Rock Fracture Centerline Extraction based on Hessian Matrix and Steger algorithm

( Weixing Wang ),( Yanjie Liang ) 한국인터넷정보학회 2015 KSII Transactions on Internet and Information Syst Vol.9 No.12

The rock fracture detection by image analysis is significant for fracture measurement and assessment engineering. The paper proposes a novel image segmentation algorithm for the centerline tracing of a rock fracture based on Hessian Matrix at Multi-scales and Steger algorithm. A traditional fracture detection method, which does edge detection first, then makes image binarization, and finally performs noise removal and fracture gap linking, is difficult for images of rough rock surfaces. To overcome the problem, the new algorithm extracts the centerlines directly from a gray level image. It includes three steps: (1) Hessian Matrix and Frangi filter are adopted to enhance the curvilinear structures, then after image binarization, the spurious-fractures and noise are removed by synthesizing the area, circularity and rectangularity; (2) On the binary image, Steger algorithm is used to detect fracture centerline points, then the centerline points or segments are linked according to the gap distance and the angle differences; and (3) Based on the above centerline detection roughly, the centerline points are searched in the original image in a local window along the direction perpendicular to the normal of the centerline, then these points are linked. A number of rock fracture images have been tested, and the testing results show that compared to other traditional algorithms, the proposed algorithm can extract rock fracture centerlines accurately.

A Microfluidic Hydrogel Chip with Orthogonal Dual Gradients of Matrix Stiffness and Oxygen for Cytotoxicity Test

Weixing Wang,Lili Li,Mingyu Ding,Guoan Luo,Qionglin Liang 한국바이오칩학회 2018 BioChip Journal Vol.12 No.2

The oxygen tensions and matrix stiffness play important roles in regulating cell response to cytotoxic drugs. In recent years, single spatiotemporal oxygen or matrix stiffness gradient has been established by various technologies for cell studies. However, the synergistic effects of the two factors on tumor cells remained elusive. In this study, we created a highly integrated and easy-to-operate microfluidic device. It was capable of generating more continuous, linear, stable and diffusive hydrogel stiffness gradient over a well-defined oxygen gradient. Sodium hydroxide and pyrogallol were used to scavenge oxygen and generate oxygen gradient, skillfully avoiding the utilization of bulky pressurized gas cylinders and sophisticated flow control by conventional methods. Utilizing the newly developed microfluidic device, we successfully performed drug test with a hypoxia sensitive anti-cancer drug, triapazamine (TPZ), on A549 cells under perpendicular construction of oxygen and spatially hydrogel stiffness gradients. The cell experiment results demonstrated the matrix stiffness-dependent cell drug resistance and hypoxia-induced cytotoxicity of TPZ. In summary, the developed microfluidic device exhibits high potential in the study of matrix stiffness-dependent cell responses and oxygen-sensitive drug cytotoxicity. Furthermore, the design principle can be functionally extended to other dual factors system and will facilitate the study of cell response in complex physiological and pathological conditions.

On-line Rock Fragment Delineation on Simple Thresholding with Fuzzy Comprehensive Evaluation

Wang Weixing,Liang Yanjie,Liao Yipeng,Bai Lina 보안공학연구지원센터 2015 International Journal of Hybrid Information Techno Vol.8 No.6

The classification and measurement of rock fragments is very important in mining and construction engineering. The monitoring system acquires and analyses the fragment images from a gravitational falling stream at the end of a moving conveyor belt, and the key function of the system is to construct an image segmentation algorithm. To achieve this goal, an adaptive thresholding algorithm with fuzzy comprehensive evaluation is proposed. Firstly, a grabbed image is roughly segmented by using a global auto-thresholding algorithm. Then each of the objects is measured and analyzed if it includes the multiple fragments touching each other, based on the fuzzy comprehensive evaluation method in which the salient fragment features of area, perimeter, shape, gradient magnitude and gray-level flatness are extracted, and for each of the features, the membership function is constructed experimentally. Finally, each of the touching fragment regions, as one image, is auto-thresholded again, and this procedure is repeated until no region can be further separated. The experimental results show that compared to cluster analysis, graph based, and FCM image segmentation algorithms the new algorithm can make image segmentation well for the falling fragments on-line.

Improved Minimum Spanning Tree based Image Segmentation with Guided Matting

( Weixing Wang ),( Angyan Tu ),( Fredrik Bergholm ) 한국인터넷정보학회 2022 KSII Transactions on Internet and Information Syst Vol.16 No.1

In image segmentation, for the condition that objects (targets) and background in an image are intertwined or their common boundaries are vague as well as their textures are similar, and the targets in images are greatly variable, the deep learning might be difficult to use. Hence, a new method based on graph theory and guided feathering is proposed. First, it uses a guided feathering algorithm to initially separate the objects from background roughly, then, the image is separated into two different images: foreground image and background image, subsequently, the two images are segmented accurately by using the improved graph-based algorithm respectively, and finally, the two segmented images are merged together as the final segmentation result. For the graph-based new algorithm, it is improved based on MST in three main aspects: (1) the differences between the functions of intra-regional and inter-regional; (2) the function of edge weight; and (3) re-merge mechanism after segmentation in graph mapping. Compared to the traditional algorithms such as region merging, ordinary MST and thresholding, the studied algorithm has the better segmentation accuracy and effect, therefore it has the significant superiority.

Online Burning Material Pile Detection on Color Clustering and Quaternion based Edge Detection in Boiler

( Weixing Wang ),( Sheng Liu ) 한국인터넷정보학회 2015 KSII Transactions on Internet and Information Syst Vol.9 No.1

In the combustion engineering, to decrease pollution and increase production efficiency, and to optimally keep solid burning material amount constant in a burner online, it needs a smart method to detect the amount variation of the burning materials in a high temperature environment. This paper presents an online machine vision system for automatically measuring and detecting the burning material amount inside a burner or a boiler. In the camera-protecting box of the system, a sub-system for cooling is constructed by using the cooling water circulation techqique. In addition, the key and intelligent step in the system is to detect the pile profile of the variable burning material, and the algorithm for the pile profile tracing was studied based on the combination of the gey level (color) discontinuity and similarity based image segmentation methods, the discontinuity based sub-algorithm is made on the quaternion convolution, and the similarity based sub-algorithm is designed according to the region growing with multi-scale clustering. The results of the two sub-algoritms are fused to delineate the final pile profile, and the algorithm has been tested and applied in different industrial burners and boilers. The experiements show that the proposed algorithm works satisfactorily.

Retinex Algorithm on Changing Scales for Haze Removal with Depth Map

Weixing Wang,Lian Xu 보안공학연구지원센터 2014 International Journal of Hybrid Information Techno Vol.7 No.4

Two-dimensional air spring based semi-active TMD for vertical and lateral walking and wind-induced vibration control

Yang Wang,Liangkun Wang,Weixing Shi 국제구조공학회 2021 Structural Engineering and Mechanics, An Int'l Jou Vol.80 No.4

A slender steel pedestrian bridge suffers from excessive vibration under walking-induced excitations, which include vertical and lateral dynamic loads. Meanwhile, a slender footbridge may also be sensitive to the wind excitation. Excessive vibration will not only cause a serviceability problem, but also even a safety problem. Tuned mass dampers (TMDs) have been applied in slender steel bridges widely for vibration control. However, a passive TMD is sensitive to the frequency deviation. Though a semi-active TMD (STMD) can improve the control effect of a passive TMD to a great degree, there is no STMD and related research that can simultaneously control vertical and lateral walking and wind-induced vibrations of pedestrian bridges. To fill this blank, in this paper, a two-dimensional air spring based STMD (TDAS-STMD) is proposed. The TDAS-STMD is connected to the bridge through two vertical air springs and two lateral air springs, and the stiffness of each air spring can be retuned through adjusting its air pressure by an air pump. At the same time, the damping of TDAS-STMD can be adjusted in real time through changing the air gap between the conductor plate and permanent magnets by a step putter. The mechanical detail of TDAS-STMD and the combined variable stiffness and damping control algorithm are introduced firstly. Then, a simply supported steel footbridge which is sensitive to both vertical and lateral walking and wind-induced excitations is proposed as a case study. In the numerical simulation, the bridge is simplified as a Euler-Bernoulli beam with a constant section. A group of two optimized passive TMDs which implemented in vertical and lateral directions respectively are presented for comparison. Single pedestrian walking-induced vertical and lateral vibration, wind-induced lateral vibration, and a low-density random crowd-induced vertical and lateral vibration coupled with the wind-induced lateral vibration are both considered in the case study. Numerical results indicate that the TDAS-STMD can control vertical and lateral vibrations of the beam effectively and always has the best performance.

Adaptive Multi-class Segmentation Model of Aggregate Image Based on Improved Sparrow Search Algorithm

Mengfei Wang,Weixing Wang,Sheng Feng,Limin Li 한국인터넷정보학회 2023 KSII Transactions on Internet and Information Syst Vol.17 No.2

Aggregates play the skeleton and supporting role in the construction field, high-precision measurement and high-efficiency analysis of aggregates are frequently employed to evaluate the project quality. Aiming at the unbalanced operation time and segmentation accuracy for multi-class segmentation algorithms of aggregate images, a Chaotic Sparrow Search Algorithm (CSSA) is put forward to optimize it. In this algorithm, the chaotic map is combined with the sinusoidal dynamic weight and the elite mutation strategies; and it is firstly proposed to promote the SSA’s optimization accuracy and stability without reducing the SSA’s speed. The CSSA is utilized to optimize the popular multi-class segmentation algorithm-Multiple Entropy Thresholding (MET). By taking three METs as objective functions, i.e., Kapur Entropy, Minimum-cross Entropy and Renyi Entropy, the CSSA is implemented to quickly and automatically calculate the extreme value of the function and get the corresponding correct thresholds. The image adaptive multi-class segmentation model is called CSSA-MET. In order to comprehensively evaluate it, a new parameter I based on the segmentation accuracy and processing speed is constructed. The results reveal that the CSSA outperforms the other seven methods of optimization performance, as well as the quality evaluation of aggregate images segmented by the CSSA-MET, and the speed and accuracy are balanced. In particular, the highest I value can be obtained when the CSSA is applied to optimize the Renyi Entropy, which indicates that this combination is more suitable for segmenting the aggregate images.

Pavement Crack Detection by Ridge Detection on Fractional Calculus and Dual-thresholds

Song Hongxun,Wang Weixing,Wang Fengping,Wu Linchun,Wang Zhiwei 보안공학연구지원센터 2015 International Journal of Multimedia and Ubiquitous Vol.10 No.4

In this paper, a new road surface crack detection algorithm is proposed; it is based on the ridge edge detection on fractional calculus and the dual-thresholds on a binary image. First, the multi-scale reduction of image data is used to shrink an original image to eliminate noise, which can not only smooth an image but also enhance cracks. Then, the main cracks are extracted by using the ridge edge detection on fractional calculus in a grey scale image. Subsequently, the resulted binary image is further processed by applying both short and long line thresholds to eliminate short curves and noise for getting rough crack segments. Finally the gaps in cracks are connected with a curve connection function which is an artificial intelligence routine. The experiments show that the algorithm for pavement crack images has the good performance of noise immunity, accurate positioning, and high accuracy. It can accurately locate and detect small and thin cracks that are difficult to identify by other traditional algorithms.

Dynamical Analysis and Design of Bearingless Rotor Flexbeam

Shi, Weixing,Wang, Jidong The Society for Aerospace System Engineering 2015 International Journal of Aerospace System Engineer Vol.2 No.1

In helicopter bearingless rotor design, the flexbeam is the key component of rotor system, which plays an importantrole in the blade flapping, lead-lag movement, torsion, and load transfer. Flexbeam must have the minimum torsion stiffness with enough tension strength. In this paper, we first investigated the torsion stiffness of different cross section configurations of the flexbeam through some simple experiments. Then we analyzed a rotor's dynamical characteristics with finite element method and got the rotor's fan plot. After that, we studied the relationship between the frequency changes with the spanwise distribution of mass and stiffness in bearingless rotor. Finally, we analyzed the influence of the flexbeam on dynamical characteristics of the bearingless rotor system, and completed the design of this type of rotor flexbeam.