中子数字图像几何不锐度校正算法研究

以中子数字成像系统的开发为背景,提出一种用于中子数字图像几何不锐度校正的图像复原算法。首先分析了中子数字成像的准直成像系统,得到引起中子数字图像几何不锐度的点扩展函数。据此,提出一种正则化的Lucy-Richardson(LR)算法,该算法利用贝叶斯(Bayes)最大后验估计理论研究了小波系数的双变量层间模型,推导出一种有效的小波降噪方法,并将小波降噪引入LR算法的迭代过程,此方法可有效解决原始LR算法的噪声放大问题。将改进的LR算法用于一个测试样品中子数字图像的几何不锐度校正,结果表明,该算法可以克服原始LR算法的不足,并优于频域小波域联合正则化图像复原算法。该方法还可以推广到其他图像复原的应用中。

Correction Algorithm for the Geometric Unsharpness of Digital Neutron Radiation Image

Based on the development of digital neutron imaging system,the restoration algorithm was presented to remedy the geometric unsharpness of digital neutron radiation images.Firstly,the collimation component of digital neutron imaging system was analyzed,and the point spread function(PSF) which results in the geometric unsharpness of the neutron radiation image was estimated.Hereby,a regularized Lucy-Richardson(LR) algorithm was proposed,the algorithm investigated the bivariate model of wavelet coefficients using Bayesian maximum a posteriori(MAP) estimation theory to derive an efficient denoising method,and incorporated the wavelet denoising into the iterative step of original LR algorithm to solve the drawback of noise amplification.A real neutron radiation image of the specimen under test has been restored using this reformed algorithm.Experiments show that the restoration results are improved significantly compared with the results obtained by using the traditional LR algorithm and Fourier-Wavelet regularized algorithm.This method can also be applied to other image restoration problems.