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Article
Publication date: 23 January 2024

Guoyang Wan, Yaocong Hu, Bingyou Liu, Shoujun Bai, Kaisheng Xing and Xiuwen Tao

Presently, 6 Degree of Freedom (6DOF) visual pose measurement methods enjoy popularity in the industrial sector. However, challenges persist in accurately measuring the visual…

Abstract

Purpose

Presently, 6 Degree of Freedom (6DOF) visual pose measurement methods enjoy popularity in the industrial sector. However, challenges persist in accurately measuring the visual pose of blank and rough metal casts. Therefore, this paper introduces a 6DOF pose measurement method utilizing stereo vision, and aims to the 6DOF pose measurement of blank and rough metal casts.

Design/methodology/approach

This paper studies the 6DOF pose measurement of metal casts from three aspects: sample enhancement of industrial objects, optimization of detector and attention mechanism. Virtual reality technology is used for sample enhancement of metal casts, which solves the problem of large-scale sample sampling in industrial application. The method also includes a novel deep learning detector that uses multiple key points on the object surface as regression objects to detect industrial objects with rotation characteristics. By introducing a mixed paths attention module, the detection accuracy of the detector and the convergence speed of the training are improved.

Findings

The experimental results show that the proposed method has a better detection effect for metal casts with smaller size scaling and rotation characteristics.

Originality/value

A method for 6DOF pose measurement of industrial objects is proposed, which realizes the pose measurement and grasping of metal blanks and rough machined casts by industrial robots.

Details

Sensor Review, vol. 44 no. 1
Type: Research Article
ISSN: 0260-2288

Keywords

Article
Publication date: 5 January 2015

Tao Jin, Hongzhi Jia, Wenmei Hou and Yusaku Fujii

– This paper aims to propose a method for measuring the rotation of moving body during parabolic flight using camera.

Abstract

Purpose

This paper aims to propose a method for measuring the rotation of moving body during parabolic flight using camera.

Design/methodology/approach

An orthogonal matrix used to calculate the Euler angles of rotation is solved by means of singular value decomposition. The translation velocity and position of moving body are measured by a binocular camera system.

Findings

The experiment is executed in a jet aircraft to simulate micro-gravity during parabolic flight. And the human moving body is regarded as a rigid body. The results show that this method can calculate the angles effectively.

Practical implications

This work is useful for calculation and monitoring body’s motion in space.

Originality/value

The paper gives a method which measures the rotation of a rigid body under the microgravity by a binocular camera to modify the measurement error of the interferometer.

Details

Aircraft Engineering and Aerospace Technology: An International Journal, vol. 87 no. 1
Type: Research Article
ISSN: 0002-2667

Keywords

Article
Publication date: 29 June 2010

Yuan Tian, Tao Guan and Cheng Wang

To make an augmented image realistic, the virtual objects should be correctly occluded by foreground objects. The purpose of this paper is to propose a new approach that resolves…

Abstract

Purpose

To make an augmented image realistic, the virtual objects should be correctly occluded by foreground objects. The purpose of this paper is to propose a new approach that resolves occlusion problems in augmented reality (AR). The main interest is that it can automatically obtain the proper spatial relationship between virtual and real objects in real time.

Design/methodology/approach

The approach is divided into two steps: off‐line disparity map constructing and on‐line occlusion handling. In the off‐line stage, the disparity map of the real scene is constructed using the global stereo matching method prior and then the disparities are refined by means of the fast mean shift method. Since the depth values of objects in different positions are different, the real object that occludes the virtual object can be specified according to the depth value. In the on‐line stage, the contour of the specified object is tracked using the real time object tracking method with the combination of feature tracking method and minimum st cut method. The augmented image with correct occlusions is produced by redrawing all the tracked object pixels on the augmented image.

Findings

Compared with the existing methods, the proposed approach can automatically resolve occlusion problem in real time. The effectiveness of the method is demonstrated with several experimental results.

Originality/value

This paper makes three contributions. First, a novel framework is proposed to handle occlusion problem in AR. This framework is different to the previously proposed methods. The main procedure includes: obtain occluding real object, track the object, and redraw the pixels of the object on the composed image. It is much easier to implement and can achieve satisfactory results. Second, the disparity map is used to automatically obtain the contour of the occluding real object. To get the contour of the occluding real object precisely, the mean shift method is used to refine the disparity map. By comparing the depth value, the occluding real object can be extracted automatically. Third, the tracking method combining feature tracking method and minimum st cut method ensures the real‐time requirement. The occlusion problem can be handled in real‐time.

Details

Sensor Review, vol. 30 no. 3
Type: Research Article
ISSN: 0260-2288

Keywords

Article
Publication date: 10 August 2020

Bin Li, Yu Yang, Chengshuai Qin, Xiao Bai and Lihui Wang

Focusing on the problem that the visual detection algorithm of navigation path line in intelligent harvester robot is susceptible to interference and low accuracy, a navigation…

Abstract

Purpose

Focusing on the problem that the visual detection algorithm of navigation path line in intelligent harvester robot is susceptible to interference and low accuracy, a navigation path detection algorithm based on improved random sampling consensus is proposed.

Design/methodology/approach

First, inverse perspective mapping was applied to the original images of rice or wheat to restore the three-dimensional spatial geometric relationship between rice or wheat rows. Second, set the target region and enhance the image to highlight the difference between harvested and unharvested rice or wheat regions. Median filter is used to remove the intercrop gap interference and improve the anti-interference ability of rice or wheat image segmentation. The third step is to apply the method of maximum variance to thresholding the rice or wheat images in the operation area. The image is further segmented with the single-point region growth, and the harvesting boundary corner is detected to improve the accuracy of the harvesting boundary recognition. Finally, fitting the harvesting boundary corner point as the navigation path line improves the real-time performance of crop image processing.

Findings

The experimental results demonstrate that the improved random sampling consensus with an average success rate of 94.6% has higher reliability than the least square method, probabilistic Hough and traditional random sampling consensus detection. It can extract the navigation line of the intelligent combine robot in real time at an average speed of 57.1 ms/frame.

Originality/value

In the precision agriculture technology, the accurate identification of the navigation path of the intelligent combine robot is the key to realize accurate positioning. In the vision navigation system of harvester, the extraction of navigation line is its core and key, which determines the speed and precision of navigation.

Details

Industrial Robot: the international journal of robotics research and application, vol. 47 no. 6
Type: Research Article
ISSN: 0143-991X

Keywords

Article
Publication date: 23 October 2007

Jie Zhao, Shuchun Yu and Hegao Cai

The paper seeks to develop a stereo vision system based on a new binocular device. It aims to present an explicit‐implicit correction method to correct radial and tangential…

Abstract

Purpose

The paper seeks to develop a stereo vision system based on a new binocular device. It aims to present an explicit‐implicit correction method to correct radial and tangential distortion of image synchronously. It also aims to propose a step‐rotation rectification method to rectify epipolar error between stereo pairs.

Design/methodology/approach

Least squares technique was used in solving the explicit‐implicit correction model. When the step‐rotation rectification method was implemented, the technology of rotating image space was used.

Findings

The paper finds that the stereo vision system based on a new binocular device can be used in different circumstances, and it can obtain more eyeshot of cameras. The explicit‐implicit correction method can eliminate radial and tangential distortion of images, and the solution to this method is so easy that it can be solved by least squares technique. The theory of step‐rotation rectification is simple, and it is effective for rectifying epipolar error.

Practical implications

The explicit‐implicit correction method and step‐rotation rectification method can be used in correcting image distortion and epipolar error in stereo pairs collected by a stereo vision system. The new binocular device can be used in building a stereo vision system.

Originality/value

A new binocular device is developed in the paper. Explicit distortion method and implicit distortion method are united to correct image distortion. A step‐rotation rectification method is proposed to rectify epipolar error.

Details

Industrial Robot: An International Journal, vol. 34 no. 6
Type: Research Article
ISSN: 0143-991X

Keywords

Article
Publication date: 19 January 2015

Haixia Wang, Xiao Lu, Zhanyi Hu and Yuxia Li

The purpose of this paper is to present a fully automatic calibration method for hand-eye serial robot system is presented in this paper. The so-called “fully automatic” is meant…

Abstract

Purpose

The purpose of this paper is to present a fully automatic calibration method for hand-eye serial robot system is presented in this paper. The so-called “fully automatic” is meant to calibrate the robot body, the hand-eye relation, and the used measuring binocular system at the same time.

Design/methodology/approach

The calibration is done by controlling the joints to rotate several times one by one in the reverse order (i.e. from the last one to the first one), and simultaneously take pictures of the checkerboard patterns by the stereo camera system attached on the end-effector, then the whole robot system can be calibrated automatically from these captured images. In addition, a nonlinear optimization step is used to further refine the calibration results.

Findings

The proposed method is essentially based on an improved screw axis identification method, and it needs only a mirror and some paper checkerboard patterns without resorting to any additional costly measuring instrument.

Originality/value

Simulations and real experiments on MOTOMAN-UP6 robot system demonstrate the feasibility and effectiveness of the proposed method.

Details

Industrial Robot: An International Journal, vol. 42 no. 1
Type: Research Article
ISSN: 0143-991X

Keywords

Article
Publication date: 30 January 2020

Guoyang Wan, Fudong Li, Wenjun Zhu and Guofeng Wang

The positioning and grasping of large-size objects have always had problems of low positioning accuracy, slow grasping speed and high application cost compared with ordinary small…

Abstract

Purpose

The positioning and grasping of large-size objects have always had problems of low positioning accuracy, slow grasping speed and high application cost compared with ordinary small parts tasks. This paper aims to propose and implement a binocular vision-guided grasping system for large-size object with industrial robot.

Design/methodology/approach

To guide the industrial robot to grasp the object with high position and pose accuracy, this study measures the pose of the object by extracting and reconstructing three non-collinear feature points on it. To improve the precision and the robustness of the pose measuring, a coarse-to-fine positioning strategy is proposed. First, a coarse but stable feature is chosen to locate the object in the image and provide initial regions for the fine features. Second, three circular holes are chosen to be the fine features whose centers are extracted with a robust ellipse fitting strategy and thus determine the precise pose and position of the object.

Findings

Experimental results show that the proposed system has achieved high robustness and high positioning accuracy of −1 mm and pose accuracy of −0.5 degree.

Originality/value

It is a high accuracy method that can be used for industrial robot vision-guided and grasp location.

Details

Sensor Review, vol. 40 no. 1
Type: Research Article
ISSN: 0260-2288

Keywords

Article
Publication date: 2 December 2021

Yanwu Zhai, Haibo Feng and Yili Fu

This paper aims to present a pipeline to progressively deal with the online external parameter calibration and estimator initialization of the Stereo-inertial measurement unit…

Abstract

Purpose

This paper aims to present a pipeline to progressively deal with the online external parameter calibration and estimator initialization of the Stereo-inertial measurement unit (IMU) system, which does not require any prior information and is suitable for system initialization in a variety of environments.

Design/methodology/approach

Before calibration and initialization, a modified stereo tracking method is adopted to obtain a motion pose, which provides prerequisites for the next three steps. Firstly, the authors align the pose obtained with the IMU measurements and linearly calculate the rough external parameters and gravity vector to provide initial values for the next optimization. Secondly, the authors fix the pose obtained by the vision and restore the external and inertial parameters of the system by optimizing the pre-integration of the IMU. Thirdly, the result of the previous step is used to perform visual-inertial joint optimization to further refine the external and inertial parameters.

Findings

The results of public data set experiments and actual experiments show that this method has better accuracy and robustness compared with the state of-the-art.

Originality/value

This method improves the accuracy of external parameters calibration and initialization and prevents the system from falling into a local minimum. Different from the traditional method of solving inertial navigation parameters separately, in this paper, all inertial navigation parameters are solved at one time, and the results of the previous step are used as the seed for the next optimization, and gradually solve the external inertial navigation parameters from coarse to fine, which avoids falling into a local minimum, reduces the number of iterations during optimization and improves the efficiency of the system.

Details

Industrial Robot: the international journal of robotics research and application, vol. 49 no. 2
Type: Research Article
ISSN: 0143-991X

Keywords

Article
Publication date: 19 June 2017

Qian Sun, Ming Diao, Yibing Li and Ya Zhang

The purpose of this paper is to propose a binocular visual odometry algorithm based on the Random Sample Consensus (RANSAC) in visual navigation systems.

Abstract

Purpose

The purpose of this paper is to propose a binocular visual odometry algorithm based on the Random Sample Consensus (RANSAC) in visual navigation systems.

Design/methodology/approach

The authors propose a novel binocular visual odometry algorithm based on features from accelerated segment test (FAST) extractor and an improved matching method based on the RANSAC. Firstly, features are detected by utilizing the FAST extractor. Secondly, the detected features are roughly matched by utilizing the distance ration of the nearest neighbor and the second nearest neighbor. Finally, wrong matched feature pairs are removed by using the RANSAC method to reduce the interference of error matchings.

Findings

The performance of this new algorithm has been examined by an actual experiment data. The results shown that not only the robustness of feature detection and matching can be enhanced but also the positioning error can be significantly reduced by utilizing this novel binocular visual odometry algorithm. The feasibility and effectiveness of the proposed matching method and the improved binocular visual odometry algorithm were also verified in this paper.

Practical implications

This paper presents an improved binocular visual odometry algorithm which has been tested by real data. This algorithm can be used for outdoor vehicle navigation.

Originality/value

A binocular visual odometer algorithm based on FAST extractor and RANSAC methods is proposed to improve the positioning accuracy and robustness. Experiment results have verified the effectiveness of the present visual odometer algorithm.

Details

Industrial Robot: An International Journal, vol. 44 no. 4
Type: Research Article
ISSN: 0143-991X

Keywords

Article
Publication date: 1 October 2006

Christine Connolly

To explore the phenomenon of stereoscopic vision and its exploitation in engineering and other professional applications, and in entertainment.

Abstract

Purpose

To explore the phenomenon of stereoscopic vision and its exploitation in engineering and other professional applications, and in entertainment.

Design/methodology/approach

Starts with a review of how stereo vision works, and the techniques used in 3D movies to present the illusion of depth and movement at right angles to the screen. Looks at some engineering products that build on these techniques, and then at the development of 3D television, based on a different image separation method. Finally looks at developments in stereo machine vision.

Findings

A variety of techniques exist to present left and right views of a scene to the correct eyes and stimulate 3D perception: for example, light‐filtering, alternate‐frame sequencing and optical separation. Fatigue occurs when there is crosstalk between those images, or when the images are presented at too low a frame rate. Many computer modelling software providers produce programs with 3D‐viewing capability for professional engineers. There are some exciting recent developments, such as add‐on PC stereo systems, and 3D TV.

Originality/value

Makes the general scientist aware of the wide range of professional uses of stereo vision, and of the engineering challenges behind 3D film and television.

Details

Sensor Review, vol. 26 no. 4
Type: Research Article
ISSN: 0260-2288

Keywords

1 – 10 of 93