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Zhang Xianhong,Zhang Chunrui 보안공학연구지원센터 2016 International Journal of Signal Processing, Image Vol.9 No.10
GGAC is an improvement based on geodesic active contour model (GAC). GGAC model is a widely used method for image segmentation. But, it will be difficult to achieve satisfactory segmentation results to the texture, uneven structure, edge particles, weak edge and other features of the wood surface image. Therefore, the author proposes a segmentation method that integrates the improved Canny edge detection result integrated into the improved GGAC model redrawing boundary stop function, and uses the improved variational level set method to achieve the numerical solution. The algorithm has reduced the choice sensitivity to the initial contour and enhanced the scalability, which can make the profile curve converge to defect edges more rapidly, avoid the local optimum, and improve segmentation effects of weak edges and uneven image. The results are clearer, more consistent and real-time. It has provided a more effective way to segment the wood surface defects, and broadened the application scope of Canny operator and an improved geodesic active contour model.
Hopf bifurcation in numerical approximation for delay differential equations
Chunrui Zhang,Mingzhu Liu,Baodong Zheng 한국전산응용수학회 2004 Journal of applied mathematics & informatics Vol.14 No.-
In this paper we investigate the qualitative behaviour of numerical approximation to a class delay differential equation. We consider the numerical solution of the delay differential equations undergoing a Hopf bifurcation. We prove the numerical approximation of delay differential equation had a Hopf bifurcation point if the true solution does.
HOPF BIFURCATION IN NUMERICAL APPROXIMATION FOR DELAY DIFFERENTIAL EQUATIONS
Zhang, Chunrui,Liu, Mingzhu,Zheng, Baodong 한국전산응용수학회 2004 Journal of applied mathematics & informatics Vol.14 No.1
In this paper we investigate the qualitative behaviour of numerical approximation to a class delay differential equation. We consider the numerical solution of the delay differential equations undergoing a Hopf bifurcation. We prove the numerical approximation of delay differential equation had a Hopf bifurcation point if the true solution does.
Hopf bifurcation in numerical approximation of the sunflower equation
Chunrui Zhang,Baodong Zheng 한국전산응용수학회 2006 Journal of applied mathematics & informatics Vol.22 No.1-2
In this paper we consider the numerical solution of the sun- flower equation. We prove that if the sunflower equation has a Hopf bifurcation point at a = a0, then the numerical solution with the Euler-method of the equation has a Hopf bifurcation point at ah = a0 + O(h).
Canny Optimization Algorithm Based on Improved Anisotropic Diffusion Function Filtering
Zhang Xianhong,Zhang Chunrui 보안공학연구지원센터 2016 International Journal of Signal Processing, Image Vol.9 No.7
Image edge detection is an important part of image processing, and the effect of edge detection is also directly affected by image analysis, recognition and understanding. Canny operator is the most commonly used image edge detection operator. However, this operator has some limitations. The traditional Canny operator uses Gaussian filtering which may bring problems such as missing edge information and false edge. Besides, the selection of high and low thresholds of the traditional Canny operator are not accurate, and cannot be carried out by self-adaption. In order to solve these problems, this paper presents an optimized algorithm for Canny operator. In this paper, an improved anisotropic diffusion function is used to filter the image, and the improved filtering not only reduces the noise, but also maintains the edge information of the image. Additionally, this paper has improved the maximum between-class variance method (OTSU) to select the high and low thresholds of Canny operator by self-adaption. The improved algorithm is applied to edge detection of various images, and the results indicated that the improved Canny operator is effective in reducing noise and extracting edge.
HOPF BIFURCATION IN NUMERICAL APPROXIMATION OF THE SUNFLOWER EQUATION
Zhang, Chunrui,Zheng, Baodong 한국전산응용수학회 2006 Journal of applied mathematics & informatics Vol.22 No.1
In this paper we consider the numerical solution of the sunflower equation. We prove that if the sunflower equation has a Hopf bifurcation point at a = ao, then the numerical solution with the Euler-method of the equation has a Hopf bifurcation point at ah = ao + O(h).