scholarly journals A new vision measurement method based on active object gazing

2017 ◽  
Vol 14 (4) ◽  
pp. 172988141771598 ◽  
Author(s):  
De Xu ◽  
Qingbin Wang
Keyword(s):  
Measurement Method ◽  
Measurement Accuracy ◽  
Rotation Angle ◽  
Vision System ◽  
Three Dimensional ◽  
Active Object ◽  
Intrinsic Parameters ◽  
Vision Measurement ◽  
Cartesian Space ◽  
New Vision

A new vision measurement system is developed with two cameras. One is fixed in pose to serve as a monitor camera. It finds and tracks objects in image space. The other is actively rotated to track the object in Cartesian space, working as an active object-gazing camera. The intrinsic parameters of the monitor camera are calibrated. The view angle corresponding to the object is calculated from the object’s image coordinates and the camera’s intrinsic parameters. The rotation angle of the object-gazing camera is measured with an encoder. The object’s depth is computed with the rotation angle and the view angle. Then the object’s three-dimensional position is obtained with its depth and normalized imaging coordinates. The error analysis is provided to assess the measurement accuracy. The experimental results verify the effectiveness of the proposed vision system and measurement method.

Block Thickness Measurement of Using the Structured Light Vision

2018 ◽  
Vol 33 (01) ◽  
pp. 1955001 ◽  
Author(s):  
Fenghui Lian ◽  
Qingchang Tan ◽  
Siyuan Liu
Keyword(s):  
Machine Vision ◽  
Measurement Method ◽  
Measurement Accuracy ◽  
Thickness Measurement ◽  
Base Plane ◽  
Vision Measurement ◽  
Measurement Results ◽  
Measurement Equations ◽  
Structured Light Vision ◽  
Measuring Base

A method for measuring block thicknesses is proposed by the machine vision measurement. Equations of the measuring base plane and the light plane are formed by calibration. Then, the equation of the light strip image, that is, the image of the intersection between the base plane and light one, is established by the projection relation. Equation of the image of the light strip on the measured plane can be determined by the fitting. Since the light strip on the measuring base plane is parallel to one on the measured plane, the thickness of the measuring block is measured by using the two equations. The experiment evaluates the measurement accuracy of the measurement method and analyzes the influence of some factors on the measurement results.

scholarly journals Vision-Based Three-Dimensional Reconstruction and Monitoring of Large-Scale Steel Tubular Structures

2020 ◽  
Vol 2020 ◽  
pp. 1-17
Author(s):  
Yunchao Tang ◽  
Mingyou Chen ◽  
Yunfan Lin ◽  
Xueyu Huang ◽  
Kuangyu Huang ◽  
...  
Keyword(s):  
Point Cloud ◽  
Large Scale ◽  
Learning Algorithm ◽  
Vision System ◽  
Three Dimensional ◽  
Steel Tube ◽  
Dynamic Monitoring ◽  
Complex Environments ◽  
Cross Sectional ◽  
Vision Measurement

A four-ocular vision system is proposed for the three-dimensional (3D) reconstruction of large-scale concrete-filled steel tube (CFST) under complex testing conditions. These measurements are vitally important for evaluating the seismic performance and 3D deformation of large-scale specimens. A four-ocular vision system is constructed to sample the large-scale CFST; then point cloud acquisition, point cloud filtering, and point cloud stitching algorithms are applied to obtain a 3D point cloud of the specimen surface. A point cloud correction algorithm based on geometric features and a deep learning algorithm are utilized, respectively, to correct the coordinates of the stitched point cloud. This enhances the vision measurement accuracy in complex environments and therefore yields a higher-accuracy 3D model for the purposes of real-time complex surface monitoring. The performance indicators of the two algorithms are evaluated on actual tasks. The cross-sectional diameters at specific heights in the reconstructed models are calculated and compared against laser rangefinder data to test the performance of the proposed algorithms. A visual tracking test on a CFST under cyclic loading shows that the reconstructed output well reflects the complex 3D surface after correction and meets the requirements for dynamic monitoring. The proposed methodology is applicable to complex environments featuring dynamic movement, mechanical vibration, and continuously changing features.

Effect of Calibration Grid Size and Position on Machine Vision Measurement

2012 ◽  
Vol 220-223 ◽  
pp. 1303-1306
Author(s):  
Jie Sun ◽  
Zeng Pu Xu ◽  
Cong Ling Zhou ◽  
Yong Qiang Wang
Keyword(s):  
Machine Vision ◽  
Measurement Errors ◽  
Measurement Accuracy ◽  
Corner Point ◽  
Vision System ◽  
Grid Size ◽  
Machine Vision System ◽  
Opposite Edge ◽  
Measuring Point ◽  
Vision Measurement

In order to improve the measurement accuracy of machine vision, this paper focuses on the effect of calibration grid size and position on machine vision measurement accuracy by analysing the measurement error of the points inside and outside of the grid. The experimental results show that the measurement accuracy of the internal points is higher than that of the external points. The measurement errors increase firstly, then decrease, increase, and finally decrease which measuring point from the edge to the opposite edge in the calibration grid. While measurement errors of outside points increases with the increasing distance to the corner point. If the center of calibration grid coincides with the center of calibration board, measurement accuracy is high. However, if the center of calibration grid doesn't coincide with the center of calibration board, measurement accuracy is low. This results may provide direct means for the application of machine vision system in engineering.

scholarly journals LAND UNMANNED COMPLEX WITH PASSIVE RANGE MEASUREMENT

2021 ◽  
pp. 11-16
Author(s):  
Volodymyr I. Mikitenko ◽  
Volodymyr M. Senatorov ◽  
Anatolii Gurnovych
Keyword(s):  
Measurement Method ◽  
Measurement Accuracy ◽  
Vision System ◽  
Distance Measurement ◽  
Measuring Channel ◽  
Wide Field ◽  
Range Finder ◽  
Fixed Base ◽  
Movement Parameters ◽  
Base Range

The automatic robotic complex will obviously become one of the main subjects in the conduct of military actions in the near future. To control movement parameters, as well as search, target detection and aiming, the complex includes a technical vision system. The minimum sufficient configuration of such a system includes a television search camera with a wide field of view, television and thermal imaging sights, and a rangefinder. The use of laser rangefinders ensures high accuracy of aiming weapons, but generates a powerful unmasking feature. To ensure the secrecy of the functioning of the robotic complex, range finders can operate in a passive mode using information from on-board television cameras. But at the same time, the metrological characteristics of the information measuring channel are significantly deteriorated. Accuracy of five methods of passive distance measurement with application of TV-systems of land unmanned complex is assessed in paper. Classic method of TV-sight external-base range-finder with scale, designed on human height 1,65 m, is ensuring measurement accuracy 135 m on distance 1000 m. External base method, when a range finger scale is forming on remote display as variable length vertical line in process of target framing, is ensuring measurement accuracy 100,3 m on dis-tance 1000 m. Fixed-base range-finder method, when distance between entrance pupils of TV-sight and wide viewing field camera using as base, is ensuring measurement accuracy 76 m on distance 1000 m.  Distance measurement method due to displacement of land unmanned complex ensures a measurement accuracy up to 168 m on distance 1000 m. Measurement method due to using zoom-objective is not suitable for land unmanned complex. Proposals have been formulated for the spatial layout of the computer vision system, in which the method of the fixed-base rangefinder is implemented, which ensures the highest measurement accuracy.

Research on Measurement Method of Joint Angle for Underwater Manipulator

2014 ◽  
Vol 1039 ◽  
pp. 256-261
Author(s):  
Ding Hao Feng ◽  
Xi Zhang ◽  
Xu Zhang ◽  
Wei Qing Chu
Keyword(s):  
Measurement Method ◽  
Joint Angle ◽  
Vision System ◽  
Three Dimensional ◽  
Angle Measurement ◽  
Robot Arm ◽  
Circle Fitting ◽  
Fitting Algorithm ◽  
Stereo Reconstruction ◽  
Underwater Manipulator

Measurement method of joint angle for underwater manipulator is studied in this paper. The swing of a manipulator can be described as a circular motion in spatial. Therefore this paper proposes a spatial circle fitting algorithm. The points for spatial circle fitting come from multiple stereo vision system. At first, attach the designed target to the robot arm, then proposes algorithm to track the target in real time. Then three-dimensional coordinates of target’s movement in space at each location can be obtained by using stereo reconstruction techniques. At last, the center and radius of the circle can be calculated by spatial circle fitting. Through the theory of analytic geometry, the manipulator’s joint angle can be calculated. Experiments show that the algorithm proposed in this paper is well used in manipulator’s joint angle measurement.

Stereo vision–based non-contact dynamic measurement method for vehicle braking time sequence

2018 ◽  
Vol 233 (11) ◽  
pp. 2912-2928
Author(s):  
Libin Zhang ◽  
Dao Wu ◽  
Hongying Shan ◽  
Lele Zhang
Keyword(s):  
Stereo Vision ◽  
Measurement Method ◽  
High Efficiency ◽  
Low Cost ◽  
Three Dimensional ◽  
Time Sequence ◽  
Vision Measurement ◽  
Binocular Stereo Vision ◽  
Marquardt Algorithm ◽  
Binocular Stereo

The braking stability of semi-trailer train is directly related to the safety of driving. The braking time sequence of vehicle in braking process directly determines the braking stability of the vehicle. To overcome the limitations of the existing technology, this paper proposes a novel non-contact vehicle braking time sequence measurement method. The proposed method is based on binocular stereo vision that has high precision, high efficiency and low cost. First, the binocular stereo vision measurement principle is introduced, the camera is calibrated by three-dimensional target and the Levenberg–Marquardt algorithm is used to optimize the calibration parameters. Then, a series of image processing techniques are used to extract the wheel marker and perform three-dimensional coordinate reconstruction. Finally, the universality and the applicability of the proposed method are verified by conducting repetitive experiments and accuracy experiments for the same vehicle and different types of vehicles according to the designed experimental process and the established evaluation index. The experimental results show that the method proposed in this paper can achieve fast detection, with high accuracy and good repeatability. Moreover, the method can be extended to various types of vehicles.

scholarly journals Vision Measurement of Gear Pitting Under Different Scenes by Deep Mask R-CNN

Sensors ◽  
2020 ◽  
Vol 20 (15) ◽  
pp. 4298
Author(s):  
Dejun Xi ◽  
Yi Qin ◽  
Yangyang Wang
Keyword(s):  
Quantitative Measurement ◽  
Measurement Accuracy ◽  
Tooth Surface ◽  
Vision Measurement ◽  
Multi Level ◽  
New Vision ◽  
Vision Detection ◽  
Sample Set ◽  
Different Levels ◽  
Measurement Approach

To accurately and quantitatively detect the gear pitting of different levels on the actual site, this paper studies a new vision measurement approach based on a tunable vision detection platform and the mask region-based convolutional neural network (Mask R-CNN). The shooting angle can be properly set according to the specification of the target gear. With the obtained sample set of 1500 gear pitting images, an optimized deep Mask R-CNN was designed for the quantitative measurement of gear pitting. The effective tooth surface and pitting was firstly and simultaneously recognized, then they were segmented to calculate the pitting area ratio. Considering three situations of multi-level pitting, multi-illumination, and multi-angle, several indexes were used to evaluate detection and segmentation results of deep Mask R-CNN. Experimental results show that the proposed method has higher measurement accuracy than the traditional method based on image processing, thus it has significant practical potential.

Study on 3-D Measurement Method in Shake Table Tests Using Image Processing Technique: 3rd Report, Examination of Upgrading for Measurement Accuracy in Actual Fracturing Test

2005 ◽  
Author(s):  
Satoshi Fujita ◽  
Osamu Furuya ◽  
Hiroki Mizuno
Keyword(s):  
Image Processing ◽  
Measurement System ◽  
Measurement Method ◽  
Measurement Accuracy ◽  
Three Dimensional ◽  
Processing Technique ◽  
Image Processing Technique ◽  
Shake Table ◽  
Shake Table Tests ◽  
Dynamic Displacement

In recent years, the importance of the fracturing test using the full-scale model is recognized in order to upgrade an earthquake resistant design. It is, moreover, important to develop a new measurement method which can measure a complex three-dimensional behaviour in such fracturing test. This study has been doing research and development of three-dimensional measurement method using an image processing technique for a measurement of dynamic displacement in shake table test without any contact. This measurement system is a very convenient system because it can measure the three-dimensional dynamic displacement in the simple experimental condition that the several makers are only attached to the surface of an experimental structure. The system therefore is the most suitable measurement system for an evaluation of complex 3-dimensional behavior of test model. Fundamental hardware and software for the measurement system has been constructed until now. The fundamental dynamic measurement accuracy and effectiveness of the measurement system has been also confirmed from several shake table tests. This paper describes the examination of the upgrading for the measurement accuracy in actual fracturing test. Moreover, the shake table test results using actual wooden house model were also indicated.

scholarly journals Study of the Error Caused by Camera Movement for the Stereo-Vision System

2021 ◽  
Vol 11 (20) ◽  
pp. 9384
Author(s):  
Yan Liu ◽  
Zhendong Ge ◽  
Yingtao Yuan ◽  
Xin Su ◽  
Xiang Guo ◽  
...  
Keyword(s):  
Stereo Vision ◽  
Measurement Accuracy ◽  
Rotation Angle ◽  
Vision System ◽  
Distance Measurement ◽  
3D Measurement ◽  
Relative Rotation ◽  
Distance Error ◽  
Stereo Vision System ◽  
Coordinate Error

The stereo-vision system plays an increasingly important role in various fields of research and applications. However, inevitable slight movements of cameras under harsh working conditions can significantly influence the 3D measurement accuracy. This paper focuses on the effect of camera movements on the stereo-vision 3D measurement. The camera movements are divided into four categories, viz., identical translations and rotations, relative translation and rotation. The error models of 3D coordinate and distance measurement are established. Experiments were performed to validate the mathematical models. The results show that the 3D coordinate error caused by identical translations increases linearly with the change in the positions of both cameras, but the distance measurement is not affected. For identical rotations, the 3D coordinate error introduced only in the rotating plane is proportional to the rotation angle within 10° while the distance error is zero. For relative translation, both coordinate and distance errors keep linearly increasing with the change in the relative positions. For relative rotation, the relationship between 3D coordinate error and rotation angle can be described as the nonlinear trend similar to a sine-cosine curve. The impact of the relative rotation angle on distance measurement accuracy does not increase monotonically. The relative rotation is the main factor compared to other cases. Even for the occurrence of a rotation angle of 10°, the resultant maximum coordinate error is up to 2000 mm, and the distance error reaches 220%. The results presented are recommended as practice guidelines to reduce the measurement errors.

Study on 3-D Measurement Method in Shake Table Tests Using Image Processing Technique: 2nd Report - Measurement Accuracy in Actual Fracturing Test Using Full Scale Wooden House Model

2004 ◽  
Author(s):  
Satoshi Fujita ◽  
Osamu Furuya ◽  
Tadashi Mikoshiba
Keyword(s):  
Measurement System ◽  
Measurement Method ◽  
Measurement Accuracy ◽  
Three Dimensional ◽  
Processing Technique ◽  
Image Processing Technique ◽  
Shake Table ◽  
Shake Table Tests ◽  
Wooden House ◽  
Three Dimensional Measurement

This study has been examined about a three-dimensional measurement method that can measure a position and an attitude of test object without any contact. Fundamental hardware and software in measurement system has been constructed until now. Moreover, the fundamental dynamic measurement accuracy and effectiveness of the proposed measurement system has been confirmed from the several shake table tests. This paper describes the effectiveness of the proposed system for the measurement in fracturing test using real scale wooden house model.

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