A Multi-Scale Line Filter for Automatic Crack Inspection Based on X-Ray Images

Yiqiang Lai,Shaohu Peng 보안공학연구지원센터 2016 International Journal of Signal Processing, Image Vol.9 No.8

Crack inspection is a critical processing step in an AXI (automatic X-ray inspection) system. There are challenges for crack inspection since images are usually with serious noise, non-uniform brightness, etc. This paper proposes a novel line filter that can segment various widths of crack regions in those inhomogeneity brightness and noisy X-ray images. First, the input image is smoothed by the Gaussian functions with different scales, resulting in an image pyramid. Second, the adjacent images in the pyramid are subtracted to generate a Difference of Gaussian (DoG) pyramid and the extreme points from the subtracting result are selected as the output of the method. An edge suppression function is then defined to remove the edge response of the filter. Finally, the output of the proposed filter is defined as the combination of the DoG extreme result and the suppression function. The proposed method was applied to an AXI system and it performed better than the other two exited approaches. Experimental results showed that the proposed filter is robust to the image noise, crack sizes and brightness.

Low-speed rolling bearing fault diagnosis based on EMD denoising and parameter estimate with alpha stable distribution

Qing Xiong,Yanhai Xu,Yiqiang Peng,Weihua Zhang,Yongjian Li,Lan Tang 대한기계학회 2017 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.31 No.4

When low-speed rolling bearings fail, it is hard to diagnose the extent of their damage. We developed a test rig to simulate the lowspeed rolling bearing operating condition, where bearings with various fault states are installed on the test wheelset and subjected to the same external loading condition. The collected bearing box acceleration time histories are processed with the Empirical mode decomposition (EMD) method combined with kurtosis criterion to filter the trend and noise components. Five characteristic parameters of Alpha stable distribution (ASD) are identified by fitting the ASD distribution to the vibration acceleration signals and computing the Probability density function (PDF). To highlight the advantage of ASD method in feature extraction, kurtosis also has be calculated. Through sensitivity and stability analysis of the six parameters and utilization of Least squares support vectors machine (LSSVM) with Particle swarm optimization (PSO), three most sensitive and stable feature parameters including the characteristic exponent a, the scale factor g and the peak value of the PDF h are located and applied to evaluate the low-speed rolling bearings’ damage position and damage extent. The proposed method was validated by test data, and the results demonstrated that the ASD characteristics combined with PSO-LSSVM can not only achieve fault diagnosis of low-speed rolling bearings' damage position and damage extent, but also have better diagnosis accuracy and operational efficiency than other methods.

ESVD: An Integrated Energy Scalable Framework for Low-Power Video Decoding Systems

Ji, Wen,Chen, Min,Ge, Xiaohu,Li, Peng,Chen, Yiqiang Hindawi Publishing Corporation 2010 Eurasip Journal on Wireless Communications and Net Vol.2010 No.-

<P>Video applications using mobile wireless devices are a challenging task due to the limited capacity of batteries. The higher complex functionality of video decoding needs high resource requirements. Thus, power efficient control has become more critical design with devices integrating complex video processing techniques. Previous works on power efficient control in video decoding systems often aim at the low complexity design and not explicitly consider the scalable impact of subfunctions in decoding process, and seldom consider the relationship with the features of compressed video date. This paper is dedicated to developing an energy-scalable video decoding (ESVD) strategy for energy-limited mobile terminals. First, ESVE can dynamically adapt the variable energy resources due to the device aware technique. Second, ESVD combines the decoder control with decoded data, through classifying the data into different partition profiles according to its characteristics. Third, it introduces utility theoretical analysis during the resource allocation process, so as to maximize the resource utilization. Finally, it adapts the energy resource as different energy budget and generates the scalable video decoding output under energy-limited systems. Experimental results demonstrate the efficiency of the proposed approach.</P>

Diagnosing axle box bearings’ fault using a refined phase difference correction method

Qing Xiong,Weihua Zhang,Yanhai Xu,Yiqiang Peng,Pengyi Deng 대한기계학회 2019 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.33 No.1

The wheelset treads and axle box bearings of railway vehicles often suffer from fatigue failures. Their regular maintenance highly depends on manual off-line inspection with low working efficiency and poor precision for early failure detection. This study proposes a fault diagnosis method by band-pass filtering and by enveloping the accelerations collected from the axle box bearing on the underfloor wheelset lathe to improve the maintenance efficiency. This process is followed by the refined phase difference correction using the fourterm third derivative Nuttall-windowed fast Fourier transform (RPNWF) to extract accurate amplitudes of the fault characteristic frequency and its harmonics. The integration scheme, work flow, and application examples of the fault diagnosis system are presented. Simulation analysis and results show that the developed method can achieve effective diagnosis of the fault and fault degree of axle box bearings as well as yield better correction accuracy than the commonly used discrete spectrum correction methods.

MiR-1224-5p modulates osteogenesis by coordinating osteoblast/osteoclast differentiation via the Rap1 signaling target ADCY2

Hu Liangcong,Xie Xudong,Xue Hang,Wang Tiantian,Panayi Adriana C.,Lin Ze,Xiong Yuan,Cao Faqi,Yan Chengcheng,Chen Lang,Cheng Peng,Zha Kangkang,Sun Yun,Liu Guodong,Yu Chenyan,Hu Yiqiang,Tao Ranyang,Zhou 생화학분자생물학회 2022 Experimental and molecular medicine Vol.54 No.-

MicroRNAs (miRNAs) broadly regulate normal biological functions of bone and the progression of fracture healing and osteoporosis. Recently, it has been reported that miR-1224-5p in fracture plasma is a potential therapy for osteogenesis. To investigate the roles of miR-1224-5p and the Rap1 signaling pathway in fracture healing and osteoporosis development and progression, we used BMMs, BMSCs, and skull osteoblast precursor cells for in vitro osteogenesis and osteoclastogenesis studies. Osteoblastogenesis and osteoclastogenesis were detected by ALP, ARS, and TRAP staining and bone slice resorption pit assays. The miR-1224-5p target gene was assessed by siRNA-mediated target gene knockdown and luciferase reporter assays. To explore the Rap1 pathway, we performed high-throughput sequencing, western blotting, RT-PCR, chromatin immunoprecipitation assays and immunohistochemical staining. In vivo, bone healing was judged by the cortical femoral defect, cranial bone defect and femoral fracture models. Progression of osteoporosis was evaluated by an ovariectomy model and an aged osteoporosis model. We discovered that the expression of miR-1224-5p was positively correlated with fracture healing progression. Moreover, in vitro, overexpression of miR-1224-5p slowed Rankl-induced osteoclast differentiation and promoted osteoblast differentiation via the Rap1-signaling pathway by targeting ADCY2. In addition, in vivo overexpression of miR-1224-5p significantly promoted fracture healing and ameliorated the progression of osteoporosis caused by estrogen deficiency or aging. Furthermore, knockdown of miRNA-1224-5p inhibited bone regeneration in mice and accelerated the progression of osteoporosis in elderly mice. Taken together, these results identify miR-1224-5p as a key bone osteogenic regulator, which may be a potential therapeutic target for osteoporosis and fracture nonunion.