中子数字图像几何不锐度校正算法研究

金炜; 魏彪

光学学报, 2007, 27 (10): 1765, 网络出版: 2007-10-24

中子数字图像几何不锐度校正算法研究

Correction Algorithm for the Geometric Unsharpness of Digital Neutron Radiation Image

论文大纲

金炜 ^1,*魏彪 ²

作者单位

¹ 宁波大学信息科学与工程学院, 宁波 315211

² 重庆大学光电技术及系统教育部重点实验室, 重庆 400044

摘要

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。

Abstract

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.

参考文献

[1] . Jo, William J. Spiesman, Naeem M. Abdurrahman. Development of a neutron imaging facility at the University of texas TRIGA reactor[J]. IEEE Southwest Symposium on Image Analysis, 1996, 8(4): 43-47.

[2] . Image reconstruction and multiple hole apertures in neutron radiography at FRM-Ⅱ[J]. Nuclear Instruments and Methods in Physics Research A, 2006, 566(2): 654-661.

[3] N. Kardjilova, S. W. Leeb, E. Lehmannc et al.. Improving the image contrast and resolution in the phase-contrast neutron radiography[J]. Nuclear Instruments and Methods in Physics Research A, 2005, 542(1～3): 100～105

[4] R. Hassanein, E. Lehmann, P. Vontobel. Methods of scattering corrections for quantitative neutron radiography[J]. Nuclear Instruments and Methods in Physics Research A, 2005, 542(1～3): 353～360

[5] Shao Junming, Lu Hongnian, Cai Hui. A point spread function model for X-ray imaging[J]. Acta Optica Sincia, 2005, 25(8): 1148～1152 (in Chinese)
邵军明,路宏年,蔡慧. X射线成像的一种点扩展函数模型[J]. 光学学报, 2005, 25(8): 1148～1152

[6] . . Study on Wiener filtering for restoration of defocus blur image[J]. Chin. J. Scientific Instrument, 2007, 28(3): 479-482.

[7] Zhao Wenqian, Rao Changhui, Geng Zexun. Myopic image deconvolution of point source based on joint estimation of object and point spread function[J]. Acta Optica Sincia, 2007, 27(1): 52～57 (in Chinese)
赵文倩,饶长辉,耿则勋. 基于目标和点扩展函数联合估计的点源目标图像近视解卷积[J]. 光学学报, 2007, 27(1): 52～57

[8] . ForWaRD: Fourier-wavelet regularized deconvolution for Ⅲ-conditioned systems[J]. IEEE Trans. on Signal Processing, 2004, 52(2): 418-433.

[9] Jan Biemond, R. L. Lagendijk, R. M. Mersereau. Iterative methods for image deblurring[C]. Proc. IEEE, 1990, 78(5): 856～882

[10] Chen Lizhi, Wang Hongxia, Luo Yong. Theory and Applications of Wavelet Transform[M]. First Edition, Beijing: Science Press, 2004. 269～286 (in Chinese)
成礼智,王红霞,罗永. 小波的理论与应用[M]. 第一版, 北京: 科学出版社, 2004. 269～286

[11] Zong Siguang, Wang Jiangan. Multi-scale mathematical morphology fusion filtering and the evaluation of the filtered image[J]. Acta Optica Sincia, 2005, 25(9): 1176～1180 (in Chinese)
宗思光,王江安. 多尺度形态算子融合图像滤波技术及滤波质量评价[J]. 光学学报, 2005, 25(9): 1176～1180

[12] . Selesnick. Bivariate shrinkage functions for wavelet-based denoising exploiting interscale dependency[J]. IEEE Trans. on Signal Processing, 2002, 50(11): 2744-2756.

金炜, 魏彪. 中子数字图像几何不锐度校正算法研究[J]. 光学学报, 2007, 27(10): 1765. 金炜, 魏彪. Correction Algorithm for the Geometric Unsharpness of Digital Neutron Radiation Image[J]. Acta Optica Sinica, 2007, 27(10): 1765.

中子数字图像几何不锐度校正算法研究

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