• Title/Summary/Keyword: 2D 투영 변환

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A Study on the Hybrid-Pattern Recognition System using Projection of 2-D Image (2차원 영상의 투영을 이용한 복합패턴인식시스템에 관한 연구)

  • 반재경;박한규
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.11 no.6
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    • pp.421-429
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    • 1986
  • In this paper, new hybrid-pattern recognition system is proposed using Radon transform. Transforming the 2-D image into the 1-D projection data, Fourier spectrum at each projection angle is obtained by the Fourier transforming the projection data using the A/0. After extracting the suitable features from the Fourier spectrum and projection data, the input pattern is recognized using the wquared Mahalanobis distance. The results of this system showed the 100% recognition rate for the 10 input patterns.

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Performance Analysis of Hybrid Equiangular Cubemap (HEC) for 360 Video Coding (360 비디오 부호화를 위한 HEC 투영 성능분석)

  • Kim, Nam-Cheol;Kim, Hyun-Ho;Yoon, Yong-Uk;Kim, Jae-Gon
    • Proceedings of the Korean Society of Broadcast Engineers Conference
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    • 2018.11a
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    • pp.141-142
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    • 2018
  • 360 비디오는 VR 미디어의 확산과 함께 몰입형 미디어로 주목 받고 있으며, JVET(Joint Video Experts Team)에서는 post-HEVC 로 진행중인 VVC(Versatile Video Coding) 표준화에 360 비디오 부호화도 함께 포함하고 있다. 현재 JVET 에서는 360 비디오를 부호화 하기 위한 다양한 구(sphere) 영상의 2D 투영기법이 고려되고 있다. 이러한 2D 투영에서는 구 영상의 화소 샘플이 2D 영상에 비 균일하게 매핑되는 변환 왜곡이 발생하며, 이는 360 비디오의 부호화 효율을 저하시키는 원인이 된다. 본 논문에서는 CMP 의 개선된 투영기법인 기존의 EAC(Equi-Angular Cubemap)와 HEC(Hybrid Equiangular Cubemap)를 소개하고, 이를 바탕으로 HEC 의 확장 변환 기법을 제시하여 객관적/주관적 부호화 성능을 확인한다.

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Denoising neural network to improve the foam effect via screen projection method (스크린 투영 방식의 거품 효과를 개선하기 위한 노이즈 제거 신경망)

  • Kim, Jong-Hyun;Kim, Donghui;Kim, Soo Kyun
    • Proceedings of the Korean Society of Computer Information Conference
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    • 2021.07a
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    • pp.663-666
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    • 2021
  • 본 논문에서는 바다와 같은 스케일이 큰 장면인 물 시뮬레이션에서 표현되는 거품 효과(Foam effects)를 노이즈 없이 디테일하게 표현할 수 있는 프레임워크를 소개한다. 거품이 생성될 위치와 거품 입자의 이류는 기존의 접근법인 스크린 투영 방법을 통해 계산한다. 이 과정에서 중요한 것이 투영맵이지만 이산화된 스크린 공간에 운동량을 투영하는 과정에서 노이즈가 발생한다. 본 논문에서는 노이즈 제거 신경망(Denoising neural network)을 활용하여 이 문제를 효율적으로 풀어낸다. 투영맵을 통해 거품이 생성될 영역이 선별되면 2D공간을 3D공간으로 역변환(Inverse transformation)하여 거품 입자를 생성한다. 결과적으로 깔끔한 거품 효과뿐만 아니라, 노이즈 제거 과정으로 인해 소실되는 거품 없이 안정적으로 거품 효과를 만들어냈다.

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Frequency filtering on Fourier Transform Profilometry for the Measurement of 3-D shapes (푸리에 변환법을 이용한 3차원 형상측정에서의 필터 효과)

  • 박준식;나성웅;박승규;백성훈
    • Proceedings of the Optical Society of Korea Conference
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    • 2003.02a
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    • pp.94-95
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    • 2003
  • 광학식 3차원 형상측정 기술은 산업현장과 의료분야 등에서 광범위하게 사용되어지고 있으며, 이에 대한 연구도 활발히 진행되고 있다. 본 연구에서는 푸리에 변환법에 의한 위상정보 추출 기술을 개발하고, 주파수 영역에서의 창함수 필터에 따른 위상추출 특성을 분석하였다. 광조사 장치로는 LCD 프로젝터를 이용한 투영방식(그림 1)과 레이저 간섭계 투영방식(그림 2)을 사용하였다. (중략)

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Refinement of Projection Map Based on Artificial Neural Networks to Represent Noise-Reduced Foam Effects (노이즈가 완화된 거품 효과를 표현하기 위한 인공신경망 기반의 투영맵 정제)

  • Kim, Jong-Hyun
    • Journal of the Korea Computer Graphics Society
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    • v.27 no.4
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    • pp.11-24
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    • 2021
  • In this paper, we propose an artificial neural network framework that can represent the foam effects expressed in liquid simulation in detail without noise. The position and advection of foam particles are calculated using the existing screen projection method, and the noise problem that appears in this process is solved through an proposed artificial neural network. The important thing in the screen projection approach is the projection map, but noise occurs in the projection map in the process of projecting momentum into the discretized screen space, and we efficiently solve this problem by using an artificial neural network-based denoising network. When the foam generating area is selected through the projection map, 2D is inversely transformed into 3D space to generate foam particles. We solve the existing denoising network problem in which small-scaled foam particles disappear. In addition, by integrating the proposed algorithm with the screen-space projection framework, all the advantages of this approach can be accommodated. As a result, it shows through various experiments whether it is possible to stably represent not only the clean foam effects but also the foam particles lost due to the denoising process.

Epipolar Resampling for High Resolution Satellite Imagery Based on Parallel Projection (평행투영 기반의 고해상도 위성영상 에피폴라 재배열)

  • Noh, Myoung-Jong;Cho, Woo-Sug;Chang, Hwi-Jeong;Jeong, Ji-Yeon
    • Journal of Korean Society for Geospatial Information Science
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    • v.15 no.4
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    • pp.81-88
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    • 2007
  • The geometry of satellite image captured by linear CCD sensor is different from that of frame camera image. The fact that the exterior orientation parameters for satellite image with linear CCD sensor varies from scan line by scan line, causes the difference of image geometry between frame and linear CCD sensor. Therefore, we need the epipolar geometry for linear CCD image which differs from that of frame camera image. In this paper, we proposed a method of resampling linear CCD satellite image in epipolar geometry under the assumption that image is not formed in perspective projection but in parallel projection, and the sensor model is a 2D affine sensor model based on parallel projection. For the experiment, IKONOS stereo images, which are high resolution linear CCD images, were used and tested. As results, the spatial accuracy of 2D affine sensor model is investigated and the accuracy of epipolar resampled image with RFM was presented.

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2D-3D Vessel Registration for Image-guided Surgery based on distance map (영상유도시술을 위한 거리지도기반 2D-3D 혈관영상 정합)

  • 송수민;최유주;김민정;김명희
    • Proceedings of the Korean Information Science Society Conference
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    • 2004.04a
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    • pp.913-915
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    • 2004
  • 시술 중 제공되는 2D영상은 실시간으로 환자와 시술도구의 상태정보를 제공해주지만 환부의 입체적ㆍ해부학적 파악이 어렵다. 따라서 긴 촬영시간으로 시술 전 획득되는 3D영상과 시술 중 얻어지는 2D영상간 정합영상은 영상 유도술에 있어서 유용한 정보를 제공한다. 이를 위해 본 논문에서는 볼륨영상으로부터 혈관모델을 추출하고 이를 평면으로 투영하였다. 두 2D영상에서 정차대상이 되는 혈관골격을 추출한 후 혈관의 분기특성을 고려 한 초기정합을 수행하였다. 크기와 초기 위치를 맞춘 혈관골격을 골격간 거리가 최소가 되도록 반복적으로 혈관을 기하변환시키고 최종 변환된 혈관골격을 시술 중 제공되는 2D영상에 겹쳐 가시화 하였다. 이로써 시술시간 경감과 시술성공률 향상을 유도할 수 있는 시술경로맵을 제시하고자 하였다.

Fast 3D mesh generation using projection for line laser-based 3D Scanners (라인 레이저 기반 3차원 스캐너에서 투영을 이용한 고속 3D 메쉬 생성)

  • Lee, Kyungme;Yoo, Hoon
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.20 no.3
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    • pp.513-518
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    • 2016
  • This paper presents a fast 3D mesh generation method using projection for line laser-based 3D scanners. The well-known method for 3D mesh generation utilizes convex hulls for 4D vertices that is converted from the input 3D vertices. This 3D mesh generation for a large set of vertices requires a lot of time. To overcome this problem, the proposed method takes (${\theta}-y$) 2D depth map into account. The 2D depth map is a projection version of 3D data with a form of (${\theta}$, y, z) which are intermediately acquired by line laser-based 3D scanners. Thus, our 2D-based method is a very fast 3D mesh generation method. To evaluate our method, we conduct experiments with intermediate 3D vertex data from line-laser scanners. Experimental results show that the proposed method is superior to the existing method in terms of mesh generation speed.

3D Object Modeling and Feature Points using Octree Model (8진트리 모델을 사용한 3D 물체 모델링과 특징점)

  • 이영재
    • Journal of Korea Multimedia Society
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    • v.5 no.5
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    • pp.599-607
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    • 2002
  • The octree model, a hierarchical volume description of 3D objects, nay be utilized to generate projected images from arbitrary viewing directions, thereby providing an efficient means of the data base for 3D object recognition and other applications. We present 2D projected image and made pseudo gray image of object using octree model and multi level boundary search algorithm. We present algorithm for finding feature points of 2D and 3D image and finding matched points using geometric transformation. The algorithm is made of data base, it will be widely applied to 3D object modeling and efficient feature points application for basic 3D object research.

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A Moving Camera Localization using Perspective Transform and Klt Tracking in Sequence Images (순차영상에서 투영변환과 KLT추적을 이용한 이동 카메라의 위치 및 방향 산출)

  • Jang, Hyo-Jong;Cha, Jeong-Hee;Kim, Gye-Young
    • The KIPS Transactions:PartB
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    • v.14B no.3 s.113
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    • pp.163-170
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    • 2007
  • In autonomous navigation of a mobile vehicle or a mobile robot, localization calculated from recognizing its environment is most important factor. Generally, we can determine position and pose of a camera equipped mobile vehicle or mobile robot using INS and GPS but, in this case, we must use enough known ground landmark for accurate localization. hi contrast with homography method to calculate position and pose of a camera by only using the relation of two dimensional feature point between two frames, in this paper, we propose a method to calculate the position and the pose of a camera using relation between the location to predict through perspective transform of 3D feature points obtained by overlaying 3D model with previous frame using GPS and INS input and the location of corresponding feature point calculated using KLT tracking method in current frame. For the purpose of the performance evaluation, we use wireless-controlled vehicle mounted CCD camera, GPS and INS, and performed the test to calculate the location and the rotation angle of the camera with the video sequence stream obtained at 15Hz frame rate.