• Title/Summary/Keyword: Grid Reconstruction Method

Search Result 56, Processing Time 0.028 seconds

3D Terrain Reconstruction Using 2D Laser Range Finder and Camera Based on Cubic Grid for UGV Navigation (무인 차량의 자율 주행을 위한 2차원 레이저 거리 센서와 카메라를 이용한 입방형 격자 기반의 3차원 지형형상 복원)

  • Joung, Ji-Hoon;An, Kwang-Ho;Kang, Jung-Won;Kim, Woo-Hyun;Chung, Myung-Jin
    • Journal of the Institute of Electronics Engineers of Korea SC
    • /
    • v.45 no.6
    • /
    • pp.26-34
    • /
    • 2008
  • The information of traversability and path planning is essential for UGV(Unmanned Ground Vehicle) navigation. Such information can be obtained by analyzing 3D terrain. In this paper, we present the method of 3D terrain modeling with color information from a camera, precise distance information from a 2D Laser Range Finder(LRF) and wheel encoder information from mobile robot with less data. And also we present the method of 3B terrain modeling with the information from GPS/IMU and 2D LRF with less data. To fuse the color information from camera and distance information from 2D LRF, we obtain extrinsic parameters between a camera and LRF using planar pattern. We set up such a fused system on a mobile robot and make an experiment on indoor environment. And we make an experiment on outdoor environment to reconstruction 3D terrain with 2D LRF and GPS/IMU(Inertial Measurement Unit). The obtained 3D terrain model is based on points and requires large amount of data. To reduce the amount of data, we use cubic grid-based model instead of point-based model.

Composition of effective monitoring system using an interpolation (보간법을 이용한 효율적인 모니터링 시스템 구성)

  • Lee, Sang-Hyeok;Kang, Feel-Soon;Jung, Da-Hun
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
    • /
    • 2007.10a
    • /
    • pp.235-238
    • /
    • 2007
  • This paper presents an efficient data storage and reconstruction method in data acquisition and processing of monitoring system. The proposed method extracts minimum data using an interpolation from raw data which are acquired from a target system. The algorithm for data acquisition and reconstruction is based on Cubic Hermite interpolation. To verify the validity of the proposed scheme, we presents simulation results and it is applied to a monitoring system for grid-connected photovoltaic power generation system to prove the high-performance of the proposed method.

  • PDF

Pixel Reconstruction of Edge Boundary Block using Multi-Buffer (다중버퍼를 이용한 경계영역 블록의 화소 재조합)

  • 한병준;손창훈;김응성;이근영
    • Proceedings of the IEEK Conference
    • /
    • 1999.11a
    • /
    • pp.1117-1120
    • /
    • 1999
  • The main purpose of padding methods is to extend the boundary segments of arbitrarily shaped objects to a regular grid so that the common block based coding technique, such as 8${\times}$8 DCT, can be applied. In the conventional padding methods used in MPEG-4: LPE and zero padding, the main process is based on 8${\times}$8 blocks. On the contrary, we propose a new padding method based on pixel-by-pixel. The proposed method puts pixels into a multi-busier using the typical value of each boundary blocks and reproduces new boundary blocks. Simulation results show that the proposed method reduces the conventional padding method and improves the coding efficiency of the conventional padding method.

  • PDF

Correction of Image Distortion and Coordinate Calibration of the x-ray three dimensional imaging system (X선 3차원 영상 시스템에서의 영상 왜곡 및 영상 좌표계 보정)

  • 노영준;김재완;조형석;전형조;김형철;주효남
    • 제어로봇시스템학회:학술대회논문집
    • /
    • 2000.10a
    • /
    • pp.413-413
    • /
    • 2000
  • In this paper, we propose a series of calibrations f3r the x-ray three dimensional imaging system. In the developed x-ray system, a three dimensional inner and outer shape of an object can be reconstructed out of two dimensional transmitted x-ray image set, which are acquired by projecting x-ray to the object from different views. To achieve this, a reconstruction algorithm which estimates and updates the three dimensional volume from x-ray images is developed. The algorithm is named as uniform and simultaneous algebraic reconstruction technique(USART) which is an iterative method estimating a 3D volume based on its projected images. In this method, it is assumed that the imaging conditions that are the relative positions between the x-ray sources, object and the image planes are blown. Practically it is not easy to know the three dimensional coordinate of the components of the system, since the x-ray is not visible and the image distortions are present due to the optical components in the system. In this paper, methods of correcting image distortions are present firstly. Then the coordinates of the x-ray systems are calibrated from the x-ray images of the grid pattern. Some experimental results on these calibrations are present and discussed.

  • PDF

Joint FrFT-FFT basis compressed sensing and adaptive iterative optimization for countering suppressive jamming

  • Zhao, Yang;Shang, Chaoxuan;Han, Zhuangzhi;Yin, Yuanwei;Han, Ning;Xie, Hui
    • ETRI Journal
    • /
    • v.41 no.3
    • /
    • pp.316-325
    • /
    • 2019
  • Accurate suppressive jamming is a prominent problem faced by radar equipment. It is difficult to solve signal detection problems for extremely low signal to noise ratios using traditional signal processing methods. In this study, a joint sensing dictionary based compressed sensing and adaptive iterative optimization algorithm is proposed to counter suppressive jamming in information domain. Prior information of the linear frequency modulation (LFM) and suppressive jamming signals are fully used by constructing a joint sensing dictionary. The jamming sensing dictionary is further adaptively optimized to perfectly match actual jamming signals. Finally, through the precise reconstruction of the jamming signal, high detection precision of the original LFM signal is realized. The construction of sensing dictionary adopts the Pei type fast fractional Fourier decomposition method, which serves as an efficient basis for the LFM signal. The proposed adaptive iterative optimization algorithm can solve grid mismatch problems brought on by undetermined signals and quickly achieve higher detection precision. The simulation results clearly show the effectiveness of the method.

A Semi-Implicit Method for the Analysis of Two-Dimensional Fluid Flow with Moving Free Surfaces

  • Lee, Woo-Il;Park, Jong-Sun;Kim, Min-Soo;Lee, Joon-Sik
    • Journal of Mechanical Science and Technology
    • /
    • v.16 no.5
    • /
    • pp.720-731
    • /
    • 2002
  • Flow with moving free surfaces is analyzed with an the Eulerian coordinate system. This study proposes a semi-implicit filling algorithm using VOF in which the PLIC (Piecewise Linear Interface Calculation) -type interface reconstruction method and the donor-acceptor-type front advancing scheme are adopted. Also, a new scheme using extrapolation of the stream function is proposed to find the velocity of the node that newly enters the computational domain. The effect of wall boundary conditions on the flow field and temperature field is examined by numerically solving a two-dimensional casting process.

THE METHOD OF REGULARIZATION RATIOS APPLIED TO RECONSTRUCTIONS OF ELASTIC RIGID OBSTACLES VIA THE FACTORIZATION METHOD

  • Kim, K.;Leem, K.H.;Pelekanos, G.
    • East Asian mathematical journal
    • /
    • v.32 no.1
    • /
    • pp.129-138
    • /
    • 2016
  • In this paper, we propose an efficient regularization technique (The Method of Regularized Ratios) for the reconstruction of the shape of a rigid elastic scatterer from far field measurements. The approach used is based on the factorization method and creates via Picard's condition ratios, baptized Regularized Ratios, that serve to effectively remove unwanted singular values that may lead to poor reconstructions. This is achieved through the use of a sophisticated algorithm that progressively adjusts an initially set moderate tolerance. In comparison with the well established Tikhonov-Morozov regularization techniques our new algorithm appears to be more computationally efficient as it doesn't require computation of the regularization parameter for each point in the grid.

An Adaptive FLIP-Levelset Hybrid Method for Efficient Fluid Simulation (효율적인 유체 시뮬레이션을 위한 FLIP과 레벨셋의 적응형 혼합 기법)

  • Lim, Jae-Gwang;Kim, Bong-Jun;Hong, Jeong-Mo
    • Journal of the Korea Computer Graphics Society
    • /
    • v.19 no.3
    • /
    • pp.1-11
    • /
    • 2013
  • Fluid Implicit Particle (FLIP) method is used in Visual Effect(VFX) industries frequently because FLIP based simulation show high performance with good visual quality. However in large-scale fluid simulations, the efficiency of FLIP method is low because it requires many particles to represent large volume of water. In this papers, we propose a novel hybrid method of simulating fluids to supplement this drawback. To improve the performance of the FLIP method by reducing the number of particles, particles are deployed inside thin layers of the inner surface of water volume only. The coupling between less-disspative solutions of FLIP method and viscosity solution of level set method is achieved by introducing a new surface reconstruction method motivated by surface reconstruction method[1] and moving least squares(MLS) method[2]. Our hybrid method can generate high quality of water simulations efficiently with various multiscale features.

Super-Resolution Image Processing Algorithm Using Hybrid Up-sampling (하이브리드 업샘플링을 이용한 베이시안 초해상도 영상처리)

  • Park, Jong-Hyun;Kang, Moon-Gi
    • The Transactions of The Korean Institute of Electrical Engineers
    • /
    • v.57 no.2
    • /
    • pp.294-302
    • /
    • 2008
  • In this paper, we present a new image up-sampling method which registers low resolution images to the high resolution grid when Bayesian super-resolution image processing is performed. The proposed up-sampling method interpolates high-resolution pixels using high-frequency data lying in all the low resolution images, instead of up-sampling each low resolution image separately. The interpolation is based on B-spline non-uniform re-sampling, adjusted for the super-resolution image processing. The experimental results demonstrate the effects when different up-sampling methods generally used such as zero-padding or bilinear interpolation are applied to the super-resolution image reconstruction. Then, we show that the proposed hybird up-sampling method generates high-resolution images more accurately than conventional methods with quantitative and qualitative assess measures.

MULTIDIMENSIONAL INTERPOLATIONS FOR THE HIGH ORDER SCHEMES IN ADAPTIVE GRIDS (적응 격자 고차 해상도 해법을 위한 다차원 내삽법)

  • Chang, S.M.;Morris, P.J.
    • Journal of computational fluids engineering
    • /
    • v.11 no.4 s.35
    • /
    • pp.39-47
    • /
    • 2006
  • In this paper, the authors developed a multidimensional interpolation method inside a finite volume cell in the computation of high-order accurate numerical flux such as the fifth order WEND (weighted essentially non-oscillatory) scheme. This numerical method starts from a simple Taylor series expansion in a proper spatial order of accuracy, and the WEND filter is used for the reconstruction of sharp nonlinear waves like shocks in the compressible flow. Two kinds of interpolations are developed: one is for the cell-averaged values of conservative variables divided in one mother cell (Type 1), and the other is for the vertex values in the individual cells (Type 2). The result of the present study can be directly used to the cell refinement as well as the convective flux between finer and coarser cells in the Cartesian adaptive grid system (Type 1) and to the post-processing as well as the viscous flux in the Navier-Stokes equations on any types of structured and unstructured grids (Type 2).