLT를 적용한 방법 보다 더 좋은 성능을 보여주었다.

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Geometric Modelling and Coordinate Transformation of Satellite-Based Linear Pushbroom-Type CCD Camera Images (선형 CCD카메라 영상의 기하학적 모델 수립 및 좌표 변환)

  • 신동석;이영란
    • Korean Journal of Remote Sensing
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    • v.13 no.2
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    • pp.85-98
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    • 1997
  • A geometric model of pushbroom-type linear CCD camera images is proposed in this paper. At present, this type of cameras are used for obtaining almost all kinds of high-resolution optical images from satellites. The proposed geometric model includes not only a forward transformation which is much more efficient. An inverse transformation function cannot be derived analytically in a closed form because the focal point of an image varies with time. In this paper, therefore, an iterative algorithm in which a focal point os converged to a given pixel position is proposed. Although the proposed model can be applied to any pushbroom-type linear CCD camera images, the geometric model of the high-resolution multi-spectral camera on-board KITSAT-3 is used in this paper as an example. The flight model of KITSAT-3 is in development currently and it is due to be launched late 1998.

Log-Polar Image Watermarking based on Invariant Centroid as Template (불변의 무게중심을 템플릿으로 이용한 대수-극 좌표계 영상 워터마킹 기법)

  • 김범수;유광훈;김우섭;곽동민;송영철;최재각;박길흠
    • Journal of KIISE:Computing Practices and Letters
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    • v.9 no.3
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    • pp.341-351
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    • 2003
  • Digital image watermarking is the method that can protect the copyright of the image by embedding copyright information, which is called watermark. Watermarking must have robustness to intentional or unintentional data changing, called attack. The conventional watermarking schemes are robust to waveform attacks such as image compression, filtering etc. However, they are vulnerable to geometrical attacks such as rotation, scaling, translation, and cropping. Accordingly, this paper proposes new watermarking scheme that is robust to geometrical attacks by using invariant centroid. Invariant centroid is the gravity center of a central area in a gray scale image that remains unchanged even when the image is attacked by RST including cropping and proposed scheme uses invariant centroids of original and inverted image as the template. To make geometrically invariant domain, template and angle compensated Log -Polar Map(LPM) is used. Then Discrete Cosine Transform(DCT) is performed and the watermark is embedded into the DCT coefficients. Futhermore, to prevent a watermarked image from degrading due to interpolation during coordinate system conversion, only the image of the watermark signal is extracted and added to the original image. Experimental results show that the proposed scheme is especially robust to RST attacks including cropping.

Teaching method of the ellipse in Transformation Geometry (변환 기하학적 관점에서 본 타원의 지도 방안)

  • Cho, Cha-Mi
    • School Mathematics
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    • v.14 no.3
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    • pp.331-355
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    • 2012
  • All the method used in teaching the ellipse was to have students draw the points which have the same sum of distances from the two points so that they can confirm the shapes of the ellipse before showing them the definition of ellipse. In this process, students would not get an opportunity to think or make the definition of ellipse for themselves. This deductive way can hinder students from having clear understanding of why such definition was made. This paper introduces a method of defining the ellipse based on the similarity between a circle and an ellipse, leading into the equation. This method is possible by introducing Analytic Geometry taught in current school mathematics and Transformation Geometry. By doing so, this paper will discuss a fundamental understanding about the ellipse and the feature of the ellipse expandable by intuition. Furthermore this paper will also show various advantages which can be given by defining the ellipse in Transformation Geometry.

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Licence Plate Recognition Using Improved IAFC Fuzzy Neural Network (개선된 IAFC 퍼지 신경회로망을 이용한 차량 번호판 인식)

  • Lee, Si-Hyun;Choi, Si-Young;Lee, Se-Yul;Kim, Yong-Soo
    • Journal of the Korean Institute of Intelligent Systems
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    • v.19 no.1
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    • pp.6-12
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    • 2009
  • In this paper, we propose a system that extracts licence plate and recognizes numerals in the licence plate. The candidate area of licence plate is extracted using the improved IAFC(Integrated Adaptive Fuzzy Clustering) fuzzy neural network. And the morphological filters are used to reduce noise from the extracted licence plate. The extracted licence plate is standardized using Hough transform and geometric transform. Backpropagation neural network is used to recognize numerals that are separated using the projection technique.

Underwater Acoustic Image Classification of a Cylindrical object using the Hough Transformation and Nth Degree Polynomial Interpolation (N차 다항식 보간법과 허프 변환을 이용한 원통형 수중 물체 영상 식별)

  • Jeong, Euicheol;Shim, Taebo;Kim, Jangeun
    • Journal of the Institute of Electronics and Information Engineers
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    • v.50 no.2
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    • pp.193-200
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    • 2013
  • In this paper, underwater acoustic image classification of a cylindrical object using the Hough transformation is proposed. Hough transformation is often used to classify a cylindrical object in the optical systems. However, it is difficult to apply to the underwater acoustic image system because of lower resolution and noisier underwater environments. Thus, the cylindrical object was modeled and its geometric depth(GD) pixels were restored in order to make them suitable for the Hough transformation by using moving average filter and a polynomial interpolation method. As a result, restored GD pixels are similar to original ones and test results show high performance in classification.

2D/3D Video Conversion Method using Differential Depth Information by Grouped Object (그룹화된 객체별 깊이정보를 차등 적용한 2D/3D 동영상 변환 기법)

  • Han, Sung-Ho;Hong, Yeong-Pyo;Lee, Jong-Yong;Lee, Sang-Hun
    • Proceedings of the KAIS Fall Conference
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    • 2011.12b
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    • pp.445-448
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    • 2011
  • 본 논문은 그룹화된 객체별 깊이정보를 차등 적용한 2D/3D 동영상 변환 기법에 관한 연구이다. 기존의 연구에서는 프레임의 움직임 정보와 기하학적 깊이 단서를 이용해 깊이정보를 추출하여 2D/3D 동영상 변환을 한다. 그러나 영상의 움직임 정보를 획득할 수 없는 영역의 경우 정확한 깊이정보를 얻을 수 없어 해당 영역의 3D 효과를 얻을 수 없는 문제점이 있다. 제안하는 기법에서는 객체 및 배경을 추출하고 움직임 정보와 기하학적 단서를 이용한 깊이정보를 그룹화된 객체별 차등 적용하여 움직임 정보가 없는 영역에서도 3D 효과를 얻을 수 있는 방법을 제안한다. 최종적으로 원본 영상과 생성된 깊이맵을 DIBR(Depth Image Based Rendering) 과정을 통해 3D 동영상을 생성한 결과 움직임 정보가 없는 영역에서도 3D 효과를 얻을 수 있었다.

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