• Title/Summary/Keyword: Image Jacobian

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Adaptive Iterative Depeckling of SAR Imagery

  • Lee, Sang-Hoon
    • Korean Journal of Remote Sensing
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    • v.23 no.5
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    • pp.455-464
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    • 2007
  • Lee(2007) suggested the Point-Jacobian iteration MAP estimation(PJIMAP) for noise removal of the images that are corrupted by multiplicative speckle noise. It is to find a MAP estimation of noisy-free imagery based on a Bayesian model using the lognormal distribution for image intensity and an MRF for image texture. When the image intensity is logarithmically transformed, the speckle noise is approximately Gaussian additive noise, and it tends to a normal probability much faster than the intensity distribution. The MRF is incorporated into digital image analysis by viewing pixel types as states of molecules in a lattice-like physical system. In this study, the MAP estimation is computed by the Point-Jacobian iteration using adaptive parameters. At each iteration, the parameters related to the Bayesian model are adaptively estimated using the updated information. The results of the proposed scheme were compared to them of PJIMAP with SAR simulation data generated by the Monte Carlo method. The experiments demonstrated an improvement in relaxing speckle noise and estimating noise-free intensity by using the adaptive parameters for the Ponit-Jacobian iteration.

Image Restoration of Remote Sensing High Resolution Imagery Using Point-Jacobian Iterative MAP Estimation (Point-Jacobian 반복 MAP 추정을 이용한 고해상도 영상복원)

  • Lee, Sang-Hoon
    • Korean Journal of Remote Sensing
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    • v.30 no.6
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    • pp.817-827
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    • 2014
  • In the satellite remote sensing, the operational environment of the satellite sensor causes image degradation during the image acquisition. The degradation results in noise and blurring which badly affect identification and extraction of useful information in image data. This study proposes a maximum a posteriori (MAP) estimation using Point-Jacobian iteration to restore a degraded image. The proposed method assumes a Gaussian additive noise and Markov random field of spatial continuity. The proposed method employs a neighbor window of spoke type which is composed of 8 line windows at the 8 directions, and a boundary adjacency measure of Mahalanobis square distance between center and neighbor pixels. For the evaluation of the proposed method, a pixel-wise classification was used for simulation data using various patterns similar to the structure exhibited in high resolution imagery and an unsupervised segmentation for the remotely-sensed image data of 1 mspatial resolution observed over the north area of Anyang in Korean peninsula. The experimental results imply that it can improve analytical accuracy in the application of remote sensing high resolution imagery.

Position Control of Robot Manipulator based on stereo vision system (스테레오 비젼에 기반한 6축 로봇의 위치 결정에 관한 연구)

  • 조환진;박광호;기창두
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2001.04a
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    • pp.590-593
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    • 2001
  • In this paper we describe the 6-axes robot's position determination using a stereo vision and an image based control method. When use a stereo vision, it need a additional time to compare with mono vision system. So to reduce the time required, we use the stereo vision not image Jacobian matrix estimation but depth estimation. Image based control is not needed the high-precision of camera calibration by using a image Jacobian. The experiment is executed as devide by two part. The first is depth estimation by stereo vision and the second is robot manipulator's positioning.

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Image-based Robust Control of Robot Manipulators with Image Jacobian and Dynamics Uncertainties (영상 자코비안 및 동특성 불확실성을 포함하는 로봇 매니퓰레이터의 영상기반 강인제어)

  • Kim, Chin-Su;Mo, Eun-Jong;Lee, Kang-Woong
    • Journal of Institute of Control, Robotics and Systems
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    • v.14 no.10
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    • pp.1047-1052
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    • 2008
  • In this paper, we design an image-based robust controller to compensate uncertainties with image Jacobian and robot dynamics due to uncertain depth measurement and load variations. The proposed controller with eye-in-hand structure has separate terms to compensate each of uncertainties. The ultimate boundedness of the closed-loop system is proved by the Lyapunov approach. The performance of the proposed control system is demonstrated by simulation and experimental results a 5-link robot manipulator with two degree of freedom.

Control of an Omni-directional Mobile Robot Based on Camera Image (카메라 영상기반 전방향 이동 로봇의 제어)

  • Kim, Bong Kyu;Ryoo, Jung Rae
    • Journal of the Korean Institute of Intelligent Systems
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    • v.24 no.1
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    • pp.84-89
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    • 2014
  • In this paper, an image-based visual servo control strategy for tracking a target object is applied to a camera-mounted omni-directional mobile robot. In order to get target angular velocity of each wheel from image coordinates of the target object, in general, a mathematical image Jacobian matrix is built using a camera model and a mobile robot kinematics. Unlike to the well-known mathematical image Jacobian, a simple rule-based control strategy is proposed to generate target angular velocities of the wheels in conjunction with size of the target object captured in a camera image. A camera image is divided into several regions, and a pre-defined rule corresponding to the target-located image region is applied to generate target angular velocities of wheels. The proposed algorithm is easily implementable in that no mathematical description for image Jacobian is required and a small number of rules are sufficient for target tracking. Experimental results are presented with descriptions about the overall experimental system.

A Study on Image Based Visual Tracking for SCARA Robot

  • Shin, Hang-Bong;Kim, Hong-Rae;Jung, Dong-Yean;Kim, Byeong-Chang;Han, Sung-Hyun
    • 제어로봇시스템학회:학술대회논문집
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    • 2005.06a
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    • pp.1944-1948
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    • 2005
  • This paper presents how it is effective to use many features for improving the speed and the accuracy of the visual servo systems. Some rank conditions which relate the image Jacobian and the control performance are derived. It is also proven that the accuracy is improved by increasing the number of features. Effectiveness of the redundant features is evaluated by the smallest singular value of the image Jacobian which is closely related to the accuracy with respect to the world coordinate system. Usefulness of the redundant features is verified by the real time experiments on a Dual-Arm Robot manipulator made in Samsung Electronic Co. Ltd

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Uncalibrated Visual Servoing through the Efficient Estimation of the Image Jacobian for Large Residual

  • Kim, Gon-Woo
    • Journal of Electrical Engineering and Technology
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    • v.8 no.2
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    • pp.385-392
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    • 2013
  • An uncalibrated visual servo control method for tracking a target is presented. We define the robot-positioning problem as an unconstrained optimization problem to minimize the image error between the target feature and the robot end-effector feature. We propose a method to find the residual term for more precise modeling using the secant approximation method. The composite image Jacobian is estimated by the proper method for eye-to-hand configuration without knowledge of the kinematic structure, imaging geometry and intrinsic parameter of camera. This method is independent of the motion of a target feature. The algorithm for regulation of the joint velocity for safety and stability is presented using the cost function. Adaptive regulation for visibility constraints is proposed using the adaptive parameter.

Dynamic tracking control of robot manipulators using vision system (비전 시스템을 이용한 로봇 머니퓰레이터의 동력학 추적 제어)

  • 한웅기;국태용
    • 제어로봇시스템학회:학술대회논문집
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    • 1997.10a
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    • pp.1816-1819
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    • 1997
  • Using the vision system, robotic tasks in unstructured environments can be accompished, which reduces greatly the cost and steup time for the robotic system to fit to he well-defined and structured working environments. This paper proposes a dynamic control scheme for robot manipulator with eye-in-hand camera configuration. To perfom the tasks defined in the image plane, the camera motion Jacobian (image Jacobian) matrix is used to transform the camera motion to the objection position change. In addition, the dynamic learning controller is designed to improve the tracking performance of robotic system. the proposed control scheme is implemented for tasks of tracking moving objects and shown to outperform the conventional visual servo system in convergence and robustness to parameter uncertainty, disturbances, low sampling rate, etc.

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A Study on Feature-Based Visual Servoing Control of Robot System by Utilizing Redundant Feature

  • Han, Sung-Hyun;Hideki Hashimoto
    • Journal of Mechanical Science and Technology
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    • v.16 no.6
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    • pp.762-769
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    • 2002
  • This paper presents how effective it is to use many features for improving the speed and accuracy of visual servo systems. Some rank conditions which relate the image Jacobian to the control performance are derived. The focus is to describe that the accuracy of the camera position control in the world coordinate system is increased by utilizing redundant features in this paper. It is also proven that the accuracy is improved by increasing the number of features involved. Effectiveness of the redundant features is evaluated by the smallest singular value of the image Jacobian which is closely related to the accuracy with respect to the world coordinate system. Usefulness of the redundant features is verified by the real time experiments on a Dual-Arm robot manipulator made by Samsung Electronic Co. Ltd..

Non-rigid Image Registration using Constrained Optimization (Constrained 최적화 기법을 이용한 Non-rigid 영상 등록)

  • Kim Jeong tae
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.29 no.10C
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    • pp.1402-1413
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    • 2004
  • In non-rigid image registration, the Jacobian determinant of the estimated deformation should be positive everywhere since physical deformations are always invertible. We propose a constrained optimization technique at ensures the positiveness of Jacobian determinant for cubic B-spline based deformation. We derived sufficient conditions for positive Jacobian determinant by bounding the differences of consecutive coefficients. The parameter set that satisfies the conditions is convex; it is the intersection of simple half spaces. We solve the optimization problem using a gradient projection method with Dykstra's cyclic projection algorithm. Analytical results, simulations and experimental results with inhale/exhale CT images with comparison to other methods are presented.