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2nd International Conference on Service Robotics Technologies, ICSRT 2019

作者： Sun, Fang Sun, Xiangyi Guan, Banglei Li, Tao Sun, Cong Liu, Yingchao College of Aerospace Science and Engineering National University of Defense Technology Changsha410073 China Hunan Provincial Key Laboratory of Image Measurement and Vision Navigation Changsha410073 China Bank of China Beijing100818 China

ISBN: (纸本)9781450362467

Simultaneous Localization and Mapping (SLAM) is a popular topic in autonomous robots navigation. It has been studied for decades in both computer vision and robotics communities. Monocular systems is more cost effective compared to RGBD or Stereo systems;however, it is relatively complicated to initialize due to scale uncertainty. Under certain conditions, it is assumed that the camera only moves in a planar scene, which provides us with homography constraints. In this paper, the efficiency of monocular initialization was improved based on the open source platform ORB-SLAM2, employing the algorithm based on planar homography constraints. We compared the improved algorithm with the source code of ORB-SLAM2 on the public datasets. It showed that our algorithm has better stability and robustness in the planar scene dataset and more initializing map points. © 2019 Association for Computing Machinery.

关键词： Cost effectiveness

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Accurate Aspect Ratio Estimation in Scale Adaptive Tracking

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Journal of Physics: Conference Series 2021年第1期1971卷

作者： Weikang Lu Ang Su Wenlong Zhang Yang Shang College of Aerospace Science and Engineering National University of Defense Technology Changsha Hunan 410073 China Hunan Provincial Key Laboratory of Image Measurement and Vision Navigation Changsha Hunan 410073 China

In visual object tracking, robust scale estimation is always a challenging problem. Because of the fast movement of the target, the background, the relative distance and relative azimuth angle between the target and the background usually change greatly. However, traditional correlation filtering tracking method cannot track the target accurately or even lose the target when the target scale and aspect ratio change. To address these problems, this paper adds two independent filters for the length and width scale estimation to complete the adaptive tracking on the basis of the translation filter. The experimental results in the public data set show that: compared with the original trackers, our method improves the tracking accuracy significantly, and meets the needs of real-time target tracking.

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Improved Harris Corner Detection Algorithm Based on Canny Edge Detection and Gray Difference Preprocessing

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Journal of Physics: Conference Series 2021年第1期1971卷

作者： Chuan Luo Xiaoliang Sun Xiangyi Sun Junyao Song College of Aerospace Science and Engineering National University of Defense Technology Changsha Hunan 410073 China Hunan Provincial Key Laboratory of Image Measurement and Vision Navigation Changsha Hunan 410073 China

Harris corner detection algorithm has been widely used in many computer vision allocations. However, it has low efficiency and accuracy, poor noise immunity and needs to set an artificial threshold. In this paper, an improved algorithm based on Canny edge detection and gray difference preprocessing is proposed. Firstly, Canny edge detection and gray difference preprocessing are used for corner prescreening to improve the detection efficiency, anti-noise, and rotation invariance. Secondly, non-maximum suppression is applied to the screened corners to reduce the number of false corners. Finally, the average of adjacent points method is used to solve the problem of corner cluster, and the detection results are compared the measurement accuracy is improved to sub-pixel level. Experimental results indicate that the proposed algorithm can accurately extract the corners in the image and remove the false corners and corner clusters. It achieves superior performance than existing methods.

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A New 2-Correspondences Monocular vision navigation Method Under Planar Motion

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Journal of Physics: Conference Series 2021年第1期1971卷

作者： Yingjian Yu Xiangyi Sun Banglei Guan College of Aerospace Science and Engineering National University of Defense Technology Changsha Hunan 410073 China Hunan Provincial Key Laboratory of Image Measurement and Vision Navigation National University of Defense Technology Changsha Hunan 410073 China

vision navigation has non-contact, high-precision and low-cost characteristics compared with other navigation method. This paper proposes a vision navigation method for planar moving platform in known scene based on two 2D-3D correspondences. Taking account of the arbitrary direction of camera and the relative pose between the camera and the platform, we propose a linear solver with unique solution, whose minimal number of requirement correspondences is 2 and can cope with arbitrary number of correspondences bigger than 2 directly. Our method is evaluated on both synthetic data and real-world data. The experimental results demonstrate that our method is high-accuracy and fast for vision navigation of planar moving platform.

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Rigid Body Pose Estimation from Line Correspondences

Rigid Body Pose Estimation from Line Correspondences

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International Conference on image, vision and Computing (ICIVC)

作者： Yantao Yue Xiangyi Sun College of Aerospace Science and Engineering Hunan Provincial Key Laboratory of Image Measurement and Vision Navigation Changsha China

ISBN: (纸本)9781538649923

In this paper, we aim to solve pose estimation of rigid body motion in real time with 3d lines model. According to the line's perspective projection model, we design a new error function expressed by the average integral of the distance between line segments to estimate parameters. Considering the continuely of motion, we restore cracked line segements with re-projection of Model lines Constrianted. Last, we proposal to estimate many frames jointly in framework of SFM and get better precious while bears slow speed. Comparisons on synthetic and real images demonstrate that baseline methods get accuracy estimations in complex environments. For plane objects, the precious of pose on x, y, z axes are better than 0.5m in 100m distance, and those of relative positions perpendicular to the optical axis and along the optical axis are better than 0.3%.

关键词： Three-dimensional displays image segmentation Solid modeling Optimization Estimation Mathematical model Cameras

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Structure extraction of straight wing aircraft using consistent line clustering 2

Structure extraction of straight wing aircraft using consist...

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2nd International Conference on image, vision and Computing, ICIVC 2017

作者： Luo, Jing Xichao, Teng Xiaohu, Zhang Lijun, Zhong Hunan Provincial Key Laboratory of Image Measurement and Vision Navigation National University of Defense Technology Changsha China

ISBN: (纸本)9781509062379

In this paper, we propose a new method to automatically extract the main structure (fuselage and wings) of straight wing aircraft in photographic images using line clustering. We exploit the location, length and orientation features (parallel constraint) of line segments to group them into line clusters. The different line clusters correspond to the different structure of straight wing aircraft, and we can extract fuselage and wing of straight wing aircraft accordingly. We adopt line segment detector to extract line features, mean-shift and k-means++ approaches are applied to group line segments. The experimental results demonstrate that our method is effective for the structure extraction of straight wing aircraft. © 2017 IEEE.

关键词： Extraction

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3D-shape reconstruction based on a sub-pixel-level mapping relationship between the camera and projector

3D-shape reconstruction based on a sub-pixel-level mapping r...

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Chinese Society for Optical Engineering Conferences, CSOE 2016

作者： Lin, Huijing Liu, Haibo Yao, Linshen College of Aerospace Science and Engineering National University of Defense Technology Changsha Hunan410073 China Hunan Provincial Key Laboratory of Image Measurement and Vision Navigation Changsha Hunan410073 China

ISBN: (纸本)9781510610118

To some extent, the mapping relationship between the camera and projector images determines the precision of surface reconstruction in digital close-range photogrammetry. In this paper, a new method is presented to achieve sub-pixel-level mapping between the camera and projector images. Instead of mapping the stripe from the camera to the projector, which is pixel-precision-based, a set of pixels that share the same decoded number were picked out on the camera images and their barycenter was calculated to mapped onto the pixel on the projector images. In most cases, the calculation of the barycenter is able to achieve sub-pixel precision. Compared with existing approaches based on the direct mapping of the stripe on the camera image to the projector image, the proposed method is characterized by higher accuracy in mapping the points and thus the surface reconstruction performance. The experimental results are presented to show the effectiveness of the proposed method in the improvement of the accuracy of shape reconstruction. © 2017 SPIE.

关键词： Cameras

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Pose optimization based on integral of the distance between line segments

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Science China Technological Sciences 2016年第1期59卷 135-148页

作者： ZHANG YueQiang LI Xin LIU HaiBo SHANG Yang YU QiFeng College of Aerospace Science and Engineering National University of Defense Technology Hunan Provincial Key Laboratory of Image Measurement and Vision Navigation

In this paper, new solutions for the problem of pose estimation from correspondences between 3D model lines and 2D image lines are proposed. Traditional line-based pose estimation methods rely on the assumption that the noises(perpendicular to the line) for the two endpoints are statistically independent. However, these two noises are in fact negatively correlated when the image line segment is fitted using the least-squares technique. Therefore, we design a new error function expressed by the average integral of the distance between line segments. Three least-squares techniques that optimize both the rotation and translation simultaneously are proposed in which the new error function is exploited. In addition, Lie group formalism is utilized to describe the pose parameters, and then, the optimization problem can be solved by means of a simple iterative least squares method. To enhance the robustness to outliers existing in the match data, an M-estimation method is developed to convert the pose optimization problem into an iterative reweighted least squares problem. The proposed methods are validated through experiments using both synthetic and real-world data. The experimental results show that the proposed methods yield a clearly higher precision than the traditional methods.

关键词： machine vision perspective-n-line problem line distance function pose optimization M-estimation

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Hull deformation measurement for spacecraft TT&C ship by Photogrammetry

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Science China(Technological Sciences) 2015年第8期58卷 1339-1347页

作者： LIU HaiBo SUN Cong ZHANG YueQiang LIU XinMing LIU JinBo ZHANG XiaoHu YU QiFeng College of Aerospace Science and Engineering National University of Defense Technology Hunan Provincial Key Laboratory of Image Measurement and Vision Navigation China Satellite Maritime Tracking and Control Department

When voyaging,ships are subject to inevitable hull deformations caused by the changes in the environmental temperature and external *** are a crucial source of errors when measuring data using a spacecraft tracking,telemetry,and control(TT&C) ship.A prototype system based on photogrammetry was developed for the real-time measurement of a spacecraft TT&C ship's hull *** system has high accuracy,a simple structure,and convenient maintenance,and requires few changes to the ship's *** improve its performance,an estimation approach is proposed for hull deformation *** the proposed approach,the central positions of cross spots in successive frames can be predicted based on the prediction of the camera's attitude,and their extract locations can be found by defining a series of small windows around each predictive ***,the optimal estimate of the camera's attitude is updated by the designed extended Kalman filter using the extracted cross spots and their corresponding local coordinates,with which the hull deformation angles can be *** verify the proposed measurement approach,its performance was tested during the normal sailing,floating,and rocking on the sea of a spacecraft TT&C *** experimental testing results demonstrated that the proposed approach performs well in terms of accuracy and *** can satisfy the hull deformation measurement requirement for a spacecraft TT&C ship in real time.

关键词： photogrammetry ship deformation spacecraft TT＆C ship EKF

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Deformable Patch-based NCC Measure for Visual Tracking

Deformable Patch-based NCC Measure for Visual Tracking

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2016 International Conference on Computer, Mechatronics and Electronic Engineering (CMEE 2016)

作者： Xian-guo YU Qi-feng YU Liang XIE Jin-bo LIU College of Aerospace Science and Engineering National University of Defense Technology Hunan Provincial Key Laboratory of Image Measurement and Vision Navigation National University of Defense Technology

This paper tries to solve the visual tracking problem in a simple and intuitive way. In particular, we extend the traditional NCC measure with deformable part-based models(DPM) to get a new image similarity measurement and feed it into the particle filtering framework for visual object tracking. The proposed target model consists of a root template and a set of patch templates. The root is the whole target image, and patches are sub-regions of the target image. NCC responses are calculated for the root template with test images, and every patch template with their corresponding sub-regions of test images. The likelihood between the target and a test image is calculated by integrating all template responses. Instead of directly accumulating all responses, we employ the idea of DPM that combines global and local responses using an elastic model to get a robust image likelihood measure. We also explore an exhaustive patch representation mechanism by introducing the dense NCC feature map. The proposed feature map enables the usage of all patches in the target region for target description and similarity measure. Finally, we provide both qualitative and quantitative experiments against state-of-the-arts on the TB50 dataset. Experimental results show that the proposed similarity measure is effective for visual tracking under challenging scenarios.

关键词： Visual tracking Deformable patches Similarity measurement

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