As the differences of sensor＇s precision and some random factors are difficult to control,the actual measurement signals are far from the target signals that affect the reliability and precision of rotating machinery...As the differences of sensor＇s precision and some random factors are difficult to control,the actual measurement signals are far from the target signals that affect the reliability and precision of rotating machinery fault diagnosis.The traditional signal processing methods,such as classical inference and weighted averaging algorithm usually lack dynamic adaptability that is easy for trends to cause the faults to be misjudged or left out.To enhance the measuring veracity and precision of vibration signal in rotary machine multi-sensor vibration signal fault diagnosis,a novel data level fusion approach is presented on the basis of correlation function analysis to fast determine the weighted value of multi-sensor vibration signals.The approach doesn＇t require knowing the prior information about sensors,and the weighted value of sensors can be confirmed depending on the correlation measure of real-time data tested in the data level fusion process.It gives greater weighted value to the greater correlation measure of sensor signals,and vice versa.The approach can effectively suppress large errors and even can still fuse data in the case of sensor failures because it takes full advantage of sensor＇s own-information to determine the weighted value.Moreover,it has good performance of anti-jamming due to the correlation measures between noise and effective signals are usually small.Through the simulation of typical signal collected from multi-sensors,the comparative analysis of dynamic adaptability and fault tolerance between the proposed approach and traditional weighted averaging approach is taken.Finally,the rotor dynamics and integrated fault simulator is taken as an example to verify the feasibility and advantages of the proposed approach,it is shown that the multi-sensor data level fusion based on correlation function weighted approach is better than the traditional weighted average approach with respect to fusion precision and dynamic adaptability.Meantime,the approach is adaptable and easy to use,can be applied to other areas of vibration measurement.展开更多
Belief functions theory is an important tool in the field of information fusion. However, when the cardinality of the frame of discernment becomes large, the high computational cost of evidence combination will become...Belief functions theory is an important tool in the field of information fusion. However, when the cardinality of the frame of discernment becomes large, the high computational cost of evidence combination will become the bottleneck of belief functions theory in real applications. The basic probability assignment （BPA） approximations, which can reduce the complexity of the BPAs, are always used to reduce the computational cost of evidence combination. In this paper, both the cardinalities and the mass assignment values of focal elements are used as the criteria of reduction. The two criteria are jointly used by using rank-level fusion. Some experiments and related analyses are provided to illustrate and justify the proposed new BPA approximation approach.展开更多
To overcome the shortcomings of 1 D and 2 D Otsu’s thresholding techniques, the 3 D Otsu method has been developed.Among all Otsu’s methods, 3 D Otsu technique provides the best threshold values for the multi-level ...To overcome the shortcomings of 1 D and 2 D Otsu’s thresholding techniques, the 3 D Otsu method has been developed.Among all Otsu’s methods, 3 D Otsu technique provides the best threshold values for the multi-level thresholding processes. In this paper, to improve the quality of segmented images, a simple and effective multilevel thresholding method is introduced. The proposed approach focuses on preserving edge detail by computing the 3 D Otsu along the fusion phenomena. The advantages of the presented scheme include higher quality outcomes, better preservation of tiny details and boundaries and reduced execution time with rising threshold levels. The fusion approach depends upon the differences between pixel intensity values within a small local space of an image;it aims to improve localized information after the thresholding process. The fusion of images based on local contrast can improve image segmentation performance by minimizing the loss of local contrast, loss of details and gray-level distributions. Results show that the proposed method yields more promising segmentation results when compared to conventional1 D Otsu, 2 D Otsu and 3 D Otsu methods, as evident from the objective and subjective evaluations.展开更多
This article proposes a VGG network with histogram of oriented gradient(HOG) feature fusion(HOG-VGG) for polarization synthetic aperture radar(PolSAR) image terrain classification.VGG-Net has a strong ability of deep ...This article proposes a VGG network with histogram of oriented gradient(HOG) feature fusion(HOG-VGG) for polarization synthetic aperture radar(PolSAR) image terrain classification.VGG-Net has a strong ability of deep feature extraction,which can fully extract the global deep features of different terrains in PolSAR images,so it is widely used in PolSAR terrain classification.However,VGG-Net ignores the local edge & shape features,resulting in incomplete feature representation of the PolSAR terrains,as a consequence,the terrain classification accuracy is not promising.In fact,edge and shape features play an important role in PolSAR terrain classification.To solve this problem,a new VGG network with HOG feature fusion was specifically proposed for high-precision PolSAR terrain classification.HOG-VGG extracts both the global deep semantic features and the local edge & shape features of the PolSAR terrains,so the terrain feature representation completeness is greatly elevated.Moreover,HOG-VGG optimally fuses the global deep features and the local edge & shape features to achieve the best classification results.The superiority of HOG-VGG is verified on the Flevoland,San Francisco and Oberpfaffenhofen datasets.Experiments show that the proposed HOG-VGG achieves much better PolSAR terrain classification performance,with overall accuracies of 97.54%,94.63%,and 96.07%,respectively.展开更多
In order to improve the accuracy of rolling bearing fault diagnosis when the motor is running under non-stationary conditions,an AC motor rolling bearing fault diagnosis method was proposed based on heterogeneous data...In order to improve the accuracy of rolling bearing fault diagnosis when the motor is running under non-stationary conditions,an AC motor rolling bearing fault diagnosis method was proposed based on heterogeneous data fusion of current and infrared images.Firstly,VMD was used to decompose the motor current signal and extract the low-frequency component of the bearing fault signal.On this basis,the current signal was transformed into a two-dimensional graph suitable for convolutional neural network,and the data set was classified by convolutional neural network and softmax classifier.Secondly,the infrared image was segmented and the fault features were extracted,so as to calculate the similarity with the infrared image of the fault bearing in the library,and further the sigmod classifier was used to classify the data.Finally,a decision-level fusion method was introduced to fuse the current signal with the infrared image signal diagnosis result according to the weight,and the motor bearing fault diagnosis result was obtained.Through experimental verification,the proposed fault diagnosis method could be used for the fault diagnosis of motor bearing outer ring under the condition of load variation,and the accuracy of fault diagnosis can reach 98.85%.展开更多
Background: cervical spondylotic myelopathy is a common health problem that neurosurgeons face in Egypt. The aim of this study is to evaluate the efficacy of PEEK cage only in 4 levels anterior cervical discectomy as ...Background: cervical spondylotic myelopathy is a common health problem that neurosurgeons face in Egypt. The aim of this study is to evaluate the efficacy of PEEK cage only in 4 levels anterior cervical discectomy as one of surgical option other than anterior cervical corpectomy, fixation by plat or posterior approach for cervical laminectomy, and assessment of post spinal surgery pain. Methods: this prospective study on 28 patients with cervical spondylotic myelopathy (CSM) over a period of 3 years (between April 2012 and April 2015) with mean period of follow up 30 months. We have done anterior cervical discectomy with fixation by cage only for all cases with perioperative assessment and scoring clinically and radiologically (Japanese Orthopaedic Association [JOA] scores, Visual Analogue Scale [VAS] scores for assessment of neck and arm pain, perioperative parameters (hospital stay, blood loss, operative time), the European Myelopathy Scoring (EMS) and Odom’s criteria, and the incidence of complication,post spinal surgery pain assessment). Results: clinical outcome was excellent (28.55), good (50%) and fair (21.5) according to Odom criteria. The European Myelopathy Scoring (EMS), improved from 10 to 16. The mean JOA score improved from 10.1 ± 2.1 to 14.2 ± 2.3. Fusion failure had been seen in 4 patients in one level for each secondary to anterior displacement of the cage with no other major complications. Conclusion: 4 levels anterior cervical discectomy with PEEK cage only is an effective, save and less costly with less post operative complication and hospital stay and less post spinal surgery pain.展开更多
图像异常检测旨在识别并定位图像中的异常区域,针对现有算法中不同层次特征信息利用不充分的问题,提出了基于多层次特征融合网络的图像异常检测算法。通过使用融合了异常先验知识的伪异常数据生成算法,对训练集进行了异常数据扩充,将异...图像异常检测旨在识别并定位图像中的异常区域,针对现有算法中不同层次特征信息利用不充分的问题,提出了基于多层次特征融合网络的图像异常检测算法。通过使用融合了异常先验知识的伪异常数据生成算法,对训练集进行了异常数据扩充,将异常检测任务转化为监督学习任务;构建了多层次特征融合网络,将神经网络中不同层次特征进行融合,丰富了特征中的低层纹理信息和高层语义信息,使得用于异常检测的特征更具区分性;训练时,设计了分数约束损失和一致性约束损失,并结合特征约束损失对整个网络模型进行训练。实验结果表明,MVTec数据集上图像级检测接收机工作特性曲线下面积(area under the receiver operating characteristic, AUROC)平均值为98.7%,像素级定位AUROC平均值为97.9%,每区域重叠率平均值为94.2%,均高于现有的异常检测算法。展开更多
为提升自动驾驶车辆在多车道行驶与作业时的道路环境感知能力,提出了自动驾驶环境下车道级雷视融合方法 LLV-SLAM(lane-level LiDAR-visual fusion SLAM),并构建了适用于雷视融合的实时定位与建图算法(simultaneous localization and ma...为提升自动驾驶车辆在多车道行驶与作业时的道路环境感知能力,提出了自动驾驶环境下车道级雷视融合方法 LLV-SLAM(lane-level LiDAR-visual fusion SLAM),并构建了适用于雷视融合的实时定位与建图算法(simultaneous localization and mapping,SLAM)。首先,在视觉特征点提取的基础上引入直方图均衡化,并利用激光雷达获取特征点深度信息,通过视觉特征跟踪以提升SLAM系统鲁棒性。其次,利用视觉关键帧信息对激光点云进行运动畸变校正,并将LeGO-LOAM(lightweight and groud-optimized lidar odometry and mapping)融入视觉ORBSLAM2(oriented FAST and rotated BRIEF SLAM2)以增强闭环检测与矫正性能,降低系统累计误差。最后,将视觉图像所获取的位姿进行坐标转换作为激光里程计的位姿初值,辅助激光雷达SLAM进行三维场景重建。实验结果表明:相比于传统的SLAM方法,融合后的LLV-SLAM方法平均定位时延减少了41.61%;在x、y、z方向上的平均定位误差分别减少了34.63%、38.16%、24.09%;在滚转角、俯仰角、偏航角方向上的平均旋转误差减少了40.8%、37.52%、39.5%。LLV-SLAM算法有效抑制了LeGO-LOAM算法的尺度漂移,实时性和鲁棒性有显著提升,能够满足自动驾驶车辆对多车道道路环境的感知需要。展开更多
基金supported by National Hi-tech Research and Development Program of China (863 Program, Grant No. 2007AA04Z433)Hunan Provincial Natural Science Foundation of China (Grant No. 09JJ8005)Scientific Research Foundation of Graduate School of Beijing University of Chemical and Technology,China (Grant No. 10Me002)
文摘As the differences of sensor＇s precision and some random factors are difficult to control,the actual measurement signals are far from the target signals that affect the reliability and precision of rotating machinery fault diagnosis.The traditional signal processing methods,such as classical inference and weighted averaging algorithm usually lack dynamic adaptability that is easy for trends to cause the faults to be misjudged or left out.To enhance the measuring veracity and precision of vibration signal in rotary machine multi-sensor vibration signal fault diagnosis,a novel data level fusion approach is presented on the basis of correlation function analysis to fast determine the weighted value of multi-sensor vibration signals.The approach doesn＇t require knowing the prior information about sensors,and the weighted value of sensors can be confirmed depending on the correlation measure of real-time data tested in the data level fusion process.It gives greater weighted value to the greater correlation measure of sensor signals,and vice versa.The approach can effectively suppress large errors and even can still fuse data in the case of sensor failures because it takes full advantage of sensor＇s own-information to determine the weighted value.Moreover,it has good performance of anti-jamming due to the correlation measures between noise and effective signals are usually small.Through the simulation of typical signal collected from multi-sensors,the comparative analysis of dynamic adaptability and fault tolerance between the proposed approach and traditional weighted averaging approach is taken.Finally,the rotor dynamics and integrated fault simulator is taken as an example to verify the feasibility and advantages of the proposed approach,it is shown that the multi-sensor data level fusion based on correlation function weighted approach is better than the traditional weighted average approach with respect to fusion precision and dynamic adaptability.Meantime,the approach is adaptable and easy to use,can be applied to other areas of vibration measurement.
基金co-supported by Grant for State Key Program for Basic Research of China(No.2013CB329405)National Natural Science Foundation of China(Nos.61104214,61203222)+3 种基金Foundation for Innovative Research Groups of the National Natural Science Foundation of China(No.61221063)Specialized Research Fund for the Doctoral Program of Higher Education(No.20120201120036)China Postdoctoral Science Foundation(No.20100481337),China Postdoctoral Science Foundation-Special fund(No.201104670)Fundamental Research Funds for the Central Universities
文摘Belief functions theory is an important tool in the field of information fusion. However, when the cardinality of the frame of discernment becomes large, the high computational cost of evidence combination will become the bottleneck of belief functions theory in real applications. The basic probability assignment （BPA） approximations, which can reduce the complexity of the BPAs, are always used to reduce the computational cost of evidence combination. In this paper, both the cardinalities and the mass assignment values of focal elements are used as the criteria of reduction. The two criteria are jointly used by using rank-level fusion. Some experiments and related analyses are provided to illustrate and justify the proposed new BPA approximation approach.
文摘To overcome the shortcomings of 1 D and 2 D Otsu’s thresholding techniques, the 3 D Otsu method has been developed.Among all Otsu’s methods, 3 D Otsu technique provides the best threshold values for the multi-level thresholding processes. In this paper, to improve the quality of segmented images, a simple and effective multilevel thresholding method is introduced. The proposed approach focuses on preserving edge detail by computing the 3 D Otsu along the fusion phenomena. The advantages of the presented scheme include higher quality outcomes, better preservation of tiny details and boundaries and reduced execution time with rising threshold levels. The fusion approach depends upon the differences between pixel intensity values within a small local space of an image;it aims to improve localized information after the thresholding process. The fusion of images based on local contrast can improve image segmentation performance by minimizing the loss of local contrast, loss of details and gray-level distributions. Results show that the proposed method yields more promising segmentation results when compared to conventional1 D Otsu, 2 D Otsu and 3 D Otsu methods, as evident from the objective and subjective evaluations.
基金Sponsored by the Fundamental Research Funds for the Central Universities of China(Grant No.PA2023IISL0098)the Hefei Municipal Natural Science Foundation(Grant No.202201)+1 种基金the National Natural Science Foundation of China(Grant No.62071164)the Open Fund of Information Materials and Intelligent Sensing Laboratory of Anhui Province(Anhui University)(Grant No.IMIS202214 and IMIS202102)。
文摘This article proposes a VGG network with histogram of oriented gradient(HOG) feature fusion(HOG-VGG) for polarization synthetic aperture radar(PolSAR) image terrain classification.VGG-Net has a strong ability of deep feature extraction,which can fully extract the global deep features of different terrains in PolSAR images,so it is widely used in PolSAR terrain classification.However,VGG-Net ignores the local edge & shape features,resulting in incomplete feature representation of the PolSAR terrains,as a consequence,the terrain classification accuracy is not promising.In fact,edge and shape features play an important role in PolSAR terrain classification.To solve this problem,a new VGG network with HOG feature fusion was specifically proposed for high-precision PolSAR terrain classification.HOG-VGG extracts both the global deep semantic features and the local edge & shape features of the PolSAR terrains,so the terrain feature representation completeness is greatly elevated.Moreover,HOG-VGG optimally fuses the global deep features and the local edge & shape features to achieve the best classification results.The superiority of HOG-VGG is verified on the Flevoland,San Francisco and Oberpfaffenhofen datasets.Experiments show that the proposed HOG-VGG achieves much better PolSAR terrain classification performance,with overall accuracies of 97.54%,94.63%,and 96.07%,respectively.
基金supported by National Natural Science Foundation of China(No.61903291)Shaanxi Province Key R&D Program(No.2022GY-134)。
文摘In order to improve the accuracy of rolling bearing fault diagnosis when the motor is running under non-stationary conditions,an AC motor rolling bearing fault diagnosis method was proposed based on heterogeneous data fusion of current and infrared images.Firstly,VMD was used to decompose the motor current signal and extract the low-frequency component of the bearing fault signal.On this basis,the current signal was transformed into a two-dimensional graph suitable for convolutional neural network,and the data set was classified by convolutional neural network and softmax classifier.Secondly,the infrared image was segmented and the fault features were extracted,so as to calculate the similarity with the infrared image of the fault bearing in the library,and further the sigmod classifier was used to classify the data.Finally,a decision-level fusion method was introduced to fuse the current signal with the infrared image signal diagnosis result according to the weight,and the motor bearing fault diagnosis result was obtained.Through experimental verification,the proposed fault diagnosis method could be used for the fault diagnosis of motor bearing outer ring under the condition of load variation,and the accuracy of fault diagnosis can reach 98.85%.
文摘Background: cervical spondylotic myelopathy is a common health problem that neurosurgeons face in Egypt. The aim of this study is to evaluate the efficacy of PEEK cage only in 4 levels anterior cervical discectomy as one of surgical option other than anterior cervical corpectomy, fixation by plat or posterior approach for cervical laminectomy, and assessment of post spinal surgery pain. Methods: this prospective study on 28 patients with cervical spondylotic myelopathy (CSM) over a period of 3 years (between April 2012 and April 2015) with mean period of follow up 30 months. We have done anterior cervical discectomy with fixation by cage only for all cases with perioperative assessment and scoring clinically and radiologically (Japanese Orthopaedic Association [JOA] scores, Visual Analogue Scale [VAS] scores for assessment of neck and arm pain, perioperative parameters (hospital stay, blood loss, operative time), the European Myelopathy Scoring (EMS) and Odom’s criteria, and the incidence of complication,post spinal surgery pain assessment). Results: clinical outcome was excellent (28.55), good (50%) and fair (21.5) according to Odom criteria. The European Myelopathy Scoring (EMS), improved from 10 to 16. The mean JOA score improved from 10.1 ± 2.1 to 14.2 ± 2.3. Fusion failure had been seen in 4 patients in one level for each secondary to anterior displacement of the cage with no other major complications. Conclusion: 4 levels anterior cervical discectomy with PEEK cage only is an effective, save and less costly with less post operative complication and hospital stay and less post spinal surgery pain.
文摘图像异常检测旨在识别并定位图像中的异常区域,针对现有算法中不同层次特征信息利用不充分的问题,提出了基于多层次特征融合网络的图像异常检测算法。通过使用融合了异常先验知识的伪异常数据生成算法,对训练集进行了异常数据扩充,将异常检测任务转化为监督学习任务;构建了多层次特征融合网络,将神经网络中不同层次特征进行融合,丰富了特征中的低层纹理信息和高层语义信息,使得用于异常检测的特征更具区分性;训练时,设计了分数约束损失和一致性约束损失,并结合特征约束损失对整个网络模型进行训练。实验结果表明,MVTec数据集上图像级检测接收机工作特性曲线下面积(area under the receiver operating characteristic, AUROC)平均值为98.7%,像素级定位AUROC平均值为97.9%,每区域重叠率平均值为94.2%,均高于现有的异常检测算法。
文摘为提升自动驾驶车辆在多车道行驶与作业时的道路环境感知能力,提出了自动驾驶环境下车道级雷视融合方法 LLV-SLAM(lane-level LiDAR-visual fusion SLAM),并构建了适用于雷视融合的实时定位与建图算法(simultaneous localization and mapping,SLAM)。首先,在视觉特征点提取的基础上引入直方图均衡化,并利用激光雷达获取特征点深度信息,通过视觉特征跟踪以提升SLAM系统鲁棒性。其次,利用视觉关键帧信息对激光点云进行运动畸变校正,并将LeGO-LOAM(lightweight and groud-optimized lidar odometry and mapping)融入视觉ORBSLAM2(oriented FAST and rotated BRIEF SLAM2)以增强闭环检测与矫正性能,降低系统累计误差。最后,将视觉图像所获取的位姿进行坐标转换作为激光里程计的位姿初值,辅助激光雷达SLAM进行三维场景重建。实验结果表明:相比于传统的SLAM方法,融合后的LLV-SLAM方法平均定位时延减少了41.61%;在x、y、z方向上的平均定位误差分别减少了34.63%、38.16%、24.09%;在滚转角、俯仰角、偏航角方向上的平均旋转误差减少了40.8%、37.52%、39.5%。LLV-SLAM算法有效抑制了LeGO-LOAM算法的尺度漂移,实时性和鲁棒性有显著提升,能够满足自动驾驶车辆对多车道道路环境的感知需要。
