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PCB基准点的探针式鲁棒定位方法 被引量:1
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作者 曾友 高健 岑誉 《组合机床与自动化加工技术》 北大核心 2016年第6期30-34,共5页
为了提高印刷电路板(PCB)基准点的定位鲁棒性与定位精度,减少因基准点损坏而定位不准或者不能定位现象,提出了探针式基准点定位方法。该方法分粗定位与精定位两步,粗定位阶段首先采用区域增长法进行图像分割,通过圆度阈值筛选出圆形区域... 为了提高印刷电路板(PCB)基准点的定位鲁棒性与定位精度,减少因基准点损坏而定位不准或者不能定位现象,提出了探针式基准点定位方法。该方法分粗定位与精定位两步,粗定位阶段首先采用区域增长法进行图像分割,通过圆度阈值筛选出圆形区域,运用所提出的探针定位方法建立探针法数学模型,实现基准点的粗定位。基于粗定位所得基准点区域图像,提取其图像亚像素边缘,提出基于稳健估计算法的几何距离法圆拟合方法,实现基准点的精定位。实验结果表明:在复杂背景下该探针式定位法的基准点识别结果的正确率达100%,可有效降低基准点误定率;定位方法对基准点污损不敏感,在基准点损坏50%的情况下定位精度还能达到0.021个像素。 展开更多
关键词 PCB基准点 计算机视觉定位 探针法 边缘检测 几何法圆拟合
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An improved RANSAC algorithm for 3D wheel alignment
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作者 CHENG Wei ZHU Zhifeng +3 位作者 YAO Yong WANG Bing ZHOU Fang TANG Dezhi 《Journal of Measurement Science and Instrumentation》 CAS CSCD 2022年第4期407-417,共11页
Aiming at the defects of traditional four-wheel aligner such as many sensors,complex operation and slow detection speed,a fast and accurate 3D four-wheel alignment detection method is studied.Firstly,a new and special... Aiming at the defects of traditional four-wheel aligner such as many sensors,complex operation and slow detection speed,a fast and accurate 3D four-wheel alignment detection method is studied.Firstly,a new and special circle center target board is designed to calibrate the camera,and then the registration of the homography matrix is optimized by using the improved RANSAC(Random sample consensus)algorithm combined with the designed special target board,and the parameters of the wheel alignment system are adjusted by using the space vector principle.Accurate measurements are made to obtain the parameters of the four-wheel alignment.Design a calibration comparison experiment between the traditional target board and the new type of target board,and conduct a comparative test with the existing four-wheel aligner of the depot.The experimental results show that the use of the new target board-binding optimization algorithm can improve the calibration efficiency by about 9%to 21%,while improving the calibration accuracy by about 10.6%to 17.8%.And through the real vehicle test,it is verified that the use of the new target combined with the optimization algorithm can ensure the accuracy and reliability of the four-wheel positioning.This method has a certain significance in the rapid detection of vehicle four-wheel alignment parameters. 展开更多
关键词 computer vision four-wheel alignment binocular calibration RANSAC algorithm homography matrix
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Performance analysis of visual markers for indoor navigation systems
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作者 Gaetano C.LA DELFA Salvatore MONTELEONE +2 位作者 Vincenzo CATANIA Juan F.DE PAZ Javier BAJO 《Frontiers of Information Technology & Electronic Engineering》 SCIE EI CSCD 2016年第8期730-740,共11页
The massive diffusion of smartphones, the growing interest in wearable devices and the Internet of Things, and the exponential rise of location based services(LBSs) have made the problem of localization and navigati... The massive diffusion of smartphones, the growing interest in wearable devices and the Internet of Things, and the exponential rise of location based services(LBSs) have made the problem of localization and navigation inside buildings one of the most important technological challenges of recent years. Indoor positioning systems have a huge market in the retail sector and contextual advertising; in addition, they can be fundamental to increasing the quality of life for citizens if deployed inside public buildings such as hospitals, airports, and museums.Sometimes, in emergency situations, they can make the difference between life and death. Various approaches have been proposed in the literature. Recently, thanks to the high performance of smartphones' cameras, marker-less and marker-based computer vision approaches have been investigated. In a previous paper, we proposed a technique for indoor localization and navigation using both Bluetooth low energy(BLE) and a 2D visual marker system deployed into the floor. In this paper, we presented a qualitative performance evaluation of three 2D visual markers, Vuforia,Ar Uco marker, and AprilT ag, which are suitable for real-time applications. Our analysis focused on specific case study of visual markers placed onto the tiles, to improve the efficiency of our indoor localization and navigation approach by choosing the best visual marker system. 展开更多
关键词 Indoor localization Visual markers Computer vision
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