A modified version of the Cotte, Lions, Morel and Coil theory for image selective smoothing and edge detection is proposed. Comparing with their model, the most important advantage of this modification is that the con...A modified version of the Cotte, Lions, Morel and Coil theory for image selective smoothing and edge detection is proposed. Comparing with their model, the most important advantage of this modification is that the convolution with Gaussian processes in the filtering process is replaced by solving an initial-boundary value problem for the heat equation, which simplifies the numerical scheme to some extent. Numerical experiments on natural images are presented for this model.展开更多
Speckle noise reduction is a key problem of the image analysis of medical UltraSound images. In this paper, two important improvements have been developed to a fast anisotropic diffusion algorithm for speckle noise re...Speckle noise reduction is a key problem of the image analysis of medical UltraSound images. In this paper, two important improvements have been developed to a fast anisotropic diffusion algorithm for speckle noise reduction. The Gaussian filter is firstly used before gradient calculation, and then the adaptive algorithm of the factor k is proposed. Numerous experimental results show that the proposed model is superior to other methods in noise removal, fidelity and edge preservation. It is suitable for the preprocessing of a great number of medical UltraSound images, such as three dimen- sional reconstruction.展开更多
Based on a nonlocal Laplacian operator,a novel edge detection method of the grayscale image is proposed in this paper.This operator utilizes the information of neighbor pixels for a given pixel to obtain effective and...Based on a nonlocal Laplacian operator,a novel edge detection method of the grayscale image is proposed in this paper.This operator utilizes the information of neighbor pixels for a given pixel to obtain effective and delicate edge detection.The nonlocal edge detection method is used as an initialization for solving the Allen-Cahn equation to achieve two-phase segmentation of the grayscale image.Efficient exponential time differencing(ETD)solvers are employed in the time integration,and finite difference method is adopted in space discretization.The maximum bound principle and energy stability of the proposed numerical schemes are proved.The capability of our segmentation method has been verified in numerical experiments for different types of grayscale images.展开更多
基金Partially supported by National Natural Science Foundation and the Shanghai Qimingxing grant. # 97QA14040
文摘A modified version of the Cotte, Lions, Morel and Coil theory for image selective smoothing and edge detection is proposed. Comparing with their model, the most important advantage of this modification is that the convolution with Gaussian processes in the filtering process is replaced by solving an initial-boundary value problem for the heat equation, which simplifies the numerical scheme to some extent. Numerical experiments on natural images are presented for this model.
基金Supported by National Natural Science Foundation of China (No.60272060)Doctoral Foundation of Ministry of Education (No.20030610032)Sichuan Youth Science and Technology Foundation (No.04ZQ026-013).
文摘Speckle noise reduction is a key problem of the image analysis of medical UltraSound images. In this paper, two important improvements have been developed to a fast anisotropic diffusion algorithm for speckle noise reduction. The Gaussian filter is firstly used before gradient calculation, and then the adaptive algorithm of the factor k is proposed. Numerous experimental results show that the proposed model is superior to other methods in noise removal, fidelity and edge preservation. It is suitable for the preprocessing of a great number of medical UltraSound images, such as three dimen- sional reconstruction.
基金supported by the CAS AMSS-PolyU Joint Laboratory of Applied Mathematics.Z.Qiao’s work is partially supported by the Hong Kong Research Grant Council RFS grant RFS2021-5S03GRF grants 15300417,15302919Q.Zhang’s research is supported by the 2019 Hong Kong Scholar Program G-YZ2Y.
文摘Based on a nonlocal Laplacian operator,a novel edge detection method of the grayscale image is proposed in this paper.This operator utilizes the information of neighbor pixels for a given pixel to obtain effective and delicate edge detection.The nonlocal edge detection method is used as an initialization for solving the Allen-Cahn equation to achieve two-phase segmentation of the grayscale image.Efficient exponential time differencing(ETD)solvers are employed in the time integration,and finite difference method is adopted in space discretization.The maximum bound principle and energy stability of the proposed numerical schemes are proved.The capability of our segmentation method has been verified in numerical experiments for different types of grayscale images.
