• 제목/요약/키워드: three-dimensional reconstruction

검색결과 455건 처리시간 0.029초

삼차원 구조 복원을 위한 스테레오 비전의 가변윈도우법 (A Variable Window Method for Three-Dimensional Structure Reconstruction in Stereo Vision)

  • 김경범
    • 한국정밀공학회지
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    • 제20권7호
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    • pp.138-146
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    • 2003
  • A critical issue in area-based stereo matching lies in selecting a fixed rectangular window size. Previous stereo methods doesn't deal effectively with occluding boundary due to inevitable window-based problems, and so give inaccurate and noisy matching results in areas with steep disparity variations. In this paper, a variable window approach is presented to estimate accurate, detailed and smooth disparities for three-dimensional structure reconstruction. It makes the smoothing of depth discontinuity reduced by evaluating corresponding correlation values and intensity gradient-based similarity in the three-dimensional disparity space. In addition, it investigates maximum connected match candidate points and then devise the novel arbitrarily shaped variable window representative of a same disparity to treat with disparity variations of various structure shapes. We demonstrate the performance of the proposed variable window method with synthetic images, and show how our results improve on those of closely related techniques for accuracy, robustness, matching density and computing speed.

Three-Dimensional Photon Counting Imaging with Enhanced Visual Quality

  • Lee, Jaehoon;Lee, Min-Chul;Cho, Myungjin
    • Journal of information and communication convergence engineering
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    • 제19권3호
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    • pp.180-187
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    • 2021
  • In this paper, we present a computational volumetric reconstruction method for three-dimensional (3D) photon counting imaging with enhanced visual quality when low-resolution elemental images are used under photon-starved conditions. In conventional photon counting imaging with low-resolution elemental images, it may be difficult to estimate the 3D scene correctly because of a lack of scene information. In addition, the reconstructed 3D images may be blurred because volumetric computational reconstruction has an averaging effect. In contrast, with our method, the pixels of the elemental image rearrangement technique and a Bayesian approach are used as the reconstruction and estimation methods, respectively. Therefore, our method can enhance the visual quality and estimation accuracy of the reconstructed 3D images because it does not have an averaging effect and uses prior information about the 3D scene. To validate our technique, we performed optical experiments and demonstrated the reconstruction results.

Analysis of Density Distribution for Unsteady Butane Flow Using Three-Dimensional Digital Speckle Tomography

  • Ko, Han-Seo;Park, Kwang-Hee;Kim, Yong-Jae
    • Journal of Mechanical Science and Technology
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    • 제18권7호
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    • pp.1213-1221
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    • 2004
  • Transient and asymmetric density distributions have been investigated by three-dimensional digital speckle tomography. Multiple CCD images captured movements of speckles in three angles of view simultaneously because the flows were asymmetric and transient. The speckle movements between no flow and downward butane flow from a circular half opening have been calculated by a cross-correlation tracking method so that those distances can be transferred to deflection angles of laser rays for density gradients. The three-dimensional density fields have been reconstructed from the deflection angles by a real-time multiplicative algebraic reconstruction technique (MART).

Three dimensional reconstruction and measurement of underwater spent fuel assemblies

  • Jianping Zhao;Shengbo He;Li Yang;Chang Feng;Guoqiang Wu;Gen Cai
    • Nuclear Engineering and Technology
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    • 제55권10호
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    • pp.3709-3715
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    • 2023
  • It is an important work to measure the dimensions of underwater spent fuel assemblies in the nuclear power industry during the overhaul, to judging whether the spent fuel assemblies can continue to be used. In this paper, a three dimensional reconstruction method for underwater spent fuel assemblies of nuclear reactor based on linear structured light is proposed, and the topography and size measurement was carried out based on the reconstructed 3D model. Multiple linear structured light sensors are used to obtain contour size data, and the shape data of the whole spent fuel assembly can be collected by one-dimensional scanning motion. In this paper, we also presented a corrected model to correct the measurement error introduced by lead-glass and water is corrected. Then, we set up an underwater measurement system for spent fuel assembly based on this method. Finally, an underwater measurement experiment is carried out to verify the 3D reconstruction ability and measurement ability of the system, and the measurement error is less than ±0.05 mm.

X-ray microtomography를 이용한 치아의 3차원 재구성 (THREE DIMENSIONAL RECONSTRUCTION OF TEETH USING X-RAY MICROTOMOGRAPHY)

  • 신동훈
    • Restorative Dentistry and Endodontics
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    • 제28권6호
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    • pp.485-490
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    • 2003
  • Complete understanding of the exterior and interior structure of the tooth would be prerequisite to the successful clinical results, especially in the restorative and endodontic treatment. Although three-dimensional reconstruction method using x-ray microtomography could not be used in clinical cases, it may be the best way to reconstruct the morphologic characteristics of the tooth structure in detail without destructing the tooth itself. This study was done to three dimensionally reconstruct every teeth in the arch in order to increase the understanding about the endodontic treatment and to promote the effective restorative treatment by upgrading the knowledge of the tooth morphology. After placing tooth between the microfocus x-ray tube and the image intensifier to obtain two-dimensional images of each level. scanning was done under the condition of 80 keV, $100{\;}\mu\textrm{m}$, 16.8 magnification with the spot size of $8{\;}\mu\textrm{m}$. Cross-section pixel size of $16.28{\;}\mu\textrm{m}$ and 48.83 cross-section to cross-section distance were also used. From the results of this study, precise three dimensional reconstructed images of every teeth could be obtained. Furthermore, it was possible to see image that showed interested area only, for example. enamel portion only, pulp and dentin area without enamel structure, pulp only, combination image of enamel and pulp, etc. It was also possible to see transparent image without some part of tooth structure. This image might be used as a guide when restoring and preparing the full and partial crown by showing the positional and morphological relationship between the pulp and the outer tooth structure. Another profit may be related with the fact that it would promote the understanding of the interior structure by making observation of the auto-rotating image of AVI file from the various direction possible.

충돌 제트 분석을 위한 3차원 토모그래피 기법 개발 (Development of Three-dimensional Tomography Technique for Analysis of Impinging Jet)

  • 김용재;안성수;고한서
    • 한국가시화정보학회:학술대회논문집
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    • 한국가시화정보학회 2004년도 추계학술대회 논문집
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    • pp.34-35
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    • 2004
  • Three dimensional density distributions of impinging and eccentric flames have been investigated by digital speckle tomography. The flames have been ignited by a mixture of butane and air from a circular nozzle and impinged against a plate located at the upper side of the burner exit. For comparison with experimental data, computer synthesized phantoms of impinging and eccentric flames have been reconstructed by a developed three-dimensional multiplicative algebraic reconstruction technique (MART). The advanced reconstruction in the stagnation flow region involved the sharp change of the flow direction and pressure gradient has been developed using a cross-correlation method and new scanning technique for the speckle displacement.

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3차원 영상분석을 활용한 석탑의 해체와 재조립 : 심곡사칠층석탑 사례 연구 (Disassembly and Reconstruction of Stone Pagoda Using 3-Dimensional Image Analysis : Case Study in Simgoksa Seven-storied Stone Pagoda)

  • 최희수;이찬희;한성희;이성민
    • 보존과학회지
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    • 제32권4호
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    • pp.561-570
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    • 2016
  • 이 연구는 심곡사칠층석탑의 해체와 재조립에 3차원 영상분석 기법을 적용하여 원형에 가깝게 보수한 기술적 사례로써 의미가 있다. 석탑의 해체와 재조립 과정에서 전체적인 변형상태와 변위를 분석하였으며 구조적 안정성 검토를 통하여 재조립에 따른 변형을 최소화하였다. 또한 석탑의 원위치도 재검토하여 보수에 적용하였다. 재조립에 앞서 오염된 석재의 표면은 과학적 표면세정을 통해 이끼류와 지의류 등을 제거하였고, 석탑의 지반은 강회를 이용한 판축과 유사한 형식으로 다짐하여 보강하였다. 이 결과는 석탑의 해체와 재조립 과정에 중요한 자료로 활용될 수 있을 것이다.

작물의 저해상도 이미지에 대한 3차원 복원에 관한 연구 (Study on Three-dimension Reconstruction to Low Resolution Image of Crops)

  • 오장석;홍형길;윤해룡;조용준;우성용;송수환;서갑호;김대희
    • 한국기계가공학회지
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    • 제18권8호
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    • pp.98-103
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    • 2019
  • A more accurate method of feature point extraction and matching for three-dimensional reconstruction using low-resolution images of crops is proposed herein. This method is important in basic computer vision. In addition to three-dimensional reconstruction from exact matching, map-making and camera location information such as simultaneous localization and mapping can be calculated. The results of this study suggest applicable methods for low-resolution images that produce accurate results. This is expected to contribute to a system that measures crop growth condition.