- 标题
- 摘要
- 关键词
- 实验方案
- 产品
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Development of six-DOF welding robot with machine vision
摘要： The application of machine vision to industrial robots is a hot topic in robot research nowadays. A welding robot with machine vision had been developed, which is convenient and flexible to reach the welding point with six degrees-of-freedom (DOF) manipulator, while the singularity of its movement trail is prevented, and the stability of the mechanism had been fully guaranteed. As the precise industry camera can capture the optical feature of the workpiece to reflect in the camera’s CCD lens, the workpiece is identified and located through a visual pattern recognition algorithm based on gray scale processing, on the gradient direction of edge pixel or on geometric element so that high-speed visual acquisition, image preprocessing, feature extraction and recognition, target location are integrated and hardware processing power is improved. Another task is to plan control strategy of control system, and the upper computer software is programmed in order that multi-axis motion trajectory is optimized and servo control is accomplished. Finally, prototype was developed and validation experiments show that the welding robot has high stability, high efficiency, high precision, even if welding joints are random and workpiece contour is irregular.
关键词： image recognition,linear structured light,Welding robot,machine vision
更新于2025-09-10 09:29:36
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Azimuthal modulation of electromagnetically induced transparency using structured light
摘要： Recently a scheme has been proposed for detection of the structured light by measuring the transmission of a vortex beam through a cloud of cold rubidium atoms with energy levels of the Λ-type configuration [N. Radwell et al., Phys. Rev. Lett. 114, 123603 (2015)]. This enables observation of regions of spatially dependent electromagnetically induced transparency (EIT). Here we suggest another scenario for detection of the structured light by measuring the absorption profile of a weak nonvortex probe beam in a highly resonant five-level combined tripod and Λ (CTL) atom-light coupling setup. We demonstrate that due to the closed-loop structure of CTL scheme, the absorption of the probe beam depends on the azimuthal angle and orbital angular momentum (OAM) of the control vortex beams. This feature is missing in simple Λ or tripod schemes, as there is no loop in such atom-light couplings. One can identify different regions of spatially structured transparency through measuring the absorption of probe field under different configurations of structured control light.
关键词： orbital angular momentum,spatially dependent absorption,electromagnetically induced transparency,quantum interference,structured light
更新于2025-09-10 09:29:36
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[IEEE 2018 IEEE International Conference on Mechatronics and Automation (ICMA) - Changchun (2018.8.5-2018.8.8)] 2018 IEEE International Conference on Mechatronics and Automation (ICMA) - Weld Seam Type Recognition System Based on Structured Light Vision and Ensemble Learning
摘要： In this paper, we propose a weld seam recognition system based on structured light vision and ensemble learning. The proposed system consists of an industrial robot, a structured light vision sensor and a computer. The recognition procedures of proposed system include weld seam feature extraction and weld seam classification. In feature extraction part, the input images are processed by the following steps: noise filtration, laser stripe pattern extraction, main line extraction, edge points detection and feature computation. In classification part, ensemble learning models including BP-Adaboost and KNN-Adaboost are established to classify the images by the feature extracted. The experiment results validate the effectiveness and robustness of the proposed recognition system.
关键词： ensemble learning algorithm,structured light vision,feature extraction,weld seam type recognition
更新于2025-09-09 09:28:46
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A novel 3D path extraction method for arc welding robot based on stereo structured light sensor
摘要： With the rapid development of computer vision and industrial technology, the requirements of the intelligent welding robots are increasing in the real industrial production. The traditional teaching-playback mode and the off-line programming mode cannot meet the automation demand and self-adaptive ability of welding robots. In order to improve the efficiency of welding robots, this paper proposes a novel three-dimensional(3D) path extraction method of weld seams based on stereo structured light sensor. Faced with the low efficiency of the line structured light and the poor robustness of passive vision, the seam extraction based on point cloud processing algorithm is proposed which could well adapt to the weld seams with different types and different groove sizes. Meanwhile, the position information and pose information of weld seam are established to serve the 3D path teaching of welding robot.The experimental results show that the maximum path extraction error of V-type butt joint is less than 0.7mm. The proposed scheme could well serve for the 3D path teaching task before welding.
关键词： path model,welding robot,3D reconstruction,seam extraction,path teaching,stereo structured light
更新于2025-09-09 09:28:46
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A precise initial weld point guiding method of micro-gap weld based on structured light vision sensor
摘要： Initial weld point guiding is the premise of intelligentized welding process. At present, many initial weld point guiding methods based on structured light vision sensors and passive vision sensors have been presented. However, the methods based on structured light vision sensors are not suitable for micro-gap weld and the methods based on passive vision sensors have large guiding errors, which limits their application for micro-gap weld. Therefore, a precise initial weld point guiding method of micro-gap weld is proposed in this paper. This initial weld point guiding method consists of two parts. In the vision sensing part, a structured light vision sensor with a narrow-band optical ?lter and a LED light is designed to acquire clear image including laser stripe and micro-gap weld seam. Then, the image processing method is designed to detect feature point and the 3D coordinates of the feature point can be obtained based on established vision model. In the control part, combining the 3D coordinates of the feature point with the initial weld point guiding model, the 3D coordinates of initial weld point can be determined. Then, the initial weld point guiding controller is adopted to make welding torch align with the initial weld point. Finally, many initial weld point guiding experiments are carried out. Experimental results show that the proposed method can achieve the initial weld point guiding of planar and curved surface micro-gap weld accurately, and the guiding accuracy is improved compared previous methods, which can be applied in welding production.
关键词： micro-gap weld,structured light vision,Initial weld point guiding,robot welding
更新于2025-09-09 09:28:46
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[IEEE 2018 24th International Conference on Pattern Recognition (ICPR) - Beijing, China (2018.8.20-2018.8.24)] 2018 24th International Conference on Pattern Recognition (ICPR) - Adaptive Albedo Compensation for Accurate Phase-Shift Coding
摘要： Among structured light strategies, the ones based on phase shift are considered to be the most adaptive with respect to the features of the objects to be captured. Inter alia, the theoretical invariance to signal strength and the absence of discontinuities in intensity, make phase shift an ideal candidate to deal with complex surfaces of unknown geometry, color and texture. However, in practical scenarios, unexpected artifacts could still result due to the characteristics of real cameras. This is the case, for instance, with high contrast areas resulting from abrupt changes in the albedo of the captured objects. In fact, the not negligible size of pixels and the presence of blur can produce a mix of signal integration from adjacent areas with different albedo. This, in turn, would result in a bias in the phase recovery and, consequentially, in an inaccurate 3D reconstruction of the surface. While this problem affects most structure light methods based on phase shift or derived techniques, little effort has been put in addressing it. With this paper we propose a model for the phase corruption and a theoretically sound correction step to be adopted to compensate the bias. The practical effectiveness of our approach is well demonstrated by a complete set of experimental evaluations.
关键词： structured light,phase shift,albedo compensation,3D reconstruction
更新于2025-09-09 09:28:46
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[IEEE 2018 24th International Conference on Pattern Recognition (ICPR) - Beijing, China (2018.8.20-2018.8.24)] 2018 24th International Conference on Pattern Recognition (ICPR) - Neighborhood-Based Recovery of Phase Unwrapping Faults
摘要： Among several structured light approaches, phase shift is the most widely adopted in real-world 3D reconstruction devices. This is mainly due to its high accuracy, strong resilience to noise and straightforward implementation. However, Phase shift also exhibits an inherent weakness, that is the spatial ambiguity resulting from the periodicity of the sinusoidal wave adopted. Of course many phase unwrapping methods have been proposed to solve such ambiguity. One of the most promising methods exploits additional signals of mutually prime periods, in order to observe a distinct combination of phases for each spatial point. Unfortunately, for such combination to be properly recognized, a very high accuracy in phase recovery must be attained for each signal. In fact, even modest errors could lead to unwrapping faults, making the overall approach much less resilient to noise than plain phase shift. With this paper we introduce a feasible and effective fault recovery method that can be directly applied to multi-period phase shift. The combined pipeline offers an optimal accuracy and coverage even with high noise conditions, overcoming the setbacks of the original method. The performance of such pipeline is established by means of an in depth set of experimental evaluations and comparison, both with real and synthetically generated data.
关键词： structured light,noise resilience,3D reconstruction,phase unwrapping,phase shift
更新于2025-09-09 09:28:46
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Surface scanning for 3D dose calculation in intraoperative electron radiation therapy
摘要： Dose calculations in intraoperative electron radiation therapy (IOERT) rely on the conventional assumption of water-equivalent tissues at the applicator end, which defines a flat irradiation surface. However, the shape of the irradiation surface modifies the dose distribution. Our study explores, for the first time, the use of surface scanning methods for three-dimensional dose calculation of IOERT. Two different three-dimensional scanning technologies were evaluated in a simulated IOERT scenario: a tracked conoscopic holography sensor (ConoProbe) and a structured-light three-dimensional scanner (Artec). Dose distributions obtained from computed tomography studies of the surgical field (gold standard) were compared with those calculated under the conventional assumption or from pseudo-computed tomography studies based on surfaces. In the simulated IOERT scenario, the conventional assumption led to an average gamma pass rate of 39.9% for dose values greater than 10% (two configurations, with and without blood in the surgical field). Results improved when considering surfaces in the dose calculation (88.5% for ConoProbe and 92.9% for Artec). More accurate three-dimensional dose distributions were obtained when considering surfaces in the dose calculation of the simulated surgical field. The structured-light three-dimensional scanner provided the best results in terms of dose distributions. The findings obtained in this specific experimental setup warrant further research on surface scanning in the IOERT context owing to the clinical interest of improving the documentation of the actual IOERT scenario.
关键词： Intraoperative radiotherapy,Structured-light 3D scanner,IOERT,Dose distribution,Surface scanning,Conoscopic holography
更新于2025-09-04 15:30:14
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[Institution of Engineering and Technology 12th European Conference on Antennas and Propagation (EuCAP 2018) - London, UK (9-13 April 2018)] 12th European Conference on Antennas and Propagation (EuCAP 2018) - Evaluation of Positioning Techniques for Millimeter-wave Portable Scanners
摘要： Hybrid methods that combine electromagnetic and optical three dimensional (3D) imaging can be used to scan objects or bodies at millimeter-wave frequencies by merging multiview information. The first goal of the optical model is to obtain a 3D representation of the external surface of the target under test. The second goal lies in the estimation of positions and attitude angles of the electromagnetic scanner in order to properly combine the data collected at each acquisition view. In this contribution, two different positioning techniques are evaluated. The first one is based on a conventional optical camera, whereas the second one relies on a depth camera. Finally, an example of application to security screening is used to evaluate the accuracy of both methods.
关键词： millimeter-wave imaging,RGB-D,photogrammetry,portable scanner,depth camera,structured light
更新于2025-09-04 15:30:14
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Fast 3D reconstruction of dental cast model based on structured light
摘要： To quickly obtain accurate 3D data of dental cast model, this paper proposes a 3D reconstruction method for dental cast model based on structured light. This method combines the structured light with the motor turntable to obtain a group of 3D data for the dental cast model from multiple angles, and automatically registers the dental 3D data from multiple angles through the ball calibration of turntable. Compared with the real data of the dental cast model, the maximum error of the 3D reconstruction results in this paper is 0.115 mm. The reconstruction time of this process is about 130 s. The experimental results show that the method has high precision and high scanning speed for the 3D reconstruction of the dental cast model.
关键词： ball calibration,structured light,motor turntable,dental cast model,3D reconstruction
更新于2025-09-04 15:30:14